SESSION 4
MANAGEMENT SYSTEMS

COMMUNAL AREA LIVESTOCK MANAGEMENT SYSTEMS IN ZIMBABWE

F.M. Chinembiri
Principal Livestock Specialist, Department of Agritex, P.O. Box CY369, Causeway, Harare, Zimbabwe

Introduction

The main grazing animals in the Zimbabwe communal areas include cattle, goats, sheep and donkeys. Cattle are the most populous species both in terms of number (standing at 3.8 m, C.S.O. 1997) and in terms of animal bio-mass estimated at 89 percent of total grazing animal bio-mass (G.F.A. 1987). Goats come second with a population of almost 2.6 million.

Analysis of the livestock communal area management systems should be undertaken with a clear mind of the farmers' objectives. This livestock herd plays an important role in the socio-economy of the of the small holder farmer in the Communal Areas of Zimbabwe through provision of draught power, milk, meat, occasional sales and use at social functions. This paper looks at the management systems practised in this sector as they relate to the stated communal area farmer objectives. In discussing the management systems two questions need, in particular, to be addressed:

• Do the management systems meet the farmers objectives or expected outputs? and
• How sustainable are the systems in place?

To be able to do this one needs to understand that management in livestock implies the “direction applied by the farmer or stockman to his/her livestock, either to promote or hinder their productivity.” Communal area livestock management systems are a product of indigenous knowledge, farmer objectives, economic pressures and affordability. It is, therefore, not surprising to see that most of the “standard recommendations” are modified to meet these realities. The subject is broken into the following sections:

• General management systems
• Grazing management systems
• Breeding systems
• Routine operations
• Feeding and finishing systems
• Small holder dairy production systems
• Drought management systems

In discussing the above management systems it must be made clear from the outset that the above breakdown is just for convenience, the systems form a continuum and strong systems relationships do exist. Weaknesses and strengths of each system and areas requiring strengthening will be highlighted in each sub section.

General livestock management

A common feature of the Zimbabwe communal area agricultural system is that the system of production is mixed i.e. crop-livestock, with crops playing a major direct economic role in the high rainfall areas of natural regions I to III while livestock assume a more important economic role in the lower rainfall areas of natural regions IV and V. According to Agritex reports the cash income contribution of livestock to household income in the communal areas ranges between two to 6.5 percent in natural regions II and III while the contribution of livestock in Nswazi in natural region IV is 13.6 percent. The GFA report (1987) also concluded that the value of crops did not come near that of livestock in natural regions IV and V. However, regardless of natural regions, systems of production in communal areas reflect complementary, supplementary and competitive interaction with cropping without much specialisation. Any specialisation is a recent development confined to smallholder dairy, ostriches and poultry. These relationships manifest themselves in the management systems practised and have an impact in the changing management systems being experienced.

As implied, grazing in the Zimbabwe Communal Areas is characterised by communal use of grazing resources. This is so because land in the communal areas is still under the communal system of land tenure. According to Gapare (1988), technical inputs are limited by this land tenure system. Thus a communal area farmer is not at liberty to try recommended technologies since grazing land is under communal use. It is partly for this reason and the farmer's objectives that generally, and except for dairy production systems, those communal area management systems are low input systems but expect “high output”. Notwithstanding the afore-said, it must be stated that communal area management systems are dynamic and changing with time, especially with the recent economically imposed emergence of a new ex-urban dweller farmer. As a result of the changes brought about by the adoption and adaption of new technology, the recent influx of the former urban dweller, growth in land pressure, general economic growth especially around growth points and national moves towards commercialisation communal livestock systems are being transformed more and more towards commercial production. This is particularly noticeable in milk and goat production.

Grazing management systems

The grazing system in communal areas entails grazing animals in designated grazing areas during the growing season and kraaling them at night. Animals are allowed free access to crop residues and stubble after harvesting. There are no strict regulations governing the use of these resources. There are small variations in this system which reflect of agro-ecological regions and human population density. In the lower rainfall areas, where human and animal populations are sparse, cattle are sometimes neither herded nor kraaled at night. They are allowed to graze freely away from homelands. This system of management as a whole tends to lead to abuse and difficult decision making for the proper management of the resource. Due to the above, and high stocking rates estimated at double the recommended ecological carrying capacities, most of the communal areas are degraded resulting in reduced feed availability and subsequent depressed animal performance.

In trying to address this problem, grazing schemes and range reinforcement with forage legumes were promoted by the department of agitex (with donor assistance) and some non-government organisations (NGOs) have also promoted legumes. These schemes were supposed to bring in a new technology in rangeland management, which incorporated rotational grazing or split season veld management. However, due to lack of responsibility and authority and involvement of farmers at planning and implementation stages there have been no positive results from established grazing schemes (Cousins, 1988). This finding was further confirmed by a range monitoring programme conducted by agritex over five years (1986–1991) which indicated zero or negligible response in terms of herbage yield and species composition. In fact, in most of the grazing schemes, application of the recommended short duration grazing or split season grazing management system was non-existent. Furthermore, it was observed that stocking rates in the fenced schemes increased. Siratro and fine stem legumes established in these grazing schemes could not persist due to the heavy grazing pressure. A notable feature in some of these grazing schemes was that only the internal fences were vandalised leaving the external fences, which protected their crops and reduced herding labour, intact. In view of the fact that grazing constitutes about 55 percent of the communal areas today it is imperative that an acceptable range management system or approach is developed to ensure reduction in degradation and sustainability in the management of this critical resource. The improvement in the management system could include:

• implementation of schemes only where farmers show total commitment through, for example, a high cash contribution
• capacity building and institution building in the local community to manage the grazing resource or
• employment of grazing scheme “managers” by the local communities. The scheme managers could oversee the implementation of the management system and do fence repairs.

Breeding systems

Generally there are no specialised and managed breeding systems in the communal areas of Zimbabwe. Females run with bulls all year round without much reference as to which bull serves which cow or heifer. It is also a case that selection and culling of any breeding animal is the sole responsibility of an individual owner. This is despite the fact that bulling is random. However it has been observed that in some communities, e.g. in Gwanda and Filabusi, young bulls have to pass a “community approval test” for the animal to join the breeding herd as a bull. This practice is still to be widely adopted. Also observed has been a sort of assortive mating practice of confining “superior” bulls. Farmers then bring their cows on heat for service. Under this system the bull owner charges a fee.

A number of “genetically superior” bulls were donated to communities across the country. These bulls were to be owned and used by the respective communities to upgrade their breeding herd. It is notable that these introductions of exotic bull breeds into communal areas was not the decision of all the farmers affected. Because of the communal grazing system most farmers just find themselves with unplanned - for cross breeds. Thus the farmer is always handling an ever-changing genotype he/she has not planned for or has the experience to manage. These introductions have eroded the indigenous genotype base, which is known to be adaptable to the communal area environment. It is also unfortunate that no studies or evaluations were undertaken to assess the impact of this exercise. Nationally, the impact of these innovations is minimal but assertive mating and “community approval tests” are a big and positive start in as far as collective decision making and planned and controlled breeding are concerned.

Routine operations

Routine operations like castration, de-horning and branding are practised in communal area livestock management systems, but with varying degrees of modification and adaptation. Castration is mainly carried out to ensure docility in oxen and is carried out much later in life. Animals up to two years and sometime older are castrated. The most commonly used castration method is burdizzo. On the other side de-horning is one practice which has not been widely adopted. Horn “tipping off” as a modification to de-horning is a more common practice.

However, in the major cattle producing areas like Matabeleland, the southern part of the Midlands and Masvingo routine cattle castration and de-horning are done timeously. This, in most cases, is done at the age of less than six months old. In these areas livestock herds are bigger and commercial beef production is an objective in cattle keeping that off-takes (to the official meat trade) of up to 15 percent are common compared to an average of 2.5 percent in the high rainfall areas of Mashonaland.

Feeding and finishing systems

From the technical point of view insufficient feed supply in terms of both quantity and quality, is usually cited as the major cause of poor livestock production in communal areas (Hamudikuwanda, 1988: Smith, 1988). Winter or dry season is the time when the feed is in shortest supply. At this time of the year, the feeds available are deficient in protein, the content of which could be as low as 2.5 percent crude protein. It is a rare occurrence that smallholder farmers in communal areas ever offer food supplements to their animals. The lack of supplementary feeding of proteins, minerals or concentrates is due to lack of cash and to the relatively low importance of commercial production from the cattle herd. After harvesting animals are allowed to forage randomly on crop residues in the arable areas. In fact the G.F.A. (1987) reported that up to 50 to 55 percent of grazing animal energy requirements in natural regions II and III were supplied by crop residues. For a short time, therefore, animals will be on a high plane of nutrition. The general feeding regime evolves around:

• communal grazing in summer
• foraging on crop residues and vleis in winter and
• browsing on new leaf, crop residues and vleis in spring

Access to browse, as a critical animal feed resource, is an important characteristic of animal management in the communal areas of Zimbabwe. It implies animals gain access to highly nutritious feed towards the end of the dry season but this is still insufficient. Because of the high grazing pressure during this time of the year a big overlap in herbivory occurs, as most animals would not subsist on browse. It follows that animals without any offer of supplements are in poor condition at the onset of rains in October or November and that heavy losses are incurred at this time of the year as the animals body reserves are very low and unable to generate enough energy to keep the animals warm.

