Reproduction and milk yield of Holstein cows in the US Virgin Islands as influenced by time of year and coat color
Records of 520 Holstein cows, over a period of 27 years, on the Caribbean island of St. Croix, were analyzed to determine the influence of season and hair coat color on reproduction and lactation. Calving intervals were longest (P<.05) for cows that calved during January through April (warm, dry season; 527±8 d) and decreased as month of the year progressed (P<.0001), so that shortest calving intervals were experienced by cows calving during October through December (warm, wet season; 468±7 d). Cows that began lactating in June through September (hot, dry season; 4643±81 kg) produced less (P<.05) milk than cows that began in October through December (5070±73 kg). The distribution of calvings exhibited seasonal pattern (P<.002) with most births (52%) occurring during October through January. The population was skewed toward darker cows with a mean percentage black hair coat of 74.1 (±19.7). Calving interval was not increased and milk yield was not reduced in cows with predominately black coat (P<.10). These data indicate that Holstein cows in a Caribbean climate exhibit seasonal patterns of reproduction and milk yield that are most likely related to forage availability, which in turn is related to rainfall and temperature. Hair coat color did not influence milk yield or reproduction, and is of minimal consequence in this semi-arid, tropical environment.
Copyright (c) 1996 Robert W. Godfrey , Peter J. Hansen
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.