Special Report on Diseases of the Horse · United States. Bureau of Animal Industry
Part 25
Chapter 25 of 81 · 14 min read
DIFFICULT PARTURITION FROM NARROW PELVIS.—A disproportion between the fetus got by a large stallion and the pelvis of a small dam is a serious obstacle to parturition, sometimes seen in the mare. This is not the rule, however, as the foal up to birth usually accommodates itself to the size of the dam, as illustrated in the successful crossing of Percheron stallions on mustang mares. If the disproportion is too great the only resort is embryotomy.
FRACTURED HIP BONES.—More commonly the obstruction comes from distortion and narrowing of the pelvis as the result of fractures. (Plate XIII, fig. 2.) Fractures at any point of the lateral wall or floor of the pelvis are repaired with the formation of an extensive bony deposit bulging into the passage of the pelvis. The displacement of the ends of the broken bone is another cause of constriction, and between the two conditions the passage of the fetus may be rendered impossible without embryotomy. Fracture of the sacrum (the continuation of the backbone forming the croup) leads to the depression of the posterior part of that bone in the roof of the pelvis and the narrowing of the passage from above downward by a bony ridge presenting its sharp edge forward.
In all cases in which there has been injury to the bones of the pelvis the obvious precaution is to withhold the mare from breeding and to use her for work only.
If a mare with a pelvis thus narrowed has got in foal inadvertently, abortion may be induced in the early months of gestation by slowly introducing the oiled finger through the neck of the womb and following this by the other fingers until the whole hand has been introduced. Then the water bags may be broken, and with the escape of the liquid the womb will contract on the solid fetus and labor pains will ensue. The fetus being small will pass easily.
TUMORS IN THE VAGINA AND PELVIS.—Tumors of various kinds may form in the vagina or elsewhere within the pelvis, and when large enough will obstruct or prevent the passage of the fetus. Gray mares, which are so subject to black pigment tumors (melanosis) on the tail, anus, and vulva, are the most liable to suffer from this. Still more rarely the wall of the vagina becomes relaxed, and being pressed by a mass of intestines will protrude through the lips of the vulva as a hernial sac, containing a part of the bowels. If a tumor is small it may only retard and not absolutely prevent parturition. A hernial protrusion of the wall of the vagina may be pressed back and emptied, so that the body of the fetus engaging in the passage may find no further obstacle. When a tumor is too large to allow delivery the only resort is to remove it, but before proceeding it must be clearly made out that the obstruction is a mass of diseased tissue, and not a sac containing intestines. If the tumor hangs by a neck it can usually be most safely removed by the ecraseur, the chain being passed around the pedicel and gradually tightened until that is torn through.
HERNIA OF THE WOMB.—The rupture of the musculo-fibrous floor of the belly and the escape of the gravid womb into a sac formed by the peritoneum and skin hanging toward the ground is described by all veterinary obstetricians, yet it is very rarely seen in the mare. The form of the fetus can be felt through the walls of the sac, so that it is easy to recognize the condition. Its cause is usually external violence, though it may start from an umbilical hernia. When the period of parturition arrives, the first effort should be to return the fetus within the proper abdominal cavity, and this can sometimes be accomplished with the aid of a stout blanket gradually tightened around the belly. This failing, the mare may be placed on her side or back and gravitation brought to the aid of manipulation in effecting the return. Even after the hernia has been reduced the relaxed state of the womb and abdominal walls may serve to hinder parturition, in which case the oiled hand must be introduced through the vagina, the fetus brought into position, and traction coincident with the labor pains employed to produce delivery.
TWISTING OF THE NECK OF THE WOMB.—This condition is very uncommon in the mare, though occasionally seen in the cow, owing to the greater laxity of the broad ligaments of the womb in that animal. It consists in a revolution of the womb on its own axis, so that its right or left side will be turned upward (quarter revolution), or the lower surface may be turned upward and the upper surface downward (half revolution). The effect is to throw the narrow neck of the womb into a series of spiral folds, turning in the direction in which the womb has revolved, closing the neck and rendering distention and dilatation impossible.
