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

## TL;DR

Twin pregnancies in dairy cows lead to lower milk production, fertility issues, and financial losses for farms in Romania.

## Contribution

This study quantifies the economic and reproductive impact of twin calvings in a Romanian dairy herd over three years.

## Key findings

- Twin pregnancies occurred in 11% of calvings and reduced milk yield by 742 kg per lactation.
- Twin cows required more inseminations and had longer service periods, lowering fertility.
- Each twin calving caused an estimated EUR 379 loss due to veterinary costs and reduced calf value.

## Abstract

Twinning in dairy cattle may seem advantageous because it produces two calves at once, but in dairy herds, it often causes serious problems. This study examined twin calvings in a dairy herd in Romania over three years. Twin pregnancies occurred in 11% of all calvings and were linked with lower milk yield after calving, poorer fertility, and higher veterinary costs. Cows with twins produced 742 kg less milk per lactation, needed more inseminations, and took longer to become pregnant again. More than half of twin pairs were mixed-sex, meaning many female calves were freemartins and unable to reproduce. Altogether, each twin calving caused an estimated loss of about EUR 379. These results show that twinning has clear negative effects on both animal performance and farm profitability. Managing and detecting twin pregnancies early can help reduce these losses and improve herd efficiency.

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; p < 0.05), decreased fertility (2.3 vs. 1.4 inseminations; 103 vs. 79 days service period; p < 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.