D. Ochodnicky
INTRODUCTION
The level of global sheep production for individual years and periods in Czechoslovakia is a part of the State plan. There are short-term and long-term plans. Increased production is a result of the growth of two basic indicators, i.e. of the stock and the average efficiency per animal.
The increase in the number of sheep as a complementary animal in the intensive agriculture of Czechoslovakia is given by reserves created in fodder resources. In the summer period we still have unused areas which are suitable for sheep, though they are in remote parts. It is a question of good financial rewards for employees and of creating such working and social conditions as can be found in other agricultural sectors. It is a relation between what we can expect from the exploitation of these areas, and how much we are willing to invest for improving the conditions, firstly of the people but also of animals. In winter it is a question of increasing the fodder production so that the stock would be provided with optimal nutrition. The further condition is represented by finding investment for housing the stock.
Recent developments, especially in Bohemia, have shown that the small animal breeders are able to respond very promptly and to increase production by utilizing all reserves available in their area. They make use of grass growing on places inaccessible for mechanisation and produce sufficient supplies of bulky feed for the winter period. Considering the low housing demands of sheep, the breeders are able to create suitable housing conditions and shelters for the winter months with low investments. The greatest proportion of animals and of production are associated with large-scale breeding. Concerning the required production, it is necessary to create conditions in the fodder base, especially in this sector, where there are substantial reserves. In the sector of investments we have achieved outstanding progress by building new modern facilities and farms providing for mechanisation of most of the work for 11 per cent of the sheep stock. Since 1975 to the 1st January 1985 the sheep have achieved a lambing rate of 132 per cent.
PUREBREEDING
Besides providing optimal nutrition, the most important factor for increasing the production is the breeding work. In Czechoslovakia the breeding work is a natural continuation and extension of suitable breeding procedures proved effective in the past and those suggested after experimental verification. All certified breeds in Czechoslovakia (Merino, Tsigai breed and Improved Valachian sheep) are bred for combined efficiency with progressive differentiation to give two types:
milk-wool type.
Sheep Breeding Center, Trenchin, Czechoslovakia.
Type A is characterised by prevailing wool utility, approximated by the Merino breed (which accounts for 38 percent of sheep in Slovakia and 75 percent in Bohemia). This type will be worked out by selective pressure at pure breeding, or by combination crossing for improving the slaughter utility. The breeding aim of this breed, in the frame of the whole population, is to
- produce 5.2kg greasy wool per ewe
- have wool quality A, AB, (resp. 25 and 27 urn)
- have a staple length of 7 cm
- have liveweight of ewe = 55 kg
- to produce 1.3lambs with one lambing per year or 1.6lambs per year with more frequent lambing
- Achieve average daily gains, in intensive fattening, of 280–300 g.
In Bohemia Type A includes also other medium-wool breeds (Tsigai breed, Improved Valachian sheep and Improved Schumava breed). The future breeding targets for these breeds is to achieve 125–130 percent fecundity in the population plus a moderate increase in wool production while maintaining wool quality.
The production Type B is specific for the conditions of Slovakia and is represented by the breeds “Tsigai” and Improved “Valachian sheep” (37 and 25 percent of stock in Slovakia, respectively). Both characteristics are evaluated equally in this production type. Increased milk production will be provided by: selection for the quantity of milk production and an udder type suitable for machine milking. Improved nutrition of the milked sheep must also be used to obtain increased production.
| The breeding targets are: | Tsigai | Impr. Valachian |
| - greasy fleece weight (kg) | 3.0 | 3.0 |
| - wool quality | BC-CD | CD-DE |
| - fibre diameter | 31–35 μm | 35–40 μm |
| - staple length | 9–12 cm | 18 cm |
| - ewe liveweight | 50 kg | 45 kg |
| - No. of lambs per year | 1.2 | 1.2 |
| - milk yield after weaning of lambs (ℓ) | 120 | 100 |
The selection indicator for the “Tsigai breed is the occurence of coloured fibres. White wool is required. In the case of Improved Valachian sheep the selection indicator is represented by the ratio of the undercoat length to the kemp (it is to be more than 70 per cent).
In the case of the breeds “Tsigai” and “Improved Valachian” the breeding of lines for specific productive conditions will continue, aiming for types
- with increased milk production and probably decreased wool production, and
- a meat-wool type, to the detriment of milk output, but with selection on the reproductive abilities of ewes and the fattening capacity of lambs.
CROSSBREEDING
Commercial crossing plays an important role in Czechoslovakia. Its use in hybridisation programmes for improving of slaughter production alternates between
- two-breed crossing, which is less complex on the level of the organisation of activity,
- three and more-breed crossing with more demands on the organisation and links between individual stocks.
The further aim is to continuously produce suitable biological material, to expand particular forms of breeding work; by pure breeding, by improving crossing and the commercial crossing. Testing procedures for objective evaluation are also used. The following are used in Czechoslovakia:
- stations for fattening ability and slaughter value,
- laboratory for analysing sheep wool and milk, for objective judging of wool and some of its qualitative features,
- rearing centres for rams (from weaning up to use in breeding) with testing of wool production, of the rate of live-weight gain and the quality of sperm.
For the perspective period, the programme supposes the rise of qualitative indicators, but first of all the quality of wool; to improve the reproduction abilities by increasing the fecundity and prolonging the mating season; to increase the yield of edible carcass and the quality of the pelt. But the rate of live-weight gain and the efficiency of fodder utilization will be critical.
In the research sector it is necessary:
- to continue in improving work for combined productivity;gradual differentiation of types,
- to make more effective the methods of creating breed and productive types,
- to focus the attention on creating of synthetic breeds, resp. lines for increasing of productive abilities of sheep,
- after the experimental verification to include among selective criteria elements of polymorphic systems,
- to use, in experimental breeding, several genetically determined elements of quantitative and qualitative biochemical indicators, by creating smaller differentiated items in the frame of the breed.
PRODUCTION
One of the methods used to increase production is based on goal-seeking management of the reproduction process. It allows a high level of slaughter lamb production. Based on experimental results in our Institute we have elaborated a practical methodology for running a programme based on ewes producing three lamb crops every 2 years. The system is illustrated in Figure 1. This enables us to provide regular filling of larger fattening stations three times per year. The system can be utilised on specialised farms, where e.g. 2000 ewes are held, or in the framework of cooperatives. Half of ewes (in this case 1000 ewes) are mated according to the system A, the mating of the second half is delayed by 4 months according to the system B. In the 4th month sheep pregnancy status is determined and those, which are not pregnant, are shifted from the system A to the system B (or from the system B to the system A). In the case of purebred Tsigai sheep, which lambed three times in a course of 2 years, 175 per cent fecundity was reached.
The second method for increasing the number of lambs and simultaneously the slaughter production, is represented by earlier mating of ewe lambs e.g. at 7–10 months of age with a nominal weight of 33–35 kg. A higher incidence of estrus, fertilisation and fecundity was reached by application of hormonal therapy, i.e. Czechoslovak Agelin (vaginal sponges)+ 500 i.u. PMSG or the French Chronogest + 500 i.u. PMSG. In the case of Agelin the fertilisation of tested lamb-ewes reached 75% compared with 85% for Chronogest.
FIGURE 1. Design for the organisation of a ewe flock for three lambings per ewe per 2 year period