The period and pains of parturition arrive, but in spite of continued efforts no progress is made, neither water bags nor liquids appearing. The oiled hand introduced into the closed neck of the womb will readily detect the spiral direction of the folds on its inner surface.
The method of relief which I have successfully adopted in the cow may be equally effective in the mare. The dam is placed (with her head uphill) on her right side if the upper folds of the spiral turn toward the right, and on her left side if they turn toward the left, and the oiled hand is introduced through the neck of the womb and a limb or other part of the body of the fetus is seized and pressed against the wall of the womb, while two or three assistants turn the animal over on her back toward the other side. The object is to keep the womb stationary while the animal is rolling. If success attends the effort, the constriction around the arm is suddenly relaxed, the spiral folds are effaced, and the water bags and fetus press forward into the passage. If the first attempt does not succeed, it may be repeated again and again until success crowns the effort. Among my occasional causes of failure have been the prior death and decomposition of the fetus, with the extrication of gas and overdistention of the womb, and the supervention of inflammation and inflammatory exudation around the neck of the womb, which hinders untwisting. The first of these conditions occurs early in the horse from the detachment of the fetal membranes from the wall of the womb; and as the mare is more subject to fatal peritonitis than the cow, it may be concluded that both these sources of failure are more probable in the former subject.
When the case is intractable, though the hand may be easily introduced, the instrument shown in Plate XIV, figure 7, may be used. Each hole at the small end of the instrument has passed through it a stout cord with a running noose, to be passed around two feet or other portion of the fetus which it may be possible to reach. The cords are then drawn tight and fixed around the handle of the instrument; then, by using the cross handle as a lever, the fetus and womb may be rotated in a direction opposite to that causing the obstruction. During this process the hand must be introduced to feel when the twist has been undone. This method may be supplemented, if necessary, by rolling the mare as described above.
EFFUSION OF BLOOD IN THE VAGINAL WALLS.—This is common as a result of difficult parturition, but it may occur from local injury before that act, and may seriously interfere with it. This condition is easily recognized by the soft, doughy swelling so characteristic of blood clots, and by the dark-red color of the mucous membrane. I have laid open such swellings with the knife as late as 10 days before parturition, evacuated the clots, and dressed the wound daily with an astringent lotion (sulphate of zinc 1 dram, carbolic acid 1 dram, water 1 quart). A similar resort might be had, if necessary, during parturition.
CALCULUS (STONE) AND TUMOR IN THE BLADDER.—The pressure upon the bladder containing a stone or a tumor may prove so painful that the mare will voluntarily suppress the labor pains. Examination of the bladder with the finger introduced through the urethra will detect the offending agent. A stone should be extracted with forceps. (See "Lithotomy.") The large papillary tumors which I have met with in the mare's bladder have been invariably delicate in texture and could be removed piecemeal by forceps. Fortunately, mares affected in this way rarely breed.
FECAL IMPACTION OF THE RECTUM.—In some animals, with more or less paralysis or weakness of the tail and rectum, the rectum may become so impacted with solid feces that the mare is unable to discharge them, and the accumulation both by reason of the mechanical obstruction and the pain caused by pressure upon it will impel the animal to cut short all labor pains. The rounded swelling surrounding the anus will at once suggest the condition, when the obstruction may be removed by the well-oiled or well-soaped hand.
SPASM OF THE NECK OF THE WOMB.—This occurs in the mare of specially excitable temperament, or under particular causes of irritation, local or general. Labor pains, though continuing for some time, produce no dilatation of the neck of the womb, which will be found firmly closed so as to admit but one or two fingers; this, although the projection at the mouth of the womb may have been entirely effaced, so that a simple round opening is left, with rigid margins.
The simplest treatment consists in smearing this part with solid extract of belladonna, and after an interval inserting the hand with fingers and thumb drawn into the form of a cone, rupturing the membranes and bringing the fetus into position for extraction, as advised under "Prolonged retention of the fetus." Another mode is to insert through the neck of the womb an ovoid rubber bag, empty, and furnished with an elastic tube 12 feet long. Carry the free end of this tube upward to a height of 8, 10, or 12 feet, insert a filler into it, and proceed to distend the bag with tepid or warm water.
