Source: Government of Manitoba
Sandcracks are a vertical fissure or split on the front claw (usually affecting the outside claw) of beef cows. The cause is not clearly understood however; nutrition, pasture management, cow age and weight play a role in the incidence of occurrence and subsequent control and prevention. These vertical splits in the hoof wall can be extremely painful resulting not only in lameness but also negatively impacting cow condition, breeding performance and culling rates. Frequently sandcracks result from existing hardship grooves. Hardship grooves are horizontal fissures or depressions in the wall of the claw. The horizontal grooves can weaken the hoof wall resulting in broken toes and/or vertical splits.
The weakened hoof wall usually results from a disruption of normal hoof growth and development. The hoof wall grows in a downward manner, from the coronary band to the tip of the toe, at a rate of 4 mm/month (thus the date of stress can be calculated by measuring the distance from the groove to the coronary band and dividing by 4). Disruption of hoof growth is commonly linked to periods of stress in the animal’s life. Animals can experience stress during periods of handling, aggression, from changes in nutrition and disease and pain. Stress due to nutrition typically occurs when there is a sudden change in the quality of the forage and/or pasture the animals are consuming and/or trace mineral imbalances. For example, when cows have been on preserved hay for the winter and then turned out on lush spring pastures the protein levels of the feed increase and fiber levels decrease. This sudden change in feed quality, without a suitable adjustment period, can result in a metabolic disorder such as acidosis, thus causing stress on the animal. This stress disrupts the normal growth patterns of the hoof wall.
Control and Prevention
Implement good grazing management strategies to avoid sudden changes in feed quality.
- Avoid turning animals out on the lush spring growth.
- Delay spring turnout.
- Manage pasture/rangeland to allow for residue in the fall.
- Avoid grazing fertilized pastures first thing in the spring.
- Offer good quality preserved forages on pasture for the first 10 days in the spring.
Ensure all nutritional requirements of the beef animal are met throughout the season.
- Trace mineral and vitamin requirements are important, especially Zinc, Copper, Molybdenum, Manganese, Vitamins A and E.
- Biotin supplementation has been effective in reducing the incidence of sandcracks.
- Feed test forages and/or pastures.
- Recent research has found sandcracks have a heritablity of 0.45, thus indicating culling of affected individuals and families is an effective method of control. As well, older and heavier cows tend to have a higher level of incidence, thus allowing for addition culling criteria to reduce the incidence in the herd.
References
Greennough, Paul R.; Schugel, LaVerne M.; Johnson, A. Bruce. Zinpro Corporations Illustrated Handbook on Cattle Lameness. Zinpro Corporation.
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