dc.description.abstract | Nineteen Quarter horse geldings (466 to 697 kg BW; 9 to 18 yr age) were used in a randomized design to determine the difference in nutrient utilization of either pelleted or extruded concentrate. Horses were randomly assigned to one of two treatments: a pelleted diet (PEL; n = 10) or an extruded diet (EXT; n = 9, Life Plus, Muenster Milling, LLC, Muenster, TX). Diets were formulated to be isocaloric and isonitrogenous with 8% fat and 14% protein, respectively. Dietary treatments were fed at 0.5% BW (as fed) daily, and all horses received 1.5% BW coastal bermudagrass (Cynodon dactylon) hay (as fed) daily. Horses were fed at 0630 and 1830 h daily, and refusals (ORTs) were collected and weighed 3 h after feeding.
The first 14-d were used as a dietary adaptation period, followed by 4-d total fecal collection. Fecal samples were collected from fecal harnesses (Bun-bag, Sagle, ID) every 6 h, weighed, homogenized, and subsampled. Additionally, concentrate rate of intake was measured over 5 feedings and averaged to determine kg consumed/min.
Data were analyzed using PROC MIXED procedure of SAS. Concentrate rate of intake was influenced by treatment (P = 0.05) with PEL eating at 0.16 kg/min and EXT eating at 0.13 kg/min. Concentrate dry matter intake was greater (P = 0.02) for EXT than PEL (0.46 and 0.44%, respectively) this difference resulted from a higher DM content for the EXT than the PEL. There were also no differences in hay intake (P = 0.70), total dry matter intake (P = 0.99), digestible dry mater intake (P = 0.17), or starch intake (P = 0.62). Dry matter digestion was greater (P = 0.03) for PEL at 51% compared to 48% for EXT. In accordance, organic matter digestion followed a similar response (P = 0.03) with digestibilities of 51% and 48% for PEL and EXT, respectively. Starch digestion was greater (P = 0.02) for PEL 90% compared to 87% for EXT and GE digestion was influenced by treatment (P = 0.03) with PEL being higher than EXT. In conclusion, digestion and rate of intake was decreased by extrusion feed processing. | en |