A. J.D. Ambali,1 J. W. Banda2 and L.A. Kamwanja2
1. Molecular Biology and Ecology Research Unit Department of Biology, University of Malawi, Chancellor College, Box 280, Zomba, Malawi
Genetic improvement of the local Malawi goat
Reflection on the MGLDP's goat improvement programme
Status of the indigenous goat gene pool in Salima district
A goat breed improvement programme was initiated at Lifidzi Goat Breeding Centre in Salima District in the mid 1980s with the objective of improving meat production and animal population at the household level through crossbreeding. An exotic Boer breed was introduced from South Africa and crossbred with the local Malawi goat. Three main breeding strategies emerged in the area covered, namely stud breeder programme, buck centre programme and uncontrolled breeder mating system. While the first two programmes were controlled at the beginning, the last method was not controlled once the buck had been purchased from a stud breeder. This study was carried out to determine the genetic impacts of the programme with the aim of making recommendations for sustainable programmes that would increase production without compromising conservation of indigenous genetic resources. Between 1985 and 1998, goat populations have increased in Salima District from less than 82,210 to 149,930 due to deliberate selection for prolific indigenous females into the breeding programme. Growth rates of the hybrid goats improved and the offspring easily attained weaning weights of at least 20 kg in 12 months. The number of hybrids in the communal grazing areas visited, proliferated with more than 40% of the animals being Boer and local crosses. The improvement programme was however implemented without proper mechanisms for conserving the indigenous gene pools. In a setup where animals are subjected to communal grazing and uncontrolled mating, it has been impossible to maintain pure breeds of indigenous goats. Farmers have recently started to resent the hybrids due to low disease resistance and yet chances of re-establishing pure populations of local breeds seem to be low. The farmers and the animals have been abandoned the introduced Boers have succumbed to diseases due to lack of veterinary services. The Malawi case therefore serves as a typical example of the genetic improvement programmes in developing countries where increased production through importation of exotic breeds is being carried out without proper planning for sustainable conservation of indigenous gene pools.
Ruminant livestock contribute substantially to the animal protein supply of Malawi where a total ruminant population of 2,319,000 was estimated in 1998 (MoAI 1998). This comprised 618,800 cattle, 1,597,500 goats and 102,700 sheep. Of the cattle population, 95.2% is owned by small-scale rural farmers and the rest is shared by large-scale commercial operators in estates and peri-urban areas (MoAI 1998). About 97% of the herd comprise the Malawi Zebu, which is a naturalised indigenous breed in the country comprising several phenotypes with varied origin (Butterworth and McNitt 1994; Jere and Msiska 2000). A similar trend is also observed in the other two ruminant species where 98% and 95% of goats and sheep, respectively, are owned by small-scale rural farmers. The sheep and goats constitute the small ruminant livestock of the country, of which more than 90% are indigenous breeds raised by small-scale farmers at an average of six animals per household distributed in the low-lying areas (Jere and Msiska 2000).
It is observed in Figure 1 that during the period 1987 and 1996 the sheep population declined and did not reach the 1983–85 population levels. The decline in sheep population was due to high demand for mutton/lamb in the urban areas and parasite infestation (Chikagwa-Malunga, unpublished). The goat population however picked up from the 1987-drop and maintained annual population levels of more than 82,000 animals. In the early 1990s the flock growth rate was estimated at 1.8% annually, contributing about 3,700–4,400 tonnes of meat per annum which represented about 11% of the total livestock meat consumed in the country (Banda et al. 1993). Banda (1992) observed that the rural households in Malawi readily accept goat and sheep milk, only that it is not available due to low production. This paper appraises the genetic improvement efforts that have been carried out on goats in the country, with the most emphasis on the Malawi German Livestock Development Project.
Source: MoAI (1998).
Figure 1. Goat and sheep population in Malawi, 1983–96.
Goats are usually tethered and herded during different times of the year. Tethering is practised during the rainy season when most arable land is subjected to intensive cultivation and little area is available for grazing. Tethering limits the amount of feed available to the animals and as a result they lose weight and kid birth weight also reduces. However, this does not significantly affect reproductive performance (Banda et al. 1993). Herding is practised during the dry season when crops have been harvested. The alternative system involves tethering during the morning hours and herding in the afternoon. Those who feed their animals in communal grazing areas tend to expose their goats to an extensive system where goats browse, graze and scavenge.
Mortality tends to be high in kids primarily due to poor management, which include overcrowding, poor nutrition, parasites and diseases. Effects of these have been discussed in Banda et al. (1993).
The local goats in Malawi are naturalised indigenous stock that originated from Asia and spread southwards from Egypt and Ethiopia to East Africa and then Malawi (Epstein 1971). There are speculations that they could also be some stock that came in from the south by the Zulu people (Banda et al. 1993). These collections have adapted to harsh climates and low management regimes over the years. Although the local goats are adapted, they generally have been described as low producers compared to exotic breeds, hence efforts have been carried out to improve their performance using genetics and improved management approaches.
