Brittle Hooves

Kate Hore RNutr(Animal). Snr Nutritionist at NAF

As we get into the warmer and drier days of summer brittle hooves are an all too common occurrence, and something horse owners will frequently ask about. The hoof wall, made up of the protein keratin, is a viscoelastic material, exhibiting both the properties of an elastic solid which will moves under force but returns to its original form when the pressure is removed, and also the properties of a viscous liquid, resistant to flow but with the ability to move under force. This viscoelasticity results in a healthy hoof which is both firm and resilient, but retains a certain flexibility. These properties are vital to the hoof wall’s role in protection of the hoof capsule, propulsion, acceleration, braking and absorption of concussive forces. However the flexible elasticity of the hoof means that it is subject to pressures from a number of areas, and an imbalance in any one of those areas may result in poor hoof health. Those areas include nutrition, conformation, trimming and the environment. In this article we’ll be looking at environmental pressures on the hoof wall.

Maintaining the correct hydration level in the hoof and sole is vital, as a dry hoof wall is prone to shrinking and cracking, which all too often can lead to lost shoes, splits and lameness. Naturally the moisture level of the horn is slightly higher at the coronet band, around 30% moisture, moving to around 25-27% at the bottom of the hoof. Research has shown that if the bottom of the hoof is allowed to grow excessively it becomes distinctly drier and prone to cracking, so just one reason for ensuring regular trimming on both shod and barefoot horses. The environment can affect hoof health, which is hardly surprising given that the modern horse and pony may be subject to changes in environment from standing in a wet, boggy field all day, to being stabled on dry shavings and working in a sand school. Moisture levels of the sole and frog are particularly sensitive to changes in environmental moisture levels, so particular care should be taken on maintaining a healthy hydration level of those areas.

Of course one of the risks of overly wet conditions, is that they increase the porous nature of the hoof and sole and so allowing unwanted, and potentially harmful, microorganisms to flourish. The anerobic (low oxygen) bacteria which are the causal agents of thrush, are ideally suited to wet and unhygienic conditions under foot, so care should be taken to avoid such conditions. Splits, cracks and nail holes are another port of entry, and may exacerbate a hoof microbial challenge. This is one area where the correct application is strongly recommended. Zinc sulphate is well known for its antimicrobial properties, and is licensed in agriculture for the control of foot rot, which is similarly caused through infection of the sole by anaerobic bacteria. Particular care should be taken to ensure that any application for sole issues gets well into the central and collateral grooves of the frog, and into any splits or extended nail holes, where microbial growth can proliferate.

In conclusion we can say that the right choice of the right application can help the farrier and horse owner to maintain both essential moisture levels and hoof hygiene, and so reduce the risk of splits and cracks from brittle hooves.