Effects of Dry Cow Grouping Strategy and Prepartum Body Condition Score on Performance and Health of Transition Dairy Cows

摘要

Multiparous Holstein cows (n = 337) on two commercial dairy farms were used to determine the effects of feeding a close-up diet for 21 (treatment S) or 60 d (treatment L). Milk yield was not affected by treatment; however, cows fed treatment S tended to have increased yields of fat, 3.5% fat-corrected milk, and protein during the first 5 mo of their subsequent lactation compared to treatment L. Cows fed treatment L gained more body condition score (BCS) during the dry period and had longer days to first service. As a secondary objective, relationships of BCS at dry off and subsequent performance were evaluated. Cows with initial BCS≤3.0 (thinner) tended to produce more milk during early lactation than cows with initial BCS≥3.25 (fatter). A trend for an interaction of treatment and initial BCS existed for milk yield such that thinner cows fed treatment S produced the most milk and fatter cows fed treatment S produced the least amount of milk; cows fed treatment L regardless of BCS produced an intermediate amount of milk. Subsequent reproductive performance was similar among thinner and fatter cows. These data indicate that 2 group nutritional strategies for dry cows are preferred, and BCS at dry off should be considered when determining grouping and nutritional strategies for dry cows. Furthermore, moderately thin cows at dry off do not have impaired performance during their subsequent lactation compared to cows of greater BCS.