Small Ruminant Breeding (Goat and and Sheep)

Small Ruminant Breeding (Goat and and Sheep) Introduction

The Zimbabwean goat population is estimated to be over 2,5 million (CSO, 1994) and sheep number about 400 000 (CSO, 1994). The majority of small ruminants (sheep and goats) are found in the small holder sector. At present, in Zimbabwe, there are nearly 250 commercial sheep and goat producers. The majority of these producers regard sheep and goat as a subsidiary enterprise, with little labor input and as an adjunct to a cropping system. This retards their genetic improvement.

Small ruminants are valued primarily for the production of meat, milk, skins, and fiber (hair, mohair and pashmina). Small ruminants contribute to the health and nutrition of millions of people in developing countries, particularly those on the poverty datum line. In addition to their main functions, tropical small ruminants are also important in a number of miscellaneous ways. These include investment, insurance against the failure of crops ownership, slaughter during religious and customary rites, and festive occasions, recreation, supply of manure, transport and the supply of horns, hooves, blood and bone meal, all of which have commercial value. Those of us who grew in the rural areas of Zimbabwe are well too familiar with almost all these practices. In Zimbabwe, sheep and goats are mainly kept for meat and milk especially in the rural areas.

In recent years, in Zimbabwe, there has been a dramatic increase in interest and research concerning small ruminants in all sectors. This is a result of the record of their potential in improving the nutritional and social status of smallholder farmers. Most of the research has been in nutrition and reproductive physiology with very little work on their genetic improvement through animal breeding strategies. Crossbreeding in order to exploit heterotic effects, has been practiced in both sheep and goats, with some success stories. In order to maximize genetic progress, breed characterizations are important, and within breed selections need to be done to complement crossbreeding programmes in both species. Objectives

1. Describe briefly breeds and traits of economic importance in small ruminants (sheep and goats)

2. Outline current genetic evaluation or improvement schemes in sheep and goats

3. Explain the major drawbacks to small ruminant genetic improvement and,

4. Suggest future genetic improvement programmes in sheep and goats Goats Breeds in Zimbabwe Local breeds of goats have developed more through genetic isolation and natural selection than through deliberate intervention by man. Many of these breeds have never been accurately described, or they have been described only superficially, with no data on any aspect of importance to production (such as prolificacy, milk yield, growth rate and seasonality of breeding). There is a risk of losing local through uncontrolled breeding and indiscriminate crossbreeding (sometimes with the intended aim of improvement). The crossbreeding is taking place before the special, and perhaps valuable, characteristics of local breeds have been identified (Devendra and Burns, 1983). It is estimated that there are approximately 300 breeds and types of goats, the majority of which are found in the tropics and subtropics. Of these, Epstein (1971) distinguishes at least 70 breeds and varieties in Africa.

In Zimbabwe, there are basically two main indigenous goat breeds. These are the Small East African (SEA) and the Matabele goat. The most popular exotic breed found in Zimbabwe is the Boer goat of South Africa.

The Small East African goat

This is a small, but not dwarfed goat. It is found over a wide range in East Africa (Kenya, Uganda and Tanzania), where its main products are meat and skins. They are also found in Malawi, Zimbabwe and Botswana. The Small East African goat is commonly short-haired, with relatively small light horns and ears which vary in type from short and prick to short and horizontal. The colour patterns are variable, but black, black and tan, red and white, and grey predominate. Beards are common in males, but not in females. Long hair may occasionally occur on the hindquarters of some animals. Size is variable, but adult female live weight is usually around 30kg. Height at withers is about 57cm. These animals breed at any time of the year: twinning rate is about 10% of total births (Devendra and Burns 1983).

The Matabele Goat

The Zimbabwean Matebe goat is found in the South and Western part of Zimbabwe, mainly in Matabeleland. The breed resembles the Botswana goat breed in Botswana. They are large indigenous goat, as opposed to the smaller type of goat found in the Eastern and Central parts of the country. The indigenous Matabele type goat in Zimbabwe are white, brown, black spotted or pied in colour and have ears that are normally long and lopped with turned up ends, but they may be horizontal (Mason and Maule 1960). The Horns of the Matabele goat, when present are short and erect. The average height at the withers is about 70cm in adult males and 64.6cm in adult females ( Mason and Maule, 1960). Compared to other indigenous goat types in Zimbabwe the Matabele goat is the largest. Adult males weigh between 40 and 65 kg and females weigh between 30 and 45 kg (Mason and Maule, 1960). Exotic Breeds of Goats

In this section, we four types of exotic breeds of goats which are as follows.