FIBROUS BANDS CONSTRICTING OR CROSSING THE NECK OF THE WOMB.—These, occurring as the result of disease, have been several times observed in the mare. They may exist in the cavity of the abdomen and compress and obstruct the neck of the womb, or they may extend from side to side of the vagina across and just behind the neck of the womb. In the latter position they may be felt and quickly remedied by cutting them across. In the abdomen they can be reached only by incision, and two alternatives are presented: (1) To perform embryotomy and extract the fetus piecemeal, and (2) to make an incision into the abdomen and extract by the Caesarean operation, or simply to cut the constricting band and attempt delivery by the usual channel.
FIBROUS CONSTRICTION OF VAGINA OR VULVA.—This is probably always the result of direct mechanical injury and the formation of rigid cicatrices which fail to dilate with the remainder of the passages at the approach of parturition. The presentation of the fetus in the natural way and the occurrence of successive and active labor pains without any favorable result will direct attention to the rigid and unyielding cicatrices which may be incised at one, two, or more points to a depth of half an inch or more, after which the natural expulsive efforts will usually prove effective. The resulting wounds may be washed frequently with a solution of 1 part of carbolic acid to 50 parts of water, or of 1 part of mercuric chlorid to 1,000 parts of water.
FETUS ADHERENT TO THE WALLS OF THE WOMB.—In inflammation of the mucous membrane lining the cavity of the womb and implicating the fetal membranes the resulting embryonic tissue sometimes establishes a medium of direct continuity between the womb and fetal membranes; the blood vessels of the one communicate freely with those of the other and the fibers of the one are prolonged into the other. This causes retention of the membranes after birth, and a special risk of bleeding from the womb, and of septic poisoning. In exceptional cases the adhesion is more extensive and binds a portion of the body of the foal firmly to the womb. In such cases it has repeatedly been found impossible to extract the foal until such adhesions were broken down. If they can be reached with the hand and recognized, they may be torn through with the fingers or with a blunt hook, after which delivery may be attempted with hope of success.
EXCESSIVE SIZE OF FETUS.—It would seem that a small mare may usually be safely bred to a large stallion, yet this is not always the case; and when the small size is an individual rather than a racial characteristic or the result of being very young, the rule can not be expected to hold. There is always great danger in breeding the young, small, and undeveloped female, and the dwarfed representative of a larger breed, as the offspring tend to partake of the large race characteristics and to show them even prior to birth. When impregnation has occurred in the very young or in the dwarfed female there are two alternatives—to induce abortion or to wait until there are attempts at parturition and to extract by embryotomy if impracticable otherwise.
CONSTRICTION OF A MEMBER BY THE NAVEL STRING.—In man and animals alike the winding of the umbilical cord around a member of the fetus sometimes leads to the amputation of the latter. It is also known to get wound around the neck or a limb at birth, but in the mare this does not seriously impede parturition, as the loosely attached membranes are easily separated from the womb and no strangulation or retarding occurs. The foal may, however, die from the cessation of the placental circulation unless it is speedily delivered.
WATER IN THE HEAD (HYDROCEPHALUS) OF THE FOAL.—This consists in the excessive accumulation of liquid in the ventricles of the brain so that the cranial cavity is enlarged and constitutes a great, projecting, rounded mass occupying the space from the eyes upward. (See Plate XIII, fig. 3.) With an anterior presentation (fore feet and nose) this presents an insuperable obstacle to progress, as the diseased cranium is too large to enter the pelvis at the same time with the fore arms. With a posterior presentation (hind feet) all goes well until the body and shoulders have passed out, when progress is suddenly arrested by the great bulk of the head. In the first case, the oiled hand introduced along the face detects the enormous size of the head, which may be diminished by puncturing it with a knife or trocar and cannula in the median line, evacuating the water and pressing in the thin, bony walls. With a posterior presentation, the same course must be followed; the hand passed along the neck will detect the cranial swelling, which may be punctured with a knife or trocar. Oftentimes with an anterior presentation the great size of the head leads to its displacement backward, and thus the fore limbs alone engage in the passages. Here the first object is to seek and bring up the missing head, and then puncture it as above suggested.
