Pulse.—The pulse in a grown animal of the bovine species in a state of good health beats from 45 to 55 times a minute. Exercise, fright, fear, excitement, overfeeding, pregnancy, and other conditions aside from disease may affect the frequency and character of the pulse. It assumes various characters according to its rapidity of beat, frequency of occurrence, resistance to pressure, regularity, and perceptibility. Thus we have the quick or slow, frequent or infrequent, hard or soft, full or imperceptible, large or small pulse, the character of each of which may be determined from its name; also that known as the intermittent, either regular or irregular. We may have a dicrotic, or double, pulse; a thready pulse, which is extremely small and scarcely perceptible; the venous, or jugular, pulse; the "running down" pulse, and so on. (See [p. 76].)
In cattle the pulse is conveniently felt over the submaxillary artery where it winds around the lower jawbone, just at the lower edge of the flat muscle on the side of the cheek. If the cow is lying down the pulse may be taken from the metacarpal artery on the back part of the fore fetlock. The pulsations can be felt from any superficial artery, but in order to ascertain the peculiarities it is necessary to select an artery that may be pressed against a bone.
There is a marked difference in the normal or physiological pulse of the horse and that of the cow, that of the horse being full and rather tense, while in the cow it is soft and rolling. The pulse is faster in young or old cattle than it is in those of middle age.
Auscultation.—Auscultation and percussion are the chief methods used to determine the various pathological changes that occur in the respiratory organs. Auscultation is the act of listening, and may be either mediate or immediate. Mediate auscultation is accomplished by aid of an instrument known as the stethoscope, one extremity of which is applied to the ear and the other to the chest of the animal. In immediate auscultation the ear is applied directly to the part. Immediate auscultation will answer in a large majority of cases. Auscultation is resorted to in cardiac and certain abdominal diseases, but it is mainly employed for determining the condition of the lungs and air passages. Animals can not give the various phases of respiration, as can the patients of the human practitioner. The organs themselves are less accessible than in man, owing to the greater bulk of tissue surrounding them and the pectoral position of the fore extremities, all of which render it more difficult in determining pathological conditions. (See [Pl. VIII].)
The air going in and out of the lungs makes a certain soft, rustling sound, known as the vesicular murmur, which can be heard distinctly in a healthy state of the animal, especially upon inspiration. Exercise accelerates the rate of respiration and intensifies this sound. The vesicular murmur is heard only where the lung contains air and its function is active. The vesicular murmur is weakened as inflammatory infiltration takes place and when the lungs are compressed by fluids in the thoracic cavity, and disappears when the lung becomes solidified in pneumonia or the chest cavity filled with fluid as in hydrothorax. The bronchial murmur is a harsh, blowing sound, heard in normal conditions by applying the ear over the lower part of the trachea, and may be heard to a limited extent in the anterior portions of the lungs after severe exercise. The bronchial murmur when heard over other portions of the lungs generally signifies that the lung tissue has become more or less solidified or that fluid has collected in the chest cavity.
Other sounds, known as mucous râles, are heard in the lungs in pneumonia after the solidified parts begin to break down at the end of the disease and in bronchitis where there is an excess of secretion, as well as in other conditions. Mucous râles are of a gargling or bubbling nature. They are caused by air rushing through tubes containing secretions or pus. They are said to be large or small as they are distinct or indistinct, depending upon the quantity of fluid that is present and the size of the tubes in which the sound is produced. According to their character they are divided into dry and moist. The friction sound is produced by the rubbing together of roughened surfaces and is characteristic of pleurisy.