What are the survival and reproductive risk factors for culling in Holstein herds with at least 200 cows? Research from the University of Florida published in the February Journal of Dairy Science reveals some answers.
The results were calculated from 2,345,015 Dairy Herd Improvement lactation records from 727 herds in 36 states from 2001 to 2006. The researchers found:
- The risk of culling increased as lactation number increased. Cows in their sixth lactation had a three times greater risk of being culled than cows in their first lactation.
- Risk of culling peaked within 30 days after calving and then again later in lactation — after 280 days — in older cows. First-lactation cows risk of culling peaked earlier — within 10 days after calving — and these animals had a lower risk of culling later in lactation.
- Pregnant cows had a three- to seven-times lower chance of culling than open cows.
- Risk of culling increased for cows that had greater calving difficulty, gave birth to males or twins, were in a herd with shorter days to first breeding or had longer days to conception.
- The use of synchronized breeding programs increased from 21.9 percent in 2001 to 41.4 percent in 2006. Cows in herds not using a synchronization program had a lower risk of culling than cows in herds using synchronization protocols.