Twin Pregnancies in Dairy Cattle: Incidence, Reproductive Performance, and Farm-Level Economic Impact in a Red Holstein Herd in Romania

This study evaluated the biological and economic impact of twin calvings in a commercial dairy herd located in Harghita County, Romania. Data from 2019 to 2022 were analyzed retrospectively using production, reproductive, and veterinary records. The incidence of twin pregnancies averaged 11.0% across the study period. Mixed-sex pairs were most frequent (55.3%), followed by female-female (28.2%) and male-male (16.5%) combinations. Twin calvings were associated with significant reductions in subsequent milk yield (-742 kg per lactation; <i>p</i> < 0.05), decreased fertility (2.3 vs. 1.4 inseminations; 103 vs. 79 days service period; <i>p</i> < 0.05), and higher veterinary costs (EUR 90 per case). The expected loss of replacement value due to freemartinism was EUR 63 per twin calving. After accounting for a small gain in calf value, the total economic loss was estimated at EUR 379 per twin calving. These findings demonstrate that twin pregnancies, although relatively uncommon, substantially reduce productive efficiency and profitability in dairy systems. Early detection and targeted reproductive management are recommended to mitigate their adverse effects and enhance farm sustainability.