AABP Fact Sheet

Authored by the VERTICAL WALL CRACKS AABP LAMENESS COMMITTEE

Vertical wall cracks (sand cracks, quarter cracks) can be a significant Figure 1. cause of lameness in the cow-calf A Type III herd and they also occur occasionally vertical wall in dairy cattle. Types of cracks (I–IV) crack. Note are detailed in the box below, based the exten- on their location on the hoof wall. sion of the crack and Studies on the prevalence in Canadian the associat- beef herds have reported that 16.8-37% ed horizon- of cows have evidence of vertical wall tal defect. cracks. With a prevalence this high, loss- es due to decreased production, cost of treating lameness, and premature culling could certainly become a signifi- cant factor in the health and viability of the cow-calf enterprise.

Hoof Cracks by Type

● Type I Usually not identified, A significant factor contributing to risk to be integral in the development of associated with coronary is the conformation and strength of the quality hoof. Deficiencies in copper or band foot itself. The size and shape of the zinc, potentially exacerbated by excess ● Type II Often associated with foot contributes to its volume and, sub- molybdenum or sulfur in the diet, can horizontal (hardship) sequently, its strength. Any deviation of lead to horn of inferior quality. groove, extend from the claw from what we might consider Selenium toxicosis can contribute to coronary band to 1/3–1/2 “normal” will predispose the claw to poor quality horn that is predisposed to way down the hoof wall abnormal forces and stresses. These stress related injury and defect. Biotin ● Type III Involve the entire dorsal stresses act on aspects of the hoof that has been shown to be somewhat pro- surface of the hoof, may are most susceptible or weakened due tective in reducing incidence of vertical be unable to identify to other illness or defect. For instance, a wall cracks. Nutrition can also be consid- origin (Figure 1) horizontal groove associated with grass ered a risk factor as it is related to body ● Type IV Extend from mid-hoof founder provides a potential area of condition score (BCS). Heavier animals wall to level of sole, like- weakness from which a vertical wall are more likely to develop vertical wall ly in healing stages, may crack could originate. The importance of cracks than lighter animals. With this in have originated from conformation and hoof quality are cer- mind, monitoring BCS and adjusting level of sole tainly supported by the observation that nutritional plane appropriately, particu- ● Type V Central defect secondary some animals will have numerous cracks larly in the pre-partum period, will be to undermined stresses and chronic crack problems despite important in reducing incidence of other animals in the herd with similar cracks. Pathogenesis environmental exposure having little or no problems with hoof cracks. Other Predisposing Factors There is no single known cause of verti- Nutrition also plays an important role in Probably the most extensively studied cal wall cracks in cattle, but there is an the development of vertical wall cracks. and most controversial aspect of vertical extensive list of contributing factors Minerals such as copper, zinc, selenium, wall cracks is the inciting cause. As we that may predispose an animal to devel- and molybdenum and vitamins such as mentioned, there are many risk factors, oping cracks. Vitamin E and biotin have been shown but what is the trigger? Some have

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Vertical Wall Cracks continued argued that excessively dry environmen- provide stability to the crack. This is tal conditions serve as an inciting cause often challenging due to the shape and and/or risk factor. Perhaps the most like- extent of the defect. Use of hoof acrylic ly trigger is acute or chronic subclinical is contraindicated if exposure of the laminitis. These events provide an sensitive laminae or granulation tissue is opportunity at the level of the laminae present. Attempts to wire across the for focal points of weakness in the hoof. defect to provide stability are similarly These syndromes are often precipitated challenging. Lacing wire across the by an abrupt change in feeding patterns defect provides a scaffold for the acrylic, or diet. This is particularly true of not a tension band to prevent widening changes in protein, fiber, and rapidly of the crack. Cattle with smaller hoof fermented starches. This condition can mass may be difficult to wire due to be common in early spring when cows decreased thickness of the hoof wall. are turned out to lush pastures after calving. It is not surprising to note that An alternative to filling the defect with vertical wall cracks are often associated acrylic may be to blend the margins of temporally with these pasture and feed- the crack with the adjacent hoof wall Figure 2. A crack on the dorsal ing conditions. (Figure 2). This can reduce forces at the aspect of the hoof that has been crack margin that contribute to exten- debrided and trimmed Treatment sion of the defect. Providing appropri- ate balance to the weight bearing sur- Treatment of vertical wall cracks can be face of the claw is also important in mit- hoof grows at 5mm per month, so heal- challenging and must be considered igating these forces. ing time is prolonged. carefully. It is important to note that the use of hoof testers to verify that the A block should be applied to the unaf- Prevention crack is the cause of the lameness is fected claw to reduce stress and provide imperative. relief from discomfort. Additionally, an Appropriate monitoring of nutrient NSAID may be administered to reduce intake, BCS, vitamins, and minerals is Once the crack has been confirmed as pain and discomfort associated with the essential. Balancing these risk factors is the cause, the crack should be carefully hoof defect. likely to show benefits in other areas of explored. Care should be taken not to herd health as well. Selection of extend the crack more than necessary, After-care replacement animals and herd sires with particularly in depth as it is contraindi- good conformation and hoof health can cated to expose the sensitive laminae if Routine follow-up should be employed also be useful in reducing the incidence not already exposed. to monitor progress of the crack and of this condition. AABP hoof growth. Remember, the average The keys to exploring and debriding the crack are preventing continued exten- sion of the crack, providing appropriate exposure to the environment to allow it Important Things to Know About Vertical Wall Cracks to dry, and preventing the lesion from being packed with foreign material. If ● Vertical wall cracks are common in beef cattle and contributing factors granulation tissue is present extending appear to include conformation of the foot, hoof horn quality, and sub-clini- from the sensitive laminae, the use of a cal laminitis drying agent may be employed to pre- ● Not all wall cracks result in lameness vent exuberant granulation tissue from ● Treatment involves preventing extension and packing of the lesion, and pro- developing. Often a Dremel tool can be viding exposure useful in cleaning out cracks. ● Good nutrition and improved conformation through sire selection are impor- tant components of prevention After the crack has been appropriately debrided, hoof acrylic may be used to

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