PRINCIPLES OF INDIGENOUS SHEEP IMPROVEMENT IN NORTH AFRICA

A. Lahlou-Kassi 1/

1. INTRODUCTION

The North African region, which includes Morocco, Algeria, Tunisia, Libya and Egypt, raises some 42 million sheep, and is ranked among the top sheep production areas in the world (FAO, 1981).

These sheep are mainly raised for meat and leather production, and to a small extent for wool and milk. Only 6 to 10 percent of ewes are milked in Morocco (Livestock Survey-MARA, 1975). Mutton contributes 6 to 55 percent to the total meat consumption in each country (Egypt 6 percent, Morocco 18 percent, Tunisia 35 percent, Algeria 47 percent and Libya 55 percent - FAO, 1981). Some countries like Algeria, Libya and Egypt import 20 to 50 percent of their meat needs, and the other countries are just self-sufficient.

The meat shortage in the presence of a relatively important sheep flock can be explained by low productivity. It is estimated that the average meat production per ewe per year is around 5 to 8 kg, and carcass weight does not exceed 10 to 15 kg (OADA, 1984).

Improvement of productivity in sheep flocks is then a must, the general principles for improvement being well known (health, feeding and reproductive management, breeding and crossbreeding). However, improvement objectives and the methods to be used should be defined for each country and for each breed according to the environment and management system, as well as the type of production desired.

A better knowledge of the performance of different sheep breeds present in the region, and analysis of experiments on improvement conducted there, will allow us to elaborate some basic principles and recommendations for improving the productivity of sheep in North Africa.

2. CHARACTERISTICS AND PERFORMANCE OF INDIGENOUS SHEEP BREEDS

This is not intended to be an exhaustive study, the paper being limited to the following:

-	Phenotypic traits that seem to be linked to adaptation to heat and the general environment as well as walking ability.
-	Performance traits that will permit an evaluation of the ewes' productivity level.
-	Sheep breeds that are already identified as relatively homogeneous populations.

Most of the data presented in this paper were obtained on experimental stations, where the level of management is medium or relatively good, and consequently the breeds are better able to express their genetic potential.

2.1 Adaptation Traits

Among the most important traits for adaptation to the environment are coat type, colour, legs and temperament, as well as the size and location of fat "reserves". These have been well studied and should be considered in any improvement scheme.

2.1.1 Fat-tailed breeds

Almost all breeds of sheep in Egypt (Rahmani, Ossimi and Barki), Tunisia and Libya (Barbary) are fat-tailed.

-	Rahmani: Located in the north-west of the Nile delta, relatively long-legged with a long fleece of coarse, kemp wool, generally brown.
-	Ossimi: Raised mainly in Middle Egypt, the southern part of the Delta and upper Egypt; long-legged and has a coarse fleece, with kemp.
-	Barki: Raised in the western desert; long-legged with a coarse open fleece.
-	Barbary: Present in the steppes along the northern coast of Libya, and from the Sahara to the Tunisian coast; very hardy, long-legged and good walker.

2.1.2 Thin-tailed breeds

-	Rembi: Raised in the Saharan Atlas Mountains and Djebel Amour (Algeria); long-legged, fine fleece.
-	Hamra: Raised in the Western Plateau of Algeria; medium-legged, fine fleece.
-	Tadmit/Ouled Djellal: Raised in Biska, Tonggout and Ouled Dejellal regions (Algeria); long-legged, strong skeleton good walker, fine fleece.
-	Timahdite: Raised in Middle Atlas Mountains; medium-legged, coarse wool, semi-open fleece (Mrocco).
-	Sardi: Raised in the central plateau Tadla Morocco; long-legged, coarse wool, closed fleece.
-	Beni Guil: Raised in the high plateaux of the North and part of the sandy Pre-Saharian Zone of Missour: short-legged, coarse wool, semi-open fleece.
-	Beni Hsen: Raised in the lowlands along the Atlantic coast; long-legged, finest wool, closed fleece.
-	D'Man: Raised in the Oases of the South of Morocco; short-legged, mixed hair-wool.