The Boer Goat The Boer goat was derived principally from Hottentor Stock which inhabited the semi-arid country north of the Cape Peninsula. According to Hofmeyer (1965), the name Boer goat imported during the nineteenth century. There are now about three types of the original Boer goat population that are recognizable.

The first, a common Boer goat, is distinguished by virtue of its medium size and short glossy coat. The basic colour is white, usually with brown spots on the reddish brown head and neck.

The second Boer goat is long- haired, larger and heavier as a result it experiences later maturing than the first type. Due to its long hairy coat, skins of this type are inferior, to the polled, multicolored Boer goat with unmistakable dairy conformation, suggesting some inheritance from foreign breeds.

Since about the early 1920s, much effort has gone into improvement through selective breeding for meat production, resulting in the third Boer goat. There is a preferred color pattern of brown head and neck, with white body and legs, and pigmented skin on exposed parts as a protection against sunburn. The horns are prominent and the ears broad and drooping. They have lop ears and markedly convex noses. The hair covering is short to medium, and the body good meat conformation possessing a superior spring of rib, body length muscling. Mature improved Boer goat females weigh 60-75 kg in good conditions, and full grown castrates can attain a weight of 100kg without splintery feeding , Boer goats have a high reproductive rate (7% triples, 50% twins) yield a good milk supply( 1.3-1.8kg per day) and also produced a useful skin ( devendra and Burns 1983)

Angora goat

Very few Angora goats are found in Zimbabwe and these are mainly in the commercial sector. The Angora goat is unique in producing true fleece (mohair). They thrive best in hot, dry subtropical climates, and are intolerant of high rainfall.

Angoras are rather small goats (withers height about 54cm), lop eared, and with short, homonymous twisted horns in both sexes. They are almost always white, with a fleece of long white lustrous ringlets. They are annual breeders, usually producing singles, but occasionally twins. Milk yield is low; averaging 20-25 kg per lactation and average carcass weight is about 13kg. Average fleece weight has been doubled to about 3kg by selective breeding. There is a problem with strains of the breed of a genetic tendency to abortion (Devendra and Burns 1983)

Saanen

The Saanen dairy goat breed originated in West Switzerland. They are white, pale cream or pale biscuit in colour, with black spots on the nose, ears and udder. They have a short coat and are generally polled, and the ears are erect and point forward. They have the highest average milk yield of any breed of goat, and for this reason, have been introduced into many countries of the world. They require high levels of husbandry and nutrition to reach their high genetic potential for milk production.

Toggenburg The Toggenburg milk goat breed originated in North east Switzerland. They are large goats, and are fawn or chocolate in colour, with white or cream stripes and marings. They have a long thin neck and erect, forward – pointing, dark ears with white edges. Both sexes are polled and tastels are common. They have been introduced into the tropics. They can give up to three liters of milk per day but have been less satisfactory than Saanens as a dairy goat breed (Devendra and Burns, 1983) Breeds of Sheep in Zimbabwe

Breeds of sheep in Zimbabwe are classified under indigenous sheep, exotic sheep, dual-purpose exotic breeds, and specialized breeds for cross breeding.

Indigenous Sheep

The Sabi / Save sheep is the most common indigenous sheep in Zimbabwe. Sabi sheep are found throughout Zimbabwe, particularly in the communal areas. It is fat-tailed with a hairy coat. Save sheep range in colour from black through all shades of brown to pure white. Their ears can be very small- almost non- existent in some cases in certain families, and quite big in others. They have a wide, swinging fat – tail which would seem to function as a food reserve for periods of nutritional stress. Save sheep are small in size and are relatively slow growing. However, Save sheep are hardly and fecund under adverse conditions and, in addition, they are resistant to most of the local diseases. Exotic Sheep Breeds in Zimbabwe

There are three exotic sheep breeds Zimbabwe

The Blackhead Persian

The characteristics color marking of the breed are black head, neck and under tail with milk – white body – cover of short hair. Its thick skin is resistant to the penetration of grass seeds. The Blackhead Persian sheep has the ability to match at any time of the year. Like the indigenous sheep. It is hardy and disease resistant, and tolerant to dryness, heat and low levels of management.

Mature ewes weigh up to 55kg and lambs reach a suitable slaughter finish at about 35 kg.

