96 Evaluation of prolonged hay net use on the rostral oral cavity and salvia production in adult horses

Abstract

Previous hay net studies have focused on behavior, consumption, and feed wastage; yet none have evaluated effects in the oral cavity. To investigate the effects of prolonged hay net use on rostral soft tissue and saliva production, 8 stock-type horses were evaluated for dental health and floated by a dental technician to ensure consistency. Horses were blocked by body weight (BW; 558.6 ± 13.8kg), body condition (BC; 6.5 ± 0.2), sex (mares: n = 5; geldings: n = 3), and age (10.1 ± 1.1yr) and randomly assigned to one of 2 feeding treatments for 70d. Horses on control (CON; n = 4) were offered loose hay in a tub; horses in the experimental group (NET; n = 4) were offered hay encased in a slow-feeder hay net (Texas Hay Net, 3.81cm2 openings). Horses received coastal bermudagrass hay at 1.5% of BW daily along with a commercial concentrate (Equilene® Pellets) at ≤0.7% of BW as-fed to maintain BC. Horses were kept in individual dry pens with access to feed, water, and salt for 16 h/day, and then group-housed in dry lots with only ad-libitum water and salt for 8hr/day. Feed intake was recorded daily by the collection and weighing of orts. All horses were assessed weekly using digital and thermography (FLIR®) images to document changes in rostral oral tissue. Blind reviewers analyzed images for changes in rostral oral cavity scores (ROCS) ranging from no damage (ROCS = 7) to severe damage (ROCS = 21).Biweekly saliva measurements were taken immediately before hay offering and 1hr after consumption using 2 disposable oral swabs (Munkcare®, 18cm3 each) held at the exit of the sublingual gland. Statistics were formulated using 3-way repeated measures ANOVA using R Statistical Program®. Intake was not influenced by feeding method (P = 0.874), nor was saliva production (P = 0.570). NET horses had numerically higher pre-consumption saliva values (5.27 ± 0.41g) compared with CON horses (4.55 ± 0.49g). Saliva production increased post-1hr consumption (P ≤ 0.001) confirming production was a result of mastication. The surface temperature of the oral cavity was not affected by treatment (P = 0.471) and was within normal ranges. Average total ROCS did not differ between treatments (NET: 11.0 ± 0.2; CON: 12.2 ± 0.2; P = 0.251) but increased with time (P ≤ 0.01). Use of a hay net for 70d did not influence intake or negatively affect rostral tissue, indicating a level of safety long-term. Based on these findings, feeding from a hay net over a 1hr period did not influence saliva production; however, in future studies, saliva production should be evaluated over an entire consumption period.