Study on Productivity Improvement of Hill Goat Through Selective Breeding Programme

An Attempt for the first time ever in the livestock species has been made to the production potentiality of hill goat through selective breeding. Two tier open nucleus breeding had been assiduously applied in order to enhance the genetic gain off hill goats. Breeding records of 221 does and 1462 kids in nucleus herd, and records of 968 does and 1622 kids in on-farm condition fathered selected bucks during 1998 to 2004 were considered for the study. Selection response of the breeding programme was calculated in terms of genetic gain. Response of selection for the first generation kids in nucleus flock at station was found to be 2.77 and 9.6 per cent generation for four and six month weights respectively. Similarly, overall twinning ability of hill goats for the period was increased by 0.73 per cent reaching the level of 68.75. In on-farm condition response of selection for first generation kids per year were 0.22, 7.01 and 7.41 percent for birth, four and six month weight respectively. Likewise, twinning frequency was improved by 27 percent indicating the level of 55. In both low and mid altitudes (up to 1100 masl) of eastern hill the selection program was found effective for improving the overall productivity of local hill goats, and could be equally effective for other parts of the country. <i> Nepal Journal of Science and Technology</i> Vol. 7, 2006 pp. 1-7

Secular Changes of Twinning Rates in Nordic Populations

In each species, natural selection has resulted in an optimal litter size, to ensure the largest average number of surviving offspring and the lowest maternal mortality. The terrestrial insectivores from which the primates evolved had large litters. It has been argued that in primates adaptation to an arboreal mode of life led to a reduction of litter size to a single offspring because of the difficulty of producting and caring for a large litter in a tree [6]. A recent critical survey of the literature indicates that twinning frequency in most nonhuman primates is lower than in man [20].There are clear ethnogeographic differences in the incidence of human twinning. Among peoples of Eastern Asia, multiple maternities are rare; in Japan for instance, the twinning rate is only 3-7 per mill, according both to the official statistics and hospital records. These low rates seem not to be caused by the facts that it is customary in Japan to have children very early in life or that twin births were at one time viewed with displeasure and concealed, or sometimes twins were even killed in some areas [21].In hospital series among some Negro tribes almost 10 times higher twinning frequencies than among Japanese have been reported e.g. the Yorubas in western Nigeria with values above 60 per mill [24]. However, where national birth statistics of Blacks are available, twinning is lower, e.g. in U.S.A. 13-15 per mill [1].