Common Diseases of Farm Animals Part 23

CASTRATION.--The castration of the male is a common operation in domestic animals. The purpose of the operation is to render the animal more useful for work or meat production.

_The age_ at which the operation is performed varies in the different species. The colt is usually castrated when he is one year old, and the calf, pig and lamb when a few weeks or a few months of age. It is not advisable to castrate the young at weaning time. The operation and the weaning together may temporarily check the growth of the animal. Colts that are undeveloped and in poor flesh, or affected with colt distemper, should be allowed to recover before they are operated on. In all animals, it is advisable to wait until after they have recovered from disease and become thrifty and strong.

The spring, early summer and fall are the most suitable seasons for castrating the young. It may be practised during the hot or cold months of the year with little danger from wound infection or other complications, providing the necessary after-attention can be given.

_The preparation of the animal_ for the operation by withholding all feed for about twelve hours is very advisable. If this is practised, the stomach and intestines are not distended with feed, and the young are cleaner, easier to handle and suffer less from castration. Clean quarters and surroundings are very necessary to the success of the operation.

_The instruments required_ are sharp knives, preferably a heavy scalpel and a probe-pointed bistoury, an emasculator for large and mature animals, and surgeon's needles and suture material. Ropes and casting harness are frequently used for confining and casting the large and mature animals. Two clean pans or pails filled with a two per cent water solution of liquor cresolis compositus, or an equally reliable disinfectant, should be provided for cleaning the s.c.r.o.t.u.m and neighboring parts and the instruments. Pieces of absorbent cotton or oak.u.m may be used in washing and cleaning the s.c.r.o.t.u.m. The instruments should be sterilized in boiling water before using.

_If a number of pigs or lambs_ are to be castrated, it is best to confine them in a small, clean, well-bedded pen. This enables the attendant to catch them quickly and without unnecessary excitement or exercise. They should be taken to an adjoining pen to be castrated. The s.c.r.o.t.u.m should be washed with the disinfectant, and the t.e.s.t.i.c.l.es pressed tightly against the scrotal wall. An incision parallel with the middle line or raphe and a little to one side is made through the skin and the coverings of the t.e.s.t.i.c.l.e, and the t.e.s.t.i.c.l.e pressed out through the incision. The t.e.s.t.i.c.l.e and cords are then pulled well out and the cord broken off with a quick jerk and twist, or sc.r.a.ped off with a knife. The latter method is to be preferred in large lambs if the operator does not have an emasculator. The incision in the s.c.r.o.t.u.m should be extended from its base to the lowest part, in order to secure perfect drainage.

_Young calves_ may be castrated in the standing position or when cast and held on the side. The method of operating is the same as recommended for pigs and lambs.

_The castration of the colt_ may be performed in either the standing position or when cast. The method of operating is the same as practised in the smaller animals with the exception of cutting off the cord. The emasculator is used here. This instrument crushes the stump of the cord and prevents haemorrhage from the cut ends of the blood-vessels. Careful aseptic precautions must be observed in operating on colts, as they are very susceptible to wound infection and peritonitis.

The blood-vessels of the testicular cord are larger in the adult animals, and the danger from haemorrhage is greater than in the young. For this reason, it is advisable to use an emasculator in castrating all mature animals.

Complications Following Castration.--The _haemorrhage_ from the wound and stump of cord is usually unimportant in the young animals. Serious haemorrhage from the vessels of the cord sometimes occur in the adult, and a persistent haemorrhage results when a subcutaneous vein is cut in making the incision in the s.c.r.o.t.u.m. This complication is not usually serious, and can be prevented and controlled by observing proper precautions in cutting off the cord, or by picking up the cut ends of the vessel and ligating it.

Packing the scrotal sack with sterile gauze or absorbent cotton, and closing the incision with sutures may be practised for the purpose of stopping this form of haemorrhage. The packing should be removed in about twelve hours.

_The infection of the wound_ always follows castration. If the incision is small and the operation is followed by swelling of the neighboring tissues, the clotted blood, wound secretions and pus become penned up in the scrotal sack. Local blood poisoning or peritonitis follows. This is not an uncommon complication. It can be prevented by aseptic precautions in operating, and insuring good drainage by extending the incision to the lowest part of the scrotal sac. The scrotal sac always contracts down and becomes more or less swollen within a day or two following castration. We must keep this in mind when enlarging the opening, and be sure and make it plenty large to permit the escape of the infectious matter. In castrating sheep, all wool in the region of the scrotal sac should be clipped off, as this interferes with drainage from the wound.

