Feeding, management and equine dentistry.

This article discusses the effects of dietary changes in horses on their dental health, referred to by David McDowell’s previous letter that cited an observable shift from hay to softer corn-based feed as a possible cause for increasing dental care needs. The author emphasizes that both dietary habits and other factors like equine tack and selective breeding influence dental health and that directly correlating less feed time and usage of corn-based feeds to increased dental care requirements may oversimplify actual causes.

Diet and Dental Health

• The author points out that hay and haylage, which are both from grass, should not differ significantly in their hardness or softness given they are from the same growth stage, refuting the notion that substituting hay with haylage in horses’ diets may cause dental issues due to softer food.
• Feed’s impact on tooth wear significantly depends on its abrasiveness. Biogenic silica, the primary abrasive in grasses and cereals, can cause considerable tooth wear. This is why modern horses that eat grass and live in harsh environments have more dental wear than their ancestors, who ate less abrasive leaves.

Nature of Damage and other Factors

• Damage to teeth due to wear goes beyond diet: it is function of interaction between occlusal surfaces, time spent chewing, and the type of material being chewed.
• Bits, nosebands, and other tack may affect occlusal surfaces interaction, and selective breeding often overlooks dental conformation and health, leading to potential dental issues.
• Feeding horses with ‘corn-based feeds’ might affect their mandibular movements, potentially leading to less formation of ‘enamel points’ and ‘hooks’ as horses feed. Although, the respective wear rates have not been effectively measured.

Conclusions and Further Observations

• Reduced feeding time and eating corn-based foods might not be the only or prime reasons for increased dental care needs.
• The proportions of forage and concentrate in diet influence feeding time and mandibular excursion, which could indirectly affect tooth health.
• If corn-based feeds are indeed responsible for dental issues, racehorses (who eat diets high in concentrates) would be most likely to show symptoms, given their age and diet forms an ideal context, but this requires further investigation.
• The author claims that horses with irregular usage known as ‘happy hackers’ seem to need the most dental care, though their corn intake is minimal, suggesting other significant factors in dental care needs.