No CrossRef data available.
Published online by Cambridge University Press: 02 September 2010
The 305-day lactation milk yields and the numbers of inseminations required to obtain a pregnancy during a particular lactation were obtained from 1475 lactations of 808 daughters of eight bulls, whose Improved Contemporary Comparisons spanned two genetic standard deviations of milk yield. All lactations were completed before September 1978. Cattle requiring more than one insemination for a pregnancy produced 173 (standard error of difference = 55) kg more milk in 305 days than those requiring only one. There was no correlation between the Improved Contemporary Comparisons of the sire and either the difference in yield, or the proportion of animals needing one or those needing more than one insemination per pregnancy.