2016 ACVIM Forum Research Abstract Program

Nine cecally-cannulated Quarter horses (6-7 years, 4 mares, 5 geldings, approximately 500 kg) were divided into control (n = 4) and treatment (n = 5) groups based on gender and body weight and acclimated for 19 d to the diets and housing. The control diet consisted of 1.5% BW/d prairie grass hay (divided into 2 feedings at 0700 & 1900) and 0.5% BW/d of a 12% protein commerciallyavailable concentrate (Omolene 200Ò, Purina Animal Nutrition) top-dressed with 10 g/45.5 kg BW alfalfa pellet placebo (1 feeding at 0700). The treatment diet was identical but concentrate was topdressed with 10 g/45.5 kg BW of a pelleted proprietary yeast fermentation product. On d 19, cecal fluid samples were collected 1 h before and after feeding (À1 h, +1 h) and at + 4 h, +8 h, +12 h, +16 h, +20 h and +24 h for 2 additional days to establish baseline levels. On d 22, the morning meal consisted of 1.25% BW concentrate (challenge) followed by 0.75% BW hay. Cecal samples were collected as on previous days. Cecal fluid pH was measured in samples at the time of collection. Lactate was later assessed using colorimetric analysis. A completely randomized split-split-plot design was used to test the effects of the yeast fermentation product. Analysis of variance was done with mixed models (SAS 9.3, SAS Institute Inc., Cary, NC, USA) and least squares means were compared using Fisher's least significant difference (P < 0.05).