Dietary inclusion of nonconventional roughages for lowering enteric methane production and augmenting nutraceutical value of meat in cull sheep

Abstract

A study was undertaken to determine the effect of nonconventional roughages on nutrient utilization, enteric methane production and meat quality in cull ewes. Thirty six adult ewes (>5 yrs, BW = 30.3 ± 0.92 kg) were divided into four groups and fed for 90 days (d) on four complete feed blocks containing 400 g/kg different roughages and 600 g/kg concentrate mixture. Roughages were Cenchurus ciliaris hay (T-Cc), Crotalaria medicaginea hay (T-Cm), Blepharis scindica (T-Bs) and Trigonella foenum-graecum straw (T-Tf). Apparent digestibility of the all nutrients were higher (P < 0.05) in T-Bs treatment except crude protein. Enteric methane emission (g/kg DMI) was lower in T-Bs with an average reduction of 5.5 % digestible energy loss as compared to other treatments. Feeding of complete feed blocks containing B. scindica herbage (T-Bs) reduced enteric methane emission by 49.3 %, T. foenum-graecum straw (T-Tf) by 35.5 % and C. medicaginea (T-Cm) by 22.3 % per kg DOMI as compared to C. ciliaris hay (T-Cc). Likewise, there was a shift in rumen fermentation towards propionigenesis and higher (P < 0.05) concentration was recorded in T-Bs and T-Cm treatments. Body weight gain of cull ewes and total fat content (%) of carcass was higher (P < 0.05) in T-Cm and T-Bs treatment while, it was lower in T-Tf. However, fatty acid profile of Longissimus thoracis muscle showed higher (P < 0.05) proportion of C18:3n3, C18:2c9t11 and total PUFA in ewes fed blocks containing T. foenum-graecum straw (T-Tf). From the present findings it can be concluded that feeding of complete feed blocks consisting B. scindica and T. foenum-graecum straw to ewes reduced enteric methane emission by 49.3 and 26.8 percent respectively. Additionally, dietary inclusion of feed blocks with T. foenum-graecum straw improved desirable fatty acid contents in the muscles of ewes. Hence, including these alternative roughages in the diet of cull ewes could be a promising approach to reduce enteric methane emission and augment nutraceutical value of meat with desirable fatty acid contents.