The Government of Malawi has carried out a two-phase genetic improvement strategy for goats in the country. The first was through introduction of an exotic breed, Boer goat, at Mikolongwe Veterinary Station and Bunda College of Agriculture for crossbreeding and upgrading of the indigenous goat to improve the final slaughter weights.
The F1 hybrids grew faster than the local goat progenies (Figure 2). Average weight gains of 40g/day and 23g/day were observed in the crossbred progenies and pure local progenies, respectively. Under village conditions in Lilongwe district, Banda et al. (1993) reported results where pre-weaning body weights were higher in the local progeny than in the crossbred (L × B) with daily weight gains of 110.0 and 90.5 g/day, respectively. Mortality was also lower in the local progenies than in the crossbred with 16.7 and 37.5% mortality, respectively. Banda (1992) argues further that overall, the biological productivity rate is higher in the local progeny than in the crosses, which probably suggests that the local gene pool was more efficient than the exotic breeds and their crosses under village conditions.
Source: Modified from Zerfas (1992).
Figure 2. Growth comparison between pure local (L) and crossed local × Boer (1/2L × 1/2B) kids.
The second genetic improvement programme was carried out from 1983 to 1993 by the Malawi Germany Livestock Development Programme (MGLDP) with the objectives of producing genetically improved local bucks and does for smallholder farmers; producing pure-bred Boer bucks for small holder crossbreeding activities; carrying out breed evaluation trials; and packaging goat management innovations for farmers (Schmidt 1992).
The programme was phased out in 1993 and currently there are three sets of breeding strategies in the project areas: namely the Stud Breeder Programme, the Buck Centre Programme, and the Uncontrolled Breeder Mating System. The first two programmes were controlled during the project period. The last strategy was not controlled once the buck had been purchased from a stud breeder. In the stud breeder breeding strategy, 30 farmers were provided with 10 hybrid animals (7/8B × 1/8L) comprising nine females and one male for rapid multiplication at the farmstead. The progenies from the stud breeders were sold to other farmers who wanted to cross their local goats with the hybrids. The male goats provided in the stud breeder package were supposed to be exchanged among the stud breeders after every year, hence there were 30 bucks to be exchanged among the stud breeders.
The buck centre strategy involved farmers with local goats bringing their female goats to buck centres for mating with a Boer buck. Bucks in excess of 100 were placed in the villages in Salima District while the local males were castrated. This resulted in the proliferation of hybrids in the villages.
The uncontrolled breeder mating system was the long existing system practised by the farmers themselves whereby mating was not controlled in the communal grazing areas or in the kholas. The males in this case would be local and/or hybrids in areas where the crosses were available. Male crosses bought from stud breeders mated with the local females in communal grazing areas.
Results from the improvement programme generally suggest that the hybrids performed better than local goats as summarised below.
The local goat and hybrid progeny performance over 360 days is plotted in Figure 3. The local goat progeny had the lowest weight up to 300 days. Backcrossing the progenies to Boer yielded an improvement in growth to the effect that they easily attained 20 kg in 360 days. Similar observations were made by Schmidt (1992) who reported the highest growth rates in crossed progenies than in the local goat progenies at the age of 12 months. A high weight variation was however reported in the crossed progenies with changes in environmental conditions (Figure 4), implying that the local goats were relatively more stable to adverse environmental regimes than the hybrids.
Source: Zerfas
(1992).
Figure 3. Weight of local and hybrid goat progenies at different ages.
Parturition intervals are plotted in Figure 5. Kidding interval was lowest among the hybrid progenies than in the local goats. The decline in kidding interval with parity was however higher in the local goats than in the hybrids.
Source: Schmidt ( 1992).
Figure 5. Parturition interval among the various goat progenies.
The programme might have achieved its objectives whereby it demonstrated that genetic improvement through cross breeding improved the performance in goats for the traits of interest. There are however several factors in the programme which were not addressed and hence could affect the validity of the findings.
The local goat that was compared to the hybrids and the Boer in this programme is not genetically known. There are several phenotypes of goats in Salima district let alone the Malawi nation as a whole. The MGLDP did not genetically characterise the local goats though the Boer that was imported into the country was a well characterised breed. The data by Ayoade and Kamwanja (1985) in Figure 6 suggests that the local goat performed better than the hybrid in Lilongwe. It can therefore be argued that there may be several types of local goats in Malawi hence, if the various types had been identified and compared to the crosses the results could probably be different from what was obtained by the Project. A hypothesis can be made that not all local Malawi goat types were inferior in performance to the hybrids. This is yet to be addressed.
Source: Ayoade and Kamwanja ( 1985).
Figure 6. Pre-weaning body weight of local and hybrid progenies at household level
in Lilongwe district.
If indeed there were no genetic differences between the local goats in Salima and those in Lilongwe, there might have been significant genotype × environmental interaction. The Project did not explore the genotype × environment interaction hence the hypothesis that the superiority of hybrid goats over local goat progenies throughout the country was not tested. Salima district was the only locality that did not represent the broad environmental conditions under which goats are raised in Malawi.
