Novel genetic parameters for genetic residual feed intake in dairy cattle using time series data from multiple parities and countries in North America and Europe
Résumé
Residual feed intake is viewed as an important trait in breeding programs that could be used to enhance proving feed efficiency could improve both economic and environmental sustainability in the dairy cattle development of reliable genomic evaluations across lactation and parity for residual feed intake. Here, we estimated novel genetic parameters for genetic residual and body weight of 7,379 cows (271,080 records) from 6 countries in 2 continents were shared through the variance components estimated from first to third parity, using a random regression model across countries. Genetic residual feed intake was found to be heritable in all 3 parities, with first parity being predominant (range: 22-34%). Genetic residual feed intake was highly correlated across parities for mid-to late lactation; however, genetic correlation across parities was lower during early lactation, especially when comparing first and third parity. We estimated a genetic correlation of 0.77 +/- 0.37 between North America and Europe for dry matter intake at first parity. Published literature on genetic correlations between high input countries/ continents for dry matter intake support a high genetic correlation for dry matter intake. In conclusion, our re-sults demonstrate the feasibility of estimating variance components for gRFI across parities, and the value of sharing data on scarce phenotypes across countries. These results can potentially be implemented in genetic evaluations for gRFI in dairy cattle.