Relationship between Milk Yield and Fertility in Dairy Cattle

Abstract
In 3 studies of 51,618 Holstein, 6630 Jersey and 1524 Guernsy records, correlation was 0.07 between 120 day milk yield and number of services required for probable conception, independent of days postpartum. The partial regression coefficient for Holsteins was 0.014 .+-. 0.001 more services for each additional 100 kg of 120 day milk. For Jerseys and Guernseys, 0.028 .+-. 0.008 more services were required for each additional 100 kg of 120 day milk.