The above is the most common and generally practised system. However a few farmers collect and store crop residues. These are then rationed out or offered as feed supplements to priority animals at certain strategic times of the year. The crop residues are also used as bedding in the kraals where they decompose into cattle manure for use in crop fields. This practice has been in use for a long time but has expanded dramatically in the past six to eight years following the two catastrophic droughts of 1991/92 and 1993/94.

Cattle from the communal areas are normally sold in an unfinished state - straight from the rangeland. In a few cases, retired oxen and cull cows are pen fed or offered feed on rangeland before they are sold. Only a few groups and individuals in areas like Wedza and Mangwende are involved in this. The animals are offered concentrates at the rate of three to four kg and ad-lib maize stover for periods of up to sixty days.

Smallholder dairy production systems

This is a new specialised form of livestock production in the communal areas. It deserves special mention in that its advent has brought about the introduction and unusually high adoption of new technologies in the animal production systems of communal area farmers. To date there are only ten dairy projects scattered through out the country. In these projects, hand feeding of dairy animals using either commercial feeds or home-grown feeds is taken as a standard procedure. Modified calf rearing systems have been developed to meet both the farmers' resource base and management capabilities. Calves are allowed access to their dams to suckle for only 40–60 minutes after each milking until weaning age, which varies between 60 and 90 days. Further, management programmes in this sub-sector includes specific fodder production and conservation systems on arable lands. Under conservation, silage and hay making together with crop residue collection and storage are a common feature. Of late quality enhancement of roughages through the use of urea has been widely adopted by the small holder farmers. Animal health programme and breeding systems through the use of farmer established and managed bull centres, milk marketing and processing at milk centres to widen the product range have become an integral part of dairy production and management in this sub-sector.

Drought management systems

Drought occurrence is a natural phenomenon, which unfortunately farmers have not learnt to live with or plan for. Every drought occurrence is viewed as a new occurrence as farmers panic and seek drought mitigation strategies. In communal areas a number of strategies are employed depending on individual farmer decisions and the severity of the drought. The major strategies employed include:

• Do nothing
• Lopping and felling of trees
• Cull and sell some stock
• Sell all stock
• Seek relocation (lease grazing) and
• Feed stock.

The “do nothing” strategy works where one assumes that the period of drought will soon end. This used to be the most commonly practised strategy but has proved very costly to farmers. Due to limited resources, therefore lopping and felling of trees to allow animals access to browse is one of the first strategies to be adopted. It has been observed that, as natural feed becomes scarce, the overlap of herbivore increases among animal species and selective grazing declines, for example, animals in Masvingo were seen feeding on Lantana camara, Afzelia quansensis, and prickly pear. After the catastrophic droughts of 1999/92 and 1993/94, the approach to handling drought has changed. Since then communal farmers have become more responsive to drought so that culling and selling some stock, lease grazing and hand feeding of animals for survival has now been widely adopted. The chosen course of action depends on the farmers' circumstances i.e. resources at his/her disposal, severity of the drought, market availability and veterinary movement restrictions. However it is still a common practice that a “do nothing” approach is the first strategy employed by all farmers. In the long term, the most sustainable approach to drought mitigation is establishment of “strategic fodder reserves” through planting of fodder crops, conservation of forages and storage for use at strategic times. This should be accompanied by a pre-prepared drought plan.

Conclusion

The existing communal area livestock management systems are geared to primarily meet the input functions of livestock. There is great scope and potential to improve on the output function, in particular meat output. Achieving this objective calls for a complete change in management and attitude towards livestock production as a commercial entity in itself.

References

Agritex, 1986–1992 Veld trend monitoring reports

C.S.O. 1997, Central Statistical Office report, Zimbabwe, Zimbabwe 1997.

Cousins, B. 1988. Evaluation of Pilot Cattle Grazing Schemes. Report by EEC and Agritex, Harare.

Gapare, R.L. 1988. “Communal Farmer Constraints and Objectives in Livestock Production” in Proceedings of the Workshop on Livestock Research and Extension for Communal Area farming Systems held at Henderson Research Station 16–18 February 1988. Department of Research and Specialist Services, Zimbabwe. Harare.

GFA. 1987: Study on the Economic and Social Determinants of Livestock Production in the Communal Areas - Zimbabwe, Ministry of Lands, Agriculture and Water Development. Harare. (Report to the Department of Veterinary Services)

Hamudikuwanda, H. 1988. “Livestock on-farm Research in Zimbabwe and some aspect of it Related to Crop Production.” Paper presented at the Department of Research and Specialist Services and CIMMYT workshop, Mendel Training Centre, Marlborough, Harare, 28 June - 1 July 1988.

Marovanidze K. u.d. 1987. Silent Drought Mitigators. Agritex report, Masvingo Province, Zimbabwe.

Smith., T. 1988. “Nutritional Constraints to Ruminant Livestock Production in the Communal Sector of Zimbabwe” in Proceedings of the Workshop on Livestock Research and Extension for Communal Area Farming Systems held at Henderson Research Station 16–18 February 1988. Department of Research and Specialist Services, Harare.

MAN, CATTLE AND VELD

J. Zietsman
Pumula Farm, P O Box 100, Karoi, Zimbabwe

Introduction

Since man started domesticating grazing animals he has had a tremendous impact on the ecology of this planet. The results have generally been negative and in certain instances catastrophic. The underlying cause is a narrow perspective and inappropriate breeding and management practices resulting from ignorance of how nature functions.

The degree and speed of environmental degradation caused by destructive grazing practices depends largely on the seasonality of rainfall and humidity (brittle vs non brittle environments) together with soil type. This degradation is erroneously attributed to seasons of low rainfall and high stocking rates. Although they magnify the effects of bad management they are not the cause of degradation. Furthermore, the insidious nature of the process leads to complacency. It is only when account is taken of long term evidence in the form of anecdotes and records that the reality of the situation becomes apparent. As an example, records from a 1000 ha property in the Bandelierkop area of South Africa show that 1100 head of cattle were carried in 1923. The same area can barely carry 100 head today. There is further evidence in declining water tables, seasonality of former perennial rivers and streams, increased erosion and a decline in biodiversity.

The practice of domestication has placed the responsibility of breeding entirely in the hands of man. In the quest for superficial characteristics (size, colour, shape, etc.) and lately for maximum performance (growth and milk production) cattle have been bred that, with few exceptions, are completely out of harmony with their environment. The result is an increase in production costs in the form of supplementary feed and chemicals. A further consequence is that we have forgotten that cattle have a dual role, namely to efficiently convert grass into a marketable product and to improve, or maintain at a high level, water and nutrient cycles and the process of macro-succession.

In order for livestock production to be sustainable there has to be harmony between the stockman, his livestock and the environment. The following is an analysis of where and why we have gone wrong and an indication of where we should be going and how to get there. The determinants are the attitude and goal of the stockman as reflected in his breeding and management practices, the adaptation of the livestock to their environment as reflected in their productive efficiency and the state of the land as reflected in water and nutrient cycles, successional stage and rate of energy flow. In short, the relationship between man, cattle and veld.

Man

Man, through his control of the breeding and management of livestock, is the key to the question of harmony. As such, he is either the problem or the solution. His stock and land are a reflection of his attitude and ability.

The conventional definition of a good stockman is one who cares for his stock and breeds and manages them in a way that gives him the greatest return. This is a totally inadequate definition and reflects man's basic instinct as an exploiter and indicates a very narrow perspective. The overwhelming majority of stockmen strive for certain arbitrary production goals (heavy weaners, size, quality carcasses, etc.) These objectives are not necessarily undesirable, but being of an arbitrary and absolute nature give rise to flawed breeding and management practices. Furthermore, many are genetically antagonistic. Heavy weaners and high reconception rate is an example: there being a point beyond which milk production negatively affects reconception rate. The poorer the nutritional environment the lower down the scale this point is reached. In order to maximise performance supplementary feeding and selectivity of grazing are increased and stocking rate decreased. The result is increased production costs and environmental degradation in brittle, seasonal rainfall areas.

Orthodox thinking severely limits the potential of cattle in terms of heredity and the positive effects they can have on the land. They are handicapped by most breeders and show judges who, by the nature of their profession, are driven by fashion, glamour and everything superficial. Similarly, those striving for maximum individual performance cannot improve their land and achieve sustainable production.

We have to look at our role as custodians of the land in a new light. The laws governing the natural world are supreme. We can accept them, collaborate in breeding and managing cattle to achieve environmental harmony, or, we can follow the whims and arbitrary standards of man and go along with the resulting chaos. If we choose the path of harmony we must strive for an all-encompassing goal and embrace new knowledge to bring our breeding and management practices in line with the laws of nature.

Cattle

Cattle are generally bred and managed as though they are not part of the environment. They are kept “productive” by allowing a high degree of selective grazing at low stocking rates together with expensive feed and environmentally damaging chemicals. In other words, performance is boosted at the expense of the environment. This is clearly not sustainable.

Little progress has been made in breeding cattle for increased efficiency in converting grass to beef. Much change has been made in respect of size, shape, growth rate and milk production. However, is this related to productive efficiency? A genetically programmed increase in growth rate, size and milk production demands an increase in nutritional status. If this is not forthcoming reconception suffers. This is analogous to expecting a record time from a poorly tuned racing car running on low octane fuel on a rough country road.

