Extruded grain supplement used in an equine diet formulated for growing horses

The processing methods for horse feeds have stayed relatively constant for many years. Horse feeds are commonly high quality and high priced. These high quality feeds are needed for proper growth, maintenance, and performance. If a feed process could be developed to make grain more easily utilized by the horse, it could significantly reduce feed costs. Extrusion is a high heat process, which cooks and breaks down starch and protein bonds within the grain. Studies have shown extrusion to make nutrients more readily available to cattle and swine. The first phase of this study was performed to determine whether a dry extrusion process had beneficial effects on a mixed grain horse diet for ten, 2-50' old Quarter Horse fillies. The diet consisted of a sweet grain mix containing 23.3% com (ZeaMaysL.), 23.3% oats (Avena sativa I ) , 2.5% molasses, 0.6% trace mineral premix, and 0.4% Vitamin E supplement. The control diet was the grain mix non-extruded. The treatment diet was the grain mix, which was extruded. Alfalfa hay {Medicago sativa L.) was fed at 50% of the total diet. The experiment was a replicated crossover design with five fillies per treatment. There was a 13-d adjustment period prior to a 5-d collection period for each of two trials. During trial 1, the control diet was more digestible (P<.05) than the extruded diet and was higher (P<.01) in apparent absorption of CP than the extruded diet. However, during trial 2, the extruded diet was higher (P<.0001) in apparent absorption of CP and was higher (P<.01) in dry matter digestibility (treatment by trial interaction (P<.05)). The apparent absorption of Ca was consistently greater (P<.05) in fillies fed the extruded diet, particularly during trial 2. The second phase of this experiment was to determine whether extrusion temperature has an effect on the nutritive value of the sweet grain mix. The nutritive value was reduced as the extrusion process caused the NDF and ADF levels to increase from the non-extruded meal to the extruded product; furthermore, the TDN of the extruded product was reduced in comparison to the non-extruded meal. This experiment, as a whole, suggests that extrusion of com and oats had no obvious benefit of feed utilization or nutritive value for an equine diet formulated for growing horses.