<abstract xmlns="http://www.w3.org/1999/xhtml"><p>The effect of systematic and continuous environmental factors on milk performance traits over standard lactations in 2805 Simmental cows was evaluated using the general linear model. The systematic factors included the effect of farm or breeding area, calving season, year of birth, season of birth, lactation group and their interactions. The continuous factor analysed was the effect of age at first conception. The effect of farm, lactation group and calving season on standard lactation milk performance was found to be highly significant (P&lt;0.01), excepting the effect of calving season on milk fat percent in standard lactations which showed statistical significance (P&lt;0.05). The interactions between year and season of birth, farm and calving season, and farm and lactation group had a highly significant effect (P&lt;0.01) on all performance traits studied. Age at first conception, as a continuous factor, had a highly significant effect (P&lt;0.01) on milk yield and milk fat percent, and a non-significant effect on milk fat yield. The model used to correct the performance traits over standard lactations for the effect of systematic factors was highly significant (P&lt;0.01). The variance of the model accounted for 20.06 and 37.31% of the total variance of milk fat yield and milk fat percent, respectively. The resulting coefficients of determination (R2) ranged from 0.20 for milk fat yield to 0.37 for milk fat percent.</p></abstract>

The effect of systematic and continuous environmental factors on milk performance traits over standard lactations in 2805 Simmental cows was evaluated using the general linear model. The systematic factors included the effect of farm or breeding area, calving season, year of birth, season of birth, lactation group and their interactions. The continuous factor analysed was the effect of age at first conception. The effect of farm, lactation group and calving season on standard lactation milk performance was found to be highly significant (P<0.01), excepting the effect of calving season on milk fat percent in standard lactations which showed statistical significance (P<0.05). The interactions between year and season of birth, farm and calving season, and farm and lactation group had a highly significant effect (P<0.01) on all performance traits studied. Age at first conception, as a continuous factor, had a highly significant effect (P<0.01) on milk yield and milk fat percent, and a non-significant effect on milk fat yield. The model used to correct the performance traits over standard lactations for the effect of systematic factors was highly significant (P<0.01). The variance of the model accounted for 20.06 and 37.31% of the total variance of milk fat yield and milk fat percent, respectively. The resulting coefficients of determination (R2) ranged from 0.20 for milk fat yield to 0.37 for milk fat percent.

Effect of Non-Genetic Factors on Standard Lactation Milk Performance Traits in Simmental Cows

Department of Animal Husbandry, Faculty of Agronomy Cacak, University of Kragujevac, Serbia

Department of Zoo Techniques, Faculty of Agriculture Belgrade-Zemun, University of Belgrade, Serbia

Institute of Animal Husbandry, Belgrade-Zemun

Annals of Animal Science

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

The effect of systematic and continuous environmental factors on milk performance traits over standard lactations in 2805 Simmental cows was evaluated using...

Effect of Non-Genetic Factors on Standard Lactation Milk Performance Traits in Simmental Cows

Publicado en línea: 03 mar 2015

Páginas: 211 - 220

Recibido: 10 ene 2014

Aceptado: 05 sept 2014

DOI: https://doi.org/10.2478/aoas-2014-0073

© by D. Milun Petrović

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.