Bradford G E, Burfening P J, Cartwright T C
Dept. of Anim. Sci., University of California, Davis 95616.
J Anim Sci. 1989 Nov;67(11):3058-67. doi: 10.2527/jas1989.67113058x.
Research has been conducted as part of the Small Ruminant Collaborative Research Support Program (SR-CRSP) on evaluation of genetic resources and methods of effecting genetic improvement of small ruminants in the participating countries. In Kenya, the focus has been on development of a dual-purpose goat for milk and meat production in farming areas, utilizing two locally adapted breeds, Galla and East African, and two imported dairy breeds, Anglo-Nubian and Toggenburg, into a single stock. That research now has reached the stage of field testing. In Morocco, the performance of a highly prolific breed of sheep, the D'Man, and of a less prolific but larger breed, commonly raised under extensive management, the Sardi, and of their F1, F2 and backcross progeny has been evaluated for several reproduction and growth traits. Prolificacy of the D'Man was transmitted additively, but there was favorable heterosis for age at puberty, fertility and growth rate, resulting in substantial heterosis in total performance. In Indonesia, a high degree of variability in prolificacy in sheep appears to be due to segregation of a gene with large effect on ovulation rate, similar in some respects to the Booroola gene. In Peru, work has involved evaluation of effectiveness of current selection programs and estimation of phenotypic and genetic parameters, in unimproved and improved types of sheep, with a limited amount of work also on alpacas. Fiber production is the principal economic trait in alpacas. There also has been work on evaluation of hair sheep in Brazil, Kenya and Indonesia.
作为小型反刍动物合作研究支持项目(SR-CRSP)的一部分,已开展了相关研究,以评估参与国小型反刍动物的遗传资源及实现遗传改良的方法。在肯尼亚,重点是利用当地适应的两个品种——加拉羊和东非羊,以及两个引进的乳用品种——盎格鲁-努比亚羊和吐根堡羊,培育出一种适用于农区奶肉兼用的山羊。目前该研究已进入田间试验阶段。在摩洛哥,对一种高产绵羊品种——德曼羊,以及一种繁殖力较低但体型较大、通常粗放管理饲养的品种——萨迪羊,及其F1、F2和回交后代的多个繁殖和生长性状进行了评估。德曼羊的繁殖力呈加性遗传传递,但在初情期年龄、繁殖力和生长速度方面存在有利的杂种优势,从而在总体性能上产生了显著的杂种优势。在印度尼西亚,绵羊繁殖力的高度变异性似乎是由于一个对排卵率有重大影响的基因发生分离所致,这在某些方面与波拉努拉基因相似。在秘鲁,工作包括评估现有选择计划的有效性以及估计未改良和改良型绵羊的表型和遗传参数,同时也对羊驼开展了少量工作。纤维生产是羊驼的主要经济性状。巴西、肯尼亚和印度尼西亚也开展了对毛用绵羊的评估工作。