Major findings
Some possible interventions
The vast majority of people in SSA practice subsistence agriculture. In the region, these are the people who suffer the most from mass poverty and the well known "African food crisis". These are also the people who raise the bulk of SSA's small ruminants which they use for animal food security, income generation, acquisition of various agricultural inputs and large animals, family relation and social link strengthening. Unfortunately, because of the long-standing neglect of these animals by development programmes, the many flaws in the traditional production techniques and the lack of relevant human development schemes, output from the small ruminant subsector is low and the contribution of the sub-sector to the welfare of the poor rural producers is still below all expectations. The following is a summary of the major findings of the review of the reproductive losses in small ruminants in sub-Saharan Africa (SSA). Areas of needed interventions and possible solutions will be pointed out, without an in-depth analysis, with the hope that detailed follow-up research programmes and policies will be formulated, which can generate a positive and sustained impact at the rural family sector level.
Small ruminant growth and "production efficiency"
· Except in Latin America, small ruminant population growth in SSA was the world's poorest over 1977-1992 and 1982-1992. It was also an unsteady growth with an annual average rate of 0.4 per cent which, over 1987-1992, was 0.5, 2.2, 1.5 and 0.5 per cent below that of Africa, Asia, all developing countries and the world, respectively. Such poor performance must have worsened the food crisis situation in SSA.· Average meat production per head in SSA was the poorest in the world in 1975 and 1989. Then 1992 saw a production per livestock unit of 21, 31.5, 39.6, 31.3 and 39.5 kg below the average of Africa, Asia, Latin America, all developing countries and the world, respectively.
· Thus, the small ruminant sub-sector in SSA was not only suffering from a depressed population growth but also from a depressed meat output which may be due, among other things, to a lack of effort to increase production per unit of animal.
Reproductive performance
· Available information is generally limited, particularly in the highland zone.
· Tremendous variations exist between breeds within and between ecozones offering a good potential for improvement.
· Definitions of components of reproductive performance are oftentimes misleading and this may generate inaccurate estimates or misinterpretation of these estimates.
· Most does and ewes in traditional systems reproduce at intervals greater than 8 months, making it thus far impossible to reach the well accepted target of three lamb/kid crops in two years.
· Breeds with ability for three parturitions in two years in the unimproved traditional production systems are the Sudan Desert, Mayo-kebbi, Kirdi and WAD. There is no doubt that WAD sheep and goats are among the most fertile small ruminants breeds in the tropics.
· Ewes in the semi-arid zone have low prolificacy and can generally be considered as single pregnancy bearers. Does in that zone are generally more prolific than ewes. However, only the Red Sokoto of Niger and Nigeria, the Lamdim in Mozambique and the Sudan Desert of Sudan can be considered as prolific goat breeds in the zone. WAD sheep and goats in the humid zones stand up well among the prolific tropical breeds. The twining rate in WAD goats may be over 60 per cent.
· Ewes are generally have lower fecundity than does. Fecundity tend to be higher for sheep in the humid zones than those in the semi-arid zone. The Mayo-Kebbi and the Kirdi in the sub-humid zone, the Red Sokoto and the Massakory in the semi-arid zone are probably the ones with the second highest fecundity among sheep breeds after WAD in the humid zones.
· Goats tend to have their first progenies at earlier ages (10-18.5 months) than sheep (11-24 months). In general, most female sheep and goats conceive prior to or at 12 months of age.
Prenatal wastage
· Virtually no information is available on fertilization failure and embryo mortality in SSA. However, weight losses due to high ambient temperatures and lack of quality stud males, among other factors, do prevail in the region.· Under drought-free conditions of SSA, under-nutrition may not be an important source of embryo mortality.
· There are many confusing ways in which abortion rates are expressed, resulting in a considerable variation and misleading specification bases.
· Stillbirths have been neglected or recorded as abortions.
· Abortions in ewes and does are variable (3.7 to 40 per cent of breeding females) and are likely to be high. Ewes are less prone to abortions than does.