2.2 Reproductive Performance

2.2.1 Puberty and age at first lambing

All breeds in the region except the D'Man have a late first lambing, the average age being 22 months. Ewe lambs are not able to conceive during their first year of life because of a delayed puberty, the age at first oestrus being about 14 to 16 months. The D'Man is peculiar for its precocity, the age at first oestrus being 6 to 8 months, and the first lambing generally at 11 months (Table 1).

Table 1 PUBERTY AND AGE AT 1ST LAMBING OF INDIGENOUS SHEEP BREEDS

There is a large variation between animals in the age at puberty for the Timahdite, Ossimi and Barbary breeds, as reported by several authors (278 to 386 days for the Barbary, 240-400 days for the Timahdite).

2.2.2 Conception rate and prolificacy

Conception rates for different breeds raised in stations or experimental farms are very satisfactory. They average 95% for the thin-tailed breeds and 85% for the fat-tailed breeds. These rates are higher than those recorded in flocks raised only on pastures (60 to 70 percent), which means that principal causes of failure to conceive are feeding and health management rather than genetics.

The D'Man breeds is outstanding for its high prolificacy or litter size (1.8 to 2.7 lambs/ewe lambed). The frequency of twinning in thin-tailed breeds is 10 percent in Morocco and Algeria. Fat-tailed sheep have 15 to 20 percent twinning in Tunisia and Egypt, except for the Barki breed, which bears twins in only 5 percent of births.

This relatively low prolificacy, when compared to those of prolific breeds such as the D'Man, Romanov and Finn, is compensated by the fact that 10 to 30 percent of ewes can lamb twice in the year (Table 2).

2.2.3 Breeding season and post-partum anoestrus

The oestrous activity of different North African breeds in different months of the year and after lambing is reviewed in Table 3.

This table shows clearly that all breeds except D'Man and Rahmani have a prolonged breeding season, generally from May to January (240 to 300 days). The anoestrous season lasts from February to April. However, Lahlou-Kassi (1983) and Khaldi (1984) have noted in Moroccan and Barbary breeds respectively the existence of silent ovulations in 40 to 60 percent of ewes during this period.

Table 2 REPRODUCTIVE PERFORMANCE OF INDIGENOUS SHEEP BREEDS
(ADULT EWES)

Table 3 BREEDING SEASON AND POST-PARTUM ANOESTRUS OF INDIGENOUS
SHEEP BREEDS

^1/ Post-partum anoestrus of ewes lambed during November-February. The minimum and maximum represent individual variation.

The D'Man and Rahmani breeds have sexual activity throughout the year. The time before resumption of oestrus after lambing is also very short for the D'Man, (x = 60 days) and medium in the other breeds (100 to 160 days). The combination of these characteristics (long breeding season and relatively short post-partum anoestrus) allows these breeds to conceive and lamb more than once a year.

2.3 Production

2.3.1 Birth and weaning weights

Birth weights for the indigenous breeds range from 2.0 to 4.5 kg with an average of 3.2 kg.

Weaning weight at 90 days ranges from 14 to 26 kg, indicating the large variation in milk production for ewes of different breeds.

Highest birth and weaning weights are observed in Sardi, Timahdite (Moroccan breeds), Tadmit, Rembi (Algerian), Barbary (Tunisian) and Ossimi (Egyptian). The lowest birth and weaning weights are observed in the D'Man, due to high litter size (Table 4).

Table 4 LAMB GROWTH RATE OF INDIGENOUS SHEEP BREEDS

2.3.2 Lamb mortality

The average mortality rate varies from one flock to another according to management level. Under relatively good management, it is 5 to 10 percent from Moroccan breeds, except D'Man which has a high average rate (15 to 20 percent), due mainly to the higher losses in triplet and quadruplet lambs (Lahlou-Kassi 1983).