In order to genetically tune cattle to perform efficiently in a particular environment one has to understand certain basic concepts:

Genotype - Environment interaction

A particular environment dictates a specific genotype in line with climate, nutrition, parasites and disease. The more extreme the environment the more specific the genotype required to achieve harmony and the less room for human fancy.

Modifying influence of hormones

The balance between the different hormones has a marked influence on the degree of sexual dimorphism between males and females and the rate and degree of depressed skeletal growth at puberty. The greater the degree of femininity in a female and masculinity in a male the higher the potential fertility. Concomitant with this is a greater depression of genetically predetermined potential frame height. In other words, hormones modify skeletal size. This has far - reaching selection implications. Selection for size and absolute growth rate, as currently practised, has a negative effect on age at sexual maturity as well as subsequent reproduction. This is well illustrated by the decrease in sexual dimorphism in “frame - scored” cattle and the resultant need for selection on scrotal circumference.

The relationship between body condition, growth rate, size and adaptation to nutritional status

Cattle reach a particular body condition at different weights and age depending on their genetic growth potential and size. Smaller animals mature physiologically younger and at lighter weights. Adverse nutritional conditions accentuate these differences. At the same body condition, yet at different ages and weights, there is no difference in feed conversion efficiency between genetically small and large cattle. This implies that under poorer nutritional conditions earlier maturing, smaller framed cows that can attain the desired body condition quicker and lose it slower will be at an advantage in terms of reconception - the most important trait determining profitability This advantage will narrow under better nutritional conditions when measured on an animal unit basis but not on a land unit basis.

The selection criteria used conventionally reflect absolute values and not productive efficiency.

These are:

• rate of gain
  This is usually measured on a high plain of nutrition thereby disregarding the principle of genotype - environment interaction. The positive correlation between absolute growth rate and mature size obligates the need for improved nutrition in order to prevent reduced reconception in cows.

• milk production (weaning weight)
  Excessive milk production relative to nutritional status results in poor reconception rates owing to poor body condition.

• fertility
  The common practice of culling empty cows and selecting bulls on scrotal size does not address the general cause of poor calving rates which is poor body condition as a result of an unfavourable genotype - environment interaction.

• Conformation
  In most instances selection is based on the current fashion in vogue - usually unrelated to function. Even the more objective measurements such as frame score are used in a way that negatively affects veld productivity (late maturing, poor body condition).

• feedlot feed conversion efficiency
  Trying to extrapolate feedlot results to a veld situation violates the principles of genotype - environment interaction. There is also, in all probability, a negative correlation with maturity rate and body condition.

From the foregoing it is clear that current selection practices favour bigger, faster growing, heavier milking cattle requiring higher octane fuel. There is no improvement in veld productivity.

What attributes, as dictated by nature, does a beef animal require in order to be nutritionally and climatically adapted, tolerant of parasites, resistant to certain diseases and excel in forage intake. This is the basis from which effective selection can be made to attain high relative growth rate, optimum milk production, desirable hormonal balance, functional and well fleshed conformation and workable temperament.

For selection to be effective observable genetic variation is essential. One way to achieve this is to infuse the desired genes through crossbreeding or composite breed formation. Effectiveness can be further improved by increasing selection differential, decreasing generation interval and limiting the number of selection criteria.

Sustainable production from the veld can only be achieved by selecting for the following criteria:

• adaptation to environmental constraints

  The most effective and easiest way to achieve this is to make use of Asian and African breeds to attain climatic and nutritional adaptation, parasite tolerance and disease resistance

• fertility as an expression of adaptation and hormonal balance

• growth efficiency as a result of adaptation and genetic ability to consume forage

The most practical indicator is weight gain relative to frame size.

• optimum milk production within the limits dictated by nutritional environment
• conformation related to function and meat yield
• temperament with respect to mothering ability, herd instinct and ease of handling

Even with a perfectly adapted, veld productive animal, veld productivity is not assured. Cattle must be managed in such a way that they fulfil their naturally ordained role as agents of improvement and not destruction, as is currently the case.

Veld

As with cattle, the management of veld has been considered in isolation from a greater whole of which it is part. This has resulted in highly reductionist research and generally fallacious recommendations. The effect that cattle have on the veld is generally seen in such a negative light that the mere fact that they are on the land is considered a necessary evil. Many ranchers in southern Africa have replaced cattle with game in the mistaken belief that their “mouths and hooves” are responsible for veld degradation, overlooking the fact that animals such as buffalo and wildebeest also have mouths and hooves. Surely, it is how those mouths and hooves are managed that matters.

The following is a summary and analysis of conventional veld management beliefs and recommendations:

• low stocking rate is considered crucial to sustainability

It is believed that beyond a critical, arbitrarily defined, rate veld deteriorates. This is an extremely simplistic viewpoint when one considers that carrying capacity (grass yield) is a dependent variable. Stocking rate per se can only influence the amount of grass grazed, apart from animal performance, regardless of any other variables. This clearly illustrates the notion that cattle have a negative effect on the land and that the only way to minimise this is to limit numbers. Taking the opposite view, one can argue that if cattle are managed in a way that each individual is having a positive effect on the land then an increased stocking rate will have an increased positive effect. Therefore, the situation can arise where the veld is overstocked in terms of individual animal performance yet improving ecologically.

• overgrazing is time related

It was shown more than 50 years ago that there is a positive yield and negative quality response to severity and frequency of defoliation and that continuous defoliation without adequate recovery period results in decreased plant vigour and even death. Overgrazing is clearly time related, yet is universally confused with overstocking. Manipulating animal numbers will not alter the fact of overgrazing. Severe grazing is also confused with overgrazing. Individual plants are severely grazed largely regardless of management. Whether this is accompanied by overgrazing depends on timing.

• high animal impact (trampling) is considered bad

Without control of time it invariably is bad and without sufficient intensity it is of no benefit.

• severe grazing is considered bad

The vigour of many grasses is dependent on severe defoliation (grazing, trampling, fire). Frequency is the important management consideration.

• Periodic burning is considered essential

Although fire may play a positive role it is generally used in default to try and counter the effects of selective overgrazing at low animal impact.

• long term resting or non - disturbance of plant and soil leads to veld improvement

In seasonal rainfall (brittle) areas the opposite is true.

• trees are generally regarded as detrimental to grass growth

This is true in extreme situations. However, they are extremely important in the process of nutrient cycling, particularly in high rainfall areas and poor soils. In addition, many tress are leguminous, some bear fruit (pods) relished by livestock and most are browsed.

• six to eight paddocks per herd are the maximum required

This may be sufficient in limiting overgrazing but is hopelessly inadequate where high animal impact is required.

• grasses are categorised as desirable or undesirable

This is an oversimplification and gives rise to the expensive and often fruitless exercise of forced eradication/establishment. There are many grasses of varying palatability and nutritive value reflecting different soil types, moisture conditions, management systems, etc. They are part of a greater picture and must be considered and managed as such.

• cattle are seen solely as a means to profit and not as part of a bigger picture where they are essential agents of land improvement.

More than 30 years ago John Acocks shook veld management thinking with his assertion that “South Africa is understocked and overgrazed”. This lead to the Howells' work on Non Selective Grazing and Allan Savory's Short Duration Grazing which eventually evolved to Holistic Management.

The following is essential knowledge in order to understand why we have largely failed in conventional management and what is needed to achieve sustainability:

All-encompassing goal

Narrow, mainly production orientated, goals must be replaced by something more accommodating in terms of ecological, financial and social needs. This can only come about by first understanding those needs and, in particular, how nature functions.

The holistic character of nature

Nature is comprised of functioning wholes whose individual components are orchestrated in a way that results in symbiosis. Remove, or alter the functioning of, even one component and there is dysfunction and ecological retrogression. An example is the grass - grazer - predator relationship. Large packs of predators (lion, hyena etc) keep severe grazers (buffalo, wildebeest) bunched together in large herds trampling, dunging, urinating and constantly moving thereby benefiting the grass. Without the predators these animals would move around individually or in small groups continuously overgrazing at low impact with similar consequences as cattle.

Manage ecological process

The health of any ecosystem depends on the efficient functioning of several ecological processes - water and nutrient cycles, soil aeration, the flow of solar energy, macro-succession (the successional development of plant and animal communities) and micro - succession (genetic development of a specie). These are the processes that need to be managed in order to create functioning wholes and achieve sustainability.

Brittle vs. nonbrittle environment

There is an essential cycle to the life of a plant - germination and establishment, growth, death, decay and return of nutrients to the soil. In a perennial rainfall, nonbrittle environment this cycle can continue unhindered in the absence of any major plant and soil surface disturbance due to the action of many micro-organisms and insects. In seasonal rainfall, brittle environments this is not the case. At the end of the short wet season there is a large amount of bulked up grass that needs to be converted to dung and urine and knocked down on the ground as litter. Bare soil between plants is capped and needs to be broken. The only agents capable of doing this on a large scale are those who have hard hooves, graze severely and move around in large herds. In this age adapted cattle are the most practical and economic agents of veld rehabilitation and stabilisation.

Time in relation to grazing and trampling

As mentioned previously the overgrazing of plants is a question of time - time exposed to grazers and time allowed for recovery after grazing. The same applies to trampling. Overgrazing or overtrampling cannot be eliminated by reducing numbers yet, numbers can be increased infinitely without overgrazing or overtrampling, provided timing is appropriate.

