Prevalence and severity of lameness in early lactation in dairy cows and the effect on reproductive performance

Objective: To examine the impact of different degrees of lameness on the fertility of dairy cows. Material and methods: Seven dairy herds housed in free stall barns with cubicles were visited at 4-week intervals and all cows were examined for locomotion characteristics using a locomotion scoring system. The cows received scores from 1 (normal gait) to 5 (severely lame). During the study period of 18 months, 893 cows in the first month of lactation and 944 cows in the second, third and fourth months of lactation were evaluated. Reproductive measures between non-lame cows (score 1), mild lame cows (score 2) and cows with clear lameness (score >= 3) were compared. Results: Independent of parity and herd effects, cows with scores >= 3 in the first month of lactation displayed a 6 days longer calving to first service interval (CFSI) (86.2 +/- 35.6 vs. 80.2 +/- 34.1 days; p = 0.002) and a 16 days longer calving to conception interval (CCI) (119.7 +/- 51.4 vs. 103.8 +/- 55.5 days; p = 0.048) than non-lame cows. Additionally, the risk for non-conception was significantly higher in cows suffering from lameness in the first month of lactation (odds ratio: 2.1, 95% confidence interval: 1.095, 4.040; p = 0.026). Cows affected by mild lameness in the third month of lactation had a 4 days longer CFSI (84.7 +/- 35.6 vs. 80.1 +/- 30.5 days; p = 0.026) and a 18 days longer CCl (120.1 +/- 55.4 vs. 102.3 +/- 47.6 days; p = 0.016) than non-lame cows, while the CSFI in distinct lame cows was extended by 7 days compared to non-lame cows (87.2 +/- 34.9 vs. 80.1 +/- 30.5 days; p = 0.002). Cows with the score 1 in the first month and score 3 in the third month of lactation showed the longest CSFI (94.3 +/- 33.9 vs. 76.5 +/- 16.0 days in non-lame cows; p = 0.046). Conclusion and clinical relevance: This study suggests that both distinct and mild lameness in early lactation lead to a decline in reproduction in dairy herds. A regular determination of the lameness prevalence in dairy herds and optimizing claw health management, including early treatment of lame cows, will enhance animal welfare and reproduction efficiency.