Abstract
Feeding systems for dairy ruminants need to ensure high intake of energy to achieve maximum milk production potential. This might be accomplished by raising the dietary concentration of cereal grain. Increasing the concentration of starch in diets can lead to undesirable ruminal fermentation, and to prevent it, the partial replacement of cereal grain with low starch by-product feeds is recommended. The purpose of the present study was to compare the effect of fed two mixed diets to dairy goats differing in the type of carbohydrate (starch vs. easily degradable fiber). Energy and nitrogen balance, short chain fatty acids in rumen liquor and milk performance in dairy goats during mid lactation were determined. Enteric methane (CH4) emissions and CH4 production from manure were determined as well. Ten multiparous Muciano-Granadina goats were assigned to two isoenergetic and isoproteic diets (19.1 MJ/kg dry matter (DM) and 18.1% of CP, DM basis) in a crossover design. One group was fed a mixed ration with 21.9% of starch (HS diet) and the other (LS diet) with 7.0% of starch. HS diet had 36% of barley (as source of starch) and it was replaced with soy hulls and corn gluten feed in LS diet (as potentially digestible fiber). No differences were observed for dry matter intake in both diets (2.05 kg/d, on average). A significant increase of ruminal acetic acid was found for low starch diet (66.4 and 56.6 mol/100 mol for LS and HS diet, respectively). No significant effect was found among diets for enteric CH4 emissions (28.5 g/d, on average). Manure derived maximum potential yield was (Bo) higher in HS diet, with 5.9 L CH4/kg OM vs. 0.28 L CH4/kg OM for LS diet, probably associated with the low ADF digestibility. Differences among diets were found for milk production (2.4 vs. 2.2 kg/d for HS and LS, respectively), and greater milk fat was observed with LS diet compared with HS (6.4% vs. 5.5%, respectively).
Highlights
Feeding systems for dairy ruminants need to ensure high intake of energy, among other factors, to achieve maximum milk production potential
Experimental design was in a cross over (2 treatments × 2 periods) and, goats were fed two different mixed rations, one group was fed a mixed ration with 364 g/kg dry matter (DM) of barley grain and the other diet substituted with barley by 446 g/kg DM of by-products in the following proportion: 271 g/kg DM soy hulls and 175 g/kg DM gluten feed
Ether extract and acid detergent fiber (ADF) digestibility were higher (P < 0.05) with low starch diet compared with high starch diet
Summary
Feeding systems for dairy ruminants need to ensure high intake of energy, among other factors, to achieve maximum milk production potential. This might be accomplished by raising the dietary concentration of rapidly degraded non fibrous carbohydrates, such as starch from cereal grain. Increasing the concentration of starch in diets for dairy cows, can lead to undesirable ruminal fermentation, compromising the nutrient supply for production of milk and milk components. The review of [3] concluded that the inclusion of fibrous by-products in the diet of ruminants would likely increase enteric CH4, when inclusion was above 35% to 40% of dry matter intake. Feed ingredients provide the substrates for microbial fermentation, and differences in feed digestibility and chemical composition alter the amount of energy extracted by the microbes and the pattern of volatile fatty acids and CH4 produced [4]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
