Farin P W, Chenoweth P J, Mateos E R, Pexton J E
Department of Animal Sciences Colorado State University, Fort Collins, Colorado 80523 USA; Department of Physiology and Biophysics Colorado State University, Fort Collins, Colorado 80523 USA.
Theriogenology. 1982 Apr;17(4):365-72. doi: 10.1016/0093-691x(82)90016-4.
Beef bulls of approximately 15 months of age were placed with heifers at bull to female ratios (BFR) of 1:20 (n = 3) and 2:40 (n = 3) to compare the breeding efficiency of bulls used in either a single- or a multi-sire group. Prior to the breeding period, each bull was given a breeding soundness exam and two exposures to a libido/serving capacity test. For the purpose of synchronizing estrus, heifers received a nine-day Syncro-Mate-B((R)) (G. D. Searle & Co.) treatment. Twenty-seven hr after removal of the implants, bulls were placed with heifers and sexual activity was observed continuously for the succeeding 30 hr. With the exception of number of services per heifer, the mating performance of bulls and pregnancy rates at both BFR's were not different (P>.05). Heifers in single-sire groups were serviced more times (P<.05) than those in multi-sire groups (4.1 +/- 0.6 vs 2.6 +/- 0.2, respectively). Approximately 50% of heifers in multi-sire groups were serviced by both bulls. Due to the overlap in servicing heifers and the non-significant difference in pregnancy rates between the two BFR's, it was concluded that a single-sire mating program was more efficient.
将大约15月龄的公牛与小母牛按1:20（n = 3）和2:40（n = 3）的公母比例（BFR）放在一起，以比较单公牛组或多公牛组中公牛的繁殖效率。在繁殖期之前，对每头公牛进行繁殖健康检查，并进行两次性欲/配种能力测试。为了同步发情，小母牛接受了为期九天的Syncro-Mate-B（R）（G.D. Searle & Co.）处理。取出植入物27小时后，将公牛与小母牛放在一起，并在接下来的30小时内持续观察性行为。除了每头小母牛的配种次数外，两个BFR下公牛的交配性能和怀孕率没有差异（P>0.05）。单公牛组中的小母牛比多公牛组中的小母牛接受配种的次数更多（P<0.05）（分别为4.1±0.6次和2.6±0.2次）。多公牛组中约50%的小母牛由两头公牛配种。由于在给小母牛配种方面存在重叠，且两个BFR之间的怀孕率无显著差异，因此得出结论，单公牛配种方案更有效。
