Lameness in free stall barns in Minnesota
Lameness is a major economic and welfare problem on our dairy farms. Prevalence of lameness in the U.S. has increased in recent years. It had been about 15 years since the last study on prevalence of lameness in Minnesota dairy farms had been conducted. The dairies involved in that study were mostly tie stall herds. The current trend in the dairy industry is for housing cows in free stall systems with concrete flooring. Research has indicated that exposure to concrete flooring can potentially increase the proportion of cows with hoof disorders in comparison with other systems.
Therefore, we conducted a field study in 50 Minnesota free stall dairy herds (5626 Holstein cows housed in 53 high production groups) to determine the current prevalence of lameness. We used a locomotion scoring system on a 1 to 5 scale (a lame cow scores 3 or greater on this system). We also wanted to collect a lot of information from these herds to evaluate what could be potential risk factors for lameness. Farms were randomly selected, without any previous knowledge of lameness status of the herd and without any enrollment criteria besides cows being housed in free stalls. We sincerely thank all the dairy producers who participated in the study.
The average prevalence of lameness in the free stall herds we studied was 24.6% with a range from 3.3 to 57.3% (see Figure below). The best quartile of farms had approximately 15% of cows in the group scored as clinically lame with only approximately 2.5% of cows in the group scored as severely lame. Therefore, the presence of a relatively large percentage of severely lame cows (score = 4) could be an indication of a herd lameness problem. A goal of less than 15% clinically lame cows in a free stall herd should be achievable.
We found that the following factors did not show an association with the prevalence of lameness: number of cows in the herd or group, pen square footage per cow, pen stocking rate (cows per stall), parlor type (herringbone, parallel, step-up or rotary), parlor size (number of milking units), TMR crude protein content, TMR NDF content, feeding frequency (1, 2, or 3 times per day), use of footbath (yes or no), total daily distance between pen and parlor, number of cows per full time employee equivalent, cud chewing index (% of cows lying down chewing their cud), and barn type (2-row or 3-row configuration).
However, these factors were associated with prevalence of lameness:
- Time away from the pen. The association was positive indicating that prevalence was greater for groups of cows that spent a longer time away from their pen when being milked. Cows should spend as little time as possible away from stalls, feed and water;
- Hoof trimming frequency. Dairies that trimmed hooves only when needed showed higher risk for lameness compared to dairies that had a maintenance trimming schedule (once or twice a year for all cows, plus when needed). It is important to keep in mind that over trimming hooves can also contribute to the development of lameness;
- Cow comfort quotient (measured as number of cows lying down in stalls divided by total number of cows touching a stall). The greater the cow comfort quotient, the lower the lameness prevalence. Cow comfort quotient is an indicator of the comfort of stalls;
- Type of stall surface. Cows housed in barns with sand stalls had a lower prevalence of lameness (17.1%) than cows housed in mattress barns (27.9%);
- Height of brisket board. The higher the brisket board, the greater the prevalence. There was an additive association when the area behind the brisket board was filled with concrete. We hypothesize that these types of lunge obstructions make it more difficult for cows to rise normally, especially if they are already lame. We recommend that the brisket board be no higher than 4" above the stall surface, preferably be smooth and rounded, and that the area behind the brisket board be at the same level as the stall surface.
In conclusion, there were significant associations between the prevalence of lameness and some management and housing factors. Some of these factors could possibly be improved in order to reduce lameness in free stall housed dairy cattle.
General recommendations to reduce the prevalence of lameness:
- Build or redesign stalls to meet cows' requirements. We might make stalls more comfortable by changing the neck rail height or location, reducing the height of the brisket board and making the area in front of it the same level as the rest of the stall, adding more bedding to mattress based stalls, etc.
- Improve management factors that might be contributing to increased prevalence of lameness such as hoof trimming protocol and time away from the pen.
- Move lame cows, especially in mattress barns, to a special needs pen with comfortable bedding and better traction. A compost barn/pen would be an option.
Published in Dairy Star April 22, 2006