The Dorper

This is major mutton breed in Zimbabwe. It was developed in South Africa before the Second World War as a cross between the Dorset Horn and the Blackhead Persian. The aim was to achieve, by selection among the crossbred progeny a sheep breed that retained the hardiness, wide mating season and good mothering ability of the Blackhead Persian, with the improved frame, growth potential and mutton conformation associated with the Dorset Horn. The Dorper today is noted for its hardness, fertility, high milk production and ability to produce a good fat lamb of around 38kg live mass at five months of age under semi-extensive conditions. Well grown ewes weigh between 50 and 70kg. Both black – head and white – head Dorpers are available - the latter derived by grading up on Van Rooy ewes instead of Black head Persians.

The Wiltper

It is only exotic breed developed entirely in Zimbabwe from a cross of Witshire Horn rams with Blackhead Persian ewes. The Wiltiper has improved mutton conformation and milk production compared with the Blackhead Persian and has no localized fat- tail region. Mature ewes weigh between 55 to 70 kg live mass, and lambs reach slaughter finish at around 38kg. Young Wiltipers have a short – wool winter coat that is shed in spring. It does not develop in the mature animal. This makes the bred better suited to grass seed areas than other exotic breeds. Wiltiper sheep have three main colours, namely black, white and a brownish dun. The Dual – purpose Exotic Breeds

Under dual – purpose exotic breeds, Zimbabwe have the South African Mutton Merino and Corriedale.

The South African Mutton Merino

These provide both wool and mutton. The South African Mutton Merino are big sheep and have a good mutton conformation. Ewes weigh between 60 and 90 kg and rams between 100 and 112kg. The ewes are highly fertile over 100% lambing is common and are noted for good milk production and wide breeding season. The face and lower legs of the Mutton Merino are bare of wool. This makes them slightly more tolerant of longer grass conditions.

Wool yields are low 4 to 6 kgs, but lack the quality and handle that makes pure Merino wool so outstanding.

Corriedale

The corriedale breed was developed in New Zealand and Australia. Leicester, (long wool) rams were, crossed with Merino ewes, and from then on, the Corriedale was developed by line breeding, coupled with vigorous selection among the progeny. The Corriedale is a fairly fertile animal and ewes have plenty of milk, sufficient to support even twins successfully. Mature Corriedale ewes average 68kg while rams are normally around 90 kg, but some rams may weigh as much as 135kg. In addition to quick growth and a good mutton conformation, the Corriedale also produces a long staple, 100 mm and lustrous wool with a well- defined crimp. Ewes produce 4-6 kgs wool per year on average. Specialized Breeds for Crossbreeding

Planned crossbreeding is an important part of sheep production, particularly for mutton production. The Suffolk

One of the crossbreed the Suffolk breed has an outstanding mutton conformation. Lambs are fast growing and ewes are fairly fertile. Mature rams can weigh up to 135kg and mature up to 90kg. The Suffolk bears a moderate length (50mm) of a strong white wool.

The Dorset Horn

The Dorset Horn is one of the parent breeds of the Dorper breed. It has achieved wide popularity in Southern Africa. The Dorset Horn is a long well set-up sheep, noted for its fertility.

It is highly susceptible to pneumonia and lungworm. Another problem associated with crossing on to indigenous ewes has been a lambing difficulty arising from the large head and shoulders of the crossbred lamb.

The Wiltshire Horn.

The Wilshire Horn is one of the parent breeds of the Wiltiper breed. The lambs are noted for their high survival rate to weaning as well as for their sturdiness and good fleshing qualities.

The Van Rooy

This is a fat –tailed sheep developed in South Africa by Senator J.C Van Rooy who lived in the Bethulie district. It originated from crossed of white Blinkhaar (Shiny – haired) Afrikaner ram with Ramboullet ewes (French strain of the Merino). The F1 rams were then mated to Black – head Persian ewes. The selected progeny of these breeds were later mated to an English Wensleydale ram, a hornless long wool breed which has a good conformation and lustrous curly very strong wool. From this basic stock, the Van Rooy breed derived by selective breeding, selection was aimed at producing a strong hardly sheep of high fertility and good conformation.

The Van Roy is covered with strong chalky – white bristly hair. It has a good frame with sound bone and is slightly bigger than the Persian. It has good frame with sound bone and is slightly bigger than the Persian. It has big broad ears and medium- size semi circular dewlap. The Van Rooy is adaptable to a wide range of conditions and is well able to survive periods of adverse nutrient. It is fertile (3 lambs in two years is possible), the ewes are good mothers and generally make a satisfactory basis foe crossbreeding and upgrading details photographs of various sheep breeds Zimbabwe , refer to the Sheep Handbook 1973. Traits of Economic Importance in Small Ruminants

