Ruminant

Ruminants have a major modification in their gastrointestinal tract because the stomach is divided into four compartments. The rumen is one of the compartments. 

Source NRC (National Research Council). 1989. Nutrient Requirements of Horses. Fifth edition. National Academy Press, Washington, D.C. 

Large ruminant platelets, including cattle, goats, and sheep, are similar in stmcture and function. Bovine platelets have been studied most extensively. Resting bovine platelets are discoid in shape and vary between 1 and 5 pm in diameter. Bovine platelets contain a few large alpha granules and dense bodies and have a dense tubular system, but lacks an open canalicular system (Zucker-Franklin et al. 1985 White 1987). Lack of an open canalicular system probably is responsible for altered function of bovine platelets. Surfiice-activated bovine platelets produce pseudopods but do not spread as do platelets of other species (Grouse et al. 1990). Further, ycoprotein Ilbllla molecules do not concentrate in the center of surfiice-activated bovine platelet as fiiey do in human platelets. 

In general, ruminant platelets are less responsive to agonists compared to platelets of other species (Bondy and Gentry 1989). Bovine platelets are more sensitive to stimulation by PAF than by ADP or thrombin. ADP-induced aggregation does not induce dense granule secretion. Epinephrine, arachadonic acid, and serotonin do not aggregate bovine platelets 

Despite the fact that large ruminant platelets are relatively less functional than those of other species, platelet-related bleeding is a rare occurrence in ruminants. Alternatively, thrombotic disorders are also infrequently documented in cattle. 

A femilial platelet function defect has been documented in Simmental cattle (Searcy et al. 1990). Affected cattle have spontaneous epistaxis, and hematomas and hemorrhage following injury. Platelets from affected cattle do not aggregate in response to ADP, collagen, or calcium ionophore. The defect may result from delayed expression of functional fibrinogen binding sites on activated platelets (Frojmovic et al. 1996). 

The ultrastractural features of dog platelets are similar to those of human platelets (Jain 1993). 

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FEEDS AND FEED ADDITIVES - RUMINANT FEEDS] (Vol 10) -for dextrose prod n [SYRUPS] (Vol 23)... 

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