Genetic and breeding analyse of milk performance in a dairy herd.
1994
Novy, J. | Ostertag, I. (Vysoka Skola Polnohospodarska, Nitra (Slovak Republic). Katedra Genetiky a Plemenarskej Biologie) | Benyovszka, K. | Zatkovic, J.
Genetic and breeding analyses over 4000 lactations of Black Spotted dairy cows crosses, showing the level of production, reasons and range of variability in 7 basic parameters (milk yield, fat, protein and lactose in kg.lac** (-1) and the fat content, protein and lactose in g.kg** (-1) and 6 derived (complexed) parameters (FCM, FPCM, ECM [MJ.kg** (-1)], ECM [GJ.lac** (-1)], the content of fat and proteins in g.kg** (-1) and the index of protein production) were carried out. Significant influence of order of lactation and the origin after sires (differences between groups of halfsisters) was observed. The influence of differentiation of sires genotypes (inherited part of variability out of whole variability) was from 70 % (in ECM.kg** (-1)) to 94 %, (fat content in g.kg** (-1 )). The combining ability of sires was studied, too. Milk yield was 1300 kg, and production of FPCM up to 2666 kg. The differences in the content of fat, protein and lactose was in the range of 0.4-0.8. The analyses showed the necessity of a complex evaluation of all parameters of production which would enable objective sire breeding evaluation.
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