Cockcroft Peter D, Sorrell Emma J
School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy Campus, Roseworthy, SA 5371, Australia.
The Brambles Veterinary Surgery, Churchdown, GL3 2HE, UK.
Vet Sci. 2015 Jul 7;2(3):131-134. doi: 10.3390/vetsci2030131.
The purpose of this study was to investigate the proportion of twins carried to term and the sex ratio of twin calves at birth in Holstein-Friesian dairy cattle kept on commercial farms in Devon and Cornwall, England. Ten farms were used in the study. Fifty four cows with twin pregnancies were identified using trans-rectal ultra-sonographic examination between 30 and 70 days of gestation. The farm records were subsequently used to derive the number of calves born. Farm records of 66 additional sets of twin births with the sex of the calves recorded were also identified. Of the 54 cows diagnosed with twin pregnancies, 16 cows (29.6%) aborted or absorbed both fetuses, 11 cows (20.4%) carried one calf to term and 27 cows (50%) carried both calves to term. In the calf sex analysis of the additional 66 sets of twins: 13♂♂ calves (19.7%), 18 ♀♀ calves (27.3%) and 35 ♂♀ calves (53.0%). There was no statistically significant difference from an expected ratio of 1♂♂:2♂♀:1♀♀ ( = 0.61). This study provides bench marks for the expected abortion/absorption rates following the early ultra-sonographic diagnosis of twin pregnancies in comparable populations and supports earlier observations that the expected sex ratio for twinning approximates to1♂♂:2♂♀:1♀♀.
本研究旨在调查英格兰德文郡和康沃尔郡商业农场饲养的荷斯坦 - 弗里生奶牛双胞胎足月分娩的比例以及双胞胎小牛出生时的性别比例。研究使用了10个农场。在妊娠30至70天之间，通过经直肠超声检查确定了54头怀有双胞胎的奶牛。随后利用农场记录得出出生小牛的数量。还确定了另外66组记录了小牛性别的双胞胎出生的农场记录。在诊断为怀有双胞胎的54头奶牛中，16头奶牛（29.6%）流产或吸收了两个胎儿，11头奶牛（20.4%）产下一头足月小牛，27头奶牛（50%）产下两头足月小牛。在对另外66组双胞胎的小牛性别分析中：13头♂♂小牛（19.7%），18头♀♀小牛（27.3%）和35头♂♀小牛（53.0%）。与预期比例1♂♂:2♂♀:1♀♀相比，差异无统计学意义（ = 0.61）。本研究为可比人群中双胞胎妊娠早期超声诊断后的预期流产/吸收率提供了基准，并支持了早期的观察结果，即双胞胎的预期性别比例接近1♂♂:2♂♀:1♀♀。
