Genetic analysis of lactation traits in Jamunapari goats

Data on 1367 lactations from 57 1 Jamunapari does, maintained ( 1985 to 2005) at the Central Institute for Research on Goats, Makhdoom. Mathura, Uttar Pradesh, India, were utilized to study the lactation traits and their genetic parameters. The 90-day, 140-day and total milk yield for this breed averaged 79.89 +/- 1.41, 119.17 +/- 2.66 and 150.79 +/- 3.37 lit., respectively. The average lactation length was 162.01 +/- 2.68 days. Significant differences among sires existed within the breed for all the lactation traits. There were significant variations for all lactation traits of does among different kidding years/periods and lactation order. Does kidded from March-April had significantly higher milk yields than the does kidded from October-November. The interaction effect of period and season of kidding also yielded significant variations for all lactation traits. Both the linear and quadratic regressions of days of lactation (milking) showed significant effect on total milk yield. The heritabilities of all lactation traits were moderate in magnitude, ranging from 0.17 to 0.24. Genetic correlations among the lactation traits were medium (0.41 +/- 0.32) to high (0.99 +/- 0.01) in this study.