24 



FARMER'S CYCLOPEDIA OF LIVE STOCK 



fore incapable of carrying sufficient ox- 

 ygen to the tissues. In certain diseases 

 the white corpuscles become too numer- 

 ous and give the blood a pinkish color. 

 The function of the white corpuscles or 

 leucocytes is a hotly disputed point, but 

 they seem to have the power of protect- 

 ing the animal against disease to some 

 extent by directly destroying bacteria 

 or by secreting antitoxic substances 

 which check the action of disease germs. 

 When blood is withdrawn from the 

 blood vessels it clots as a result of the 

 formation of fibrin filaments. The 

 time required for the coagulation of the 

 blood varies in different animals from 

 V/2 to 25 minutes, being shortest in the 

 sheep and increasing in length in the 

 goat, hog, ox, dog, cat and horse. 



and the prompt removal of carbon di- 

 oxid. This interchange of gases takes 

 place in the pulmonary capillaries 

 which come in contact with the walls of 

 the alveoli of the lungs. The change 

 in the color of the blood from scarlet 

 to brownish red takes place in the sys- 

 temic capillaries and back to scarlet in 

 the lungs. 



The rate of respiration a s well as the 

 pulse is greatly influenced by exercise, 

 but as a rule in farm animals there are 

 four heart beats for each respiratory 

 movement. The rate is somewhat higher 

 in cows than in bulls and steers. In 

 cows asleep it is about 22 per minute, 

 in rumination 24 to 36. In bulls and 

 steers it is about 20 per minute. In the 

 horse at rest the rate is about 10 but 



Fig. 15 — AB'RICAN FRILLED SHEEP 



Normal heart beat — The normal pulse 

 or rate of heart beat per minute in 

 adult animals is as follows: horse 36 to 

 40, cow 45 to 50, mule and ass 46 to 50, 

 pig, sheep and goat 70 to 80, dog 90 to 

 100, cat and hare 120 to 150, chickens 

 140, geese 110, pigeon 136 to 138. In 

 the newborn colt the pulse rate is 100 

 to 120, at two weeks 80 to 96, at three 

 months 68 to 76, at six months 64 to 72, 

 at one year 48 to 56, at two years 40 to 

 48, at four years 38 to 50, in old age 

 32 to 40. 



The purpose of respiration i s to sup- 

 ply oxygen to the blood and remove car- 

 bon dioxid from the blood. The vital 

 activity of every part of the body re- 

 quires an adequate supply of oxygen 



may increase to 50 or more in active 

 motion. Similarly sheep at rest breathe 

 about 15 times per minute, but when 

 running the rate of respiration may be 

 as high as 140. In the cat the respira- 

 tory rate is 24, in the dog 15 to 18, in the 

 hare 55, in the pigeon 30. In young 

 animals the breathing is slightly faster 

 than in adults. 



The kidneys_As already stated the 

 blood not only carries all nutritive sub- 

 stances including oxygen to the tissues 

 of the body, but carries away the waste 

 products to the various excretory or- 

 gans. The kidneys are the most impor- 

 tant of these latter and excrete the 

 urine containing urea, water and various 

 mineral salts, as well as uric acid, hip- 