· Infectious abortions may be among the most important economic problems in small ruminant production in SSA. Chlamydiosis, Brucellosis and particularly Rift Valley Fever are reported as major sources of abortion.
· The dry season (with related undernourishment) in the semiarid zone and the start of rainy season in the humid and sub-humid zones are the periods of highest vulnerability to abortion in both sheep and goats.
· Abortions are most frequent in multiple foetus bearers, primiparous and immature females and also when the parturition intervals are too short.
· Slaughter of pregnant sheep and goat females is one of the most important causes of prenatal wastage in SSA.
Postnatal wastage
· There has only been a limited number of investigations of sheep and goat neonatal mortality in SSA and most studies were in the humid and sub-humid zones.· The number and proportion of kids and lambs born alive which died during the neonatal period are generally unknown as most estimates were based on percentage of total deaths.
· Neonatal mortality is likely to be above 20 per cent (probably between 20 and 30 per cent) of kids and lambs born alive and may represent 70 to 80 per cent of preweaning death.
· Major causes of neonatal mortality are weakly lamb/kid syndrome and pneumonia in that order. The most important predisposing factors are low birth weight or a birth weight-litter size combination followed by dam age, season of birth and parturition interval.
· Highest survival of neonates are obtained for animals born during the rainy seasons in the semi-arid zone and the dry seasons in humid and sub-humid areas.
· Data on preweaning mortality are limited and most investigations tend to concentrate on research stations and in the humid zones.
· Preweaning death may account for 30 to 50 per cent of deaths among kids born alive in the humid zones and 20 to 40 per cent in the semi-arid zone.
· Higher preweaning deaths are obtained for kids than for lambs. In kids these deaths are expected to be at least 20-30 per cent of animals born alive.
· In kids, causes of preweaning mortality tend to be pneumonia, weakly kid syndrome and helminthiasis in that order.
· Pneumopathies in kids are more devastating during the cool dry season in the semi-arid zone and the rainy season in the humid zones than any other time. Weakly Kid syndrome tends to be more important in the dry hot season in the semi-arid zone and helminthiasis in rainy season in the humid zones.
· Pneumopathies, weakly lamb syndrome and helminthiasis seem to be very important causes of lamb preweaning death in the humid zones, whilst weakly lamb syndrome and Pneumopathies are more important than helminthiasis in the semi-arid zone.
· Weakly lamb complex may occur all year round in SSA with dry season particularly in the semi-arid zone, premature and indiscriminate matings, lower than average birth weight and multiple birth being the predisposing factors.
· Haemonchosis and PPR are the most important sources of helminthiasis and pneumopathies, respectively.
· Investigations on lamb/kid post-weaning mortality are limited and most estimates are obtained in the humid zone.
· Losses due to post-weaning death may not be negligible and may account for at least 20 to 40 per cent of the total death recorded from birth to 12 months.
· Pneumopathies are the first cause of kid and lamb post-weaning mortality. Pneumonia of PPR origin can occur any time of the year and is more deadly in kids than in lambs.
· Helminthiasis, particularly haemonchosis is the second killer after pneumopathies. Sheep are less vulnerable to Haemonchus sp. than goats. Haemonchosis is a more limiting factor in the humid zones than in the semi-arid areas.
· Fascioliasis in humid, swampy, flooded or irrigated areas is a great threat to sheep production in SSA.
· There is a need for more investigations on every component of reproductive losses, particularly on fertilization failure, embryo mortality, stillbirth and neonatal mortalities. Meanwhile, the perinatal stage being the most critical of all periods in relation to kid and lamb survival is an area where interventions are immediately needed. Research should be extended to all ecozones and particularly to the highland area.· A guideline is needed which could help researchers to fully and accurately report their findings on reproduction performance and losses in a standardized way.
· Investigations on reproductive potential of sheep and goat breeds in their native environment along with characterization of these breeds must be done.
· Research on breeds which are more productive than others in a given ecozone should be encouraged and efforts must aim at their spread in that specific zone of adaptation. For this, the existing great variations between and within breeds in the same ecozone must be exploited.