From commercial lamb/mutton or goat meat production, the first requirements is to have sound fertile ewes and does which have good milk production characteristics and a desirable mutton or goat meat conformation. Preweaning performance of lambs and kids is also one of the most important factor determining economic returns from sheep and goats in commercial flocks in Zimbabwe. Weaning weight should therefore be considered in selection systems and in designing effective breeding plans for small ruminants in Zimbabwe. For sheep production, wool yield and quality is another important economic trait. To summarize, the most important single aspect of profitability is the fecundity of the flock that is the ability to increase and obtain the maximum number of viable lambs and kids. Following fecundity, the next most important aspect of flock profitability is the growth rate of lambs and kids. This is strongly influenced by nutritional, as well as genetic factors. Management must be concentrated on achieving the most favorable circumstances for rapid growth by both the selection methods (which are discussed under improvement programmes), and by ensuring optimal nutritional conditions. Variation

Variation in performance is the key to making genetic change. If all animals were identical in their performance that is in the expression of a trait, then there would be no way of choosing some in preference to others. Genetic variation can be inferred from:

 Differences among breeds

 Differences among crosses of breeds

 Differences crosses and pure breeds

 Part of the differences among individuals in a group.

Variation among individual animals is caused by genetic and environmental differences. If one considers all the different breeds of sheep and goats and various strains within breeds one can conclude that there is a wide variation in performance traits for our small ruminants. All traits provide a high selection potential. There is much greater potential for increasing both biological and economic efficiency of lamb and kid production through genetic improvement. Such potential depends on the magnitude of genetic parameters for the traits of economic importance. Selection for traits of economic importance has not been exploited fully in small ruminants. This is well illustrated with Matabele goat. In Matableeland South and North provinces there are differences in the Matabele goat in terms of horns and ears. This is so conspicuous that one can categorize them into local area strains. There are Matabele goat strains of Gwanda (Tuli), Kezi, Plumtree Ntabazinduna, Beitbridge and Mbembesi districts. Similarly this can also be said of the Mashona East African type of goat and the Save sheep of Zimbabwe. Genetic Parameters

To design effective breeding plans for improving weaning weight, it is necessary to obtain estimates of genetic and phenotypic parameters in the specific population. Genetic parameters help to evaluate genetic progress in a population.

Estimates of heritability reported for weaning weight in Dorper Sheep in Zimbabwe was 0.19

The repeatability estimates for weaning weight in the same study ranged from 0.27 to 0.32 (Buvanendran et, al, 1991). Repeatability is useful in selection of breeding females on the basis of their past records. The genetic correlation between weaning weigh and type score was 0.48 ± 0.28 Heritability of type score was very low , ranging from 0.03 to 0.12 (Buvanendram etal 1991). One other important finding of this study was that the heritability estimate for weaning weigh for twin lambs was higher than for singles (0.20 versus 0.11). The heritability and repeatability estimates obtained for weaning weight are within the range of estimates reported in the literature, which extend from 0.1 to 0.6 (Shrestha and Heaney, 1985; Shrestha etal 1985). Buvanendran etal, (1991) concluded that selection for weaning weight could be reasonably effective in Dorper sheep in Zimbabwe. Due to the high genetic correlation with weaning weight, there may not be any need to include type score in a selection programme

Repeatability for fertility in fine wool sheep was found to be 0.09 (Shelton and Menzies, 1970). The estimates of genetic parameters depend on the population in question. Therefore, it is necessary to obtain estimates of heritability’s and repeatability’s for the population in which they are to be used for selection. We need the estimates of genetic parameters for almost all our small ruminant breeds (sheep and goats) in Zimbabwe. The ones that are available for a few breeds are inadequate.

Differences in heritability estimates for any one trait can arise because genetic variability may differ from one breed or population to another, or because the heritability estimates are derived from animals kept in different environmental conditions

For instance, if the management and nutrition of a group of animals is particularly uniform, the heritability estimates from them are likely to be higher than estimates from an otherwise similar group kept in less uniform conditions. The method by which the heritability is calculated can also affect the estimate. Genetic Evaluation / Improvement Programmes

Genetic evaluation programmes which involve crossbreeding are classified under upgrading, pure breeding and crossbreeding.

Crossbreeding Programme in Small Ruminants

(a) Upgrading

Grading up or upgrading, involves the improvement of the flocks over successive generations by the continued use of good rams and bucks from selected breed. Where a reliable supply of good rams or bucks of a breed that is adaptable to local conditions is available, grading up, if coupled with sound within flock ewe/ doe selection, is a good breeding system to adopt.

Pure breeding

Pure breeding may involve inbreeding. The main objective is to achieve a more rapid progress towards genetic purity.

