Estimation of volatile fatty acid production in the rumen of sheep
I. Effect of infusing propionic and butyric acid in the rumen on its characteristics

D. S. DJOUVINOV

Thracian University, Faculty of Veterinary Medicine, BG-6000 Stara Zagora, Bulgaria

Abstract

DJOUVINOV, D. S., 1999. Estimation of volatile fatty acid production in the rumen of sheep. I. Effect of infusing propionic and butyric acid in the rumen on its characteristics. Bulg. J. Agric. Sci., 5: 479-486

Six ruminally cannulated sheep were fed diet consisted of 300 g/kg maize and 700 g/kg lucerne hay at two levels: 90% of ad libitum intake and two-fold lower. Diets were offered in 8 equal portions at three-hour intervals. Sheep were infused isoenergetic solutions of propionate and butyrate. Each infusion lasted twenty four hours. Rumen digesta samples were measured for pH, osmolality and protozoa concentration. In addition, fluid dilution rate and diet digestibility were estimated.
Infusions of propionic and butyric acid did not depress the appetite of sheep but increased rumen pH and osmotic pressure. The values of protozoa counts, rumen volume, fluid dilution rate and dry matter digestibility were not affected. These results suggested that within each level of intake, steady-state conditions were maintained in the rumen and factors affecting estimation of volatile fatty acids production were kept under control.

Key words: volatile fatty acids, rumen, infusion, dry matter intake, digestibility, protozoa
Abbreviations: B = butyrate; DMI = dry matter intake; H = high level of feeding and infusion; L = low level of feeding and infusion; N = nitrogen; NDF = neutral detergent fibre; OM = organic matter; OP = osmotic pressure; P = propionate; VFA = volatile fatty acids