High milk production decreases cow-calf productivity within a highly available feed resource environment
| Autor: | J. D. Hobbs, S. R. Edwards, J. T. Mulliniks |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
040301 veterinary sciences
media_common.quotation_subject Beef cattle Biology Cow-calf Article Milking reproduction 0403 veterinary science beef cattle fluids and secretions Animal science Grazing Weaning milk production media_common General Veterinary 0402 animal and dairy science food and beverages 04 agricultural and veterinary sciences 040201 dairy & animal science calf performance Pregnancy rate Productivity (ecology) Animal Science and Zoology Reproduction Water resource management |
| Zdroj: | Translational Animal Science |
| ISSN: | 2573-2102 |
| DOI: | 10.2527/tas2016.0006 |
| Popis: | The beef cattle industry tends to focus on selecting production traits with the purpose of maximizing cow-calf performance. One such trait is milking ability, which is considered the primary influence on weaning weight of the calf. Therefore, the objective of this study was to determine the effect of actual milk yield on reproductive performance, circulating blood metabolites, and calf performance in beef cows in the Southeastern US. Over a 2 yr period, data were collected from 237, 3- to 9-yr-old Angus-sired beef cows on 3 research stations in Tennessee. On approximately d 58 and 129 postpartum, 24-hr milk production was measured with a modified weigh-suckle-weigh technique using a milking machine. Subsamples of milk were collected for analysis of milk components. Milk yield data were used to retrospectively classify cows on actual milk yield as High ( ≥ 10 kg/d), Mod (8 to 9 kg/d), or Low ( < 8 kg/d). Cow body weight (BW) and body condition score (BCS) were collected weekly at each location through breeding. Calf BW was recorded at birth, mid-weight at d 58, and weaning. At d 58 and 129 of postpartum, milk yields were different (P < 0.001) among the treatment groups. Cow BW during the entire study were not different (P ≥ 0.22) with increasing milk yield. Timed-AI pregnancy rate were the lowest (P = 0.02) in the High milk producing cows with no difference (P > 0.05) between Low and Mod milk cows. In addition, overall pregnancy rate continued to be the lowest (P = 0.04) in High milk producing cows with the greatest pregnancy rate in Mod milk cows. Calf mid-weight at ∼d 58 was increased (P < 0.001) in calves from Mod and High milking cows. However, calf BW at weaning was not different (P = 0.22) among calves from different milk treatment groups. Results from this study suggest that even in management systems that modify the grazing environments with harvested feedstuffs, high milk production decreases reproductive efficiency. In addition, increasing milk production up to d 129 postpartum did not result in increased calf BW at weaning, indicating that the genetic potential for calf BW at weaning could not be improved with increased genetic potential for milk production. |
| Databáze: | OpenAIRE |
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