· In the health management area, again, a serious consideration should be given to the identification and selection of breeds, strains or individuals which, in the traditionally unimproved environment, tend to tolerate or better resist the most important pathologies or conditions. Genetic improvement of small ruminants using both conventional and the most advanced technologies (i.e., biotechnologies) must be highly encouraged.
· The necessary provision to the small ruminant producers (i.e., the poor rural households) of animals that show high fitness in their native environment and are less vulnerable to the stressful conditions of such environments should be among goals of paramount importance. The view that natural selection alone is taking care of this is not progressive.
· Extensive research on the use of monoclonal antibodies for disease diagnosis should be encouraged in small ruminant development in SSA. Investigations on the Major Histocompatibility Complex (MHC) should be extended to small ruminants and their major diseases as well.
· Simple and cost-effective breeding management schemes must be made available to help avoid indiscriminate matings and permit births to take place when survival and growth of kids and lambs are highest.
· Cost-effective health packages for PPR control are immediately needed and must be appealing to the producers. Here, it should be noted that the cool dry season in the semi-arid zone and the rainy season in the humid zone are periods of highest vulnerability. It should also be noted that immunity is established earlier and lasts longer in sheep than in goats and that preweaning and post-weaning periods are critical.
· Genetic research coupled with sustainable and cost effective control packages are needed to counteract the negative impact of haemonchosis particularly in the humid zones. Such research should be extended to weakly lamb/kid syndrome and measures to prevent or eliminate its lethal effects taken. Genetic research should also help increase the growth rate of breeds which tend to show high ages at first parturition, where quality stud males are available, as growth is positively correlated with age at puberty. In particular, research for the improvement of the trait (i.e., age at first parturition) in the Kirdi, the Mayo-and the highland breeds must be given undivided and deserved attention. Finally, WAD breeds which are highly prolific but poor milk producers should benefit from genetic studies aimed at increasing their milk production capability which, in turn, could increase the survival of their progenies.
· Studies into why pregnant females are sold and slaughtered must be undertaken and losses due to the process prevented. In the meantime, it is essential that pregnancy diagnosis be performed at the various abattoirs found in SSA prior to the slaughter of small ruminant females. Training must also be provided to farmers on simple methods of pregnancy detection. The issue is one of national or regional policy adequacy and governments' determination to make such a policy work.
· In nutrition management areas, simple techniques for feed conservation and strategic supplementation schemes should be sought and made available to producers in all ecozones as no poorly fed primiparous female or multiple pregnancy bearer can be expected to realize its production potential or exhibit high reproductive performances. In connection with this, efforts must be directed at the promotion and development of locally sustained animal feed industries.
· High production per head should be encouraged. This cannot be achieved without a good nutrition management that recognizes the critical importance of the notion of quality rations and that of production targets and the corresponding feeding strategies.
· Producers must be trained in areas of basic animal husbandry and be encouraged to use the simple and cost-effective nutrition, health and breeding packages which are made available to them. This is important because high neonatal mortality due to weakly lamb/kid syndrome and lack of basic management (including housing devices) are related.
· Quality breeding males must be made available in a required number and birth must take place when survival of the young is highest. This requires breeding to occur during appropriate periods of the year.
· High rates of loss and high incidence of serious managerial problems in a production system are highly correlated, indicating that losses are merely an aggregate response to inadequacies in such a system. Issues of small ruminant losses in SSA are not simple and should not be overlooked. In other words, for SSA to reduce to a tolerable level its sheep and goat reproductive losses, production systems and related managerial practices in the region must be improved drastically or changed all together. This in itself must be subject to an overall development package involving, among other things, rural infrastructure building, market and marketing development, inter-African trade, education and training of producers, incentive to produce and to sell, provision of adequate extension research and services. Certainly, what is needed is an active and proper government interventionist role which recognizes that the planning of any successful livestock strategy is not only technological or economical but also and essentially political, and that "development will occur only when the people most directly affected are enlisted in its support" (Herrick and Kindleberger (1988)6) through their full and active participation.
6 Henrrick, B. and C. P. Kindleberger. 1988 Economics Development. Fourth Edition. McGraw-Hill International Editions. London.
