Lameness prevalence and severity is often underestimated on dairy farms, Jeff DeFrain, Zinpro Performance Minerals, said at the 2011 DCRC Annual Meeting.
However, available data clearly supports the notion that lameness compromises reproductive performance. This appears to be associated with failed ovulation due to a reduced luteinizing hormone pulse frequency. Lameness is a multifactorial disease and troubleshooting lameness on dairies generally requires an in-depth investigation involving these three steps:
1)  Locomotion scoring of the herd or a representative sample.
2)  Analysis of herd claw lesions present.
3)  Assessment of the management, environmental and nutritional components of the dairy known to be associated with either non-infectious or infectious claw lesions present. 
Committing to routine investigation through these steps will minimize claw lesions and therefore lameness on the dairy; ultimately providing for improved reproductive performance.
Source: April 2012 Dairy Cattle Reproduction Council Newsletter