Beker, A., Gipson, T.A., Puchala, R., Askar, A.R., Tesfai, K., Detweiler, G.D., Asmare, A. and Goetsch, A.L., 2009. Energy expenditure and activity of different types of small ruminants grazing varying pastures in the summer. J. Appl. Anim. Res., 37: 1–14. Objectives were to determine the activity energy cost for different types of goats as well as a breed of sheep and to evaluate methods of prediction. Eight animals each of yearling Angora, doeling goats, yearling Boer wether goats, yearling Spanish wether goats and Rambouillet wether sheep slightly more than 2 yr of age were used. Two animals of each type were randomly allocated to one of the four pastures 9.3, 12.3, 4.6 and 1.2 ha in area. Forage conditions varied markedly among pastures. The experiment was conducted in the summer with three periods, 30, 26 and 26 d in length. Energy expenditure (EE) was estimated from heart rate (HR) on pasture and EE:HR for each animal determined in a calorimetry system. A leg position/movement monitoring system and a GPS collar with position and movement sensors were used to estimate distance traveled and. time spent grazing/eating, resting while lying, resting while standing and walking without grazing/eating. EE attributable to activity (EEa%), expressed as a percentage of the ME requirement for maintenance plus activity in confinement, was determined based on total EE, BW and ADG. ADG was similar among animal types. Distance traveled was affected by an interaction (P<0.05) between animal type and period (Angora goats: 2.98, 2.33 and 2.47; Boer goats: 3.17, 3.46 and 2.68; Spanish goats: 2.85, 5.28 and 3.30; sheep: 3.04, 3.43 and 2.25 km in periods 1, 2 and 3, respectively (SE = 0.423). Time spent grazing was lowest among animal types (P<0.05) for Angora goats (4.3, 8.4, 7.8 and 6.8 h/day) and time spent walking without grazing was lower (P<0.05) for Angora goats and sheep than for Boer goats (1.7, 2.4, 2.1 and 1.2 h/day for Angora goats, Boer goats, Spanish goats and sheep, respectively). Total EE was affected by an interaction (P<0.05) between animal type and period (Angora, goats: 5.89, 5.55, and 5.16; Boer goats: 9.63, 10.92 and 8.55; Spanish goats: 6.73, 8.17 and 7.02; sheep: 12.54, 11.84 and 12.93 MJ/day in periods 1, 2, and 3, respectively (SE = 0.442). EEa% was affected by an interaction (P<0.05) between animal type and period (Angora goats: 15.7, 17.4 and 15.1; Boer goats: 59.7, 67.4 and 34.4; Spanish goats: 46.2, 61.7 and 41.6; sheep: 22.3, 11.8 and 21.9% in periods 1, 2 and 3, respectively (SE = 6.07). EEa% of goats was predicted with moderate accuracy (R2 = 0.40–0.41) and without bias from estimates of 5.79 and 5.05%/h spent grazing/eating and grazing/eating plus walking, respectively, determined in a companion experiment; however, these methods were not suitable for sheep.