_Exercise following castration_ is almost as essential as clean quarters.

Lack of exercise leads to _oedematous swelling_ in the region of the s.c.r.o.t.u.m, and the lips of the incision may become adhered if the animal is at rest. Colts and all mature animals that are confined in close quarters should be examined within forty-eight hours following the operation, and the condition of the wound noted. If closed, the hands should be cleaned and disinfected, and the adhesion broken down with the fingers. It is best to exercise horses daily.

It is unsafe to expose castrated animals to cold, damp, chilly weather. The shock and soreness resulting from the operation render the animal highly susceptible to pleurisy and pneumonia. This is especially true of young colts.

_Inguinal hernia_ or "_rupture_" may complicate the operation. This form of hernia is quite frequently met with in pigs, and only occasionally in the other animals. This complication is usually overcome by practising what is commonly termed the covered operation. The pig is usually held or hung up by the hind legs. A larger animal is placed on its back. The hernia is reduced by manipulating the ma.s.s of intestines with the fingers, so that they drop back into the abdominal cavity. The part is carefully cleaned and disinfected and an incision made through the scrotal wall, and the thin covering or serous sac in which the t.e.s.t.i.c.l.e is lodged is exposed. The t.e.s.t.i.c.l.e with the cord and covering is drawn well out of the s.c.r.o.t.u.m and held by an attendant. The operator then pa.s.ses a needle carrying a strong silk thread through the cord and covering, below the point where he intends severing it. The needle is removed and the cord and covering ligated at this point. The cord is then cut off about one-half an inch from the ligature, and the incision in the s.c.r.o.t.u.m made plenty large in order to insure drainage.

It is very essential to the success of this operation that the animal be dieted for twelve or eighteen hours before attempting to operate. The after-treatment consists in giving the animal separate quarters and feeding a light diet.

_Enlarged or scirrhous cords_ follow infection of the wound, usually with spores of a certain fungus (_Botryomyces_). This complication more often follows castration of cattle and pigs than of colts. Wrong methods of operating, such as leaving the stump of the cord too long and insufficient drainage for the pus and wound secretions, are the factors that favor this complication. Scirrhous cords or fibrous tumors should be dissected out and removed before they have become large and begun breaking down.

CASTRATION OF RIDGELING OR CRYPTORCHID ANIMALS.--In the ridgeling animal one or both of the t.e.s.t.i.c.l.es have not descended into the scrotal sac, and are usually lodged in the inguinal ca.n.a.l or abdominal cavity. If the t.e.s.t.i.c.l.e is lodged in the inguinal ca.n.a.l the animal is termed a "flanker."

In yearling colts the testicular cord is sometimes short, and the t.e.s.t.i.c.l.e is situated high up in the s.c.r.o.t.u.m and inguinal ca.n.a.l. In examining a supposed cryptorchid colt, he should be twitched. This may cause the t.e.s.t.i.c.l.e to descend into the s.c.r.o.t.u.m.

The castration of a true cryptorchid requires a special operation. When properly performed and the animal given special after-care, the operation is not followed by any serious complications. An abnormally large, diseased t.e.s.t.i.c.l.e is sometimes met with that cannot be removed in the usual way, and which complicates and increases the difficulty of operating.

CAPONIZING.--The castration or caponizing of the male chicken is commonly practised in certain localities. This operation changes the disposition of the c.o.c.kerel. He becomes more quiet and sluggish, never crows, the head is small, the comb and wattles cease growing and the hackle and saddle feathers become well developed. A capon always develops more uniformly and is larger than the c.o.c.kerel.

_The best time to caponize the c.o.c.kerel_ is when he weighs between two or three pounds. If older and heavier, the t.e.s.t.i.c.l.e becomes so large that it is very difficult to remove, and the danger from tearing the spermatic artery and a fatal haemorrhage resulting is greater.

There are several kinds of _caponizing instruments_. They may be purchased in sets. Each set should contain an instrument for removing the t.e.s.t.i.c.l.e; a knife for making the incision through the abdominal wall; a sharp hook for tearing through the thin membrane; spring spreader for holding the lips of the incision apart; a blunt probe for keeping the intestines out of the way of the operator; and a pair of tweezers for removing clots of blood. The different instruments for removing the t.e.s.t.i.c.l.es are a spoon-like scoop, spoon forceps and cannula. The spoon-like scoop is preferred by most operators.

_The c.o.c.kerel_ is confined for the operation by pa.s.sing a strong noose of cord around both legs, and a second noose around the wings close to the body, that have weights fastened to them. The cords pa.s.s through holes or loops in a barrel or board that is used for an operating table. This holds the c.o.c.kerel firmly and prevents his struggling.

