Data consisted of 284 performance records belonging to 63 Tharparkar cows completing at least three lactations spread over a period of fifteen years (2002 to 2016) for genetic analysis of milk production traits viz. dry period, lactation length, lactation milk yield, 300 days milk yield, milk yield per day of lactation length and milk yield per day of calving interval. The overall least-squares means were 138.47 ± 3.02 days, 281.71 ± 3.43 days, 2003.29 ± 13.40 kg, 1885.81 ± 23.07 kg, 6.65± 0.10 kg and 4.03 ± 0.04 kg, respectively. Heritabilities ranged from 0.08 to 0.59, genetic correlations between the milk production traits ranged from 0.57 to 0.93 and phenotypic correlations ranged from 0.02 to 0.56. The effect of period of calving on service period, lactation milk yield, three hundred days milk yield and milk yield per day of lactation length; effect of season of calving on lactation length were significant. The random effect of sire was observed to be highly significant (P≤ 0.01) on all the production traits.
Key words: Tharparkar, Heritability, Genetic Correlation, Phenotypic Correlations, Sire