Performance of Jamaica Hope Cattle in Commercial Dairy Herds in Jamaica

Abstract

Performance of Jamaica Hope cattle, developed in Jamaica from a crossbred foundation containing about 80% Jersey, 15% Sahiwal, and 5% Holstein breeding, was evaluated. There were 8,819 lactation records for 1969 to 1975 of Jamaica Hope and other cows from 28 herds for estimates of environmental effects. Herd, year, season, and age affected milk yield. Milk yield declined from 3890kg in 1969 to 2658kg in 1975. Effects of season and age of calving were small (5 and 13%). Progeny of Jamaica Hope sires were below other cows in milk yield (2732 versus 3013kg). Phenotypic correlations among milk yield, lactation length, and body weight were positive but were negative for milk yield and days dry. Lactation length accounted for about 35% of the variation in milk yield where-as days dry and body weight contributed less than 10%. Total variance for milk was small, 749,283kg2. Percentages of total variance in milk yield attributed to herd, sire, cow, and error were 29, 9, 46, and 16. For milk yield, heritability was .35 and repeatability .77. Sire values for 62 Jamaica Hope sires with at least 5 daughters were +243 to −300kg. Factors that affect performance of Jamaica Hope do not appear greatly different from those influencing other breeds in tropical areas.