_The bird should be prepared_ for the operation by withholding all feed and water for a period of twenty-four hours or longer, for the purpose of emptying out the intestine. The operator must have a strong light, in order to work quickly and safely. Direct sunlight or electric light should be used.

The instruments should be placed in a two per cent water solution of carbolic acid. A second vessel containing a two per cent water solution of liquor cresolis compound for cleaning the skin is necessary. Absorbent cotton should be used for washing the wound.

_The general method of operating_ is as follows: The incision is made between the last two ribs and in front of the thigh. The feathers over this region should be removed, and the skin pulled to one side before making the incision. An incision about one and one-half inches in length is made through the skin and muscles, and the spreader inserted. The sharp hook is then inserted and the thin serous membrane over the intestine is torn through. The t.e.s.t.i.c.l.es are situated in the superior portion of the abdominal cavity or under the back. On pushing the intestines to one side, both t.e.s.t.i.c.l.es, which are about the size of a bean and yellowish in color, can be seen. The lower one should be removed first. After removing both t.e.s.t.i.c.l.es, blood clots, feathers, or any foreign body that may have gotten into the wound should be picked up with the tweezers before removing the spreaders and allowing the wound to close. No special after-treatment is required.

_The most common complication_ is rupture of the spermatic artery. This occurs at the time the t.e.s.t.i.c.l.e is torn loose and may be due to careless methods, or operating on c.o.c.kerels that are too large. If all of the t.e.s.t.i.c.l.e is not removed from the abdominal cavity, the bird is termed a "slip." Sometimes air puffs form after the operation. These should be punctured with a sharp knife.

OVARIOTOMY, "SPAYING."--The removal of the ovaries, or ovariotomy, is practised for the purpose of rendering the female more useful for meat production, prolonging the period of lactation, overcoming vicious habits and preventing oestrum or heat. The operation is commonly performed in the heifer and b.i.t.c.h, occasionally in the mare, and at present rarely in the sow.

_Heifers_ are usually spayed between the ages of eight and twelve months; the _b.i.t.c.h_ and _sow_ when a few months old, or before the periods of heat have begun. The _mare_ is spayed when mature. It is possible to spay the female at any age, but the ages mentioned are the most convenient. Pregnant animals should not be operated on. The season of the year makes little difference in the results, providing the animal can be kept under close observation and given the necessary care and treatment. The spring of the year, just before turning the herd on pasture, is the best season to spay heifers.

_All animals should be prepared_ for the operation by withholding all feed for at least twenty-four hours before they are operated on, and it may be advisable to give them a physic. It is easier to operate when the intestinal tract is comparatively empty, and the death rate is lower than when the animal is not properly prepared for the operation.

_The method of operating_ is not the same in the different species. In young heifers and sows, the flank operation is preferred, and in mares and cows, the v.a.g.i.n.al operation. The median line operation is practised in b.i.t.c.hes. A spaying emasculator, or ecraseur, are the special instruments need for removing the ovaries.

The animal must be properly confined for the operation. Heifers are usually held in the standing position by fastening the head securely, and crowding the left side of the animal against a solid board part.i.tion, or side of a chute. If the v.a.g.i.n.al operation is performed, the mare or cow may be confined in stocks. The b.i.t.c.h is usually anesthetized and placed on her back on a table that is inclined, so that the hind parts are elevated.

Ovariotomy cannot be successfully performed by an untrained and inexperienced operator. The necessary precautions against the infection of the part must be observed, in order to promote the healing of the wound and prevent peritonitis. The seat of the operation should be carefully cleaned and disinfected.

_Following the operation_ the animal should be fed a spare diet for a few days. This is a very necessary part of the care of the b.i.t.c.h. The general condition of the animal should be noted daily until there is no further danger from wound infection. Healing is usually completed in from seven to twelve days. The sutures should then be removed, and if st.i.tch abscesses occur, the part should be washed with a disinfectant.

QUESTIONS

1. What is the purpose of dehorning cattle? Give different methods of removing the horns.

2. Give the causes and treatment of choking.

3. What is the purpose of castration and ovariotomy?

4. At what age is it best to practise castration and ovariotomy?

5. In what way should an animal be prepared for castration? Give a description of the method of castration in the different animals.

6. What special care should be given following castration?

7. What are some of the complications that may follow castration?

PART V.--PARASITIC DISEASES

CHAPTER XXIV

PARASITIC INSECTS AND MITES

Parasitic insects are common causes of skin diseases in domestic animals.