Higher odds of abortion in dairy cows hoof trimmed late in gestation.

Until now, it is unknown whether hoof trimming late in gestation is associated with increased risk of abortion in dairy cows. Using data from 1,476,013 pregnancies in Danish dairy cows, the objective of the present study was to evaluate risk factors for abortion in cows hoof trimmed during pregnancy. Odds of abortion was lower in first parity cows, lower in Jersey cows compared to other breeds, and higher in cows pregnant with twins. Odds of abortion was 2.4 times higher in cows hoof trimmed within the last four weeks before end of pregnancy. Hoof trimming of cows in late gestation should be done with caution.