Resumo

KGARI, R.D.; MULLER, C.J.C.; DZAMA, K.  e  MAKGAHLELA, M.L.. Evaluation of female fertility in dairy cattle enterprises - A review. S. Afr. j. anim. sci. [online]. 2020, vol.50, n.6, pp.819-829. ISSN 2221-4062.  https://doi.org/10.4314/sajas.v50i6.8.

The aim of this article was to review the state of fertility of female dairy cattle in South Africa and to compare it with international efforts at improving fertility. Fertility in dairy cows is defined as the ability to conceive from first insemination soon after calving and to carry the calf full term to calving. It is one of the main profit drivers in the dairy industry and is a complex trait that is influenced by the environment, genetics, and their interaction. Generally, there has been a decline in dairy cow fertility across breeds worldwide because of intense selection for milk yield, milk components, and body conformation traits. In addition, most fertility traits are negatively correlated to milk production traits. Milk production has been the focal point of selection programmes as it is linked directly to the profitability of the dairy enterprise. The low heritability of fertility traits is one of the factors that discouraged efforts to include fertility in genetic evaluations. However, owing to its economic importance, female fertility was later included in the breeding objectives for dairy cattle in several countries. Although most fertility traits are heritable to a low degree, some additive genetic variability can be exploited.

Palavras-chave : breeding values; cow fitness; genetic improvement; heritability.

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