The problem with agricultural education and research is that it is compartmentalised and reduced to a very narrow field whereas nature functions as overlapping and interrelating wholes. Hence, most veld management researchers do not even try to manage ecological processes. The criteria generally used in evaluating management variables are basal cover, percentage “desirable” species and individual animal performance. Litter cover and soil capping are not considered in the context of water and nutrient cycles or successional change since the only conventional way to increase litter and decrease capping is through the use of expensive machinery. That cattle can do it inexpensively and on a large scale is never contemplated largely due to their negative attitude with respect to hooves and mouths and the “impossibly” large number of paddocks required. In addition to this, research has “proved” that high stock density and herd effect (the careless trampling, etc of animals in large, concentrated herd) do not achieve what is claimed (laying litter, breaking capping, increased seedling establishment, etc.). The number of animals used to simulate herd effect and the stock densities applied were so ridiculously low as to be analogous to trying to sweeten a cup of tea by the application of a few grains of sugar.

Conventionally the only variables that can be used in the management of veld are fire, rest (partial or total) and technology. By rejecting animal impact and severe grazing one rejects the only practical means to reverse the degradation and improve the ecological status of the world's seasonal rainfall, brittle environments.

The constraints of conventional fencing have made the application of sufficient animal impact and time control to enable increased stocking rates and achieve dramatic veld improvement and acceptable individual animal performance difficult in dry brittle areas and impossible in wet brittle areas. However, the advent of portable electrical fencing has changed this. Where necessary it is possible to have thousands of “paddocks” per herd and attain stock densities of up to 5000 mature cattle per ha.

The result of time controlled high animal impact and severe grazing are dramatic. Generally speaking stocking rates can be doubled and the veld improved beyond recognition in a very short period of time. This can be attributed to:

• improved water cycle due to increased infiltration and decreased evaporation
• improved and accelerated nutrient cycle
• improved soil aeration as indicated by a darker grass colour
• increased seedling establishment resulting in a denser plant population and covering of bare ground
• moribund plants being replaced by young, healthy plants
• increase in palatable, productive grasses and legumes
• increase in the palatability of existing grasses due to denser population and the resultant greater leaf: stem ratio
• increased utilisation of grasses and trees
• increased plant vigour
• improved soil structure and fertility

In the line with the Law of Diminishing Returns an increase in stocking rate (which is essential for veld improvement) will result in a decrease in individual animal performance. Under conventional management (low paddock numbers per herd) this can be extremely severe. However, this is counteracted to a larger degree at ultra high grazing densities owing to several moves a day onto fresh grazing, competitiveness for grazing, a relatively even plain of nutrition over time and a dramatic increase in browsing. In the medium to long term productive efficiency per animal can be improved by breeding, in particular, for improved nutritional adaptation.

Summary

Current breeding and management practices are environmentally damaging and consequently not sustainable. They reflect very narrow goals and ignorance of Nature's laws.

Sustainable ranching practices in the world's brittle environments can only be achieved by creating new wholes that mimic those replaced by man. This will entail far greater, and more intensive, use of time - controlled animal impact and severe grazing. Stocking rates will increase. This, together with decreased selectivity of grazing, will move the focus from absolute to optimum animal performance entailing selection in accordance with the dictates of environment.

A change in attitude is an essential prerequisite for the implementation of knowledge in line with the decrees of the Creator. Only then can there be harmony between man, cattle and veld.

OPTIMIZING UTILIZATION OF LEGUMINOUS FRUITS (PODS) AND SORGHUM GRAIN IN THE SEMI-ARID AREAS OF ZIMBABWE

S. Ncube and Z. Magadzire
Matopos Research Station, P B K 5137, Bulawayo, Zimbabwe.

Introduction

The major constraint to livestock production in the semi-arid areas of Zimbabwe is the availability of sufficient feed, especially during the dry season or a drought. Optimum utilization of locally available feed resources is being encouraged. Drought feeding strategies have included attempts to intensify the use of browse and sorghum grain as feed for ruminants.

Acacias and other leguminous trees play an important role in livestock production in drought prone areas of Zimbabwe. They are less susceptible to climatic fluctuations than herbaceous plants, produce fruits that are available in the dry season and are readily eaten by livestock. Fruits of some species contain up to 20 percent crude protein (West, 1950; Gohl, 1981; Topps and Oliver, 1993).

Sorghum ranks third, in both area and production, among traditional cereal crops grown in Zimbabwe. Sorghum requires less water and can be successfully grown under a wider variety of conditions than maize. Although sorghum grain is also a source of energy, it has not been routinely used because it has been considered less valuable than maize grain because of its highly variable chemical composition and feeding value. The lower feeding value of sorghum grain has been attributed to environmental and varietal differences. Sorghum can replace maize, on average, with an efficiency of 89 percent (Topps and Oliver, 1993).

The objective of this study was to examine the feeding value of fruits from acacias and other leguminous trees and to assess the potential of sorghum grain in high energy finishing diets in drought prone areas of Zimbabwe.

Experimental procedure and results

Experiment 1

The chemical composition, in-vitro dry matter digestibility (IVDMD) (Tilley and Terry, 1963) and the seed to pod ratio of selected fruits was assessed. The leguminous fruits were fractionated into seed and pods and the proportion of each determined to give the individual fraction to whole pod ratio. The whole and fractionated fruits were milled through a one mm screen for chemical analysis and digestibility studies.

The seeds of the fruits had a higher crude protein content than their pods. Neutral-detergent fibre (NDF) was higher in the pods, except for Acacia nilotica and Dichrostachys cinerea. The IVDMD was higher in seeds than in pods, except for Acacia nilotica (Table 1).

Table 1. Chemical composition, IVDMD and seed to pod ratio of selected leguminous fruits.

Experiment 2

Twenty indigenous wethers (average initial live-weight 37.4 kg), about 23 months of age were blocked by weight and then randomly allocated to four treatments. They were each offered one kg of hay per day (fresh weight) and one of the following supplements (gDM/day): Mabiko (14.5); cottonseed meal (CSM) (37.0); Acacia tortilis (100) Acacia nilotica (115.0). The hay was milled through a 25 mm screen and offered ad libitum twice a day at 0800 and 1400 hours. The lambs were housed individually in metabolism crates. Intake and digestibility were measured after a 21-day acclimatization period.

Mabiko contained most CP and least NDF (Table 1). All supplements were eaten, except for A. nilotica. Hay intake was highest with Mabiko and lowest (P < 0.01) with A. nilotica. The DM digestibility was highest (P < 0.05) with acacia supplements. Neutral-detergent fibre digestibility was lowest with A. tortilis. Nitrogen retention was significantly (P < 0.05) affected by source of supplement. Unmilled seeds voided in faeces were less than one percent of the amount fed (Table 2).

Table 2. Hay intake by lambs offered supplements of + Mabiko, cottonseed meal (CSM) or acacia fruits

^abc Means in the same row with different superscripts are significantly different (p < 0.05).
⁺ Concentrate containing 39 percent urea.

Experiment 3

The chemical composition, IVDMD and in sacco dry matter digestibility of sorghum grain differing in tannin content were assessed. The sorghum grain was milled through a one mm screen for IVDMD and three mm for the 48 hour dry matter loss (DML) (Orskov et al., 1980). Three fistulated steers were fed eight kg of hay (3.5 % CP) and two kg concentrate (32.0 % CP). Rumen fluid for the IVDMD was obtained from two fistulated steers. Three rumen fistulated steers were used to estimate the DML of the grain. About three g of sample were weighed into nylon bags and incubated in the rumen of each steer for 48 hours.

The CP content of the grain ranged from 10.2 to 13.8 percent. Brown sorghum grain had significantly higher (P < 0.05) Acid Detergent Fibre (ADF) than white grain. Significant correlations between seed colour and tannin content was observed. Brown sorghum grain tended to have a higher (P < 0.05) tannin content than white sorghum. The IVDMD ranged from 66.0 to 89.0 percent and was significantly different (P < 0.01). The ADF (P < 0.001, r = -0.75) and vanillin-HCl tannins (P < 0.001, -0.74) were negatively correlated with IVDMD. The DML of the grain was lowest with macia and highest (P < 0.001) with variety 9480-H at 48 hours. Although not significantly different CP, ADF and tannins were negatively associated with DML (Table 3).

Table 3. Chemical composition (g/kg DM), IVDMD and 48-hour dry matter loss (DML) (g per kg DM) of sorghum varying in tannin content

Experiment 4

Forty steers (average initial live-weight 304 kg) were blocked by weight and breed then randomly allocated to five treatments. One group was assigned to direct slaughter. The remaining groups were offered the following diets containing 33 percent grain:

• 100 percent maize (100M);
• 50 percent maize: 50 percent sorghum (50M:50S);
• 100 percent sorghum (100S);
• 100 percent sorghum + 3g PEG per day (100S PEG)

The composition of the diets is given in Table 4.

Table 4. Diet composition (g/kg), chemical composition (g per kgDM) and metabolizable energy (ME MJ per kgDM) of the diets

The steers were individually penned. During the first two weeks of the experiment steers were offered eight kg (as fed) of the appropriate treatment diets only. After this initial period, the diets were fed ad lib twice per day at 0800 and 1400 hours for 97 days. The amount of feed offered was adjusted to allow about 20 percent refusals. Refusals were collected daily prior to morning feed, weighed and sub-sampled and stored to await analysis. Water was available at all times.

