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摘要
The objective of this study was to understand the associations of calf growth traits with subsequent milk yield and body weight (BW). Data were collected for 281 Holstein heifer calves from 6 different calf trials of varying lengths (4 to 8 wk) conducted at Pennsylvania State University between 2003 and 2010. Calves were classified as high, medium, or low for hip height, starter feed intake, BW, and growth rate. Milk yield and cow BW were recorded during subsequent lactations. In total, there were 169,734 daily milk records and 136,153 cow BW records available. Data were evaluated using mixed model equations. Separate models were used for each calf growth trait initially, followed by models that considered multiple growth measures. Each model included age at calving, treatment within trial, parity, days in milk, lactation, and one of the calf growth traits as well as the interaction between lactation and days in milk as fixed effects. Cow and calendar week by year were fitted as random effects. Heifers from the low hip height classification as calves produced less milk across lactations after accounting for BW differences. Cows from the medium BW classification as calves produced more milk in early lactation than cows from the high BW classification as calves after accounting for differences in height. Calves that grew more quickly, ate more, and weighed more were heavier as first-lactation heifers and as mature cows. Our results suggest that the type of preweaning growth is an important consideration for future milk yield. Calves that were the shortest had the lowest milk production potential and were the least likely to remain in the herd until first lactation.
- 出版日期2016-10
