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Relation of First Lactation Production and Conformation to Lifetime Performance and Profitability in Jerseys

Animal Science Institute, Agricultural Research, Science and Education Administration, US Department of Agriculture, Beltsville, MD 20705

ABSTRACT

Dairy Herd Improvement lactation records of 305 days or less for cows first calving from 18 through 35 mo were combined with American Jersey Cattle Club conformation (type) data for cows scored before 43 mo of age. Cows without opportunity for production through 72 mo were eliminated. Initial production and type scores were from 1967 through 1972, but lifetime measures continued through 1978.

There were 10,139 cows in 1014 herd-years of calvings. Number of lactations averaged 3.4, lifetime yield of milk was 13,813 kg, lifetime fat was 699 kg, and days in milk were 942. A profit function considered income from milk and calves and costs (fixed, operating, and cow depreciation). Multiple correlations for predicting net income per day of productive life (interval between first calving and last day of lactation) were .56 for first lactation yield, .27 for final score, .36 for all type traits, .57 for yield plus final score, and .58 for yield plus all type traits. Type traits increasing multiple correlations the most when added to milk and fat yield were final score, suspensory ligament, and mammary system.

¹ Animal Improvement Programs Laboratory.

² Now Department of Animal Science, North Carolina State University, Raleigh 27650.

³ Milk Secretion and Mastitis Laboratory; now Department of Dairy Science, Virginia Polytechnic Institute and State University, Blacksburg 24061.