GENETIC AND PHENOTYPIC TRENDS IN MILK PRODUCTION TRAITS OF ANGLO NUBIAN GOATS FROM SELECTED FARMS IN THE PHILIPPINES

Abstract

Using 570 lactation records from 172 Anglo Nubian goats produced from 21 sires and 161 dams and kidding from 2000 to 2016, heritability estimates based on dam-daughter regression were 0.52 ±0.22, 0.71 ±0.22, and 0.29 ±0.22 for total milk yield (TMY), daily milk yield (DMY), and number of lactations or parity (NLact), respectively. Heritability estimates for lactation length (LL), age at first kidding (AFK) and kidding interval (KI) were close to zero or had large standard errors. Repeatability estimates were 0.46 ±0.04 and 0.47 ±0.04 for TMY and DMY, respectively. Significant genetic correlations (P<0.01) were found between TMY and LL (r=0.72), TMY and DMY (r=0.95), TMY and NLact (r=0.97), and DMY and NLact (r=0.90). Significant phenotypic correlations (P<0.01) were found between TMY and LL (r=0.59), TMY and DMY (r=0.80), TMY and NLact (r=0.51), TMY and AFK (r=-0.36), DMY and NLact (r=0.61), DMY and AFK (r=-0.39), and NLact and AFK (r=-0.33). Comparison of genetic (doe’s estimated transmitting ability) and phenotypic trends from 1996 to 2012 showed environmental effects (doe’s year and month of birth and/or parity) comprising 52.56%, 75.83%, 13.77% and 52.13% of the average phenotypic values for TMY, LL, DMY and NLact, respectively.