u YOUR GUIDE TO LAMENESS TRAITS

LAMENESS TRAITS: UNDERUSED & UNDERESTIMATED

Chuck Sattler, vice president of genetic programs, Select Sires Inc.

Whether it’s called locomotion, mobility, hoof health or cow comfort, avoiding lameness events is a challenge for nearly all dairies. Incidence rates can vary widely from farm to farm but national statistics indicate about 13 percent of cows have lameness challenges each lactation. Lameness incidence rates increase as cows get older. So, as we raise fewer dairy replacements and our milking herds include more multiparous cows, the need to breed for reduced lameness is more important than ever.

Traditionally, we have selected sires for traits like Foot Angle, Legs Side View and Feet and Legs Composite (FLC) to improve mobility in our cows. While this strategy has been employed for decades, it has not helped us reduce the incidence of lameness. In recent years, new genetic evaluation tools have been developed that more directly address lameness resistance. These tools remain underused and deserve attention and use in sire selection decisions.

Available from Zoetis

The lameness evaluation from Zoetis, part of the CLARIFIDE® Plus testing platform, is an example of one of these new evaluations. Data from lameness events come from health events recorded in a wide range of CLARIFIDE-tested, commercial dairy farms. Lameness genomic evaluations are routinely available for Select Sires’ bulls for both Holstein and Jersey breeds.

Table 1. Reliability levels for published lameness evaluations BREED CATEGORY RELIABILITY

Holstein Genomic-tested young sire 40 to 55 Daughter-proven sire 55 to 99 Jersey Genomic-tested young sire 35 to 50 Daughter-proven sire 50 to 95

Lameness evaluations are expressed as standardized transmitting abilities (STAs) with an average of 100. Evaluations generally range from 85 to 115. Higher values indicate more resistance to lameness and are preferred.

Zoetis lameness evaluations have been publicly available since 2016. They’ve been available long enough to analyze how they perform and whether they effectively identify meaningful genetic differences between bulls.

One way to analyze the accuracy of lameness traits is to review how lameness evaluations compare to other established genetic evaluations. This is most effective when done using high-reliability sires. We studied Zoetis lameness evaluations for Select Sires bulls that have 100 or more daughters in their Council on Dairy Cattle Breeding (CDCB) evaluations. Since lameness is a management challenge on most dairy farms, we should see a positive correlation between the STA values for lameness and predicted transmitting abilities (PTAs) for Productive Life (PL) and Livability (LIV). Select Sires’ genetic lineup shows a correlation of +0.21 between lameness STA and PTA PL, and +0.22 between lameness STA and PTA LIV. In contrast, CDCB reports a correlation of -0.01 between FLC and PTA PL, and -0.11 between FLC and PTA LIV.

On-farm validation

Zoetis has conducted several validation studies published in the Journal of Dairy Science ® documenting the predictive power of lameness evaluations. One study published in 2017 tracked the performance of genomic-tested animals through their next lactation. The study tracked the performance of 3,400 heifers and cows from 11 different herds. Animals were grouped based on their STAs for lameness. Lameness incidence was 33 percent lower for top quartile animals compared to those in the bottom quartile.

A more recent study looked at the value of including lameness in Dairy Wellness Profit Index® (DWP$®). Lameness receives a relative weighting of 5 percent in the Holstein version of DWP$ and a 3 percent relative weighting in the Jersey version.

The effectiveness of DWP$ was analyzed by tracking 2,185 genomic tested heifers from 11 herds through their careers as lactating cows. Differences in lameness incidence were statistically significant between the DWP$ groups tracked in these herds. Differences by lactation are shown in Figure 1. Lameness incidence was reduced by 50% for animals in the top quartile for DWP$ as compared to those in the bottom quartile.

Figure 1. Lameness incidence by DWP$ quartile and lactation.

The bottom line

Lameness continues to be an ongoing challenge for dairies. Indirect selection to improve lameness resistance by using a variety of conformation traits has not been effective. Direct evaluations for lameness are now routinely available and their track record shows they have a solid relationship with improved longevity and profitability. If lameness is not currently included as part of your sire selection criteria, you

should strongly consider adding it. u

90%

80% Worst 25% 26-50% 51-75% Best 25%

Lameness Incidence (%)

70%

60%

50%

40%

30%

20%

10%

0% 1st 2nd

Lactation

3rd 4th

REFERENCES Adams, A. E., J. E. Lombard, C. P. Fossler, I. N. Román-Muñiz, C. A. Kopral. Associations between housing and management practices and the prevalence of lameness, hock lesions, and thin cows in US dairy operations. J. Dairy Sci. 100: 2119-2136. Cook, N. B., J. P. Hess, M. R. Foy, T. B. Bennett, R. L. Brotzman. Management characteristics, lameness, and body injuries of dairy cattle housed in high-performance dairy herds in Wisconsin. J. Dairy Sci. 99:5879-5891. Fessenden, Brenda, Daniel J. Weigel, Jason Osterstock, David T. Galligan, Fernando Di Croce. Validation of genomic predictions for a lifetime merit selection index for the US dairy industry. J. Dairy Sci. 103:10414-10428. McNeel, Anthony K., Brenda C. Reiter, Dan Weigel, Jason Osterstock, Fernando Di Croce. Validation of genomic predictions for wellness traits in US Holstein cows. J. Dairy Sci. 100:9115-9124. Vukasinovic, N., N. Bacciu, C. A. Przybyla, P. Boddhireddy, and S. K. DeNise. Development of genetic and genomic evaluation for wellness traits in US Holstein cows. J. Dairy Sci. 100:428-438

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To enhance the productivity and profitability of dairy and beef producers, Select Sires is committed to be the premier provider of highly fertile, superior genetics accompanied by effective reproductive- and herdmanagement products and services.

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