Answers are grounded in this paper and cite their sources.
The data for this study consisted of 2,063 gestations representing the five major breeds of dairy cattle in the University of Illinois herd. These data were analyzed to determine the ~heritability and the variance of the length of the gestation period, so as to indicate the possibility of shortening the duration of pregnancy in dairy cattle. A comparison of the fiducial limits of the duration of pregnancy of each of the five breeds indicated breed differences in all possible comparisons, except between Jerseys and Holstein-Friesians. The effect of sex of fetus and the variance components for service sire and sire of the dam were estimated. The effects of the sex of the fetus of Ayrshires, Holstein-Friesians, and Jerseys were statistically significant and, in general, the male calves were carried about 1.5 days longer than the females.
No takes yet. Share an insight, caveat, or question.
DeFries et al. (1959) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: