Options to reduce vulnerability to metabolic stress by genetic selection
| Autor: | J. E. Pryce, P. Løvendahl |
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| Rok vydání: | 1999 |
| Předmět: | |
| Zdroj: | Pryce, J & Løvendahl, P 1999, ' Options to Reduce Vulnerability to Metabolic Stress by Genetic Selection ', Cattle Practice, vol. 7, no. 1, pp. 119-120 . |
| ISSN: | 2053-5953 0263-967X |
| DOI: | 10.1017/s1463981500043132 |
| Popis: | Genetic selection for milk production has been very successful. However to achieve high yields, the metabolic load on dairy cows is believed to be substantial. If the size of this load is large enough then the animal may become ‘metabolically stressed’. Signs of this may include some sort of distortion of normal physiological function. There is evidence from both population studies and research herds to suggest that intense selection for milk yield has led to a deterioration in some aspects of health and fertility. Genetic correlation estimates between production and measures of fertility are unfavourable. As an example, calving intervals of high merit animals from Langhill are on average 12 days longer than those of average genetic merit, which is mostly due to a delay in days to first heat. It is suggested that some aspects of health and fertility problems in high genetic merit animals are a consequence, in part, of so-called metabolic stress. Future breeding goals should be broadened to include a broad spectrum of traits related to efficient milk production, in addition to either health and fertility traits themselves, or traits believed to be precursors of them, such as those related to metabolic stress. The complexity and subjectivity of metabolic stress and its components makes it very difficult to include in future breeding goals. However, traits related to energy balance, such as some measures of condition score, dry-matter intake and live weight may be useful in breeding programmes where one of the goals is to alleviate metabolic stress. |
| Databáze: | OpenAIRE |
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