PARTICLE POOL SIZE AND TURNOVER RATE OF INGESTA IN THE RETICULO-RUMEN OF NORMAL AND ABSESSED SHEEP

Sixteen mature sheep were fed chaffed orchardgrass hay once a day for 7 days. In 7th day, four sheep were slaughtered either prior to eating, 2, 8 or 16 hours after the commencement of eating to measure digesta pool size and particle size distribution in the reticulo-rumen. One sheep slaughtered at 8 hours after feeding had absesses at the cardia and in the lungs and could not ruminate normally. Time spent eating and rumination in the sheep on the day before slaughtering were 85 and 29 (pseudo-rumination 227) minutes a day, compared to those were 112 and 277 minutes in the other animals, respectively. Total actual chewing time in the sheep with absesses and the other animals were 98 and $373{\pm}132$ minutes, respectively. Dry matter(DM) intake in the sheep was $2.9g/kgBW^{0.75}$ which was only about 17% of that in the other animals. The pool sizes of reticulo-rumen DM and neutral detergent fiber (NDF) were somewhat smaller in the sheep than the others. The pool sizes of large particle (>1.18mm) DM and NDF in the animal were similar with those in the other animals. Mean DM retention time in the sheep was 207.4 hours which was about 4.2 times longer than that in the other animals.