Acids In Rumen Fluid Research Articles

THE COMPARATIVE NUTRITIVE VALUE OF SPARTINA PECTINATA AND TIMOTHY AT SEVERAL STAGES OF GROWTH

Spartina pectináta (Link) was harvested at four stages of growth (leaf, boot, head, and seed) from an unfertilized area of dikeland and at the final three dates following a late spring application of nitrogen fertilizer. This was compared with timothy (Phleum praténse L.) grown on unfertilized dikeland and harvested on five dates selected to include a similar range of physiological development.The digestibility of dry matter, organic matter and nitrogen, the dry matter consumption by sheep, and the nitrogen content declined as the forages matured. The rate of decline in digestibility of dry matter was greater for the timothy, but there was a maximum difference between species of only 3.5 percentage units.The timothy was consumed in greater amounts by sheep than spartina of similar digestibility. Consumption of the two species did not differ significantly at the seed stage of development, but at immature stages more timothy was consumed.All except the earliest cutting of spartina gave a significantly higher proportion of acetic acid and lower proportion of propionic acid in rumen fluid than did feeding timothy. Advancing maturity had no effect on the proportions of VFA from timothy; with spartina there was an increase in acetic acid and a decrease in butyric acid.It was concluded that spartina harvested at the conventional time in late summer is low in digestibility and is not consumed in sufficient quantity to meet the energy requirement of sheep.

Effect of Partial Deprivation of Parotid Saliva on Physiological responses of steers Fed Three Levels of Dietary Sodium

Five parotid and rumen fistulated dairy steers, when the animals were partially deprived of saliva by unilateral exteriorization of a parotid gland, were used to determine the effects of 0.22, 0.65, and 1.10% Na levels in the diet on the daily rate of parotid saliva flow, chemical properties of saliva, and concentrations and molar percentages of volatile fatty acids in their rumen fluid. In comparison with the 0.65 or 1.10% Na diet, the 0.22% Na level decreased feed intake, saliva flow rate, concentration of Na in saliva, and buffering capacity of saliva and increased the concentration of HPO4= in saliva. Also, the pH of rumen fluid from steers fed the 0.22 and 0.65% Na levels was lower than that from steers fed the 1.10% Na diet. However, the level of dietary Na fed the 1.10% Na diet. However, the level of dietary Na fed did not affect the concentration or molar percentages of acetic, propionic, or butyric acids in rumen fluid. Steers fed the 0.22% Na diet typically displayed anorexia and were dull, listless, and dehydrated in appearance.

THE EFFECT OF ORGANIC ACID SALTS ON GROWTH AND RUMEN VOLATILE FATTY ACIDS OF SHEEP FED PELLETED OR CHOPPED HIGH-ROUGHAGE RATIONS

Four experiments were conducted with sheep to compare the addition of sodium citrate and sodium propionate to pelleted and unpelleted rations and to determine the response to sodium citrate supplementation of different quality-hays. There were no significant differences in rate of gain or feed consumption of a ⅔ roughage −⅓ concentrate ration due to supplementation with sodium citrate or sodium propionate. Pelleting either the mixed ration or all-roughage rations increased feed consumption and rate of gain in all experiments. Pelleting the mixed ration decreased digestibility of dry matter, organic matter, and nitrogen in the one experiment in which this was determined. Pregnant and lactating ewes lost less body weight when fed a limited amount of long hay plus pelleted hay ad libitum than similar ewes fed a standard ration of long hay ad libitum plus 0.5 lb of concentrates per day. It was necessary to feed lambs 0.5 lb of rolled barley per day with long hay ad libitum to obtain gains equal to those of similar lambs fed pelleted hay ad libitum. The addition of sodium citrate significantly increased the rate of gain of lambs fed ad libitum a slightly moldy, weathered legume hay in the pelleted form together with 0.25 lb of long hay per head per day.The addition of sodium citrate to a mixed ration or to all-roughage rations did not usually alter the proportions of rumen volatile fatty acids. The addition of sodium propionate decreased the proportion of acetic acid while increasing that of propionic acid. In both experiments where this was determined, pelleting an all-roughage ration resulted in a decrease in the proportion of acetic acid and an increase in the longer chain volatile fatty acids in rumen fluid.

Quantitative Method for Determining the Steam Volatile Fatty Acids in Rumen Fluid by Gas Chromatography

Quantitative Method for Determining the Steam Volatile Fatty Acids in Rumen Fluid by Gas Chromatography