ABSTRACT:
Acute intestinal bloat occurs in horses and mules introduced into sprouting Panicum maximum cv. Tanzania, cv. Massai and cv. Mombaça pastures in northern Brazil during the rainy season. It has been suggested that the disease is due to high concentrations of non-structural carbohydrates in this grass. The paper aimed to study outbreaks of colics in the state of Rondônia, Brazil and contribute to the knowledge of the carbohydrates contained in P. maximum as the cause of the disease. For this, ten farms which had cases of intestinal bloat were visited. On two farms, horses were introduced into such a toxic pasture. Samples of pasture were collected for determination of digestible energy, lysine, dry matter, water soluble carbohydrates, ether soluble carbohydrates, non-fiber carbohydrates, neutral detergent fiber, acid detergent fiber, lignin, starch, and fat. Samples of P. maximum pastures from neighboring farms, where the disease was not occurring, and from Cynodon dactylon pastures where the horses had been grazing before were also collected. The results showed that colics occur in the rainy season in sprouting pasture with a morbidity of 31.6%, and lethality of 86.1%. The pastures which induce colic showed significantly (P=0.0072) higher starch concentration (8,3 and 9,2%) than pastures of P. maximum which did not cause colic (0,9 and 4,3%) as well as the Cynodon dactylon pastures ingested previously by the horses (0.2 and 0.8%. On another farm, the disease was produced experimentally in a horse receiving in the feeder P. maximum collected from a toxic pasture with 6.5% of starch. The same pasture did not cause colic from November to February with starch content of 2.7 to 5.1%. It is suggested that the cause of colic in equids ingesting sprouting pasture of P. maximum is the high starch content of this pasture during the groth period.
INDEX TERMS:
Bloat; carbohydrates; equids; starch; Panicum maximum.
Thumbnail
