Without dominant or stable characters, in at least one parent, no stability in transmission can be looked for, and without purity of breeding for generations dominant characters cannot be secured. Hence the great importance of purity of blood in effecting improvement in domestic animals. Since some inferior animals will occasionally appear, even where the breeding is the most skilful, the necessity will always exist for the exercise of a most rigorous selection on the part of every breeder who is to stand on the upland of success. When aided by judicious selection, the law that like produces like enables us to effect improvement until a certain standard of excellence is reached, to maintain improvement when it has been secured, and to mould new types and form new breeds. By the law or principle of variation is meant the tendency sometimes found in animals to produce characters in the progeny which differ from those of the parental type. These changes relate to both form and function; in time they may become modifications of the systems of animals. They may be classed as gradual, or general and ordinary; and as sudden, or spontaneous and extraordinary. General variation is that tendency to change from the original type which characterizes in a greater or a less degree all the individuals of a breed. Illustrations of the principle of general variation may be found, first, in the tendency of grain to deteriorate which has fallen upon an unkindly soil; and second, in the quick deterioration of the heavy breeds of sheep when confined to unproductive and rugged pastures. Chief among the numerous causes leading to general variation are changed conditions of life in animals, as climate, food, habit, and environment. Sometimes these influences act independently and sometimes in conjunction. The principle of spontaneous variation may be defined as that tendency sometimes found in animals to produce progeny more or less unlike either of the parents or the ancestry of these. Illustrations of the operation of this principle may be found in the occasional production of progeny very unlike the parents or the ancestry in color, form, and other characteristics, and in the existence of hornless breeds of cattle. By atavism is meant that innate tendency in animals to revert to the original type. It differs from the principle that like produces like in the reproduction of resemblances to an ancestry more or less remote rather than to the parents, and differs from spontaneous variation in producing resemblances to an ancestry more remote than the immediate parents, whereas the latter produces characters unlike those of the ancestry, whether near or remote. lustrations of atavic transmission are found in the occasional apearance of scars or horns in the polled breeds of cattle bred pure for many successive generations, and in the occasional appearance of tan-colored spots on the ears and face of the American merino. Il It is evident, therefore, that an intimate knowledge of the principles which govern breeding is highly important to those engaged in the production of live-stock. Hence they should study these with the utmost care and should embody them in their practice to the greatest possible extent. III. VETERINARY SCIENCE. COMMON DISEASES OF FARM ANIMALS. I. HORSES. The common method of administering medicine to the horse is in the form of a drench. In drenching a horse the bottle should be clean, strong, and smooth. The head should be elevated just enough to prevent the horse from throwing the 'iquid from the mouth. If the animal refuses to swallow, tickle the roof of the mouth with the finger or the neck of the bottle. Do not rub, pinch, or pound the throat, nor draw the tongue These in no way aid the horse to swallow and often do harm. If coughing occurs or by any mishap the bottle is crushed in the mouth, lower the head at once. Do not attempt to pour medicine through the nose; it is liable to strangle the animal. out. Irritating substances, as turpentine, should be given in bland fluids such as oil or milk. Warm-water injections are of great value in treating many bowel troubles. A very good injection pipe may be made with about 30 inches of inch rubber hose and an ordinary tin funnel. Oil the hose and insert it in the rectum from 12 to 18 inches, and elevate the funnel above the back and pour in the water. force of gravitation will carry it into the bowels. The Soap and water, or salt and water, may be injected in this manner in quantitities of a gallon or more every hour. Spasmodic Colic. CAUSES.-Error in diet is the most prolific cause, as improper food in improper quantities at irregular intervals; large draughts of cold water when warm; eating when exhausted; intestinal parasites; or foreign bodies in the bowels. SYMPTOMS.-The horse manifests uneasiness, moves forward and back in the stall, looks toward the flank, switches the tail, paws, lies down and rolls; after a little the spasm will subside and the animal become quiet. Soon the spasm returns with increased severity. As the disease progresses, the animal will become more violent and the intervals between the spasms shorter. TREATMENT. -Always urgent, as it often runs a rapid course, terminating fatally in a few hours. Give as a drench laudanum 1 oz., baking-soda one tablespoonful, sweet spts. nitre I oz., water one half-pint. This may be repeated in half an hour if not relieved. Always give injections of soap and warm water. Blanket the ani mal and rub the abdomen briskly. If inclined to hang on, apply a paste of mustard to the abdomen and give raw linseed oil I pt., chloral hydrate 4 dr., dissolved in warm water. Flatulent Colic. The causes and symptoms are similar to those of spasmodic colic. The pain is not so severe at the outset and gradually increases in severity as the bowels become distended by gas. No intervals of ease as in spasmodic colic. The abdomen becomes rapidly distended and the animal dies from suffocation or rupture of the bowels unless soon relieved. TREATMENT.-Usually necessary to puncture with a trocar and canula, which requires a knowledge of the anatomy of the parts. Internally give hyposulfite of soda 2 oz., fl. ex. ginger dr., spts. turpentine 4 dr., water I pint. Repeat in half an hour if necessary. Give injection of soap and warm water at short intervals. Pneumonia-Lung Fever. The most common cause is exposure to a cold draught when tired and sweaty. SYMPTOMS.-It is usually ushered in with a chill, followed by fever. The ears and legs are cold, pulse-rate increased, labored breathing, elbows turned out, increased working of the ribs, the animal persistently stands, appetite usually lost. TREATMENT.-Place in a comfortable well-ventilated boxstall. Blanket warmly, rub the legs and apply bandages. During the chill give large doses of stimulants, as whisky, alcohol, ginger, etc., at short intervals. If the breathing is not relieved in a few hours, apply mustard over the ribs, just back of the shoulder-blades. Give nourishing, easily digested food. Keep the animal perfectly quiet. Give 1-oz. doses of nitrate of potash in the drinking-water three times daily. After the chill is relieved keep a pail of fresh water before the animal at all times. Azoturia-Black-water. This disease is quite common among farm horses, and is due solely to overfeeding on nitrogenous foods and lack of exercise, followed by the accumulation in the system of waste matters. SYMPTOMS.-The animal is taken from the barn after a few days' rest on full rations, apparently as well as usual. After driving from half a mile to six or eight miles the horse will begin to lag and sweat profusely. Shortly will begin to go lame, usually in one hind limb. If urged on, will soon lose the use of the limbs and ground, unable to rise. The urine if be dark and coffee-colored. fall to the passed will This is a diagnos tic symptom. The muscles over the hips become hard and swollen, and the animal will struggle convulsively and attempt to rise. Fold TREATMENT.-Unhitch the animal as soon as the first symptoms are noticed and take the horse to the nearest barn. a woolen blanket and wring out of hot water and place over the hips, covering with a dry blanket. Repeat as soon as it becomes cool, and continue this until the more acute symptoms are relieved. Internally give laudanum 1 oz., raw linseed oil one pint, and repeat the laudanum in an hour if the pain is not relieved. If possible, the urine should be drawn with a catheter, as it is rarely passed when the animal is down. Give injections of soapy warm water at frequent intervals. Distemper-Strangles. This is a contagious disease due to a specific virus that very few horses escape. It usually runs a benign course and terminates favorably. |