Effect of calf birth weight on milk production of Holstein dairy cattle in desert climate
Rahbar, RabieAbdullahpour, RohullahSadeghi-Sefidmazgi, Ali
The hypothesis in this study was that calf birth weight (CBW) would effect on cow"s milk production. Data were collected from two commercial dairy milking 15,000 Holsteins in central region of Iran from 2006 to 2012. Animals were enrolled at parturition until 7,737 calvings were available for analysis. Data consisted of on-farm measurements of calf birth weight and milk production, and data were analyzed using a multivariable regression model. Independent variables were parity, herd-year-season, calving interval, calving age, retained placenta, days open, dry period length, days in milk, linear and quadratic CBW. The mean CBW was 40.84 ± 4.9 kg (SD) with a range of 20 to 60 kg. There was a trend for milk305 based on calf birth weight, i.e., the amount of milk305 of dam was significantly dependent on that weight of calf was born (P 0.01). Cows with CBW between 20 and 25 kg had the lowest of milk production. By increasing of CBW range up to 40 and 45 kg, the trend of milk production increased and then decreasing trend observed. In conclusion, calf birth weight could be considered as an important trait in dairy cattle breeding programs.(AU)
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