Reproduction and reproductive disorders in dogs and cats

Reproduction and Reproductive Disorders in Dogs and Cats

Contents:		Brought to you by...
CATS: Estrus Gestation Normal Birth DOGS: Estrus Mating Gestation Normal Birth Care of Newborn Puppies Care of Bitch After Whelping	Other situations: Acute Metritis Artificial Insemination Birth Control in Dogs Cesarean Section Cryptorchidism Hypocalcemia in Lactating Bitches Pyometra Termination of Pregnancy	Back to home page

Back to health info table of contents

. CATS Estrus in Cats (heat cycles) General Information: Estrus ("heat") is the mating periods of female animals. When estrus occurs, animals are said to be "in heat" or "in season." Cats normally have their first estrous cycle between 5 and 10 months of age, with the average around 6 months.
.
The female cat has 2-4 estrous periods every year, each lasting 15-22 days. If she is bred, estrus seldom lasts more than 4 days.
.
If successful mating does not occur, estrus may last for 7-10 days and recur at 15 to 21 day intervals. It is possible for an unmated female to cycle every 3-4 weeks indefinitely.
.
Cats also have an estrous period 1-6 weeks after giving birth, so a female may be nursing one litter while pregnant with another.
. Behavior: Since there is usually no obvious vaginal discharge or swelling of the genitals during estrus in cats, as is seen in dogs, behavioral changes are the only obvious signs that your cat is in estrus.
.
A cat in estrus carries her tail to one side, keeps her hindquarters elevated, exhibits "treading" movements of the hind legs, and seems unusually affectionate. She spends a good deal of time rolling on the floor and seems much more restless than usual. The cat’s voice seems more piercing than usual and she may "call" for 1-2 days before she accepts the male.
.
Normal Gestation in Cats General Information: The term gestation means the period when the young are developing in the mother’s uterus. In cats, gestation normally lasts 63-65 days. Siamese cats may carry their kittens for 67 days.
.
There are no practical blood or urine tests available for early diagnosis of pregnancy in the cat. The earliest possible time of diagnosis may be 3-4 weeks after breeding, when the veterinarian may be able to detect pregnancy by feeling the abdomen.
.
During the first 4-5 weeks of pregnancy, there are few noticeable changes. Weight gain and enlargement of the abdomen generally become noticeable after the fifth week. The increase, of course, varies with the size of the litter.
.
The mammary glands may begin to enlarge during the fifth week, but typically no increase in size is noticeable until the seventh week. Milk is normally present 1-2 days before delivery.
.
During the last weeks of pregnancy, your cat may have difficulty finding a comfortable position and may seem restless. Many queens (female cats) seek seclusion. Occasionally the cat may soil the house because the heavy uterus is pressing the bladder or colon.
.
Normally no restriction of exercise is required during the first 6-7 weeks. Your cat should be kept in the house during the last 2 weeks because she may attempt to have her kittens in an unsafe outside location.
.
Good nutrition is essential to the health of both mother and kittens. It is nearly impossible to overfeed a pregnant cat, since she requires 2-4 times as much food as normal. Harmful feeding practices include feeding raw egg whites, raw fish, and exclusive meat or fish diets. The veterinarian may prescribe a special diet or supplementation.
.
Normal Birth in Cats (kindling, queening)
. General Information: You should begin to prepare for birth of the kittens before the queen gives birth. A box should be provided so that the mother becomes accustomed to sleeping in it and will deliver the kittens there. Most cats prefer a covered delivery box. Food and water can be kept nearby. Place the box in a secluded yet familiar area of the home, away from traffic, to allow the mother and kittens solitude and rest.
.
Newspapers make excellent bedding because they can be changed easily, are absorbent, and can be shredded by the mother as she makes her "nest." If such materials as old quilts, rugs, blankets, or mattress pads are used, they should be laundered frequently.
.
If you want to know more precisely when delivery is near, check the rectal temperature twice daily, starting on the 60th day. Rectal temperature drops below 100 F within 24 hours before the onset of labor. Normal rectal temperature ranges from 100.5 to 102 F.
.
During the first stage of labor, the mother cat (queen) seems uneasy and restless. She may refuse food or water. The cat’s rectal temperature drops, and she seeks dark, secluded places. Considerable howling may occur. This stage lasts 12-24 hours. In the second, contractions and expulsions of the kittens begin.
.
Delivery starts with a small, greenish sac protruding from the vaginal opening. This is followed by a kitten and the attached placenta. The normal presentation of the kitten is nose first, lying on its abdomen. Some kittens, however, are born hindquarters first. After the delivery, the mother normally opens the sac by licking and biting, cleans off the kitten and severs the umbilical cord. You may have to perform these functions for the mother if she refuses to do it herself. Make sure the sac is removed from the kitten immediately if the mother doesn’t do so. After each kitten is born, remove all membranes covering the kitten, clean off its face, and remove mucus from its nose and mouth. Rub the kitten with a clean, dry towel to dry it and to stimulate breathing and circulation. After a few minutes of rubbing, the kitten should begin to squirm and cry. The umbilical cord should be tied about 1 inch from the body with a fine thread and cut on the side of the knot away from the kitten. Apply a drop of iodine or merthiolate to the end of the cord after it is cut.
.
The third stage of labor is a resting stage, which follows delivery of each kitten. This stage may last from a few minutes to one hour. Occasionally, two kittens are delivered within a few minutes, followed by a resting.
.
If a kitten seems to be lodged in the birth canal and the mother cannot expel it, assistance is necessary. There may not be time to call your veterinarian and drive to the hospital if you wish to save the kitten. Grasp the kitten with a clean towel and exert steady, firm traction. Do not jerk or pull suddenly. The best place to grasp the kitten is by the skin of the back, but gentle traction on the legs may be necessary.
. Notify your veterinarian if any of the following occur:

