Behavior of Boer goat wethers grazing high quality forage and effects of two methods of determining energy used for activity

Ten yearling Boer goat wethers (44.4±0.95 kg) consuming fresh Sudangrass ad libitum while grazing a 0.8-ha pasture or confined in nearby 1.2 × 1.2 m pens were used in a crossover experiment. Heat energy (HE) was estimated from heart rate (HR) measured over 24 h in 5-min intervals and the ratio of HE to HR previously determined for each animal with a stationary calorimetry system for 24 h while consuming a moderate quality grass hay. A GPS collar and leg activity monitor were used when HR was measured to classify activity as resting-lying (L), resting-standing (S), grazing (G), and walking (W), each with different HE averages. Behavior in confinement was assessed with the leg activity monitor as L or S. The grazing activity method (GAM) was based on time spent in the different activities multiplied by their corresponding HE values, with the grazing activity energy cost (GAEC) assumed the sum of differences between S, G, and W relative to L. The confinement method (COM) entailed subtracting total HE while confined from that when grazing. For goats while grazing, percentages of the day (33.8, 53.9, 11.4, and 0.9%; SE = 2.44) and daily HE attributable to the activities differed (P