Eddy R G, Davies O, David C
Veterinary Centre, Somerset.
Vet Rec. 1991 Dec 14;129(24):526-9.
The effect of twinning on the subsequent health, production and reproductive performance of dairy cattle was studied by analysing the data derived from 19,755 calvings which occurred during three years on 37 farms. The data formed part of the database of a veterinary practice operating the DAISY dairy cow recording scheme for its dairy farmer clients. The average twinning rate was 2.5 per cent. For first calf heifers the rate was 0.9 per cent, and the rate increased with increasing parity to over 5 per cent for cows calving for their sixth and subsequent lactations. Although they produced more milk than their contemporaries, twin-bearing cows suffered an increased incidence of retained placenta and vulval discharges and their calving to conception interval was extended by 33 days. Furthermore, 35 per cent of these cows were culled compared with 21 per cent of their contemporaries. The benefit of having more calves for sale was reduced owing to 15 per cent of them being born dead. It is calculated that producing twins resulted in an average loss of income of 74 pounds/cow, a deficit of 15 per cent compared with cows having single calves.
通过分析来自37个农场三年内19755次产犊的数据，研究了双胎对奶牛后续健康、生产和繁殖性能的影响。这些数据是一家兽医诊所数据库的一部分，该诊所为其奶农客户实施DAISY奶牛记录计划。平均双胎率为2.5%。头胎小母牛的双胎率为0.9%，随着胎次增加，第六胎及以后产犊的奶牛双胎率增至5%以上。尽管双胎奶牛比同龄奶牛产奶更多，但它们发生胎盘滞留和外阴分泌物的发生率增加，产犊至受孕间隔延长33天。此外，这些奶牛中有35%被淘汰，而同龄奶牛的淘汰率为21%。由于15%的双胎犊牛出生时死亡，出售更多犊牛带来的收益减少。据计算，产双胎导致每头奶牛平均收入损失74英镑，与产单胎的奶牛相比亏损15%。
