A lameness scoring system that uses posture and gait to predict dairy cattle reproductive performance.

Lameness has contributed to reproductive inefficiency and increased the risk of culling in dairy cows. We developed a 5-point lameness scoring system that assessed gait and placed a novel emphasis on back posture. Our objective was to determine if this system predicted future reproductive performance and the risk of culling. The study was conducted at a commercial dairy farm with a history of declining reproductive efficiency and an increasing prevalence of lameness. A total of 66 primipara and pluripara calved, received an initial lameness score, and completed their 60-d voluntary waiting period. The overall prevalence of lameness (mean lameness score >2) was 65.2%. Scoring continued at 4-wk intervals and ceased with conception or culling. The percentage of cows confirmed pregnant and culled was 77.3 and 22.7, respectively. For each reproductive endpoint, a 2 x 2 table was constructed with lameness score >2 as the positive risk factor and either performance greater than the endpoint mean or being culled as the positive disease or condition. Positive and negative predictive values, relative risk, Chisquare statistic and regression analysis were used to evaluate the data. The positive predictive values for days to first service, days open, breeding herd days, services per pregnancy and being culled were 58, 68, 65, 39 and 35%, respectively. Similarly, the negative predictive values were 79, 96, 100, 96 and 100%, respectively. Except for one reproductive endpoint, the total number of services, all linear regressions were significant at P < 0.01. Having a lameness score >2 predicted that a cow would have extended intervals from calving to first service and to conception, spend or be assigned to (explained herein) more total days in the breeding herd, require more services per pregnancy and be 8.4 times more likely to be culled. We believe that this lameness scoring system effectively identifies lame cows. Observation of the arched-back posture in a standing cow (> or =LS 3) should trigger corrective interventions.