Genetic evaluation of sires in Surti buffalo
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Date
2006
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MPUAT, Udaipur
Abstract
Data on 554 buffaloes maintained at Livestock Research Station, Vallabhnagar, Udaipur over a period of 29 years (1976-2004) were utilized for the present study.
The means for TMY, 305 FLMY, FLL and FPY were 1065.08 ± 15.27 kg, 1034.61 ± 13.45 kg, 266.33 ± 2.87 days and 6.90 ± 0.06 kg respectively. The variation in terms of CV among first lactation production traits ranged from 18.84 per cent (FPY) to 33.75 per cent (TMY). The average initial milk yield in first month was 151.61 ± 1.56 kg. The peak yield was attained in 2nd month averaging 163.28 ± 1.71 kg and thereafter it declined to a minimum of 110.14 ± 1.60 kg in 5th month. The coefficient of variation for cumulative milk yield ranged from 21.80 to 23.05 per cent. However, the averages for cumulative milk yield upto 60, 90, 120 and 150 days were 314.89 ± 2.92, 477.95 ± 4.54, 607.36 ± 5.85 and 717.50 ± 7.03 kg, respectively. The average test day milk yield varying from a minimum of 3.57 ± 0.06 kg on 10th test day (155th day) to a maximum of 5.40 ± 0.07 kg on 6th test day (95th day) with the variability of test day milk yield ranging from 25.70 to 41.84 per cent.
The TMY, 305 FLMY, FLL and FPY were significantly affected by sire and period of calving. The season of calving also significantly affected the TMY, 305 FLMY, FPY while its effect on FLL was non-significant. Duncan’s new multiple range test indicates that buffalo that calved during summer season produced significantly higher milk yield (TMY, 305 FLMY, FPY) as compared to buffalo that calved during other seasons. Different segments of the monthly and cumulative milk yield under study were significantly influenced by sire, period and season of calving.
The effect of sire was significant on all the test day traits except TDMY7. The variation due to period of calving was observed in TDMY1, TDMY3, TDMY4, TDMY6 and TDMY7 only while season of calving significantly influence all the test day yield. The coefficients of heritability for TMY and 305 FLMY was higher and significant at 0.509 ± 0.152 and 0.412 ± 0.140, respectively. However, heritability estimates for FLL and FPY were moderate and significant at 0.251 ± 0.119 and 0.242 ± 0.118, respectively. The heritability estimates for monthly milk yield ranged from 0.254 ± 0.119 (MMY1) to 0.551 ± 0.156 (MMY2). The coefficients of heritability for cumulative milk yield from CMY60 to CMY150 were almost similar ranging from 0.526 ± 0.154 to 0.585 ± 0.160. The heritability estimated for TDMY1 was moderate and significant at 0.327 ± 0.129 and on the other hand, heritability reduced to 0.191 ± 0.110 for TDMY2 and start increasing which reaches to maximum at 0.387 ± 0.137 for TDMY6. The heritability for TDMY7 to TDMY10 was low to moderate and non-significant.
The genetic and phenotypic correlation coefficients among TMY, 305 FLMY, FLL and FPY were positive high and significant. The genetic and phenotypic correlation coefficients among part lactation milk yield were positive, high and significant. Most of the genetic correlation among test day milk yield were positive ranging from low to high in magnitude. The phenotypic association among test day milk yield showed that coefficients was higher in the initial test day milk yield and decreased when test day interval were increased. The correlation coefficients between consecutive test day were found very high through out the test day included in the study.
The genetic and phenotypic correlation of monthly and cumulative milk yield with TMY and 305 FLMY were positive and moderate to high. The genetic correlation coefficients of test day milk yield with first lactation milk yield were positive ranging from 0.220 ± 0.260 to 0.902 ± 0.090 for TMY and 0.297 ± 0.266 to 0.984 ± 0.222 for 305 FLMY. The coefficients increases with increase test day milk yield from TDMY1 to TDMY5. The coefficients of phenotypic correlation of test day milk yield with TMY and 305 FLMY were positive and significant, showing increasing trend over test day period advanced.
The relative efficiency of selection on the basis of MMY2 to MMY5 over TMY and 305 FLMY were higher. Similarly the efficiency of selection on the basis of cumulative milk yield from days 60 to 150 were also higher and varied with in a narrow range. The relative efficiency of selection on the basis of TDMY1 and TDMY2 over TMY and 305 FLMY were considerably lower than TMDY3 to TDMY10.
The estimates of average breeding value for first 305 days or less milk yield by contemporary comparison method proposed by Jain and Melhotra (1971a) was 1044.34 kg. In this method, the BV of 25 sires (49.0 %) were above the average BV and 26 sires (51.0 %) were below the average breeding value.
The error variance of Regressed least-squares method (RLS) was lowest. The error variance for Jain’s contemporary comparison was followed by RLS method. Maximum error variance was found in RCC method.
The coefficient of variation was highest (21.59 %) in RLS which was more close to CV of unadjusted data and lowest (10.93 %) in RCC method.
The breeding value estimated by JCC, RCC and RLS had slightly positive skewness. The breeding value estimated by JCC and RLS showed no kurtosis.
The rank correlation between RCC and HMC and OLS and RLS were positive and significant. The product moment and rank correlations between breeding values of sires estimated by RLS and JCC methods for 305 FLMY and FPY was high and significant. Similarly, the product moment and rank correlations between breeding value estimated by RLS method for first lactation milk yield (305 FLMY and first lactation peak yield, part lactation milk yield) (MMY2, MMY3, CMY60 and CMY90) were also positive and highly significant.
The product moment and rank correlation coefficients between breeding value of sires for 305 FLMY and test day milk yield was also positive high and significant. The coefficient varied within a narrow range from 0.863 to 0.907 (product moment) and 0.841 to 0.849 (rank correlation). Similar trend was observed for breeding value estimated by JCC method.
It was observed that the correlation of son’s breeding value estimated by RLS and JCC methods (most efficient and stable method of sire evaluation) with dam’s as well as paternal and maternal grand dams first lactation, best lactation, average of first two lactation and average of first three lactation milk yield were low and non-significant .
The coefficients of correlation of son’s breeding value estimated by both the methods with average first lactation milk yield of 5, 10, 15 and all available paternal sisters and average first lactation milk yield of 2, 3 and all available material sisters were also non-significant.
The association between son’s breeding value and average first lactation milk yield of 5, 10 and all available paternal half sib of sires were also non-significant. On the other hand, positive and significant correlation was observed between son’s breeding value and breeding value of sire and grand sire
Description
Genetic evaluation of sires in Surti buffalo
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Citation
Singh and Tailor, 2006