Genetic Parameters for Dry Matter Intake at Different Lactation Stages among Primiparous Holstein, Jersey and Red Cows

Abstract Text: This study evaluated the genetic variation in Dry Matter Intake (DMI) at 6 lactation stages over the first 24 lactation weeks in a population including Holstein, Jersey and Red cows. In total, 830 primiparous cows from Sweden and Denmark were included. Genetic parameters were estimated based on a linear mixed model. Heritability for DMI ranged between 0.16 and 0.35 across lactation stages. The lowest repeatability and heritability were found during the first 4 weeks of lactation, indicating large residual variance and low response to selection for DMI from early lactation. Genetic correlations between DMI across lactation stages ranged from 0.46 to 0.99. The weakest genetic correlation occurred between early and mid lactation, indicating a different genetic basis for DMI along lactation. A potential difference in genetic variation was found between Jersey and the other two breeds, requiring a further study within breed.

Keywords:
dairy cow
Dry Matter Intake
genetic parameters