Intake and digestibility of alkaline hydrogen peroxide-treated wheat straw-alfalfa hay combinations fed to sheep

Abstract

A 5 × 5 Latin square experiment utilizing mature wethers (78 kg) was conducted to investigate the effects of feeding combinations of alkaline hydrogen peroxide-treated wheat straw (AHP-WS) and alfalfa hay on intake and nutrient digestibility. Diets consisted of an 80:20 forage to concentrate ratio on a dry matter (DM) basis. Dietary designations were based on ratios of AHP-WS: alfalfa hay in the diet. Quadratic responses (P < 0.05) were noted for both DM intake (DMI) as a percentage of body weight and organic matter intake (OMI) expressed as g d−1. Greater DMI and OMI were noted when wethers were fed diets containing combinations of AHP-WS and alfalfa (40:40 and 20:60) than when fed those containing AHP-WS or alfalfa as the sole forage (80:0 or 0:80). No effects of diet on digestibilities of dietary components were observed, with digestibility of DM and OM averaging 67 and 69%, respectively, across diets. Wethers consumed greater amounts of digestible OM when fed combinations of the two forages than when either was fed alone. Molar proportions of all ruminal volatile fatty acids (VFA) except acetate responded in a quadratic (P < 0.05) manner due to diet. Molar proportion of propionate decreased while molar proportions of other VFA increased with increasing level of alfalfa. Ruminal liquid and particulate dilution rates were not affected by diet. Time spent ruminating by sheep was increased linearly (P < 0.05) by inclusion of alfalfa hay in the diet. Favorable comparisons of AHP-WS to high quality alfalfa hay demonstrate the effectiveness of the AHP treatment process to enhance the nutritive value of WS. Key words: Intake, digestibility, treated wheat straw, alfalfa, sheep