Effects of total replacement of soybean meal and corn on ruminal fermentation, volatile fatty acids, protozoa concentration, and gas production

The main purpose of this study is to evaluate the effect of total replacement of soybean meal and corn with triticale and faba bean or field pea on rumen fermentation, protozoa counts, and gas production of lactating ewes. A total of 30 Sicilo-Sarde ewes were randomly allocated into three groups and were fed 1.8 kg drymatter of oat hay plus 500 g of one of three concentrates: the first concentrate (CS) was mainly composed of soybean meal, corn, and barley; the second (TFB) was formed by triticale and faba bean; and the third (TFP) was composed of triticale and field pea. The type of concentrate did not affect ruminal pH or ammonia nitrogen concentration (P > 0.05). The individual concentrations of volatile fatty acids showed a significant interaction between the type of concentrate and sampling time (P < 0.05), except for Butyric and Isobutyric acids. Within a post-feeding time, the pattern of evolution of total volatile fatty, acetic, and propionic acids differed significantly at 2 h post feeding (P < 0.05), while butyric and valeric acid changed at 0 and 4 h post feeding. The type of concentrate affected the total number of ciliate protozoa and the Isotricha species (P < 0.05), whereas Entodinium, Ophryoscolex, and Polyplastron were similar among concentrates (P > 0.05). The cumulative gas production from the in vitro fermentation, the time of incubation, and their interaction was affected by concentrate (P < 0.001). The substitution of soybean meal and corn in the concentrate with faba bean or field peas and triticale might maintain rumen parameters of dairy ewes.