Sire by Region Interaction for Production Traits in Dairy Cattle

Interaction between Genotype and Environment in Sire Evaluation for Milk Production

“…Estimated correlations between breeding values for sires tested in different regions or countries have turned out to approximate the expected correlations, thus indicating that the genetic correlation is unity (Lytton & Legates, 1966;Lindstrom et al, 1970;Petersen, 1975;Powell & Dickinson, 1977). Genetic correlations between different levels of production within national populations have ranged between 1.0 and 0.85 (Robertson et al, 1960;Syrstad, 1966;McDaniel & Corley, 1967;Averdunk & Alps, 1971; Verde et al, 1972).…”

Estimation of Genetic Parameters for Milk and Fat Yields of Dairy Cattle in Spain and the United States

“…72, No. 11,1989 cost per round. Size of the Frobenius norm (computed as square root of sum of squares of elements of the matrix of differences in variance components between successive rounds) relative to estimates of variance components (which was smaller than.…”

“…Numerous studies have dealt with genotype by environment interactions in dairy cattle. Most (4,6,7,11,12,25) showed no such interaction of practical importance for different definitions of environment within countries. The relatively large interac-1989 J Dairy Sci 72: [3013][3014][3015][3016][3017][3018][3019][3020][3021][3022] 3013 tion between sire and amount of grain fed in summer detected by Mao and Burnside (12) with Canadian data is an exception.…”

Genotype × Environment Interaction for Age at First Calving in Brazilian and Colombian Holsteins

“…Comparative reproductive characteristics and G×E studies in cattle populations located in different regions or countries are needed to determine whether imported genotypes exhibit reproductive problems in (sub)tropical countries. For Lytton and Legates (1966), G×E can be observed in reproductive characteristics and such variables could be weighted along with production traits in animal selection programs. The objective of this study was to determine the genotype × environment interaction of age at first calving of Holstein cattle between Brazil and Colombia.…”