For the Barbary, lamb mortality averages 8 to 13 percent, with 15 to 25 percent for twins (Khaldi 1984) and for Egyptian breeds, 12 to 18 percent.

2.4 Summary

Analysis of adaptation traits and performance of the different North African sheep breeds leads to the following general conclusions.

2.4.1 Interesting traits for future improvement

-	Variability of adaptation traits (coat, conformation, fat reserve) for various climates and land types existing in the region (semi-arid, arid, mountain and Sahara).
-	Long breeding season and relatively short post-partum anoestrus in these breeds allow good reproductive efficiency even in years where there is a delay in rainfall and vegetation growth and a second lambing, at least for part of the flock, when the year is good.
-	Existence of a well adapted prolific breed within the region (D'Man) which can be included in cross-breeding schemes for prolificacy improvement.
-	Large individual variability within the same flock and between flocks for either reproductive or productive traits allows good opportunity for improvement through selection.

2.4.2 Actual limiting traits

-	Late age of puberty and age at first lambing in the majority of indigenous breeds.
-	Relatively slow lamb growth rate from birth to meaning in relation to milk potential of the mother.
-	Low or medium fecundity of the majority of the breeds, for intensive sheep production systems.
-	Large between-breed variability in quantity and quality of wool.

3. TRIALS IN THE REGION FOR IMPROVING LOCAL SHEEP

3.1 Selection Trials

3.1.1 Improvement of general conformation

National programmes of selection for the improvement of local breeds have been established in Egypt, Algeria, Tunisia and Morocco, the major purpose being:

-	Initial phase: Homogenization of phenotype for each breed, based essentially on colour and body conformation.
-	Second phase: Improvement of production performance in each breed.

The first phase of the programmes has been achieved with some success in some countries, after establishment of national breeding policies based on the following (Moroccan example):

-	Production of selected rams in national selection farms, specific to each breed; these rams are sold to farmers.
-	Mapping and delimitation of the area of origin for each breed, called the "zone berceau de race".
-	Creation of the National Association for Sheep production, which includes professionals from different areas and breeders. This Association has as its role production of selected rams, and organization of livestock shows and competitions.
-	Appointment of the Commision for Sheep Selection, composed of government officials and representatives of breeders. This Commission is in charge of the registration of selected animals in the "Flock book".

Unfortunately no data are yet available on the evluation of this kind of programme.

3.1.2 Improvement of fecundity

To our knowledge, none of these programmes have included fecundity parameters such as age at first lambing or prolificacy in the selection scheme.

The selection programme for prolificacy improvement in D'Man sheep, which started in 1973 at the ORMVA, Quarzazate, Morocco, shows that average litter size in the selected flock increased from 1.66 to 2.33 in 8 years. However the reported data do not make it clear whether this improvement is due to a genetic gain or to improvement of management and feeding.

Because of the tremendous variability existing between individuals at the age of first lambing and duration of breeding season and prolificacy in each breed reviewed here, it is of value to include these criteria in selection schemes.

3.2 Crossbreeding Trials

3.2.1 Crossbreeding for improving fecundity

Different trials have been conducted for improving the fecundity of local sheep through crossbreeding with imported prolific breeds (Finn, Romanov, Chios) or the indigenous prolific breed (D'Man). We review here briefly the two main trials conducted in Egypt and Morocco.

1. Moroccan trial:

With the financial help of the Small Ruminant Programme (CRSP) and the collaboration of Prof. Eric Bradford from the University of California, Davis, a crossbreeding scheme between Sardi and D'Man breeds was conducted to evaluate the reproductive and growth performance of the two parental breeds and their crosses. Preliminary results are summarized in Table 5 and 6.

Performance of ewe lambs (Table 5): at 10-12 months of age, the conception rate of Fl (D'Man x Sardi) ewe lambs is higher than that of Sardi ewe lambs (64-78 percent vs. 0.27 percent) and similar to that of D'Man. The prolificacy of Fl ewe lambs is intermediate (1.3 vs 1.0 and 1.6).

