Exploring Genetic Parameters and Correlations Among Growth, Reproductive, and Survival Traits in Doyogena Sheep
Authors:
In central Ethiopia region, the community-based breeding program (CBBP) for improving Doyogena sheep has utilized growth traits as a primary selection criterion since its establishment. Growth, reproduction, and survival traits play a vital role in the overall productivity, so it is critical to evaluate how these traits changing overtime. This study purposed to examine variance components, genetic parameters for growth, reproductive, and survival traits, and correlations between growth and other economically important traits in Doyogena CBBPs. The data was gathered over 10 years (2013–2022) and traits considered were birth weight (BWT), weaning weight (WWT), weight at 6 months (SMW), annual reproductive rate (ARR), lambing interval (LI), litter weight at birth (LWB), litter size at birth (LSB), litter weight at weaning (LWW), litter size at weaning (LSW), ewe postpartum weight (EPPW), preweaning lamb survival (PWLS), and lamb survival up to 6 months (LSSM). Using a restricted maximum likelihood procedure, WOMBAT software was used to analyze the traits in a multitrait animal model. The values for additive heritability estimates for BWT, WWT, SMW, LSB, LWB, LSW, LWW, LI, ARR EPPW, PWLS, and LSSM were 0.37, 0.26, 0.21, 0.10, 0.24, 0.03, 0.22, 0.15, 0.12, 0.14, 0.10, and 0.08, respectively. The majority of performance traits show positive and significant (p < 0.001) annual genetic trends in breeder cooperatives, indicating the feasibility of breed improvement programs. Positive and low to moderate genetic correlations were observed between growth (WWT and SMW) with most of the reproduction and lamb survival traits. The medium heritability and the moderate correlations between growth and litter weight traits (LWB and LWW) suggest the importance of considering litter weight in addition to growth traits in selection processes. In conclusion, optimizing the Doyogena sheep breeding program and improving management conditions are recommended to achieve the best outcomes and ensure long-term sustainability.