95 Equine chewing is influenced by dental intervention

Abstract

The mechanical breakdown of feedstuffs via mastication is the primary digestive function in the mouth, and dental abnormalities may impact the horses’ ability to adequately reduce particle size. It was hypothesized that chewing parameters would differ in horses pre- and post-dental intervention when consuming different feedstuffs. Mature Quarter horses (n = 4) and Thoroughbreds (n = 4) with an average age of 17.2 years were utilized in a trial evaluating chewing characteristics pre- and post-dental intervention. Before the start of the trial, all horses were examined by a veterinarian and assigned a dental score based on the quality of dentition. No horses utilized on the trial had received any dental intervention for 12 mo prior. The trial was separated into pre- and post-dental periods consisting of 3 weeks of data collection each. Following the final week of data collection in the pre-dental period, all horses underwent a dental floating by a veterinarian. The average dental score of horses during the pre-dental period was 3.1 indicating the presence of dental abnormalities. Following the mid-point floating, dental scores improved to an average of 2.0 indicating that abnormalities had been resolved. During each period, 5 dietary treatments (long stem hay, chopped hay, 75% Purina Ⓡ Equine Senior Ⓡ + 25% chopped hay, soaked Purina Ⓡ Equine Senior Ⓡ , and dry Purina Ⓡ Equine Senior Ⓡ ) were evaluated for 5 consecutive feedings each with horses randomly assigned a dietary treatment order in each period. Data were collected utilizing the BioNomadix EMG Device (Biopac Ⓡ Systems Inc.). Briefly, leads were attached via adhesive electrodes to both the left and right side of the horses’ jaw, corresponding to the M. Masseter muscles. Data were collected and analyzed via proprietary software to determine chew amplitude, strength, length, and rate. All dietary treatment data were analyzed via ANOVA while the pre vs. post analysis was conducted utilizing a paired Student's t -test in SAS 9.4 (Cary, NC). Chew length was longer for horses pre-dental (0.251 s) vs. post-dental (0.235 s; P < 0.05 ). Chew strength was stronger pre-dental (0.04 mV/sec) vs. post dental (0.03 mV/sec; P < 0.05 ). Horses pre-dental had a higher maximum amplitude of chews pre-dental (0.275 mV) vs. post-dental (0.235 mV; P < 0.05 ). Chew rate was lower pre-dental (1.46 chews/sec) vs. post-dental (1.54 chews/sec P < 0.05 ). Dietary treatment impacted chewing characteristics, however, no interactions existed between individual feedstuffs and chewing characteristics pre- and post-dental. These data indicate that dental intervention impacts chewing in horses, possibly allowing for more optimal mastication and breakdown of feedstuffs.