The sorghum based diet contained the most tannins. The energy values were slightly lower for sorghum than for maize-based diets (Table 4). Intake and growth performance of steers is shown in Table 5. Dry matter and ME intake were highest with the 50M:50S diet and lowest (p < 0.01) with the 100S PEG diet. The maize and sorghum-based diets had similar intakes. Steers on the 50M:50S diet had the highest growth rates and the sorghum plus PEG diet the lowest (p < 0.05). Although there were no significant differences between treatments (P>0.05), feed conversion ratio was better with the 50M:50S diet and least with sorghum-based diets.

Table 5. Feedlot performance of steers fed sorghum based diets with or without PEG

^ab Means in the same row with different superscripts are significantly different (p < 0.05).

Carcass traits of the steers are shown in Table 6. Daily carcass gains were highest with the 50M:50S diet and lowest (P < 0.01) with the 100S PEG diet. Dressing proportions were similar for all treatments. Carcass fleshing grades were lower (P < 0.01) for steers offered 100S PEG compared to the other treatments.

Table 6. Carcass characteristics of steers fed sorghum based diets with or without PEG

^ab Means in the same row with different superscripts are significantly different (p <0.05).

Fleshing grade was coded; A+ = 1, A- = 2, B+ = 3, ------E+ = 9, E- = 10, where 1 = very well fleshed and 10 very poorly fleshed (Cattle Producers Association, 1991).

Discussion

Browse

The higher CP content in the seeds compared to pods (Table 1) indicates that a high proportion of seeds passing undigested through the alimentary canal would lower the nutritive value of fruits. The IVDMD was higher for seeds, except for A. nilotica, confirming the importance of the contribution of seeds to overall nutritive value.

Hay intake (experiment 2) by lambs given cottonseed meal was not significantly different from those given A. tortilis, although DM and OM digestibility were higher with A. tortilis. Nitrogen retention was highest with Mabiko and A. nilotica even though N intake was lowest with A. nilotica. Seeds voided in faeces relative to seeds consumed were negligible. Tanner et al., (1990) observed that up to 46 percent of the seeds of A. tortilis and only six percent for A. nilotica passed undigested. The higher digestibility of seeds in this study may have been due to the damage of seeds by insects, which was 21 and 11 percent for A. tortilis and A. nilotica, respectively.

Sorghum grain

In sorghums, a significant correlation between seed colour and tannin content has been observed (Harris et al., 1970; McMillan et al., 1972). Brown sorghums tend to have a higher tannin content than white or red sorghums (Arora and Luthra, 1974).

The brown sorghums in experiment 3 gave a higher CP, ADF and tannin content compared to white sorghum grain. The IVDMD was in the range reported by Arora and Luthra (1970), and there was a negative correlation between tannin content and IVDMD. Harris et al., (1970) found a negative correlation between tannin content and IVDMD when examining 43 varieties of sorghum grain ranging from brown to yellow. The lower digestibility was probably due to tannins combining chemically with protein to form complexes which reduce the nutritive value of the grain (Reed, 1987). On the other hand, vanillin-HCl tannins had no significant effect on the in sacco DM degradability. Arora and Luthra (1974) observed that tannin, as measured by the vanillin-HCl, may not be the only factor influencing digestibility as he observed high IVDMD in high tannin sorghum grain.

The sorghum used in experiment 4 was brown in colour and high in vanillin-HCl tannins (6.2 % CP). Amira (1992) recommends a maximum of 30 percent of brown sorghum inclusion and no upper limit or restriction for white sorghums in pen finishing diets. The grain inclusion in experiment 4, at 33 percent, was in the range reported by Amira (1992).

The results (Table 5) are similar to the work by Smith et al., (1992) who substituted maize with sorghum at the rate of 0, 25, 50, 75, 100 percent in pen finishing diets for steers at a grain inclusion rate of 70 percent. The 50:50 maize to sorghum diets gave the best animal performance. On the other hand, these results differ with those of Loyacano et al., (1973) who observed that the level of sorghum in the ration had a significant effect on average daily gains and feed conversion ratio both worsening as the level of sorghum in the ration increased.

The relatively poor performance on the PEG-containing diet is consistent with earlier reports (Smith et al., 1992). In other experiments, PEG has been shown to improve intake and digestibility of high tannin feeds (Barry and Forss, 1983; Jones and Mangan, 1977). The amount of PEG given in these experiments is usually 1.5 parts per part condensed tannins (weight: weight) (Waghorn, 1990). The PEG offered in this experiment was below (3 g per day vs 149.6 g per day) the recommended level (Waghorn, 1990). In this experiment, PEG might have destroyed the positive effects of tannins in protecting protein from deamination in the rumen. Barry and Manley (1986) observed increased nitrogen retention in sheep fed high tannin compared to low tannin Lotus pedunculatus. This was attributed to an increased supply of amino acids to the small intestines as a result of protection of protein from proteolysis in the rumen.

Conclusion

The results of this work indicate that high tannin sorghums are useful as a source of energy in pen fattening diets without adversely affecting animal performance. The potential of the mixed diets (maize with sorghum) in pen finishing rations needs further investigation. Further work is in progress to determine the potential of multipurpose trees and sorghum grain as livestock (ruminants) feed.

Acknowledgements

The author thanks the staff of the Livestock Nutrition Section for care of experimental animals, and Mr J S Dube and his staff for chemical analysis.

References

Amira, C.D. 1992. Small grains in monogastric and ruminant feed formulations: prospects and problems. In: Utilisation of sorghum and millets. Eds: M.I. Gomez, L.R. House, L.W. Rooney and D.A.V. Dendy. Patancheru, A.P. 502 324, India: International Crops Research Institute for the Semi-arid Tropics. pp. 183–190.

Arora, S.K. and Luthra, Y.P. 1974. The in vitro digestibility of promising Indian varieties of sorghum and in relation with tannin content. Indian Journal of Nutrition and Dietetics. 11: 233–236.

Barry, T.N. and Forss, D.A. 1983. The condensed tannin content of vegetable Lotus pedunculatus, its regulation by fertiliser solubility. Journal of the Science of Food and Agriculture. 34: 1047–1056.

Barry, T.N. and Manley, T.R. 1986. Interrelationships between the concentrations of total condensed tannin and lignin in Lotus sp. and their possible consequences in ruminant nutrition. Journal of the Science of Food and Agriculture. 37: 248– 254.

Cattle Producers Association (CPA). 1991. Beef Production Manual (revised edition). CPA, Harare

Gohl, B. 1981. Tropical Feeds. FAO. Animal Production and Health Paper No. 12, pp. 529, Rome.

Harris, H.B., Cummins, D.G. and Burns, R.E. 1970. Tannin content and digestibility of sorghum grain as influenced by bagging. Agronomy Journal. 38: 237–243.

Jones, W.T. and Mangan, J.L. 1977. Complexes of the condensed tannins of sainfoin (Onobrychis vicifolia Scop) with fraction 1 leaf protein and with submaxillary mucoprotein and their reversal by polyethylene glycol and pH. Journal of the Science of Food and Agriculture. 28: 126.

Loyacano, A.F., Pontif, J.E., Nipper, W.A. and Hembry, F.G. 1973. Bird resistant grain sorghum in steer finishing diets. Journal of Animal Science. 36: 222 (Abstract).

McMillan, W.W., Wiseman, B.R., Burns, R.E., Harris, H.B. and Greene, G.L. 1972. Bird resistance in diverse germplasm of sorghum. Agronomy Journal. 64: 821– 822.

Orskov, E.R., Hovell, F.D. de B. and Mould, F.L. 1980. The use of the nylon bag technique for the evaluation of feedstuffs. Tropical Animal Production. 5: 195– 213.

Reed, 1987. Phenolics, fiber and digestibility in bird resistant and non bird resistant sorghum grain. Journal of Agricultural and Food Chemistry. 35: 461–464.

Smith, T., Ncube, S., Nengomasha, E.M. and Mpofu, D. 1992. Substitution of maize with sorghum in energy-rich diets for cattle. Annual Report, Division of Livestock and Pastures. Department of Research and Specialist Services.

Tanner, J.C., Reed, J.D. and Owen, E. 1990. The nutritive value of fruits (pods with seeds) from four acacia spp. Compared with extracted noug (Guizotia abyssinica) meal as supplements to maize stover for Ethiopian Highland sheep. Animal Production. 51-127–133.

Tilley, J.M.A. and Terry, R.A. 1963. A two stage technique for in vitro digestion of forage crops. Journal of the British Grassland Society. 18: 104–111.

Topps, J.H. and Oliver, J. 1993. Animal Foods of Central Africa. Rhodesia Agricultural Journal. Technical Handbook, No. 2, Harare.

West, O. 1950. Indigenous tree crops of Southern Rhodesia. Rhodesia Agricultural Journal. 47: 204–217.

Waghorn, G.C. 1990. Effect of condensed tannin on protein digestion and nutritive value of fresh herbage. Proceedings of the Australian Society of Animal Production. 18: Biotechnology Division, DSIR, Palmerston North, New Zealand.

