ASSESSMENT OF GENETIC PARAMETERS VIA REMLAND ML METHODS FOR SOME MILK TRAITS IN ZARIBIGOATS

Document Type : Original Article

Abstract

The aim of the present study is to investigate some factors affectingmilk traits in Zaribi goat and estimate its genetic parameters. The data setcomprised from 786 lactation records of 328 does, progeny of 56 sires and232 dams for total milk yield at 90 day (90 DMY), total milk yield (TMY)), dailymilk yield (DMY) and lactation period (LP) were collected from a herd of Zaribigoat raised in El-Serw Experimental Station, located in the North Eastern partof the Nile Delta, Egypt, which belongs to Animal Production ResearchInstitute (APRI), Ministry of Agriculture through 10 years from 2003 to 2012.
Fixed and random factors affecting the traits were investigated according toGLM procedure of Statistical Package Program (SAS, 2004). Also, twomethods (REML * ML) were used to obtain the variance components. Overallmeans along with their standard deviation for TMY, 90DMY, DMY and LPwere 245.21 ± 70.33(Kg), 88.53 ±24.43 (Kg), 0.997 ±0.266 (Kg) and 47.06±40.66 (day), respectively. Least squares analysis of variance revealed thatbuck, parity, birth type, kidding season and kidding year were highlysignificant (P<0.001) sources of variation for all milk traits under study exceptthe effect of kidding season was not significant. Heritability estimates viaREML were 0.27, 0.20, 0.06 and 0.16 while those estimated by ML were0.25.0.19, 0.04 and 0.14 for TMY, 90DMY, LP and DMY, respectively.Genetic, phenotypic and environmental correlations were positive showing noantagonism except that between lactation period and daily milk yield wasnegative in sign.It is concluded that the two methods for variance componentestimation gave relatively similar findings. In addition, the influence of nongeneticfactors should be considered in selection program and an adjustmentfor the significant environmental factors should be made.

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