MAINTENANCE OF FARM ANIMALS 57 



The normal temperature of different animals of the same species may 

 vary considerably. On the other hand, the temperature of an individual 

 animal, if healthy, varies only within a narrow limit, a departure of 

 even 1 degree from normal with farm animals generally indicating some 

 bodily derangement. The normal body temperature of mature horses 

 ranges from 98.4-100.8F. (36.9-38.2C.) and averages about 100.2F. 

 For mature cattle the range is from 100.4-102.8F. (38.0-39.3C.) 

 and the average about 101.5 F. The range of normal temperature is 

 greater in sheep and swine than in horses and cattle. In sheep the range 

 is 101.3-105.8F. (38.4-41.0C.) and the average about 103.5F. In 

 swine the range is 100.9 -105.4F. (38.2-40.7C.) and the average 

 about 102.6 F. 



88. Heat production.. Heat is produced by all the decompositions or 

 oxidations taking place in the body, whether of food yet within the 

 digestive tract or of nutrients in the muscular tissues or the glands. 

 We have seen previously that much heat may be evolved, especially with 

 ruminants, in the fermentation of cellulose and other plant compounds in 

 the digestive tract. (40) The remainder is produced in the tissues of the 

 body by the following processes : Thru breathing, the oxygen of the air 

 is brought to the blood. Floating in the blood stream are myriads of 

 microscopic bodies, called red blood corpuscles, which owe their color 

 to hemoglobin, an iron-containing protein. This hemoglobin absorbs 

 the oxygen and holds it loosely. As the oxygen-laden blood permeates 

 the capillary system it gives up the oxygen to the living body cells, where 

 it is used for the combustion of a portion of the body nutrients, with 

 the result that heat is formed. 



Unlike the burning of fuel in a stove, the oxidations in the body take 

 place at a comparatively low temperature. As a result of the combustion 

 in the body, where before there were glucose, fats, and proteins in the 

 tissues, there now remain carbonic acid gas, water, and urea, the latter 

 substance representing the principal nitrogenous waste of the protein 

 nutrients. In still another respect body oxidations differ radically from 

 ordinary burning of fuel. In a furnace the wider the draft is opened, 

 increasing the supply of oxygen, the more rapid will be the combustion. 

 However, in the body, so long as there is a normal supply of oxygen, 

 the rate of burning of the food nutrients is independent of the supply 

 of air. Hence the greater intake of oxygen in unusually deep breathing 

 will not in itself cause an increase in heat production, tho the increased 

 muscular work in such breathing may lead to an increased production 

 of heat. 



As has been shown in the preceding chapter (78-80), all the energy 

 used up in the various forms of internal work of the body is finally 

 changed to heat. Tho this energy is lost so far as useful production is 

 concerned, the heat generated helps to warm the body. The amount of 

 heat so produced is considerable. Even with such an easily digested feed 

 as corn, over one-third of the total energy which the digestible nutrients 