The local goats used in the breeding programme were not subjected to any prior selection before they were crossed with the Boer goats or when they were being compared to the hybrids. The data on parturition interval suggests that there was high variation among the local goats, which could be exploited through deliberate selection. The Boer was a highly selected breed while the local goats were not selected.
The environmental conditions under which the goats were raised within Salima were not uniform. Zerfas (1992) indicates that there was a tendency among the farmers who raised hybrid goats to invest relatively more in goat enterprise than those who raised local goats. In fact the criteria for choosing farmers who raised hybrids were such that the poor farmers were left out. Indeed even among the farmers, there were likely to have been environmental differences between them.
There was conflict of interest between farmers' goals and those of the Project. Small-scale farmers are primarily interested in numbers of goats and such traits as hardness and twinning ability; growth rate is a secondary trait. The Project was interested in improving growth rate. Farmers' interests could have been met by first selecting for the traits among the local goats and then growth rate would be improved by either selecting among the local goats or crossbreeding with the Boer. Unfortunately this oversight has had a negative impact on the farmer acceptability of the hybrids especially now that veterinary services have been phased out. In 1995, when farmers were offered to buy the bucks that were used for buck centre breeding, they declined because the bucks were not hardy enough to survive in the local conditions; they easily succumbed to diseases and parasites.
The statistical analyses carried out were also questionable especially regarding the sample sizes. Banda et al. (1993) cautions on the conclusions that could be drawn out of the Ayoade and Kamwanja (1985) study where the local goat outperformed the local × Boer progeny due to the small sample sizes. The data obtained by the MGLDP has similar problems where there were large sample sizes for local goats but the sample sizes for the hybrids were low. Indeed Schmidt (1992) expressed similar concern. The statistical implications of small samples for experiments of this nature could be enormous.
Although the hybrids might have performed better than local goats, their poor survival under low management regimes renders them unsuitable for the small-scale farmers in Salima and probably Malawi as a whole. The uncontrolled mating in the communal grazing areas has unfortunately led to high introgression of the Boer gene pool into the salima goat population. Hybrids of other exotic breeds like Sanean and Damascus were also observed during the study. Among the areas visited, there was a proliferation of Sanean × local hybrids in the Ngozi area where a German researcher introduced the breed and abandoned it after trials.
Dispersive genetic effects observed in 13 mixed breeds of north European cattle over 40 years suggest that Nordic breeds have lost between 1–11% of their genetic variation. Although the native breeds have retained a reasonably high genetic diversity, their genes contribute less to the genetic variation of the popular production breeds than was previously the case (Kantanen et al. 1999). It is not known at present how much of the genetic diversity in the Salima is contributed by the indigenous breed types. It could probably be low.
Poor record keeping, uncontrolled mating and lack of genetic conservation protocols might have led to decreased genetic purity of the Malawi local goat. In addition these unwitting cross breeding programmes may result in outbreeding depression where the local co-adaptive gene complex breaks down after the F1 generation. For instance in intertidal copepods (Tigriopus californicus ), Edmund (1999) observed that first generation hybrids showed some heterosis which was not related to the geographic or genetic distance separating the parents. However, mean fitness decreased and its variance increased in subsequent generations when the F1 hybrids mated among themselves. This hybrid breakdown problem in the later generations increased with the distance between the original parents. Genetic interpretation of these patterns suggests that both the beneficial effects of dominance and the detrimental effects of breaking up coadaptation are magnified by increasing evolutionary distance between populations. It is not known at present how genetically distant the parents (i.e. Boer, Sanean, Damascus etc.) are that were used to cross breed with the Malawi goat. This has gone unchecked for several years.
The Malawi case therefore serves as a typical example of the genetic improvement programmes in developing countries where increased production through importation of exotic breeds is being carried out without proper planning for sustainable conservation of indigenous gene pools. The continuous loss of the indigenous gene pool in Salima district can be arrested by discouraging farmers from continuous exchange of the hybrid goats. Non-governmental organisations like World Vision International have been involved in the transfer of hybrid goats to other districts like Dowa, Mchinji and Karonga. They should also be discouraged from such practices. There is a need for genetic characterisation of the Malawi local goat so that the various types that are available, if any, can be documented, improved and conserved as such.
Genetic improvement should start with exploiting additive genetic variation through selection. The traits of importance should be those in which farmers are interested.
The local goat gene pool that was collected by the MGLDP was lost due to lack of maintenance of in situ conservation facilities after the project was phased out. It is recommended that the government and quasi-government institutions should complement farmers' efforts of conserving indigenous gene pools by establishing in situ conservation facilities for goat genetic resources and providing continued financial support for such facilities.
We are sincerely grateful to the Lake Malawi Ecology Project for providing resources for carrying out this study. Additional funding was provided by the research grants of Dr J.W. Banda and Prof L.A. Kamwanja. We thank the Salima ADD staff, especially Messrs. Nyoni, Njoka and Nkochi for providing some of the information included in the report and all the farmers we interviewed during the study.
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