FOOD AND WATER. 89 



hydrates or fats may cause an injurious deposition of fat under 

 the skin ; into and between the fibers of vohmtary muscles, or 

 in the heart and Hver; e. g., fatty degeneration of the hver. 

 Excess of fats causes diarrhoea and checks absorption. 



Faulty intervals interfere with digestion and thrift, may 

 cause such disorders as cohc and impaction. Cow may be fed at 

 longer intervals than horse; but both should be fed regularly. 

 A horse that goes a long time without food and then gets abund- 

 ance is apt to have colic. 



Vegetable parasites, like bunt, smut, rust, ergot and mildew 

 may cause abortions, diabetes and anaemia. 



Animal parasites infest several foods ; lessen their food value 

 and cause skin troubles. 



Sudden changes, from poor to rich pastures favor anthrax, 

 hoven, impaction, and black leg. 



Class differences. — Some animals may eat with impunity 

 what others cannot. Rich cereals may cause laminitis in horse; — 

 not in cow. Pigs can eat acorns freely, but they are injurious 



to other animals. 



WATER. 



Water may be a factor in animal disease when excessive in 

 amount or deficient, when containing low forms of vegetable 

 life, when containing low forms of animal life, when it has re- 

 ceived sewage matter, when very hard ; e. g., containing much 

 calcium and magnesium salts, when given at improper intervals 

 or soon after eating, or when given in large quantities to a very 

 hot or tired horse. 



Excessive amount lessens the digestibility of foods, causes 

 an increased tissue waste and favors indigestion. Horses that 

 have been excessive drinkers are frequently more thrifty, and 

 will keep on less food when given less water. 



Deficient water supply may cause impactions in cattle and 

 lessen the excretions from skin and kidneys in horses. Horses 

 need about 2 gallons and cows giving milk about 4 gallons of 

 water per pound of dry food; i. e.. horse needs in fall and win- 

 ter about four to six gallons and in summer about eight to ten 

 gallons per day, the amount varying according to diet and con- 

 dition of the atmosphere. Cows need much more than horses 

 in proportion to weight and feed, and can be usually trusted to 



Vet. studies— 6. 