Performance of adult ewes (Table 6): crsssbred (D'Man x Sardi) ewes are distinguished from the Sardi by:

1. a higher prolificacy (1.6-2.1 vs. 1.16-1.28);
2. advanced breeding season: conception rate for the May-June mating is 9-100 percent vs 57-64 percent.

Table 5 REPRODUCTIVE PERFORMANCE OF SARDI, D'MAN AND Fl (D x S)
EWE LAMBS (10 TO 12 MONTHS OLD)

Table 6 REPRODUCTIVE PERFORMANCE OF SARDI, D'MAN AND Fl (D x S) ADULT
EWES: I - MATED DURING SEPT-NOV. 1984
II - MATED DURING MAY-JUNE 198 5

On the other hand, the weaning rate is similar for all three genotypes (D'Man, Sardi, D'Man x Sardi).

Average productivity expressed as weight weaned per ewe lambing is 20 to 22 in D'Man and Fl compared with 10 to 20 for Sardi.

The major disadvantage was a decrease in quality and quantity of wool in Fl, compared with Sardi.

2. Egyptian trial:

An ambitious programme for crossbreeding between Ossimi and Rahmani breeds and imported prolific breeds (Finn, Romanov and Chios) is in process in Egypt. Data of the resulting crossbreds, under an accelerated lambing system of a crop every 8 months, are presented in Table 7.

Prolificacy and lambing rate were increased respectively by 50 to 70 percent and 5 to 30 percent in the first crosses and by half this figure in the 1/4 Finn. Of importance, the different crossbred ewes showed a good ability for rebreeding every 8 months, which is important in a sutropical environment.

Table 7 IMPROVING FECUNDITY OF LOCAL OSSIMI (0) AND RAHMANI (R) BY CROSSING WITH FINN (F) SHEEP UNDER THE SYSTEM OF ONE CROP/8 MONTHS

The evaluation of this crossbreeding scheme, however, should include the incidence of lamb mortality and growth rate to test the adaptability of Finn sheep to a hot humid climate.

3.2.2 Crossbreeding for improving lamb production

Most of the crossbreeding schemes for improvement of lamb production are based on crosses between local breeds and European meat breeds. In Morocco, the breeds used are: Merino, Berrichon du Cher, Ile-de-France and Suffolk. These crosses are exlcusively for the production of lamb, and are conducted under intensive management, on private farms. As data are lacking, it is impossible to evaluate the results.

In Egypt crosses between Ossimi and Suffolk and Hampshire are reported by Aboul-Naga and Afiji (1980) and Aboul-Nagaga et al. (1980). Tables 8 and 9 summarize results from Hampshire x Ossimi crosses.

Table 8 LAMB PERFORMANCE TRAITS OF OSSIMI (0) AND HAMPSHIRE (H) X
OSSIMI(O) CROSSES
(Aboul-Naga and Afifi, 1980)

The different H x 0 crossbred groups were generally inferior to the Ossimi breed for all traits, the only lamb performance trait improved by upgrading the Ossimi sheep with Hampshire being the first greasy-fleece weight. Lamb survival and weaning weight decreased as the percent of Hampshire increased.

Table 9 REPRODUCTION TRAITS OF OSSIMI (0), HAMPSHIRE (H) AND THEIR
CROSSBRED GROUPS OF EWES
(Aboul-Naga and Afifi, 1980)

4. CONCLUSIONS

This review points out some important principles that should be taken into consideration in any programme for improving sheep productivity in North Africa. These can be summarized as follows:

-	Precise knowledge of reproductive and production performance, as well as adaptation of local breeds, as needed.
-	Objectives of the improvement programme should be well defined namely, improvement of growth, reproduction of wool.
-	The environment and type of management in which the programme is to be conducted (pasture only, or with supplementation, intensive) should be defined.

REFERENCES

^{1 /} Department of Animal Reproduction and A.I., I.A.V. Hassan II, B.P. 6202 Rabat-Instituts, Morocco.