Effects of supplemental concentrate level and forage source on intake and digestion by growing and yearling Boer goat wethers and evaluation of a method of predicting negative feedstuff associative effects

TitleEffects of supplemental concentrate level and forage source on intake and digestion by growing and yearling Boer goat wethers and evaluation of a method of predicting negative feedstuff associative effects
Publication TypeWeb Article
Year of Publication2015
AuthorsDolebo, AT, Puchala, R, Gipson, TA, Dawsoh, LJ, Sahlu, T, Goetsch, AL
Series TitleJournal of Animal Science
Edition93
Type of Medium(E-Supplement)
Abstract

Negative associative effects between supplemental concentrate and forage were investigated with 12 growing (24 kg BW; SE = 0.48) and 12 yearling (47 kg; SE = 1.0 kg) Boer wethers in eight simultaneous 3 × 3 Latin squares, four with each animal type. Treatments in the different squares were 0, 15, 30, and 45 g/kg BW0.75 (DM) of supplemental concentrate (primarily ground corn), and in periods within squares three sources of grass hay were consumed ad libitum (Low: 5% CP, 79% NDF, and 13% ADL; Moderate: 8% CP, 71% NDF, and 9% ADL; High: 12% CP, 69% NDF, and 12% ADL). Forage intake in g/kg BW0.75 was similar between animal types (34.9 and 30.8 for growing wethers and yearlings; SE = 1.96), highest (P 30 > 45 g/kg BW0.75 of concentrate (48.5, 41.8, 25.9, and 15.2; SE = 2.77). There was an interaction (P = 0.026) in forage intake in g/d between animal type and level of supplementation (458, 449, 345, and 199 for growing wethers and 810, 730, 383, and 22 for yearlings with 0, 15, 30, and 45 g/kg BW0.75; SE = 59.1). There also was an animal type by concentrate level interaction (P = 0.021) in NDF digestibility (57.3, 60.6, 61.4, and 58.4% for growing wethers and 56.6, 62.9, 56.8, and 30.0% for yearlings with 0, 15, 30, and 45 g/kg BW0.75 of concentrate; SE = 3.41). Based on NDF digestibility without concentrate, the decrease in basal forage NDF digestibility in yearlings given 45 g/kg BW0.75 of concentrate was substantial compared with moderate effects of 45 g/kg BW0.75 with growing wethers and 30 g/kg BW0.75 with yearlings and no depressions with other treatments. The web-based goat nutrient calculation system of Langston, available at www2.luresext.edu/goats/research/suppcon.html, includes a system to address negative and positive associative effects between feedstuffs. The system was accurate in predicting TDN (total digestible nutrients) intake, particularly with the low level of supplementation and the moderate level with growing wethers. These production scenarios would be much more common than with the highest level of supplementation wither either animal type or the moderate level with the yearling wethers and their relatively low nutritional requirements.