Impact of Herd Size on Milk Production in a Dairy Cattle Farm under Semi-arid Climate

Background: This study examines the impact of herd size on milk production in semi-arid regions, where productivity and efficiency are critical. Herd size (HS) is a key determinant of both milk yield and quality. Methods: Data from 88 farms in the Souss-Massa region, affiliated with the COPAG cooperative, were analyzed to assess Total milk yield (TMY), standardized 305-day milk yield (305-dMY), Standardized fat yield (MFY), Fat content (FC) and lactation duration (LD) in holstein cows. Result: The average values recorded were: 7052.19±1849.68 kg for TMY, 324.92±42.93 days for LD, 6596.66±1624.99 kg for 305-dMY, 242.18±62.36 kg for MFY and 3.70±0.53% for FC. Large herds (HS greater than 150) showed significantly higher productivity (p less than 0.001), averaging 7360.86 kg for TMY, 6894.98 kg for 305-dMY and 242.33 kg for MFY, though with slightly lower fat content (3.65%). Smaller herds (HS≤30) yielded 6554.44 kg for TMY, 6095.92 kg for 305-dMY and 229.66 kg for MFY, but with higher FC (3.79%). Large farms benefit from modern management, automated health monitoring and optimized nutrition but face challenges such as higher stress, disease incidence and environmental concerns. These results highlight the need for balanced management strategies that enhance productivity while ensuring animal welfare and sustainability in semi-arid dairy farming.