Integrating Quantitative Genetics and Molecular Approaches to Improve Litter Size in Sheep Sohaib Akram1,2, Suyadi Suyadi3, VM Ani Nurgiartiningsih3*, Khadija Salka2
1University of Veterinary and Animal Sciences Lahore, 54000, Pakistan
2Student of Master^s Degree in Animal Science, Universitas Brawijaya, Malang, 65145, Indonesia
3Department of Animal Reproduction and Breeding, Faculty of Animal Science, Universitas Brawijaya, Malang, 65145, Indonesia
*Corresponding Author: vm_ani[at]ub.ac.id
Abstract
Litter size remains one of the most influential traits affecting the efficiency and profitability of sheep production. The inheritance of this trait is complex, as it has both polygenic effects and some highly significant fecundity genes that control this trait. Many quantitative genetic studies in different sheep populations always quote low to moderate heritability estimates (somewhere between 0.05 and 0.15), thus confirming prospects for genetic improvement but also environmental influence. In addition, genetic correlations indicate possible antagonisms between prolificacy, lamb survival, and growth, which need to be accounted for in breeding strategies. Advances since 2015 have improved the accuracy of heritability estimation using genomic relationship matrices, genomic BLUP, and multi-trait models, which facilitate the construction of more balanced selection indices. On the molecular side, extensive work has been carried out on significant genes such as BMPR1B (FecB), BMP15, and GDF9, together with genome-wide association studies and meta-analyses that have identified novel candidate loci related to ovulation rate and litter size. By combining quantitative and molecular approaches, sheep breeding programs can more effectively exploit both traditional pedigree-based information and DNA-based tools. It would lead to more rapid genetic advancement while still sustaining welfare-oriented livestock production associated with global development goals.