FEEDING MANAGEMENT IN DROUGHT YEARS

J.H. Hoon
Grootfontein Agricultural Development Institute Middelburg, Eastern Cape, South Africa

Introduction

Drought is possibly the greatest single factor that influences the economics of livestock production enterprises in South Africa. The fear of drought is the single most important factor that prevent stocking rates from approaching those theoretically possible, particularly on improved veld. Droughts can refer to periods of low rainfall following a “good season” when pastures mature and dry off and the quality appears too low to support cattle and sheep production. They can also refer to periods of prolonged dry weather when the livestock has consumed the available pasture. Fire can also induce a drought overnight on an individual property.

Drought feeding strategies depend on the specific conditions prevailing in any particular area. In general the farmer has to make decisions based on economics, knowledge of nutrition, the availability of feed resources and his calculated guess on the length of the drought. The options may include:

• Sell the animals when drought seems imminent and, if possible, before others sense disaster just around the corner.
• Maintain animals at a low level of productivity (or maintenance) until the drought ends.
• Feed for productivity during the drought in order to be able to capitalise on available feed resources when the drought ends and to have animals for sale to the farmer who need to restock.
• Combinations of the three situations. For instance, a farmer may sell all except his breeding animals. These are managed to ensure that the offspring are raised for the next breeding season. It seems that all farmers need to restock following a drought and therefore breeding animals must be maintained at all costs.

Prediction of drought appears now to be more of a reality with the improved knowledge of the El Nino phenomenon. However, in the backs of the mind of farmers there is a continuous nagging recognition that drought is unpredictable and imminent. Therefore the consequences of drought monopolises much of the thought that goes into the forward planning of a property particularly where drought situations are predictable, such as occurs with annual dry seasons. In South Africa, droughts can be classified in three categories:

• Protein drought - It is the same as a normal winter (or summer in the Western Cape) with sufficient dry veld (or stubble-fields). Protein is the only nutrient that is defficient.
• Protein and energy drought - It is the same as a normal late winter (or late summer in the Western Cape) when the quality as well as the quantity of veld (or stubble) are a problem. Under these circumstances it is important that protein and energy are supplemented to prevent large mass and reproduction losses.
• Total drought - Total drought situations will vary between the normal late winter (or late summer in the Western Cape) situation and a disaster drought where no roughage from the veld is available. Cattle need to be helped earlier than sheep and goats, because small stock will graze at a lower level and utilise the veld more completely and also utilise shrubs and other plants more efficiently. For the first phase of a disaster drought, it will therefore be cheaper to maintain sheep and goats.

Strategies

There seems to be three major rules when considering a strategy for drought feeding (Leng, 1987)

• When a drought is present, if you have to think about what you are doing, you will be in no position to obtain the necessary resources to apply modern concepts. You have to know what you are doing and have planned it by thinking about what you will do next if the situation gets worse.
• The aim of a drought feeding strategy should always be to optimise the efficiency of utilisation of the available least-cost resource. This is nearly always dry veld early in a drought, but becomes more and more some form of supplementary feeding as available veld is reduced.
• When a drought is prolonged and pasture is virtually absent, or the animals have grazed as much as possible without excessive soil erosion occurring, then it is important to use combinations of supplements to optimise utilisation of the least expensive (in money and labour) feed resource.

The most important nutritional consideration for both cattle and sheep is to recognise that two systems must be fed at once

• The microbes that reside in the rumen and which digest plant material, which is termed fermentative digestion.
• The animal itself which largely depends on the products of fermentative digestion and dietary nutrients that bypass fermentation for its requirements (Leng, 1986).

The important point is that when ruminants are fed drought-based diets, the products of fermentative digestion are seldom balanced (in the quantities of individual and essential nutrients) to meet productive functions or even maintain body weight.

Because of the rainfall patterns in large parts of South Africa, it seems highly probable that there are few occasions throughout the year where the grazing animal obtains a sufficiently well balanced array of nutrients to maximise the efficiency of feed utilisation for a particular productive function. It could be speculated that it is only the suckling lamb with its mother on pasture that is ever supplied with sufficient bypass nutrients.

In very few instances do we wish to feed for maximum production in a drought. In most situations we wish to use, as efficiently as possible, a restricted amount of feed to maintain animals or to feed for survival. With pregnant and lactating animals it is always necessary to feed for the maintenance of the foetus and for maintenance of a minimal milk production. In research projects in which animals are fed for maintenance, it has been illustrated that these animals are highly inefficient in utilising feeds if the nutrients available are not in balanced quantities. The effect of feeding the animal extra urea/sulphur and bypass protein respectively on low digestibility roughage diets (45% digestible, 3% protein) is illustrated in Table 1.

Table 1. The effect of protein feeding on hay intake and production of growing or pregnant cattle

Source: Leng (1987)

The results presented in Table 1 indicate the principles of ruminant feeding which involves providing nutrients for two systems (i.e. the rumen organisms and the animal). When the ruminant is deficient in nitrogen or sulphur (or any growth factor), microbial growth efficiency in the rumen is low.

Hints for feeding during droughts

Which animals to sell
Old animals, animals with poor reproduction records, heifers or young ewes which have not calved/lambed, oxen/wethers. Culled animals can be fattened profitably with home-produced maize or other grains

Roughage vs. concentrates
In times of drought, roughage is scarce and often very expensive. Research has indicated that animals can survive more successfully and more economically on concentrate-rich ingredients. Disadvantages of roughages are much higher transport cost, higher cost per unit utilisable energy, more losses during feeding and also a higher fire hazard.

Frequency of feeding
Research has indicated that animals receiving daily survival diets, did not perform as well and had a higher mortality rate than animals that had been fed twice or just once a week. With daily feeding, some animals ingest more than their share while others get nothing, starve and eventually die. When more feed is supplied at once, but less frequently, each animal has a better chance to receive its part of the diet.

Early weaning
Early weaning of both lambs and calves is a strategy that can be used to save costs and to utilise scarce feed resources more efficiently. The best examples of such feed sources are creep feeding or cultivated pastures. Early should, however, not be considered if high quality green fodder or concentrate-rich mixtures are not available. Early weaning reduces stress on cows and ewes, which can then be fed cheaper ingredients. Creep feeding has the following advantages:

• It is utilised very efficiently. A young calf or lamb has a feed conversion of as low as 2:1, which changes gradually to about 7:1 at seven months of age.
• Calves/lambs are heavier at weaning.
• Calves/lambs are more uniform at weaning
• Calves/lambs can be weaned earlier, which has a positive effect on reconception.
• Weaned calves/lambs can be marketed earlier.
• Weaned calves/lambs are already adapted for the feedlot.

How much to feed
This will depend largely on the amount of veld available. If there is no grazing available, research results have shown that beef cows with an initial body weight of 440 kg, can be kept on a 3.6 kg concentrate-rich daily diet for eight months, with a weight loss of only 63 kg. This converts to a total daily TDN-intake of 2.65 kg. Sheep on the other hand need a TDN-intake of 265 g when concentrate-rich diets are supplied, and 365 g TDN in the case of roughages like lucerne.

Weight loss
The rule of thumb is normally that supplementary feeding should start before animals have lost more than 15 percent of their normal mature body weight. If animals are allowed to lose weight slowly and systematically, they will, however, be able to stay healthy on survival diets during droughts at 66 percent of their normal mature body weight (cattle - 500 kg down to 330 kg; sheep - 50 kg down to 33 kg). This rule does not apply to pregnant animals because large weight losses can lead to abortions.

Treatment of low quality roughages

The utilisation of cereal straws is very important for animal feeding in the Western Cape during the dry summer months. Chemical treatment of low quality roughages to improve digestibility has been practised for many years in South Africa. The process most commonly used is sodium hydroxide (NaOH) treatment, which hydrolyses ligno-cellulose bonds, resulting in increased digestibility. In vivo studies show an optimum treatment level of four percent NaOH on a dry matter basis and further improvement in animal performance can be obtained by the inclusion of bypass protein in the diet. A limitation of NaOH treatment is the additional energy required by the kidneys to excrete Na⁺. This has led to the development of ammoniation (NH³ treatment) as a method of upgrading low quality roughages. Results with the ammoniation of low grade roughages have indicated an increase in metabolizable energy of 1.3 MJ/kg DM, while one tonne of treated maize stover was equal in feeding value to 1.2 m/t of untreated stover plus 17 kg urea, (Meeske, 1992). The first recognisable change in cereal straw to treatment with NH³, is a change in colour (browning or caramelisation) as a result of the Maillard reaction between carbohydrates and N-containing bonds. Although very seldom the case, a problem does sometimes occurr during the process of ammoniation with the formation of a toxic compound, 4-methyl-imidazole, which can lead to animal losses (Vosloo, 1985).

Drought fodder crops

The most important single factor limiting fodder production in South Africa, is the lack of sufficient moisture. Increased plant production in these areas is thus coupled to factors which will either increase the amount of moisture or make better use of it. The most important possibility thus remains the establishment of drought fodder crops which make better use of the available moisture. The most important drought fodder crops in South Africa are oldman saltbush (Atriplex nummularia), spineless cactus (Opuntia spp.) and American aloe (Agave americana). The relative water consumption of drought fodder crops in relation to other crops is indicated in Table 2.

