# Application of the “Yuyang Muxin” Breeding Chip in Huang-Huai Sheep: A Six-Year Comprehensive Evaluation of Production and Meat Quality Traits

## TL;DR

A six-year breeding program using a custom chip improved meat quality and productivity in Huang-Huai sheep while maintaining genetic diversity.

## Contribution

The study demonstrates the effectiveness of the 'Yuyang Muxin' chip for multi-trait genetic improvement in sheep.

## Key findings

- 6-month ram body weight increased by 9.1% and meat quality improved with lower shear force and higher intramuscular fat.
- Lambs weaned per ewe per year rose from 2.38 to 2.56, indicating improved reproductive efficiency.
- CIDEa and FABP3 gene expressions were strongly correlated with meat quality traits after Bonferroni correction.

## Abstract

The Huang-huai sheep, a new breed certified in China in 2019, is well-suited for intensive farming. To enhance its genetic potential, a six-year (2020–2025) breeding program was conducted at two core farms using the custom-designed “Yuyang Muxin” breeding chip, which enables selection for reproduction, growth, and meat quality. After six years of selection, 6-month ram body weight increased by 9.1%, dressing percentage rose by 1.8 percentage points, and loin muscle area expanded by 9.4%. Meat quality improved, with shear force decreasing by 14.1% and intramuscular fat increasing by 40.0%. Lambs weaned per ewe per year increased from 2.38 to 2.56. EBV trend analysis confirmed that these gains were primarily genetic, while genetic diversity was maintained (FIS < 0.05). Strong correlations between CIDEa/FABP3 expression and meat quality traits remained significant after Bonferroni correction. Nine months was identified as the optimal slaughter age. This study demonstrates that the “Yuyang Muxin” breeding chip is an effective tool for simultaneous improvement of multiple traits in sheep.

The Huang-huai sheep (Dorper × Small-tailed Han), certified in China in 2019, initially exhibited issues with genetic uniformity and meat quality. A six-year (2020–2025) breeding program was conducted at two core farms (collectively housing ~2400 breeding ewes representing 12 bloodlines) using the custom “Yuyang Muxin” 10 K SNP chip containing functional markers for reproduction (FecB), growth (CLPG, ACTC1), and meat quality (FABP3, CIDEa). Genotyping and marker-assisted selection were integrated with BLUP breeding values. After six years, favorable FecB genotype frequency increased from 68.97% to 82.58% (p < 0.05), while genetic diversity remained stable (FIS < 0.05). Mixed model analysis accounting for farm and year random effects revealed significant genetic gains: 6-month ram body weight increased by 9.1% (58.50 to 63.80 kg, p < 0.05), dressing percentage improved from 56.02% to 57.8% (p < 0.05), and loin muscle area expanded by 9.4% (24.50 to 26.8 cm2, p < 0.05). Meat quality was enhanced, with shear force decreasing by 14.1% (38.65 to 33.20 N, p < 0.05) and intramuscular fat increasing by 40.0% (2.0% to 2.8%, p < 0.05). Lambs weaned per ewe per year increased from 2.38 to 2.56 (p < 0.05). EBV trend analysis confirmed that improvements were primarily genetic. After Bonferroni correction, CIDEa expression was strongly correlated with intramuscular fat (r = 0.89, p < 0.001) and FABP3 expression with arachidonic acid (r = 0.70, p < 0.001). Nine months was identified as the optimal slaughter age. The “Yuyang Muxin” breeding chip effectively accelerated genetic improvement in Huang-huai sheep, enabling synergistic enhancement of multiple traits.