Volatile Fatty Acids In Rumen Liquor Research Articles

Effect of condensed tannins from Leucaena leucocephala on rumen fermentation, methane production and population of rumen protozoa in heifers fed low-quality forage.

ObjectiveThe aim of the experiment was to assess the effect of increasing amounts of Leucaena leucocephala forage on dry matter intake (DMI), organic matter intake (OMI), enteric methane production, rumen fermentation pattern and protozoa population in cattle fed Pennisetum purpureum and housed in respiration chambers.MethodsFive crossbred heifers (Bos taurus×Bos indicus) (BW: 295±6 kg) were fed chopped P. purpureum grass and increasing levels of L. leucocephala (0%, 20%, 40%, 60%, and 80% of dry matter [DM]) in a 5×5 Latin square design.ResultsThe voluntary intake and methane production were measured for 23 h per day in respiration chambers; molar proportions of volatile fatty acids (VFAs) were determined at 6 h postprandial period. Molar concentration of VFAs in rumen liquor were similar (p>0.05) between treatments. However, methane production decreased linearly (p<0.005), recording a maximum reduction of up to ~61% with 80% of DM incorporation of L. leucocephala in the ration and no changes (p>0.05) in rumen protozoa population were found.ConclusionInclusion of 80% of L. leucocephala in the diet of heifers fed low-quality tropical forages has the capacity to reduce up to 61.3% enteric methane emission without affecting DMI, OMI, and protozoa population in rumen liquor.

Utilisation of white clover silage fed alone or with maize silage by lactating dairy cows

Six lactating dairy cows in mid lactation were fed either white clover silage or a mixture of white clover and maize silages (70 : 30, dry matter basis). Milk yields (about 20 L/day) and compositions were similar when cows were fed either diet. Although the mixed diet was less digestible and provided less energy and crude protein than white clover, rumen fermentation may have been improved relative to that when white clover silage was fed alone. Flow rates of fluid from the rumen were faster, pH values for rumen liquor were higher and concentrations of ammonia in rumen liquor were lower when cows were fed the mixed diet than white clover silage. Concentrations of total volatile fatty acids and the proportions of the major volatile fatty acids in rumen liquor were similar for both diets. The efficiency of utilisation of dietary nitrogen for liveweight gain and milk production also appeared to be similar for both diets. Plasma concentrations of key metabolites were consistent with the cows being well nourished when fed both diets. Overall, it was evident that white clover silage may be used effectively in combination with lower quality maize silage to meet the nutrient requirements of cows with reasonably high yields of milk during mid lactation.

The digestion of barley-based diets by cattle: the effect of feeding of three diets containing different amounts of formaldehyde-treated soybean meal

Six growing cattle, with intestinal fistulae, were fed on barley-based diets to which were added increments of formaldehyde-treated soybean meal; the latter was substituted for whole-grain barley. The digestion of organic matter (OM), �-linked glucose polymer (starch), nitrogen (N) and rumen volatile fatty acids (VFA) were measured at a restricted level of intake. The cattle were offered air-dried feed at 3.4 kg per head daily, or approximately ad libitum (i.e. 4.2 kg air-dried feed per head per day). The three diets contained 19.7, 27.8 or 42.9 g nitrogen (N) per kg and were fed in a Latin-square design. When the feed was offered ad libitum there was a significant increase in OM digestibility, from 78% on the lowest N diet to 84% on the highest N diet. Relatively large quantities of starch (140-477 g/day) entered and were apparently digested in the small intestine, especially on the 19.7 g N/kg dry matter (the highest starch diet) on ad libitum feeding. The molar proportions of VFA in rumen liquor largely reflected the amount of starch which was fermented in the rumen. The digestion of nitrogen was characterized by a net gain in flow to the duodenum compared with intake. There was a significant increase in the amount of N apparently digested in the small intestines on the 42.9 g N/kg dry matter diet. The proportion of microbial N at the duodenum declined as more formaldehyde-treated soybean meal was added to the diet. Compared with that of the lowest N diet, the amount of amino acids entering and being apparently digested in the small intestines doubled in the highest N diet, and the concentrations of plasma-free amino acids reflected this. The feed intake comparison indicated that differences in interpretations of digestion studies were likely if animals were fed solely at restricted intakes. The main discrepancies were in OM digestibility, starch digestion in the small intestine, the proportion of microbial N flow at the duodenum and in the estimation of amino acid absorption and requirement.

Studies of the effects on the fermentation pattern in the rumen of the addition of various sources and levels of the lower volatile fatty acids

AbstractThe short term effects on rumen fermentation of the direct addition to the rumen of 1·5 M and 3 M of acetate, propionate and butyrate, given as the Ca2+, Na+, and NH+4 salts and as the free acid were measured in a mature cow. Longer term effects of the oral addition of I·5 M of calcium and ammonium acetates were also measured in growing heifers.For all volatile fatty acids (VFA) each rate of addition consistently increased the level of VFA in rumen liquor, but these fell gradually over about 4 h. Total volatile fatty acids (TVFA) were lower when free acids were given than when their salts were used. There was little effect on rumen pH. Calcium acetate was unpalatable when offered orally, and it tended to depress TVFA levels. Mean effects of acetate salts given orally on molar percentage of acetate in rumen liquor were smaller than those found by direct addition.