ASCITES, OR DROPSY OF THE ABDOMEN IN THE FOAL.—The accumulation of liquid in the abdominal cavity of the fetus is less frequent, but when present it may arrest parturition as completely as will hydrocephalus. With an anterior presentation the foal may pass as far as the shoulders, but behind this all efforts fail to effect a further advance. With a posterior presentation the hind legs as far as the thighs may be expelled, but at this point all progress ceases. In either case the oiled hand, passed inward by the side of the foal, will detect the enormous distension of the abdomen and its soft, fluctuating contents. The only course is to puncture the cavity and evacuate the liquid. With the anterior presentation this may be done with a long trocar and cannula, introduced through the chest and diaphragm, or with a knife an incision may be made between the first two ribs and the lungs and heart cut or torn out, when the diaphragm will be felt projecting strongly forward, and may be easily punctured. Should there not be room to introduce the hand through the chest, the oiled hand may be passed along beneath the breast bone and the abdomen punctured. With a posterior presentation the abdomen must be punctured in the same way, the hand, armed with a knife protected in its palm, being passed along the side of the flank or between the hind limbs. It should be added that moderate dropsy of the abdomen is not incompatible with natural delivery, the liquid being at first crowded back into the portion of the belly still engaged in the womb, and passing slowly from that into the advanced portion as soon as that has cleared the narrow passage of the pelvis and passed out where it can expand.
GENERAL DROPSY OF THE FETUS.—In this case the tissues generally are distended with liquid, and the skin is found at all points tense and rounded, and pitting on pressure with the fingers. In some such cases delivery may be effected after the skin has been punctured at narrow intervals to allow the escape of the fluid and then liberally smeared with fresh lard. More commonly, however, it can not be reached at all points to be so punctured nor sufficiently reduced to be extracted whole, and resort must be had to embryotomy.
EMPHYSEMA, OR SWELLING OF THE FETUS WITH GAS.—This has been described as occurring in a living fetus, but I have met with it only in the dead and decomposing foal after futile efforts had been made for several days to effect delivery. These cases are very difficult, as the foal is inflated to such extent that it is impossible to advance it into the passages, and the skin of the fetus and the walls of the womb and vagina have become so dry that it is impracticable to cause the one to glide on the other. The hair comes off any part that may be seized, and the case is rendered the more offensive and dangerous by the very fetid liquids and gases. The only resort is embryotomy, by which I have succeeded in saving a valuable mare that had carried a colt in this condition for four days.
CONTRACTIONS OF MUSCLES.—The foal is not always developed symmetrically, but certain groups of muscles are liable to remain short, or to shorten because of persistent spasmodic contraction, so that even the bones become distorted and twisted. This is most common in the neck. The bones of this part and even of the face are drawn to one side and shortened, the head being held firmly to the flank and the jaws being twisted to the right or left. In other cases the flexor muscles of the fore limbs are contracted so that the latter are strongly bent at the knee. In neither of these cases can the distorted part be extended and straightened, so that body or limbs must necessarily present double, and natural delivery is rendered impossible. The bent neck may sometimes be straightened after the muscles have been cut on the side to which it is turned, and the bent limbs after the tendons on the back of the shank bone have been cut across. Failing to accomplish this, the next resort is embryotomy.
INCLOSED OVUM, OR TUMORS OF THE FETUS.—Tumors or diseased growths may form on any part of the foal, internal or external, and by their size impede or hinder parturition. In some cases what appears as a tumor is an imprisoned and undeveloped ovum which has grafted itself on the fetus. These are usually sacculated, and may contain skin, hair, muscle, bone, and other natural tissues. The only course to be pursued in such cases is to excise the tumor, or, if this is not feasible, to perform embryotomy.
MONSTROSITIES.—Monstrosity in the foal is an occasional cause of difficult parturition, especially such monsters as show excessive development of some part of the body, a displacement or distortion of parts, or a redundancy of parts, as in double monsters. Monsters may be divided into—
(1) Monsters with absence of parts—absence of head, limb, or other organ.
(2) Monsters with some part abnormally small—dwarfed head, limb, trunk, etc.
(3) Monsters through unnatural division of parts—cleft head, trunk, limbs, etc.



