116 VETEEINAEY STATE BOARD 



How do horses, cattle and sheep, respectively, take in their food? 

 Have these methods any bearing on swallovs^ing non-alimen- 

 tary and harmful bodies? 



Horses prehend the food mainly with the lips and thoroughly 

 masticate it. Because of this thorough mastication, any foreign 

 body is quite sure to be detected and rejected. 



Cattle use their long tongue to convey food into the mouth, 

 whence it passes directly to the rumen through a thin, distensible 

 cesophagus, hence foreign bodies are frequently swallowed. 



Sheep have a cleft upper lip which enables them to graze closely 

 and pick up very small objects. They have a delicate manner of 

 eating and are less liable to swallow foreign bodies than cattle, but, 

 owing to their method of swallowing their food with little or no 

 mastication, foreign bodies are more commonly found in their 

 stomachs than is the case with the horse. 



Name the digestive ferments. What digestive ferments act on (a) 

 fat, (b) starch, (c) proteid? 



Ptyalin, pepsin, rennin, trypsin, steapsin, amylopsin, entero- 

 kinase, erepsin, maltase, invertase and lactase. 



(a) Steapsin; (b) ptyalin and amylopsin; (c) pepsin and 

 trypsin. 



What are the physical and chemical properties of saliva? 



An alkaline, opalescent, or slightly turbid fluid which readily 

 froths when shaken. On exposure to the air it throws down a 

 deposit of calcium carbonate due to the loss of carbon dioxide. 

 It has a specific gravity of 1005. Microscopically, it consists of 

 epithelial scales and salivary corpuscles. Saliva consists of a 0.6 

 per cent, mineral matter and 0.2 per cent, organic matter, the latter 

 consisting of mucin and small amounts of proteid matter. The salts 

 are: calcium carbonate, calcium chloride, calcium phosphate, mag- 

 nesium chloride and magnesium phosphate. It contains a ferment 

 known as ptyalin which converts starches into sugar. The gases 

 of saliva are : carbon dioxide, oxygen and nitrogen. 



Name four uses of saliva. 



Assists in mastication and swallowing; stimulates the nerves of 

 taste and has an amylytie action. In ruminants, it assists in 

 rumination. 



Desctibe the cells of the parotid gland when actively secreting. 



The granular material passes toward the centre of the acinus or 

 lumen, leaving each cell with a clear outer edge and the edge next 



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