Table 2. The relative water consumption of different crops

Source: De Kock (1980)

Requirements of a drought fodder crop

• It must be relatively drought resistant. It must not only be able to survive long droughts, but must also be able to produce large quantities of fodder during periods of favourable rainfall, which can be utilised during periods of droughts.
• It must have a relatively high carrying capacity
• It must be able to supply succulent fodder for animals during droughts
• It must not have an adverse effect on the health of animals utilising it
• It must have a high recovery ability after severe utilisation
• It must have a low initial input cost; the establishment and maintenance of crops must be economical
• It must be adapted to a wide series of soil and climatic conditions in order to be planted where the cultivation of other fodder crops is and uncertain undertaking (De Kock, 1980)

Oldman saltbush (Atriplex nummularia)

Oldman saltbush is a perennial shrub, indigenous to Australia, and has been found in South Africa for the past hundred years. Oldman saltbush can be grazed from the second season after establishment. When saltbush is grazed, sufficient drinking water must be supplied, as the sheep becomes thirsty from the salt in the plants. If the drinking water is also very brackish (high total salts content), an adaptation period of two to three weeks should be allowed for animals to adapt to the very high total salt intake. After this adaptation period, feed intake and animal performance are the same as animals receiving fresh water (King et al., 1991). Apart from the drought resistance, a noteworthy characteristic of these plants is their high production of green succulent feed under relatively poor moisture conditions. An indication of the amount of edible material per ha produced by oldman saltbush is given in Table 3.

Table 3. The yield of leaves of oldman saltbush

Source: De Kock (1980)

The results in Table 3 also illustrate the ability of oldman saltbush to recover after defoliation each year. This is one of the reasons which make this crop exceptionally suitable as a grazing crop. A carrying capacity of 21.74 sheep per ha for four months of the year was calculated for oldman saltbush (2500 plants/ha), which converts to a carrying capacity of six to eight sheep per ha per year. An average number of 2800 sheep grazing days per ha of oldman saltbush per year was obtained at Grootfontein A.D.I. (De Kock, 1980). Similar values were calculated from the results obtained by Hoon and King (1992). Oldman saltbush is high in protein (16–22%) and can supply the maintenance requirements of sheep. It can also maintain ewes during late pregnancy and lactation, but for optimum production and reproduction, additional energy should be supplemented.

Spineless cactus (Opuntia spp.)

Spineless cacti possess the exceptional characteristics of being able to store large quantities of water in their succulent leaves in a relatively short period. Just a few mm of rain which would normally be of no value to ordinary fodder crops, can be utilised efficiently by this plant. Spineless cactus is not only of value as a source of succulent fodder during droughts but can also be used in the reclamation of bare patches and in the conservation of veld. Spineless cactus is deficient in protein (3–4% on a DM basis), while the high moisture content (about 90%) is a factor that limits intake. Even for maintenance of animals, it is necessary to supplement spineless cactus with one or other form of protein. The method of utilisation of spineless cactus will differ from farm to farm according to circumstances such as available labour, facilities, quantity available, etc. The different utilisation methods are the following:

• Grazing
• Chopping
• Meal
• Silage
• Supplementary feeding (De Kock, 1980)

American aloe (Agave americana)

American aloe is one of the hardiest plants which can be established for the production of fodder in the arid and semi-arid regions. American aloe has the same deficiencies as spineless cactus with regard to nutritional value, namely a high moisture (85–90%) and low protein (3–4% on DM basis) content. Like oldman saltbush and spineless cactus, the growing season of American aloe plants is in the summer months. In the autumn and dry winter months the leaves can be processed (chopped and chaffed in pieces) and fed to animals. A yield of 120 m/t of leaves per ha can be expected annually from American aloe, even on relatively poor soils (De Kock, 1980). An extensive study on the utilisation of American aloe as a feed source for sheep at Grootfontein A.D.I. has indicated that American aloe leaves were able to satisfy 64 percent of the maintenance requirements of mature sheep, but that the best results were obtained at an inclusion level of 45 percent in maintenance diets. It was concluded that the most important applications of American aloe would be as a survival diet (e.g. during serious drought conditions) or as a major component of a maintenance diet (Hoon, 1994).

Livestock feeding in developing agriculture

Leng (1991) states that livestock in developing areas are mostly restricted in their nutrition to:

• poor quality veld (often overgrazed), on soils which are infertile or with terrain that makes it impossible to utilise for crops or where erosion has made them unusable
• standing crop residues or weeds following cropping, when environmental conditions are poor for plant growth and a further crop in that year cannot be taken.
• Crop residues (cut and stored)
• Agro-industrial by-products

Apart from a general shortage of feedstuffs, the feeds that are available are fibrous and relatively high in ligno-cellulose. They are usually of low digestibility and are often deficient in critical nutrients, including protein, non-protein nitrogen and minerals. Generally, the forages consumed by ruminants in developing areas are almost always below 55 percent (usually 40–45%) digestibility and often have less than 8 percent crude protein, the protein level more often being around three to five percent (Leng, 1991). The net result of livestock farming under these conditions is an extremely low rate of productivity, being 0.1–0.25 of that of ruminants in the temperate countries grazing fertilised pastures of fed high-quality feeds based on grain and immature pasture plants.

Research has a key role to play in ensuring that animal production supports economic growth in Sub-Saharan Africa. As a result of the high population growth rate, land will become more limited particularly due to pressure for better crop/grain production. Consequently, opportunities for livestock development will increasingly necessitate technological change that includes more productive animals which are managed and fed better. Research will have to play an increasing role if higher and sustainable animal productivity is to be achieved (Henning, 1995).

Leng (1991) proposes a list of research priorities for animal nutrition in the developing areas:

Feed technologies

• Development of appropriate supplements that balance nutrition of ruminants fed poor quality forages, crop residues or agro-industrial by-products. The research requirements include:
  • development of appropriate supplements of mineral, non-protein nitrogen and other microbial factors
  • identification of protein resources naturally protected from rumen degradation

  • processing of protein resources to protect them from rumen degradation.

• Where protein is scarce, the development of systems to produce protected protein resources becomes a priority. These include:
  • protein from crops, trees, by-products

  • aquatic plants, algäe and animals.

Manipulation of digestibility

• by chemical treatment
• by microbiological treatment
• by improving fermentation in the rumen by:
  • modification of the ecosystem

  • addition of modified organisms

Manipulation of metabolism within the animal

• by chemicals or hormonal implants
• by production of transgenic animals

A comparison of the above list of research priorities with the review of ruminant research done in South Africa over the decade actually suggests that a large part of the research done locally during the decade 1985/1995 (although mostly on behalf of the commercial sector) is actually applicable to livestock farming in the developing areas. It can be argued that it is actually incorrect to discern between research for established or commercial agriculture and for emerging agriculture, since there is practically no technology, especially in the livestock sphere, which is not equally applicable to both. There is, however, a lack of compatibility between technology and the actual farming systems in the developing areas. There is also a lack of technology transfer linkages which inhibits the development of appropriate farming systems in a participatory manner (Henning, 1995).

Summary

The main lesson to be learned from a drought situation is to remember that the next drought is inevitable and drawing closer. The major questions to be asked by farmers before it arrives, are:

What lessons have I learned from the last drought?
What is my strategy for the next drought?
Should I be looking for alternatives to traditional feeding strategies?
Is it possible to drought-proof my farming enterprise and what infrastructure should I develop?
How do I optimise the use of the available resources in the next drought and how can I be sure that I will be in a position to use this strategy?

The key is maximising the efficiency of drought feeding strategies by balancing the nutrients available to the animal for productive purposes.

References

De Kock, G.C. 1980. Drought resistant fodder shrub crops in South Africa. In: Browse in Africa. Ed. H.N. le Houerou, p. 399–408.

Henning, P.H. 1995. Research to meet the needs of the small-scale farmer. Proceedings of Symposium “Recent developments in ruminant nutrition”, 18 October 1995, p. 111–123.

Hoon, J.H. and King, B.R. 1992. Determination of the voluntary intake of oldman saltbush (Atriplex nummularia) in three different forms. Karoo Agriculture. 4 (4) p. 4–6.

Hoon, J.H. 1994. The ulilisation of Agave americana L. (American aloe) as a feed source for sheep. M.Sc. Agric-dissertation, University of the Orange Free State.

King, P.R. Hoon, J.H. and King, B.R. 1991. The effect of brackish water on the intake of Atriplex nummularia (Oldman saltbush). Proceedings 30^th congress of the South African Society for Animal Production. Port Elizabeth (26–28 March 1991).

Leng, R.A. 1986. Drought feeding strategies: Theory and practice. Penambul Books, N.S.W., Australia.

Leng, R.A. 1987. Some theoretical consideration on drought feeding recommendations. In: Recent advances in Animal Nutrition in Australia -1987, p. 104–111.

Leng, R.A. 1991. Application of biotechnology to Nutrition of Animals in Developing Countries. Paper No. 90. Food and Agricultural Organisation of the United Nations, Rome.

Meeske, 1992. Improving the feeding value of low quality roughage. Proceedings of the Highveld Branch of the South African Society for Animal Production. Vol. 13: 23–30.

Vosloo, L.P. 1985. Roughage feeding of ruminants - new developments. South African Journal of Animal Science. 15 (3) p. 86–90.

