Effects of average monthly temperature, relative humidity, and rainfall during birth and weaning on calf and dam records of American Brahman cattle

摘要

Based on 128 births of American Brahman calves at ANSA Genetics, Inc. cattle farm in Lipa City, Batangas from January 2000 to July 2002, the relationships among calf and dam records and climatic data (average monthly temperature, relative humidity, and rainfall) during birth and weaning were determined. Significant correlation coefficients within and between calf and dam records were found, implying the maternal influence on calf records. Dams that weighed heavily after birth were likely to produce fast growing, bigger and heavier calves at birth and at weaning. No significant relationships (P>.05) between relative humidity during birth and calf records were found. Significant correlation (P=.07) existed between temperature during birth and gain from birth to weaning, Significant correlation values were also found between rainfall during birth and weaning weight, gain from birth to weaning, and average daily gain, implying that greater gain in weight of calves is expected at cooler temperatures andwhen there is abundant rainfall during the month of parturition. The significant negative correlation of temperature and relative humidity during weaning and calf records suggests that high temperature and relative humidity can retard weaning weight, gain from birth to weaning, and average daily gain o American Brahman calves. Higher birth weight, weaning weight, gain in weight, and average daily gain were recorded in the early months of the year. Despite the fluctuations in rainfall, no seasonality ofbreeding was observed. The low variability in weaning weight may be attributed to the year-round creep feeding ofall calves before weaning. A strategic program of creep feeding of calves only during months of limited rainfall and pasture yield is therefore recommended.