Evolution in performances of French dairy cattle herds transitioning towards 3-breed crossbreeding
Abstract
There is a lack of references on the evolution of the performance of dairy cattle herds from commercial farms, in which dairy crossbreeding is implemented in various initial breeding situations, modalities and evolution dynamics. The objective of this study was therefore to analyse the changes in zootechnical performance at the herd level (milk production, useful matter rate, fertility and udder health) induced by the introduction of crossbreeding and to evaluate the factors explaining these changes.
We relied on a sample of 13 French dairy herds, from which we extracted breed and 6,628 lactation performances data from 2009 to 2017. We modelled the evolution of performances over this period by linear regression. We considered several explanatory variables: the initial state of zootechnical performance, the initial state of farm structure and management and their evolution, modelled by linear regression. In order to assess the factors that explain evolution in performances among the explanatory variables, we performed several partial least squares (PLS) regressions.
Our results show that crossbreeding has a significant effect on the evolution of the zootechnical performance of the herds, but as one explanatory factor among others, such as the systemic changes implemented or the stage of progress in the practice of crossbreeding. The implementation of dairy crossbreeding in purebred herds contributes to improving their fertility performance at the expense of milk productivity per cow, which the vast majority of farmers compensate by increasing the size of the herd. The effects of crossbreeding on milk quality, udder health and longevity are more contrasted.
These results enhance our knowledge of dairy crossbreeding by taking into account the biological and decision-making dimensions that, in the long term, build the multi-performance of herds and the genetic diversification induced in herds by the use of crossbreeding.
Origin | Files produced by the author(s) |
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