Genetic Evaluation of Friesw Al Sires Through Part Lactation Records

Abstract

Title- Genetic Evaluation ofFrieswal Sires Through part lactation Records The present study was undertaken on first lactation production and reproduction records of 1470 Frieswal cows maintained over. a period of to years (2003-2012) at Ambala and Meerut Military farms. The overall least squares means of AFC, FL305DMY,FLMY, FLL, FSP, FOP and ICI were 921.35 ± 05.17 days, 2658.57± 42.59 kg, 2718.28 ± 44.40 days, 304.15 ± 1.4, 163.19± 24.75, 1 14.20±5.94 days and 459 ± 8.06 days, respectively. The least squares means for first ten individual monthly milk yields were 281.18 ± 4.59, 335.78 ± 5.92, 328.11 ± 5.84, 305.96 ± 5.59, 282.78 ± 5.14, 269.66 ± 4.95, 258.14 ± 4. 72, 244.93 ± 4.59, 213.59 ± 4.97 and 178.103 ± 3.41 kg, respectively. The least squares means for cumulative 30, 60, 90, 120, 150, 180, 210,240, 270 and 300 days milk yields were 281.18 ± 4.60, 616.97 ± 10.16, 945.09 ± 15.58, 1251.04 ± 20.55, 1533.83 ± 25.06, 1803.50 ± 29.34, 2061.64 ± 33.31, 2306.58 ± 37.02, 2520.17 ± 40.20 and 2719.02 ± 48.17 kg, respectively. The estimates of genetic correlation between individual monthly milk yields and FL305DMY were high and statistically highly significant (P<0.01) except for the first and second months. The first month had low (0.141 ± 0.426) and non-significant genetic correlation with the FL305DMY while the second month (0.793 ± 0.426) had high but not significant genetic correlation as the standard error was high. The tenth month yield had the lowest genetic correlation of 0.798 ± 0.2~2 while the sixth month yield had the lowest estimate of0.982 ± 0.029. The phenotypic correlations of all the individual monthly milk yields with FL305DMY were high and statistically highly significant (P<O.Ol). In general, the phenotypic correlations of monthly yields with FL305DMY increased up to 6111 month (0.925±0.013) and the estimates there after declined and the 10111 month had comparatively lower phenotypic correlation (0.598±0.028). It was also observed that in most of the cases, except the first and second individual months, the estimates for phenotypic correlations were essentially lower than the corresponding genetic correlation estimates between the same traits. The genetic correlations among various cumulative monthly milk yields and FL305DMY were high, positive and highly significant (P<O.Ol) except for the cumulative 30 days yields which was low and non-significant and cumulative 60 days which was statistically significant (P,<O.OS). lt may also be noted that the estimates of genetic correlation increased as the days of cumulative yields increased and the cumulative 240 and 270 days milk yield had maximum genetic correlation of0.998. The highly positive and significant genetic correlations between the cumulative yields and FL305DMY suggested that the merit of the cows for milk production could be assessed effectively even in the early stages of lactation. The phenotypic correlations of various cumulative monthly milk yields with FL305DMY were high, positive and highly significant (P<O.Ol). Unlike the phenotypic correlation of individual monthly milk yields with FL305DMY, the correlation estimates showed an increasing trend and the cumulative 270 days had the maximum phenotypic correlation of0.994 ± 0.004. It was also observed that in most of the cases the estimates for phenotypic correlations were essentially smaller than the corresponding genetic correlation estimates between the same traits and the trend was similar to the trend observed for the individual monthly milk yields. The breeding value of 55 Frieswal sires estimated on the basis of first lactation 305-day or less milk yield by three different methods along with their ranks. For first lactation 305-day or less milk yield the highest overall breeding value (2781.0 kg) was obtained by DFREML method and the lowest breeding value (2660.70 kg) was obtained by BLUP method. The average breeding value of Frieswal sires for individual third month milk yield were estimated as 333.40, 329.18, and 337.64 kg, respectively, by LSM, BLUP and DFREML methods; while the corresponding values for cumulative 90 days milk yield were 961.58, 947.45, and 972.81 kg, ~espectively. For all the three traits, the DFREML method was adjudged as the most efficient and stable method of sire evaluation. The relationship of EBVs among the three traits revealed higher degree of within and across methods rank correlations. It was concluded that the Frieswal sires may be evaluated on the basis of individual third month I cumulative 90 days milk yield for selecting the sires for increasing the FL305DMY.