Genetic Assessment of Growth and Reproductive Traits in Australian White Sheep
This study aimed to genetically assess the growth and reproductive traits of Australian White Sheep,providing a theoreti-cal foundation for scientific breeding,breeding stock expansion,and enhancement of desirable characteristics.Genetic evaluations were conducted on growth traits(birth weight,90-day weight,180-day weight,240-day weight,0-90 daily weight gain,90-240 dai-ly weight gain)and reproductive traits(first litter lambing number,total lambing number,first litter average weight,total litter aver-age weight,first litter total weight,total litter total weight).Using the R package AEFchida,an animal linear mixed model was es-tablished for variance components,genetic parameters,genetic correlations,and breeding values estimation.For birth weight,six animal linear mixed models with different random effects were compared using the R(v4-1-1)package AEFchida based on differ-ent maternal effects.The results indicated that the model BW1,considering individual additive effects,maternal environmental ef-fects,and maternal genetic effects,was identified as the optimal model.The calculated genetic heritability for birth weight was(0.33±0.04).The heritability of reproductive traits ranges from 0.03 to 0.12,indicating low heritability,with the heritability of live lambs(first born,multiparous)ranging from 0.03 to 0.04.The heritability of growth traits between 0.33 and 0.77 is high,with a her-itability of 0.46 to 0.67 for daily weight gain(0-90 days,90-240 days).The correlation between lambing number and growth traits was low(0～0.25),whereas the correlation between birth weight and growth traits was moderate(0.14～0.644),and phenotypic and genetic correlations were generally consistent.The breeding values for growth traits showed an overall increasing trend with in-creasing years,while the breeding values for reproductive traits exhibited a smaller degree of variation,suggesting less pronounced breeding effects.In conclusion,there is a significant difference in the genetic characteristics of reproductive and growth traits be-tween Australian white sheep.Different breeding methods should be adopted to further optimize the production performance and genetic characteristics of Australian white sheep.
Australian White SheepGrowth TraitsReproductive TraitsBirth WeightRandom ModelsGenetic Assessment
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