The goat is perhaps the most misunderstood and neglected, but nevertheless important species of livestock in the third world countries. Among the Asiatic countries, Bangladesh, a tropical agro-based developing country, possesses the third largest repository of goats, with a population of more than 34 million heads, according to the FAO. This figure represents more than 57% of total livestock in Bangladesh. More than 90% of the goats of the country are of the Black Bengal breed. Each year goat production provides 127,000 MT meat, which accounts for 25% of total red meat in Bangladesh. What is the basis for the goat’s large share in meat production? First, social refusal of pork due to religious prohibition plays a large role. Second, sheep are only a minor species in Bangladesh. Finally, high preference for goat meat has provided this opportunity. Consumption of meat is expected to increase significantly in the future in Bangladesh, which dictates that goat productivity must increase to satisfy the demand. One obstacle to meeting this requirement is that programmes for scientific breeding are practically absent, with the exception of a few recently undertaken AI services from the part of an NGO. The Black Bengal breed, therefore, demands that a comprehensive programme of genetic improvement and conservation be initiated.
About 85% of the population lives in the rural area. Their livelihood is characterized by either small holdings or landlessness, illiteracy, unemployment and malnutrition. Many of these people resort to goat production to assist in reaching self-sufficiency. Therefore, more than 98% of goats are owned by the small, marginal and landless farmers in the villages. Women and teenagers employ their labour in goat rearing as a subsidiary occupation. Because many of the farmers are essentially landless, goats in Bangladesh mainly live on collected road side grasses, tree leaves and kitchen vegetable wastes. Goat keepers in general invest practically nothing to rear their animal. Flock size ranges from 2 to 5. Male kids are castrated at early age, fattened and then marketed between 1 and 2 year of age. Wethers of this age are of high demand during the time of Muslim festival and social occasions.
The Black Bengal is a dwarf meat–type, highly prolific breed of goat (see photo). Wethers (castrated males) weigh typically weigh around 16 kg at one year of age and does of the same age weigh 12 Kg. Both sexes have short cylindrical horns. Older bucks and does have beards. The Black Bengal has several very desirable characteristics. They mature sexually quite early, at 6-8 months of age, and breed around the year. They are reported to have resistance against common diseases, can produce and reproduce in very low plane of nutrition and are well adapted to the local environment. They kid twice a year or more commonly thrice in two year giving a mean litter size of 2.2. Meat and skin obtained from the Black Bengal are of excellent quality and fetch high prices, even in the local market. Finally, research shows that there exists substantial genetic variation among individuals in the production traits, indicating scope for increasing productivity through breeding approaches. Despite the above mentioned merits, the Black Bengal does have some limitations. For example, they are said to be suboptimal in traits related to performance early in life. For birth weight is generally low (800-900g), as is growth rate (40-45g/day). This low growth rate is tied to relatively low milk yield (400-700ml/day). All of these factors contribute to relatively poor pre-weaning kid survival rate (85 %). Another limitation is not directly due to genetics of the breed, but rather the system of breeding. For many livestock species, genetic improvement relies on spreading the germplasm of the most superior males. Unfortunately, due to market conditions, almost the opposite is occurring with the Black Bengal. Because meat production is so important, the ideal situation would have the largest, fastest growing males being used to father the next generation. The animals, however, also tend to fetch the highest prices on the meat market and are thus sold prior to having a genetic impact. In fact, often the poorest males are used for breeding, leading to negative selection response.
Because of the previously mentioned shortcomings of the Black Bengal, a logical breeding goal would be to improve rate of weight gain, especially early in life. One possible trait to measure would be weight at a given age, such as at 30 or 60 days. Selection to improve this trait would help improve birth weight, growth rate, and milk production, because all three would contribute to that phenotype. Unfortunately, no formal national or even large regional breeding programme is currently in place, so wide spread genetic evaluation of commercial animals is not possible. Therefore, a logical approach to start would be to establish an open nucleus herd, perhaps in conjunction with the current AI centre. Animals within the nucleus could be monitored particularly closely for phenotypes for accurate selection. In addition, the “best” cooperating farmers using the AI service could be encouraged to record some data on growing animals, with the motivation of perhaps selling the animals or genetic material to the AI centre. The AI service could either pay a premium (above the meat price) for superior males, or collect and store semen from males for a short period, then return them to the farmer for sale to the market.
Source: Md. Ruhul Amin, Professor, Dept. of Animal Breeding and Genetics, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh. E-mail: firstname.lastname@example.org