MMN May 2024 – Reducing White Line Disease in Dairy Cows

White line disease (WLD) is the second most common cause of claw disease in dairy cows, with an average of 5.5 cases per 100 cows per year (Barker et al., 2009). This disease is caused by the separation of the wall horn from the sole horn, resulting in damage of the white line region. This damage to the horn allows for stones, slurry and soil to penetrate the white line area. White line disease is of significant economic importance, with the average case costing approximately £200.

Hoof with White Line Disease

 

Causes

The main causes of WLD include shearing forces, rough surfaces including loose stones (e.g. from poorly constructed cow tracks), roughened concrete grooving, and nutritional factors leading to poor horn quality.

Prevention

Prevention of WLD involves managing factors that lead to damage of the white line. This includes improving the housing environment, cow flow and cow comfort to maximise lying time and nutrition.

Management and housing

The risk of white line damage increases when cows are stood for long periods of time on hard surfaces. Therefore, efforts should be made to minimise standing time in the collecting yard and ensure cow comfort is sufficient to encourage cows to lie down. Observing cow comfort through various means including the Cubicle Comfort Index (Dairy cow cubicle housing design to control environmental mastitis in lactation | AHDB) will highlight whether cow comfort and cubicle size are adequate. The aim is for at least 85% of cows to be lying down at any one time. There should ideally be 5% more cubicles than cows in the building to encourage lying and choice of lying space to reduce the impact of bullying.

Damage to the white line can be caused by turning, twisting and pushing forces on the hooves. These forces tend to occur when cattle are pushing on tracks and in the collecting yard, turning sharp corners (particularly when exiting the parlour) and bullying in the shed. Rubber matting is beneficial in high-traffic areas and where cows have to turn sharp corners. If possible, walkways should be made wider and straighter to minimise twisting forces. Within the shed it would be beneficial to create cross passages in long rows of cubicles and open up blind alleys to improve the flow of cattle.

For grazing herds, the installation of grazing tracks is beneficial to minimise the damage caused by loose stones to the white line area. Astroturf is a popular choice to provide a comfortable walking surface. Cow tracks should only be used by the cattle and not machinery, be stone-free and also free-draining. Extra caution should be given around gateways and water troughs. For more information on cow tracks please visit: https://www.fas.scot/publication/technical-note-tn730-construction-of-a-cow-track-for-access-to-grazing/

Diet

Research by Thomas and Dipu (2014) showed that supplementing with 20mg per head per day of biotin reduced lameness from WLD by up to 50%. The benefit from feeding biotin is a long-term strategy as the response to improved claw health can take up to six months. Cows with a low body condition score are more susceptible to lameness due to thinning of the digital cushion, which can increase the risk of sole bruising. Ensure adequate nutrition with the aim that cows are not losing more than half a condition score unit in early lactation.

Key considerations for reducing white line disease include:

1. Reduce the amount of time cows are stood both in the collecting yard and the shed. Cows should not be away from their feeding and lying area for more than one hour at each milking.

2. Minimise the need for cows to turn and twist by ensuring walkways are wide, and also consider installing matting in areas of high traffic.

3. Installing cross passages in long rows of cubicles and removing blind passageways in buildings to improve cow flow.

4. Cow tracks should be kept machinery-free, free-draining and stone-free to reduce the risk of damage to the white line.

5. Supplementing with biotin can reduce the incidence of WLD, however this is a long-term strategy.

References are available upon request.

olivia.ward@sac.co.uk; 01539 769059