Estimation of genetic parameters for test day records of Murrah graded buffaloes

The present study was carried out using test day yield for sire evaluation in Murrah graded buffaloes. A total of 2329 test day lactation records of daughters of 79 sires distributed in 47 villages under field progeny testing programme in Anand milk shed area. Heritability estimates for Test Day Milk Yield (TDMY) records were ranged from 0.01 to 0.13. Heritability estimate for Predicted First Lactation Yield for 305 days (PFLY 305) was 0.01. The phenotypic correlations among monthly test day milk yields and with 305-day milk yield were found to be highly significant (P<0.01). The estimates of phenotypic and genetic correlation among all the monthly test day milk yields ranged from 0.22 to 0.86 and from 0.20 to 1.11 respectively. Heritability estimates for Test Day Fat Percent (TDFP) records were higher in first half than second half of lactation and ranged from 0.01 to 0.06 for TD milk fat percent. Heritability estimate for 305-days fat percent was 0.02 for milk fat percent. The phenotypic correlations among monthly test day milk fat percent and with 305-day milk fat percent were found to be highly significant (P<0.01). The estimates of phenotypic and genetic correlation among all the monthly test day milk fat percent ranged from 0.05 to 0.78 and from 0.22 to 1.99 respectively.