82 Effect of dental floating on ADF and NDF digestion after 8 weeks

Horses have hypsodont teeth that erupt from the jawbone throughout their lifetime in response to removal of enamel surfaces during feed grinding. Teeth must be floated yearly to remove sharp points that occur due to dental abnormalities and conformation defects that cause the teeth to not meet up correctly. This results in unequal wear on the grinding surface of the teeth. Diet also affects wear patterns, with horses primarily consuming grains needing more frequent floating than horses consuming primarily forages. The modern diet of horses is softer than that of their ancestors resulting in less wear during eating. Irregular wear patterns can cause poor feed digestion, weight loss, performance problems, and pain in the horse when wearing a halter or bridle. An improvement in feed digestion has been documented in horses consuming C3 forages, however this finding has not been tested in horses consuming C4 forages. C4 forages are higher in cellulose and lower in crude protein than C3 forages and these differences have an inherently negative effect on digestibility, reducing the percent of nutrients absorbed when compared with C3 forages. Improvements in digestion have been observed at 4 wks post dentistry in horses consuming C3 forages. The objective of this study was to evaluate acid detergent fiber (ADF) and neutral detergent fiber (NDF) digestibility 8 wk after dental floating as compared with unfloated controls. The study was conducted on 16 non-pregnant mares of mature age (4–17) and stock type breeding that have not previously received dental care. A diet consisting of ad libitum Cynodon dactylon and 1.36 kg of a balancer concentrate was fed daily before and during the study. Eight mares received dental work and 8 served as untreated controls. All horses had a body condition score between 5 and 6. Four-day digestion trials were conducted before and 8 wks after dental work, whereby acid insoluble ash (AIA) was used as a marker of digestibility. Feces and feed were analyzed for dry matter, AIA, NDF, and ADF using standard wet chemistry laboratory techniques. NDF was not-affected by the time by treatment interaction or treatment (P > 0.1). However, NDF digestibility was greater in wk 8 (86.3 ± 1.3%) than wk 1 (67 ± 1.3%) across treatments (P < 0.001). There was a tendency for an effect of the time by treatment interaction for ADF (P = 0.073), whereby ADF digestibility was not different for groups in wk 1 (50.3 ± 0.8% vs. 50.3 ± 0.8%; P > 0.9) but was greater (P = 0.014) in dental treated horses (59.5 ± 0.8%) than controls (56.5+0.8) in wk 8. When measured at 8 wk post dental work, horses consuming Cynodon dactylon may have improved ADF digestion.