Jersey Calf Management, Mortality, and Body Composition.
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In experiment two, tissues from a subset of calves [21/21 (n=4), 27/33 (n=5), 29/16 (n=5), MILK (n=3), baseline (n=2)] were scanned using dual energy x-ray absorptiometry to estimate mass, fat, CP, and ash. Liver, organ, and carcass mass by DXA were correlated to scale weights (R2= 0.99, 0.62, and 0.79, respectively). DXA was a poor predictor of percentage fat, CP, and ash (adjusted R2 <0.10).
Experiment three determined level of calf mortality in the United States; and identified opportunities to reduce mortality. Herds (n=88) were representative of the US Jersey population. Production averaged 7180 ± 757 kg milk annually. Herds averaged 199 births annually. Mortality was 5.0% from birth to 24 h (M24) of life and 6.7% from 24 h to 3 mo of life (M3). Level of mortality (M24) was highest in herds that calved on pasture. Lower levels of mortality (M3) were associated with use or maternity pens and earlier weaning.
- Doctoral Dissertations