A LAMENESS SCORING SYSTEM THAT USES POSTURE AND GAIT TO PREDICT DAIRY-CATTLE REPRODUCTIVE-PERFORMANCE

Lameness has contributed to reproductive inefficiency and increased th e risk of culling in dairy cows. We developed a 5-point lameness scori ng system that assessed gait and placed a novel emphasis on back postu re. Our objective was to determine if this system predicted future rep roductive performance and the risk of culling. The study was conducted at a commercial dairy farm with a history of declining reproductive e fficiency and an increasing prevalence of lameness. A total of 66 prim ipara and pluripara calved, received an initial lameness score, and co mpleted their 60-d voluntary waiting period. The overall prevalence of lameness (mean lameness score >2) was 65.2%. Scoring continued at 4-w k intervals and ceased with conception or culling. The percentage of c ows confirmed pregnant and culled was 77.3 and 22.7, respectively. For each reproductive endpoint, a 2 x 2 table was constructed with lamene ss score >2 as the positive risk factor and either performance greater than the endpoint mean or being culled as the positive disease or con dition. Positive and negative predictive values, relative risk, Chi-sq uare 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, 6 8, 65, 39 and 35%, respectively. Similarly, the negative predictive va lues were 79, 96, 100, 96 and 100%, respectively. Except for one repro ductive endpoint, the total number of services, all linear regressions were significant at P < 0.01. Having a lameness score >2 predicted th at a cow would have extended intervals from calving to first service a nd to conception, spend or be assigned to (explained herein) more tota l days in the breeding herd, require more services per pregnancy and b e 8.4 times more likely to be culled. We believe that this lameness sc oring system effectively identifies lame cows. Observation of the arch ed-back posture in a standing cow (greater than or equal to LS 3) shou ld trigger corrective interventions. (C) 1997 by Elsevier Science Inc.