Q. How does starvation affect hoof growth? 

When faced with a case of nutritional rehabilitation, should hoof health be a primary consideration or not? 

As the nutritional state changes, such as when the horse gains weight, what changes can be expected in the hooves? 

Without question, starvation negatively impacts hoof growth. Inadequate dietary energy, especially to the point of emaciation, hinders normal hoof development just as radically as it affects other body processes. While hoof growth may continue at a relatively constant rate through downturns in nutrition, the quality of hoof that develops may be severely diminished.

Hoof quality will likely improve as a horse moves from negative energy balance (too few calories in the diet to sustain body weight) to positive energy balance (calories exceeding those required for maintenance of body weight). A malnourished horse in negative energy balance will use whatever nutrition it consumes or can take away from its internal stores to fuel survival.

Balance The Diet

Therefore, meeting energy requirements with a well-balanced diet that contains high-quality forage and concentrates is the single most important factor when considering hoof growth and integrity of an emaciated horse. As the horse progresses in its recovery, alternative energy sources such as fermentable fiber and fat may be added to the diet. Though fat is a valuable feedstuff used to increase energy density of rations and to add shine to the coat, it does not seem to have a measurable effect on hoof growth or strength.

Aside from energy, a well-balanced diet must provide the nutrients required for the horse’s overall health and well being. These, in turn, will fuel sound hoof growth. High-quality protein will supply the horse with the necessary amino acids that researchers have theorized are basic for hoof growth.

Over the years, scientists have studied certain amino acids more than others, namely methionine and cystine, believing that supplementation will benefit hoof quality. While a deficiency of one or both of these amino acids may contribute to poor hoof quality, so may the deficiency of other amino acids or the interaction of amino acids when certain ones are missing.

Researchers have examined the amino acid content of both average and poor-quality hooves. They found a correlation between cystine content and hardness in normal hooves that was not present in poor-quality hooves. The protein of normal hooves contained higher levels of threonine, phenylalanine and proline. Certain of these amino acids are considered essential, which means they cannot be synthesized in the body in sufficient quantities to meet its demand for them.

High-Quality Protein Is Essential

The need for high-quality protein in all diets is critical, but perhaps doubly so in extreme weight-gaining situations. Protein sources composed of a high proportion of essential amino acids are classified as high quality. Soybean meal is the most common high-quality protein used in feed manufacture.

A well-balanced feed will feature a full complement of vitamins and minerals. Premium feeds will contain chelated forms of minerals. Chelation, a process that binds a mineral to an amino acid, enhances absorption of the mineral. Zinc has been the focus of much research, as it is involved in the health of skin, hair and hooves.

Evidence suggests that low levels of zinc may cause horses to be more susceptible to hoof problems. A study showed that 25 horses with poor-quality hooves had lower blood and hoof levels of zinc than 38 horses with normal hooves. A recent study in Japan revealed horses consuming diets low in zinc and copper were more likely to have white line disease than horses supplemented with higher levels of trace minerals.

Consultation with an equine nutritionist is advised when formulating a diet for a nutritionally neglected horse. A professional will ensure that the animal’s energy, protein, vitamin and mineral needs are met through a combination of forages and a fortified concentrate.

Once the horse is nutritionally stable and is in a state of positive energy balance, attention can be turned to its hooves. A thorough hoof assessment by a competent farrier provides a baseline for future footcare. In addition to regularly scheduled visits, a farrier may suggest other hoof-care tips.

From a nutritional point of view, a farrier might recommend the use of biotin, and justifiably so, as most of the research on hoof growth and hoof wall quality has involved the feeding of this B vitamin.

Research focusing on biotin as a means of improving hoof quality of the horse started in the mid-1980s. Over the intervening years, various studies have found a statistically significant improvement from biotin supplementation on overall hoof condition when fed at a rate of 20 milligrams per day.

New Vs. Existing Hoof Horn

Biotin only improves the growth of new hoof horn, not existing hoof, so its effectiveness depends on reliable administration at recommended levels. Because of this, several weeks may elapse before a noticeable difference exists in new hoof growth near the coronary band.

More than a year may pass before an entirely new hoof is grown. It should also be noted that some horses respond more positively to biotin supplementation than others.

As the quality of nutrition increases, so will hoof quality. As new growth appears, well-defined ridges, known as growth rings, may appear on the hoof walls. These ripples usually reflect a significant change in the health or well-being of the horse.

It is commonplace for growth rings to develop on hooves of horses that have experienced shifts in their nutritional state. For instance, some horses will develop them each year in response to spring grass. The formation of high-quality hoof tissue above the growth rings is an encouraging sign.

Most well-fed horses grow serviceably sound hooves. Like other body tissues, hooves can be compromised by inadequate nutrition. With the regular care of a farrier, the provision of a diet that meets an animal’s nutritional requirements will usually remedy any hoof problems caused by malnutrition.