Prediction of First Lactation Milk Yield Using Test Day and Part Records for Sire Evaluation in Surti Buffaloes
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Date
2011
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MPUAT, Udaipur
Abstract
Data on 453 Surti buffaloes maintained at “Network Project on Surti buffaloes’’ Livestock Research Station, Vallabhnagar, Udaipur over a period of 29 years (1976-2004) were utilized for the present study. The overall means for OMY 305 and OMYT were 1116.97 ± 13.49 and 1155.16 ± 10.93 kg respectively. The averages for predicted 305 days first lactation milk yield based on systematic and stratified random sampling schemes with fortnightly, monthly and bimonthly intervals were 1142.79 ± 11.96, 1152.82 ± 12.05, 1189.36 ± 14.65 and 1142.90 ± 12.04, 1151.44 ± 12.25, and 1192.29 ± 14.60 kg respectively.
The effect of sire and season of calving was significant on OMY305 and OMYT. The sire had significant effect on all the segments of fortnightly, monthly and bimonthly milk yield except FNY1 and FNY2. The variation due to season of calving on monthly part lactation milk yields was found to be significant. The sire and season of calving had highly significant effect on predicted 305 days first lactation milk yield based on both the sampling schemes with fortnightly , monthly and bimonthly intervals.
The coefficients of heritability for OMY305 and OMYT were higher at 0.639 ± 0.181 and 0.669 ± 0.184 respectively. The range of heritability estimates for fortnightly milk yield from 0.180 ± 0.126 (FNY12) to 0.449 ± 0.161 (FNY6), monthly milk yield from 0.189 ± 0.128 (MMY1) to 0.432 ± 0.159 (MMY5) and bimonthly milk yield from 0.327 ± 0.146 (BMY1) to 0.443 ± 0.160(BMY2). The coefficients of heritability for cumulative milk yield showed increasing trends over period advanced and varied from 0.327 ± 0.146 (CMY60) to 0.552 ± 0.172 (CMY210). The heritability estimates for predicted 305 days first lactation milk yield based on systematic sampling scheme with fortnightly, monthly and bimonthly intervals were 0.584 ± 0.176, 0.587 ± 0.176 and 0.549 ± 0.172 respectively. The respective estimates based
on stratified random sampling scheme were 0.582 ± 0.175, 0.601 ± 0.177 and 0.378 ± 0.152.
The genetic and phenotypic correlation coefficients of OMY305 with OMYT were positive and high at 0.997±0.008 and 0.954±0.143 respectively. The genetic and phenotypic correlation coefficients of OMY305 and OMYT with part yields (fortnightly, monthly, bimonthly and cumulative milk yield) as well as predicted milk yield based on systematic and stratified sampling schemes with the interval of fortnightly, monthly and bimonthly were also positive and highly significant.
More than 50% accuracy of prediction of 305 days milk yield by ratio factor method was obtained with test records drawn during 10th and 11 th fortnight when sampled by systematic and stratified random sampling schemes respectively. Similarly, the accuracy of 62.09 % was obtained by 10th fortnight part record.
The equations of choice (> 75% accuracy) for predicting first lactation milk yield for farm and field conditions are as follow
Field - Y =142.304 + 5.587 x F15S10+ 4.918 x F15S4 +5.389 x F15S14 (R2 = 77.50 %)
Field - Y = 138.422 + 5.528 x R15S11+5.194 x R15S4+5.257 x R15S14 (R2 = 77.20 %)
Farm – Y = 149.522+9.238 x FNY10+5.346 x FNY6 (R2 = 75.50 %)
Field – Y = 161.023 + 2.695 F30S6+ 2.612 x F30S3 + 2.368 x F30S7 (R2 = 76.90 %)
Field - Y = 182.793 + 2.331 x R30S6+2.628 x R30S3 +2.540 x R30S7 (R2 = 75.10 %)
Farm – Y = 91.286 + 0.534 x MMY7 + 0.302 x MMY3 (R2 = 83.20%)
Farm - Y = 6.446 + 2.762 x BMY3 + 1.517 x BMY1 (R2 = 82.80%)
The error variance of PMY under systematic sampling schemes was slightly lower than stratified random sampling schemes for the same interval of recording. Contemporary comparison method (I2) had the lowest error variance for OMY as well as PMY under all the sampling schemes. The relative efficiency of method I1 and I3 with respect to most efficient method I2 was 98.0 and 97.8 %. The rank and product moment correlations of most efficient method I2 with I1 and I3 for OMY and PMY’s under various sampling schemes were positive, high and significant.
The number of daughter with 4th to 6th fortnightly part records required to give the information equivalent to that of different progeny group size with complete lactation yield, would be nearer or slightly higher than the number of daughters with complete lactation yield.
The most efficient method i.e. contemporary comparison method (I2) , the correlation coefficients of breeding value based on 5 and 8 daughters with that of 10 or more daughters were positive, high and significant at 0.992 and 0.949 with 98.4 and 90.1 % accuracy respectively.
Description
Prediction of First Lactation Milk Yield Using Test Day and Part Records for Sire Evaluation in Surti Buffaloes
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Citation
Rathore and Tailor, 2011