Resumo

ANGEL MARIN, Paula Andrea et al. Lactation curves in hybrid goats by the use of nonlinear mathematical models. Rev. Lasallista Investig. [online]. 2009, vol.6, n.1, pp.43-49. ISSN 1794-4449.

Introduction. Lactation curves in milk cattle are now an important tool to select female animals with high genetic values, allowing the increase and optimization of milk production in herds. Objective. To identify the best mathematical functions to explain the curves of milk production, time and peak production in goats with different hybridations, kept in an Antioquian sheepfold. Materials and methods. 865 milk weightings from 32 lactations that took place in 2007 were used. The milk came from hybrid goats, from different births. Four nonlinear mathematical models were evaluated and the significant curves percentage (P< 0.05), the Akaike and Bayesino's criteria and the values of the determination quotient R2 were taken into account to select the best of those models. Results. Papajcsik and Bordero's model was identified as the one that best adjusted the lactation curves in this population, with lower AIC and BIC values, a high significance of the model (P<0.001) and a convergence of 100% of the goats, regardless of the number of lactations. Besides, peak production was estimated (y_max) for female goats with 1, 2, 3 or more births, and it was 3.06 ± 0.966, 3.10 ± 0.875 and 3.36 ± 0.691 kg, respectively. Conclusion. Papajcsik and Bordero's model allows the modeling of lactation curves in goats.

Palavras-chave : Milk production; days in milk terms; small ruminants; lactancy curve.

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