Samkange Alaster, Kandiwa Erick, Mushonga Borden, Bishi Alec, Muradzikwa Erdwin, Madzingira Oscar
School of Veterinary Medicine, Faculty of Agriculture and Natural Resources, University of Namibia, P. Bag 13301, Pioneerspark, Windhoek, Namibia.
, Windhoek, Namibia.
Trop Anim Health Prod. 2019 Sep;51(7):1829-1837. doi: 10.1007/s11250-019-01876-4. Epub 2019 Apr 8.
A retrospective study from 2004 to 2017 investigated the effect of bull age, cow age and breed on conception rates, and calving intervals of beef cattle at Neudamm farm, Khomas region, Namibia. Bulls ranging from 4 to 14 years of age were used to breed cows up to 17 years of age. A total of 1804 pregnancies were diagnosed in Afrikaner (81.8%), Nguni (14.1%), and Simmental (4.1%) cows. The overall conception rate of beef cattle during the study period was 71.7 ± 9.5%. The overall conception rate of the Nguni cows (78.3%) was significantly higher than that of the Afrikaner (70.9%) and the Simmental cows (64.9%) (p < 0.05). The age of sires had no effect on overall conception rate in all three breeds (p > 0.05). Afrikaner dams more than 10 years old had the least rate of conception (60.4%, p < 0.05) within that breed category. Nguni dams between four to 10 years had the greatest conception rate (86.5%, p < 0.05). Age of dams had no effect on conception rates in Simmental cattle (p > 0.05). The overall mean length of all calving intervals in the Nguni cows (366 ± 35 days) was significantly shorter than those of the Afrikaner cows (487 ± 62 days) and the Simmental cows (484 ± 110 days) (p < 0.05). The 2013 breeding season produced the highest overall conception rates (~ 85%), and the 2007 breeding season produced the lowest overall conception rate (~ 51%). From a fertility point of view, the Nguni breed seemed best suited for the semi-arid conditions which are prevalent in most of Namibia.
一项2004年至2017年的回顾性研究，调查了纳米比亚霍马斯地区Neudamm农场公牛年龄、母牛年龄和品种对肉牛受孕率及产犊间隔的影响。4至14岁的公牛用于给17岁以下的母牛配种。共诊断出1804例怀孕，涉及南非布尔牛（81.8%）、恩古尼牛（14.1%）和西门塔尔牛（4.1%）。研究期间肉牛的总体受孕率为71.7±9.5%。恩古尼牛的总体受孕率（78.3%）显著高于南非布尔牛（70.9%）和西门塔尔牛（64.9%）（p<0.05）。在所有三个品种中，种公牛年龄对总体受孕率均无影响（p>0.05）。10岁以上的南非布尔牛母亲受孕率最低（60.4%，p<0.05）。4至10岁的恩古尼牛母亲受孕率最高（86.5%，p<0.05）。西门塔尔牛母亲年龄对受孕率无影响（p>0.05）。恩古尼牛的所有产犊间隔总平均长度（366±35天）显著短于南非布尔牛（487±62天）和西门塔尔牛（484±110天）（p<0.05）。2013年繁殖季节总体受孕率最高（约85%），2007年繁殖季节总体受孕率最低（约51%）。从繁殖力角度来看，恩古尼品种似乎最适合纳米比亚大部分地区普遍存在的半干旱条件。