Crossbreeding Crossbreeding is the accepted conventional method of commercial lamb and goat meat production. Terminal crossbreeding and rotational crossbreeding are the most common programmes used in small – ruminants. The aim is mainly to exploit hybrid vigor which is expressed in uniformity of the progeny and an enhanced growth as well as the improved cases obtained from better / bucks crossed the foundation stock.

The Boer goat has been used as a basis of many crossbreeding programmes for meat production. The Sabi ewe offers commercial opportunities for fat lamb production when crossed with exotic fat- lamb sires (eg. Mutton Merino and Suffolk) under conditions where lamb production is hampered by sharp, barbed – awned grass of Heteropogon contortus or spear grass. The Sabi can, therefore, play a significant role in semi- intensive management systems as dam-line for crossing with less hardly, but more productive, terminal sires. A recording programme is vital to flock operators. Adequate characterization of the indigenous goat and sheep breeds of Zimbabwe is important in order to determine the potential for its improvement through selection for economically important traits. Basic genetic parameters which are inadequate in small ruminants, can be used for long- term genetic improvement in sheep and goat production. Recording Schemes

Recording discussed in cattle, is also necessary in small ruminants

Sheep and Goat Performance Testing

In addition to a lamb / kid’s genetic factors affect its growth from birth to weaning. These may include the lamb/ kid birth mass, sex, season of birth, the age of the dam , parity of the dam, whether it was a triplet, twin or a single , and flock management. All these non-genetic factors need to be recorded so that standard adjustments for these various factors can be calculated under Zimbabwean conditions. Such adjustments are essential if a valid assessment of a lamb / kids performance is to be obtained. No performance recording scheme has been developed for small ruminants (sheep and goats) in Zimbabwe.

The Zimbabwe Herd Book (ZHB) records ancestry of all recognized live stock breed societies. Almost all major small ruminant (sheep and goat) breeds have registered breed societies. Breed societies were founded for the purpose of establishing breed purity by recording ancestry and defining the standards towards which selection should be made.

Individual Farmer Recordings

Identification of sheep and goats is done by individual farmers. They also record ancestry.

There is a need for a national performance recording scheme in small ruminants. This should involve data collection by participating farmers or a responsible agent and submission to a data processing centre. The data should be analyzed at the centre to obtain estimates of breeding values of tested animals. These estimates are returned to the farmer and form the basis of section within, and between herds. Factors Limiting Genetic Progress in Small Ruminants

Genetic improvement schemes require a field base to be successful. Collection, analysis and utilization of data on technical, production, economic, biological and genetic parameters are the basis for improving small ruminant production in Zimbabwe. A recording, system is vital to flock operators.

The other factors which limit genetic progress in small ruminants (sheep and goats) include:

 Single – sire flocks

 Communal grazing

 Small flock sizes

 Ownership patterns

 Lack of basic genetic parameters

 Lack of records

 Inbreeding Future Prospects for Genetic Improvement in Small Ruminants

Group breeding schemes, with open, on station –nucleus breeding units should work well in sheep and goats. Allied to a nucleus unit must be the affective dissemination of the improved stock selected in the unit. Therefore AI has an important role in ensuring extensive dissemination of superior bucks and rams.

On station breeding units may also provide the nucleus for initial gene introduction and for rapid distribution of superior genotypes through MOET Schemes. Coupled with this, one can use DNA finger – printing and other biotechnology techniques to indentify goat and sheep strains particularly in the small holder sector. Through biotechnology one can also identify major genes that influence sheep and goat production. There is therefore a need for a national record keeping system.

Estimation of genetic parameters, particularly heritabilities and repeatabilities of production traits in sheep and goats, is essential. These two genetic parameters enable breeders to formulate effective breeding programmes and to evaluate genetic progress in a population.

Maybe there is a need for multi – disciplinary approach to sheep and goat development. The major thrust of this research team should be in solving some of the production problems. There is so much variation within and between breeds, regions and farming and management systems, such that this great variation can be exploited through selection crossbreeding programmes in small ruminants.

Suitable breeding strategies for smallholder system are intensive selection within local stocks, including initial screening for desired performance traits. In addition, development of new stocks based on crosses between improved breeds and well adapted local genotypes is another possible strategy.

Activity

1. Discuss the problems limiting genetic progress in small ruminants in Zimbabwe and suggest solutions to these problems.

2. Discuss the importance of variation and its utilization in the field of small ruminant breeding and genetics

3. How can you use Nucleus Breeding Scheme to genetically improve goat population in Zimbabwe