Genetic And Environmental Factors Influencing Birth Weight in Yankasa And Yankasa West African Dwarf Crossbred Sheep in Humid Southwest Nigeria.

Abstract

birth weight ( B W ) record of purebred Yankasa and Yarakwsa "West Africa Dwarf (WAD)
crossbred lamb raised semi-intensively in a commercial farm at Jbwdan were used to estimate the
various genetic and HOE-genetifca ctors affecting the trait using the Genera2 Linear Model (GLM)
analysis of variance pmcedare of the SAS package. Dam breed, type 4 birth, parity and brith year
exerted significant bfzp2uearce (PaO.01) on B W , sex, dam breed Sex sand dam breed *birth season
interaction signifbcanily (P.-'0.05) influenced the trait while birth seasola did not have any significant
fnjluence (P>O.05) on BRITo 7 7k~as t square meanskstrandard errors of BWT wew 2.36 + 0.20kg; 2.53
& 0.25kg and 2.18f 0.21kg respectiaselypbr otterall, male and female lambs. me phenotypic correlations
of dam weight af parturition and B W of lambs is low in each dam breed but moderately high and
sip.@cant (P<O.Ol) in the pooled data of both dam breed. Repeatability of BWr were 0.41 f 0.006;
69.29 -1- 0.14 and 0.43 5 0.005 in Yankasa, WAD and data of both dram breeds respectively. This study
rroealed that B W I of lambs is subjected to breed and environmmfa&eplw rig'euikasaas and that the BWT of
WAD sheep cran be irnprov~d by crossbreeding with Yankeasw breed.