Behavioral and metabolic responses of ponies fed a complete single diet, thermally processed and containing long fiber

Alternatives horse's feed are ways to improve nutrient utilization as well as reduce production costs. The objective of this research was to describe behavioral and metabolic changes in ponies fed with complete diets composed of different grasses as fiber sources and industrial processing (thermal). Eight ponies were randomized into two Latin squares. The treatments were: ‘control diet’ (traditional management composed of 50% Tifton 85 hay and 50% pelletized concentrate supplied separately) and ‘complete diet’ (a single product composed of 50% of a fiber source [dehydrated whole corn plant, dehydrated elephant grass or dehydrated Tifton 85 grass] plus 50% concentrate) thermally processed (pelletized or extruded). The consumption of processed diets increased the frequency of 'standing' behavior (in an alert position) and reduced the frequency of 'feeding' behavior and the 'consumption time' (in minutes) of the diet (P < 0.05). There were no differences (P > 0.05) among processed diets and control diet for the frequency of ‘rest’ (lying in sternal or lateral decubitus), ‘abnormal’ (stereotypes), ‘water’ ingestion, ‘other’ behaviors and amount of water ingested. A larger area under the curve (AUC) of glucose and insulin (P < 0.05) for the processed diets and a lower concentration of total cholesterol (P < 0.05) for the pelleted diet was found. The glucose and insulin AUC was higher when the ponies received the pelleted diet. The dehydrated whole corn plant diet resulted in greater insulin AUC. The extruded diet containing Tifton 85 resulted in higher concentrations of triglycerides (33.0 ± 4.1 mg dL⁻¹) and VLDLc (6.6 ± 0.8 mg dL⁻¹), followed by the other diets. The use of complete thermally processed diets altered the behavior of stalled ponies but did not increase the frequency of ‘abnormal’ behaviors and did not impair metabolism. More research needs to be developed to assess the effects of long-term use of pelletized or extruded complete feed for horses.