Effects of supplementation and body condition on intake, digestion, performance, and behavior of yearling Boer and Spanish goat wethers grazing grass/forb pastures

Sixteen Boer and 16 Spanish (Span) yearling wethers were used, with eight of each breed in different initial body condition (IBC; High and Low). Initial BW was 40, 25, 29, and 22 kg (SE = 1.4) and body condition score (BCS; 1 = extremely thin and 5 = very obese) was 3.9, 2.4, 3.6, and 2.7 (SE = 0.12) for Boer-High, Boer-Low, Span-High, and Span-Low, respectively. There was one wether per breed × IBC treatment in each of eight 0.4-ha grass/forb pastures. Wethers in four control (Con) pastures were not supplemented with concentrate, whereas those in supplement (Sup) pastures received 0.9% BW (DM basis) of concentrate. The experiment was 126 days, with four periods 39, 28, 37, and 22 days in length. Forage mass was 2466, 2496, 3245, and 2495 kg/ha for Con and 2226, 2378, 3100, and 2724 kg/ha for Sup in periods 1, 2, 3, and 4, respectively (SE = 199.0). The difference in intake of digested OM between breeds was much greater with than without supplemental concentrate (485 and 741 g/day for Boer and 413 and 561 g/day for Span without and with supplementation, respectively; SE = 23.2). In accordance, supplementation increased (P