Salivary Secretion Volume Related Ruminal Distension and Suppression of Dry Forage Intake in Large-type Goats

Tran Van Thang, Katsunori Sunagawa, Itsuki Nagamine, Go Ogura
2011 Asian-Australasian Journal of Animal Sciences  
On the other hand, Thang et al. (2010) has found that in esophageal-fistulated large-type goats fed dry forage twice daily, the amount of salivary secretion was larger than dry forage intake. Therefore, it is thought that salivary secretion volume during dry forage feeding may work in conjunction with consumed feed to form the ruminal load responsible for ruminal distension. Campling and Balch (1961) reported that feed intake was decreased when a balloon was inserted into the rumen and inflated
more » ... rumen and inflated with water in cows fed on hay and silage. On the other hand, Grovum (1995) reported that the increase in ruminal fluid osmolality by intraruminal infusion of the same dose of hyperosmotic NaCl, polyethylene glycol-400 (PEG), sodium acetate or sodium propionate resulted in the same-sized decreases in alfalfa pellet intake by sheep. However, Anil et al. (1993) reported that in cows, if a balloon inserted into the rumen was not filled with enough Asian-Aust. J. Anim. Sci. ABSTRACT : Two experiments under sham feeding conditions were conducted to determine whether or not ruminal distension brought about by feed boluses entering the rumen is a factor in the marked suppression of feed intake after 40 min of feeding. In experiment 1, a comparison was made between the intraruminal insertion of a water filled balloon (RIB) treatment and normal control (non-insertion of a balloon, NIB). In experiment 2, saliva lost due to sham feeding conditions was replenished via an intraruminal infusion of iso-osmotic artificial saliva. A comparison of dry forage intake was then conducted between the intraruminal replenishment of iso-osmotic artificial saliva and insertion of a balloon (RRIAS-RIB) treatment, and the intraruminal replenishment of iso-osmotic artificial saliva and non-insertion of a balloon (RRIAS-NIB) control. In experiment 1, eating rates in the RIB treatment 30 min after the commencement of feeding tended to be lower than those in the NIB control. In comparison with the NIB control, cumulative dry forage intake in the RIB treatment was 29.7% less (p<0.05) upon conclusion of the 2 h feeding period. The secreted saliva weight in the NIB control and the RIB treatment during the 2 h feeding period was 53.2% and 60.9% total weight of the boluses, respectively. In experiment 2, eating rates in the RRIAS-RIB treatment 30 min after the commencement of feeding was significantly lower (p<0.05) than those in the RRIAS-NIB control. Cumulative dry forage intake in the RRIAS-RIB treatment was a significant 45.5% less (p<0.05) compared with that in the RRIAS-NIB control upon conclusion of the 2 h feeding period. The secreted saliva weight in the RRIAS-NIB control and the RRIAS-RIB treatment during the 2 h feeding period was 54.1% and 64.2% total weight of the boluses, respectively. The level of decrease in dry forage intake in the RRIAS-RIB treatment of experiment 2 was larger than that in the RIB treatment of experiment 1. In the present experiments, due to the sham feeding conditions, the increases in osmolality of ruminal fluid and plasma, and a decrease in ruminal fluid pH which are normally associated with feeding were not observed. The results indicate that the marked decrease in feed intake observed in the second hour of the 2 h feeding period is related to ruminal distension caused by the feed consumed and the copious amount of saliva secreted during dry forage feeding. (
doi:10.5713/ajas.2011.11001 fatcat:hxvwlvzrjnbsdbd5pdxdprfttm