Selection in Marwari sheep: 3. response to selection and trends

772 lambs of an elite selected and tester groups born to 63 sires of Marwari breed were analyzed to estimate response to selection, genetic, phenotypic and environmental trends in birth, 3,6,9 and 12 months weight, greasy fleece weight in first and second six monthly clips (GFW I and GFW II) and selection index value. The observed responses were much higher than expected for all the traits in both the groups except for birth weight, GFW I and selection index value (SIV) in tester group and 3 month weight in elite group. The observed responses were higher in elite group for birth and 12 month weight, GFW I and SIV. The genetic, phenotypic and environmental trends were estimated to be positive for all traits except genetic trend for birth weight and SIV and environmental trend for greasy fleece weights where these were negative. Positive genetic trend indicated genetic improvement of the flock over the years.