Joint Effects of Parity, Age, and Season of Kidding on Milk and Fat Yields in Dairy Goats

Abstract

Dairy Herd Improvement 305-day lactation records of 120 days or more were examined for joint effects of parity, age, and season of kidding on milk and fat yields in Alpine, Saanen, and Toggenburg goats. Parity classifications were first, second, third, and fourth or greater. Seasons of kidding were December through March and April through July. Data were analyzed within geographical regions: 1) western coastal states plus their bordering inland states and 2) northeastern and north central states. There were 6,187 records from 1 covering 1970 to 78 and 4,350 records from 2 covering 1969 to 78. In both regions, parity contrasts across age-season were large, generally significant, and indicated the need to consider parity in addition to age and season in developing age correction factors for dairy goat lactations. Previous lactation experience, seasonal breeding patterns, and onset of estrus may contribute to parity and age relationships with milk and fat yields. Repeatabilities of milk and fat yields were .45 and .43 for region 1 and .48 and .45 for region 2. © 1981, American Dairy Science Association. All rights reserved.