Genetic evaluation of dairy sires using a test day model | Kontroles dienas modeļa pielietošana piena šķirņu vaislas buļļu ģenētiskajā novērtēšanā
2008
Sarma, R., Latvia Univ. of Agriculture, Jelgava (Latvia). Faculty of Agriculture. Inst. of Agrobiotechnology
Estimated breeding values (EBV) of all study groups showed the largest variation for three productivity traits when fixed district-test day effect was included in the model. Estimated breeding values were obtained in range from -921 to 1368 kg (1st lactation) and from -1014 to 1966 kg (three lactations) with average values from 27 to 28 kg (1st lactation) and from 62 to 64 kg (three lactations) for milk yield; from -38.0 to 83.6 kg (1st lactation) and from -40.8 to 93.6 kg (three lactations) with average values of 0.8 kg (1st lactation) and from 2.1 to 2.4 kg (three lactations) for fat yield; from -23.9 to 46.6 kg (1st lactation) and from -33.7 to 59.9 kg (three lactations) with average values from 0.8 to 0.9 kg (1st lactation) and from 1.9 to 2.0 kg (three lactations) for protein yield. EBV of milk yield and protein yield showed significant differences between lactation groups and three lactation groups where different fixed herd-test day or fixed district-test day effect was included in the model (p is less than 0.01). The average reliabilities of EBV were in range from 70 to 82%, from 69 to 81%, and from 72 to 83%, respectively for milk, fat, and protein yield according to the test day model. These values are lower by 3 to 15% for milk yield, by 3 to 18% for fat yield, and by 9 to 20% for protein yield using lactation model.
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