GENETIC AND NONGENETIC SOURCES OF VARIATION IN YIELD AND COMPOSITION OF MILK IN VERATA GOATS

Non-genetic sources of variation in yield of milk, fat, protein and so lids and contents in Verata goats were studied on three experimental f arms. Interval in days from kidding to first record was an important f actor of variation affecting estimates of milk yield. Herd differences existed for fat content (probably related to different feeding regime s) and for protein, fat and solids yields. Lactation number, month of kidding and number of kids affected significantly most traits. Herd-ti mes-year interaction was another important factor of variation. Herita bility of milk, protein, fat and solids yields and for protein, fat an d solids contents were 0.24, 0.04, 0.2, 0.1, and 0.14, 0.3 and 0.52. r espectively. Large errors were due to few genealogical data. However, the more precise estimates of repeatability confirmed the validity of confidence intervals for the heritabilities. Phenotypic correlations b etween milk yield, fat and protein yields were 0.82 and 0.68. Fat and protein contents were positively correlated (r=0.81).