Platelet ruminants

Ethanoic Acetic 16.7 Esterified to glycerol in ruminant milk fats, some plant triacylglycerols and as alcohol acetates in many plants. As a component of platelet-activating factor. 

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. 

With few exceptions, platelets of all species have similar ultrastmctural features and contain similar metabolic pathways. Therefore, species-dependent differences in platelet function tend to be quantitative rather than quantitative. Platelets from larger ruminants, including cattle, sheep, and goats, do not contain an open canalicular system and appear to be less functional than platelets from other species. Platelet function may be less irrqrortant to these species because they are not frequently exposed to trauma in the wild. Alternatively, carnivores are regularly exposed to trauma in the process of hunting and defending themselves. These species tend to have highly functional platelets and also can enhance platelet function at times of excitement or fear as a result of epinephrine release. 

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