60. Validation and genetic analysis of a feed efficiency criterion in French Lacaune ewes

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Machefert, Coralie | Robert-Granié, Christèle | Hassoun, Philippe | Parisot, Sara | Allain, Charlotte | Portes, David | Lagriffoul, Gilles | Astruc, J.M. | Larroque, Hélène

Edité par CCSD ; Wageningen Academic Publishers -

Improving feed efficiency have environmental, economic and social benefits for dairy ewes farming systems. Selection of animals using efficiently their feed resources while maintaining a quality milk production is therefore a major objective for breeders. However, phenotyping feed efficiency remains difficult to achieve on-farm on a large scale. For this purpose, a criterion of lactation feed conversion ratio measurable on commercial farms was proposed. First, accuracy of this criterion was evaluated on experimental data with precise phenotypes including individual intake. This criterion seemed to be, with some recommendations, a good approximation of feed efficiency, with the main limitation of collective feeding. Then, the criterion was applied to 6 test-days from 6,425 lactations of Lacaune ewes from production farms. In these conditions, the estimation of the genetic parameters of this feed efficiency criterion showed a low heritability (0.12±0.02) and a strong genetic correlation with the daily milk yield (0.80±0.03).

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