Physiological pathways linking body conformation and reproductive efficiency in Murciano-Granadina does: A novel...

This study examines the relationship between linear appraisal and long-term fertility dynamics in Murciano-Granadina goats, analyzing a dataset of 21,757 does and 32,693 artificial insemination (AI) records collected over 10 years. Fertility was assessed by day of insemination, buck batch, and semen type (fresh/chilled vs. frozen/thawed). Descriptive fertility rates revealed mean values of 52.6 % (day of insemination), 53.4 % (buck batch/day), and 48.3 % (semen type). Canonical correlation analysis (rCCA) showed significant but moderate associations between fertility and morphology (canonical correlations: 0.191, 0.144, and 0.045). First two canonical functions explained 96.7 % of variability, though redundancy coefficients were low (≤0.0146), indicating that morphology accounted for only a moderate proportion of fertility variability. Specific LAS traits provided subtle insights: chest width and rump width negatively correlated with fertility (r = -0.14 and -0.11, respectively), while bone quality showed the highest positive association (r ≈ 0.05). Rear udder insertion height and hind leg side view were positively linked to fertility resilience under frozen/thawed semen use. Conversely, excessively deep udders and large body size tended to compromise fertility, likely through mastitis risk or negative energy balance. Findings suggest skeletal robustness, udder attachment, and hind leg conformation support both fertility and productive longevity, while extreme dairy specialization may reduce reproductive outcomes. Overall, fertility in Murciano-Granadina does is multifactorial and moderately explained by linear appraisal traits, hence integrating morphological evaluation with artificial insemination strategies may enhance selection decisions. Future breeding programs should prioritize bone quality, functional udder morphology, and locomotor soundness to balance milk productivity with reproductive efficiency.