FEEDING STRATEGIES DURING DROUGHT

F. Johnson
P O Box 201, Marondera, Zimbabwe

Introduction

Probably the most famous drought happened a long time ago and became famous when recorded in the Bible. The most important factor in this was the time they were given to prepare. We do not usually have seven years notice of an impending calamity, nor do we know the length of time we have to prepare for it. Seven fat cows were eaten by seven thin cows. But we learnt some important lessons. In this paper, I will constantly refer to several situations in Zimbabwe which during my years with Agrifoods we became involved with and from which I gained a lot of experience. They were the bigger schemes, and also the most successful.

I was fortunate during the first drought I encountered after joining Agrifoods to be working with Dr. Dick Elliott who was for those who did not know him, probably one of the greats in animal science. His work was known world-wide. He was a communicator and a very practical man. He, at the time, was a consultant to Agrifoods and the Cold Storage Commission (CSC), so had a great deal to do with all our feeding strategies.

The main schemes to which I will refer are:

• The C.S.C. feeding programme at Chumfukwe Ranch, West Nicholson.
• 22000 head ± were fed in one herd
• Igava farm with the late Bob Rutherford where the entire breeding herd was penned in groups that could be accommodated, at any point, taking into consideration the amount of feed available.
• Des Howarth, South Chegutu. His tactical use of silage was very successful during frequent droughts in that area.

I found plenty in these schemes to justify what I will put to you.

If you were the Pharaoh of Egypt and said to me Joseph the dream interpreter get on with it you have seven years to save Egypt. What you gonna do?

I would draw up a list based on my experience in the past and would justify it.

• Firstly plan soundly, then demand a high level of management, equal parts of stockmanship and common sense, and an immediate disconnection of all panic buttons (for the duration of the drought).
• Assess available feedstocks.

Feedstocks

I would consider the following order of priority:-

Molasses

Molasses can be stored in tanks or in pits in the ground. The scheme at Chumfukwe hinged on a high molasses diet.
We used molasses in conjunction with cotton hulls at up to 30 percent and with milled hay at 20 to 25 percent (not quite as absorbent). The diet was very similar to the normal pen feeding diet at 11 to 12 percent CP, 60 to 65 percent T.D.N. and ± 40 percent CF.
It was fed at a rate of three kgs per head into troughs at ground level made with rail sleepers. A tractor and trailer straddled the through and the feed was dispensed from the back. 22000 head were fed in one herd necessitating the dispensing of 75 m/t of feed per day.

The plan was sound and the management was good, plenty of good stockmen were present, common sense prevailed and there was no panic. Molasses is a wonderful rumen comforter, very palatble and able to bind feeds together and hold ingredients like urea, salt etc. It is a source of easy accessible energy and therefore top of my list. The result I believe was most pleasing and the object of the exercise was achieved. A large number of breeding cows and heifers were saved when the only other option would have been slaughter.

It was always Dr. Elliott's idea that six kg every second day would have been better mainly because at least once in two days the rumen would be full instead of perpetual hunger. I have advocated this in other situations and it works well.

Silage

On Igava as I indicated we used a large amount of silage. As it was a dry land crop which did not pollinate and had little or no grain content it was of poor quality. Ensiled green, it was wet and palatable.

On Igava, herds were grouped and penned in large pens or areas. 100 to 120 cows in a paddock of up to 40 ha giving room for normal social activity and pecking order. They were planned around the available feed and situated as close as possible to the feed source so as to minimise transport, and calculated to fit the amount of feed available.

We had groups being fed silage as the main basis of their diet, others on chopped stover, milled soya stover, and milled Rhodes grass hay. No molasses was available.

Diets were calculated as near as possible to the requirements first of the pregnant cow and then adjusted as calving started. The requirements were taken from the N.R.C tables for cows of average milking ability.

From the whole scheme it was noticed that although we as far as possible kept nutrient levels as even as possible - by having analysis done on all ingredients, the pens on silage did better than the others. Intake obviously was better but even allowing for that the results from the herds on silage were far superior.

Mr. Des Howarth farms in a very dry area below Chegutu in Mash West Province. He is a great believer in silage and has a number of smallish pits on his farm, which he insists are kept full, replenishing anything used during winter as soon as possible, the following summer. He always used them in a strict rotation with the oldest first, and quite often they were a few years old.

The net result was that having planned the fodder bank he brought his cattle through many fairly serious local droughts and some very serious national droughts when people all around were having to employ panic measures to dispose of breeding cows or resort to purchasing more expensive options.

Roughage

This obviously would be any roughage, hay, stover, mopane bush meal. Anything I could put away in a heap, and utilise later. The better quality would be preferred, and if possible all should be analysed in order to balance what could be added.

Roughage is required to make the rumen function, and if molasses is available it is a very effective carrier of other ingredients.

I have over the past years seen some dreadful roughages utilised in drought situations but they are essential and needed in large quantities. Bill Smith of Union Carbide Ranches, one time Cattleman of the Year, and always an excellent cattle man whose stockmanship is always of the highest order, milled bush and leaves from mostly mopane and combretums to ensure enough roughage to keep his herd functional. Many others did but Bill's was one of the schemes that I monitored. He always had a good supply of molasses, in tanks, in his shed.

So for obvious reasons as much roughage as possible should be stored. In a home situation we try to keep at least the next winters roughage on hand, and have only this year finished some barley straw which was stored two winters ago.

I believe it is most important to look at the digestibility of some of the roughages and use as a blend if possible. I have seen cows die when fed a diet of soya stover which if one looks at its nutrient content should be quite sufficient.

Similarly a lot of trouble was experienced in a bad dry year in our lowveld region caused by the use of cane tops which were freely available but relatively indigestible.

Protein sources

Next on my list would be sources of protein. Urea is an obvious choice as it can be easily stored and used in the right way is quite adequate.

At Igava, with one exception, urea was always used, it was either watered onto the diets or in some cases it was mixed into the milled maize portion of the ration up to a maximum of the two percent in the final diet.

Cottonseed meal, soya meal and sunflower meal are all excellent sources and if available should be used in conjunction with urea. I prefer at least 25 percent of crude protein requirements to be from a natural protein source but this is not always possible. Milling offals such as hominy chop, wheat bran etc. are usually in good supply during dry years as people have to rely on purchased food. They should be stored and used when appropriate. Mineral and vitamin inclusions are also vital in most drought situations.

What were the results from these various schemes:-

• C.S.C. planned and managed a scheme which saved a large number of breeding stock, which were used to restock both commercial and communal farms
• On Igava an entire herd of ± 800 cows was carried through the droughts sound planning, excellent management, good stockmanship and no panic. It cost at the time $167.00 per head against a normal $30.00 but on the positive side the conception rate rose from 80 to 90 percent + and weaning weights were up an average of 40 kgs. The cows were bulled in their restricted areas, and only let out in December when as Bob Rutherford put it the grass had reached the second wire on the fence!
• Des Howarth with his forward planning has always come off better than average in his area.

On the subject of panic buttons, I have seen a number of schemes where panic measures were implemented and cattle moved willy nilly all over the place, spreading the management and common sense too this and although a lot of money was spent, a very poor result both physically and financially was achieved.

In closing, in our region where droughts in some areas are more the rule than the exception we do not often get warnings of droughts even with today's technology.

SESSION IV
DISCUSSION

1.   Chinembiri

Q.   What is the Zimbabwe experience with grazing schemes. Are they a complete failure?

A.   Some are, some are not. In many cases they have contributed to increased erosion and environmental degradation. Ownership is always a major problem in communal schemes. Also random breeding with unselected bulls is prevalent in communal schemes. In some areas, communal bull approval schemes are underway.

Q.   In campfire we find that immediate financial returns stimulate motivation for managed grazing schemes.

A.   Yes, I agree.

Q.   To what extent is chicken manure used in integrated systems?

A.   As the larger chicken units are close to the urban areas, there is not a lot of chicken manure available in the rural areas. It is used but only on a small scale.

2.   Zeitsman

Q.   Did rainfall have a confounding effect? What was the effect of heavy rain on bare ground?

A.   Animal impact is the major factor in this situation because it improves infiltration. This minimises erosion and promotes a quick re-growth of grass and grass cover. By the next season the soil texture has changed for the better as more organic matter has been incorporated.

Q.   Why are you interested in monitoring the situation?

A.   Although we are convinced that the principles are right, monitoring helps to determine management style and fine-tune management. You cannot do this unless you know what is happening

3.   Ncube

Q.   How do you harvest and use Acacia fruits?

A.   They are harvested by shaking the trees. This generally works well. They have a high protein content and are often stored for use in dry and needy periods. In many cases they are milled before feeding. This improves digestion.

Q.   From the results of your work, which varieties of sorghum would you recommend?

A.   The white varieties in general as they are more predictable, more digestible and have a lower tannin content. However, our results with the higher tannin brown sorghums have been encouraging.

4.   Hoon

Q.   What is the possibility of having some of the exotic drought resistant species becoming wild and invasive in South Africa.

A.   Most unlikely, as they have been used in South Africa for over 100 years. The very dry conditions and poor seeding rates prevents any rapid spread.

Q.   What about using plants with tubers, e.g. Cassava.

A.   There are large parts of South Africa where it is too dry to sustain Cassava, so presumably it would not survive under drought conditions. Drought resistant species have very low water requirements.

5.   Johnson

Q.   With the C.S.C scheme at West Nicholson involving 22000 head, what were your mortality rates?

A.   Initially there were some deaths, but once the cattle settled onto feeding mortality rates were very low.