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Genetic studies on first lactation traits and sire evaluation using different methods in Murrah buffaloes

KrishiKosh

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Title Genetic studies on first lactation traits and sire evaluation using different methods in Murrah buffaloes
 
Creator Tewari, Reetu
 
Contributor Kumar, D.
 
Subject genetic analysis, lactation stage, sires, buffaloes, buffalo breeds, dairy farming, inheritance, calving
 
Description Thesis-PhD
The present investigation was undertaken utilizing the records of 577 daughter-dam pairs of Murrah buffaloes maintained, maintained at 8 military dairy farms Ferozepur, Ambala, Jullundhar, Jhansi, Lucknow, Merrut, Bareilly and Agra) and one instructional dairy farm of G.B. Pant. Univ. of Agri. & Tech., Pantnagar for studying the inheritance pattern of different economic traits and to evaluate the sires using Least-squares (LS), Best linear unbiased prediction (BLUP) and Derivative free restricted maximum likelihood (DFREML) methods. Least squares means of age at first calving (AFC), first calving interval (FCI), first lactation milk yield (FLMY), first lactation period (FLP), weight at first calving (WFC) and first service period (FSP) of daughters were 43.38 ± 0.94 months, 418.14 ± 17.16 days, 1903.37 ± 60.67 kg, 326.43 ± 7.89 days, 509.93 ± 6.93 kg and 134.99 ± 17.11 days, respectively. The heritability estimates of AFC, FCI, FLMY, FLP, WFC and FSP traits were estimated as 0.40 ± 0.15, 0.14 ± 0.10, 0.31 ± 0.14, 0.23 ± 0.12, 0.36 ± 0.13 and 0.06 ± 0.09, respectively. The genetic and phenotypic correlations indicated that selection for lower age at first calving and higher lactation milk yield can be used as a selection criterion for the genetic improvement in the herd. The buffaloes having higher weight at first calving had longer first calving interval, lactated for longer period and conceive earlier. A total number of sixty eight Murrah buffalo sires were genetically evaluated on the basis of 300-day milk yield records of 577 dams and daughter records using six different indices, viz., simple daughter’s average index (I1), equiparent index (I2), corrected daughter average index (I3), contemporary daughter average index (I4), corrected contemporary daughter average index (I5), and dairy search index (I6). The various indices according to the least variances and least standard errors of the index values were ranked as I4, I5, I3, I2, I1 and I6 in relative descending order of superiority. The rank correlation between I1 and I4 was maximum as 0.986, thereby indicated that the index I1 and the index I4 gave the ranking of the sires in more or less in the same order. The rank correlations between I4 and the rest of the indices were found to be comparatively quite low, indicating comparatively more independency of the index I5. The rank correlations among indices I1, I2, I3 and I4 were of highly significant. The rank correlation between I5 and I6 was also highly significant.The sires were also evaluated using LS, BLUP and DFREML methods. LS and BLUP method gave the same result for evaluating the different sires considering all the traits, viz. AFC, FCI, FLMY, FLP, WFC and FSP. The values of lower error variance and high relative efficiency suggested that BLUP method was best for evaluating the different sires followed by LS and DFREML methods using different first lactation traits. The comparison among I4, I5, LS, BLUP and DFREML methods showed that the ranking of sires was different for these methods. The standard errors revealed that LS and BLUP methods were best for evaluating the sires for first lactation milk yield followed by DFREML, I4 and I5 methods.
 
Date 2016-07-23T15:55:08Z
2016-07-23T15:55:08Z
2007-04
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/69634
 
Language en
 
Format application/msword
 
Publisher G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)