Effect of Extrusion Feed Processing on Equine Digestion
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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.
Goehring, Mallory Sherrill (2017). Effect of Extrusion Feed Processing on Equine Digestion. Master's thesis, Texas A & M University. Available electronically from