Heritability and Repeatability of First, Second, Third, and Fourth Records of Varying Duration in Brown Swiss Cattle

Heritability estimates of first, second, third, and fourth lactations, averages of two, three, and four records, and of 100-and 200-day partial first lactations, were made to study the reliability of using partial or complete first records as the basis for early selection in Brown Swiss cattle. The data consisted of 8,413 ttIR records of not less than 200 or more than 305 days in length from 38 Brown Swiss herds in Wisconsin.