You cannot remove a kitten lodged in the birth canal.
Labor is strong and persistent for 30 minutes without a birth.
Labor is weak and intermittent for 5 hours without any results.
There is a dark vaginal discharge and no labor or births have occurred within 3-4 hours.
The pregnancy lasts more than 67 days.

. DOGS .
Estrus in Dogs (heat cycles) General Information: Estrus ("heat") is the mating period of female animals. When estrus occurs, animals are said to be "in heat" or "in season." Dogs generally have their first estrous cycle at 6-12 months of age. Some females of the large breeds, however, may not have their first estrus until they are 12-24 months of age.
.
The complete cycle takes about 6 months, resulting in 2 estrous periods each year. Individual variation occurs, but a given female’s pattern tends to be repeated regularly.
.
The estrous cycle can be divided into 4 stages:
1. Proestrus: This stage begins with the appearance of vaginal bleeding. It normally lasts from 4 to 9 days. Male dogs become very interested in the female; however, she will not mate with them.
2. Estrus: This is the stage in which the female will accept the male and conception can occur. The vaginal discharge is more yellowish than bloody. Ordinarily, the stage lasts 4-13 days. Your female will stand and hold her tail to the side when you touch her back or a male dog tries to mount.
3. and 4. Metestrus and anestrus: These 2 stages are periods of ovarian activity, but with no significant outward signs. False pregnancies frequently occur during metestrus.
.
You should consider your dog to be "in season" for 21 days: 7 days coming into heat, 7 days in heat, and 7 days going out. Though conception is most likely during the middle 7 days, Mother Nature doesn’t always follow the rules. Confine your dog for the entire 3 weeks. Remember that the above information is general. Not all females follow these patterns. Consult with the veterinarian if your dog does not seem typical. Sometimes cycling problems can be an early warning of more serious problems, and the sooner they are dealt with, the better.
.
Mating in Dogs General Information: Female dogs generally have 2 reproductive cycles each year. This process begins at puberty. Small breeds may start their cycles at 5-6 months of age, while some giant breeds may not cycle until 2 years of age. The average age of puberty is 7-10 months. After 4-9 days of bloody vaginal discharge, the female will accept the male and stand for breeding. This receptive stage may last a few days or as long as 2 weeks. The most commonly used breeding dates are the 9th, 11th, and 13th days from the first vaginal discharge. Repeated breedings, 48 hours apart, as long as the female accepts the male, produce the best conception rate.
.
Usually no assistance is needed for a successful mating, especially if the dogs have had previous experience. Occasionally, however, some assistance must be given. The male may need help in mounting and entering the female or the female may need to be restrained so that she does not harm the male. A muzzle (gauze, nylon stockings, etc.) tied around the female’s mouth may be helpful. If trouble is encountered, perhaps the timing is not correct. Double check the dates and consult with your veterinarian.
.
Near the conclusion of a normal mating, the dogs will become "tied" together for up to ½ hour. Occasionally, the male turns around and the dogs appear "end to end." This is normal and no cause for alarm. If one of the dogs becomes active during this time, gentle restraint is advisable. Do not attempt to forcefully pull the dogs apart, as this may cause injury.
.
Female dogs should be bred during the first heat period. Wait until the second or third heat to breed your female.
.
Since pregnancy represents a considerable strain on the mother, females should not be bred every "season." Acceptable breeding programs include breeding every other heat or breeding during two consecutive and skipping the third.
.
If a pregnancy results from the mating, the puppies should be born in approximately 63 days. Begin counting from the first breeding.
.
If you are considering mating your dog, discuss the matter with your veterinarian. A thorough examination is recommended before breeding to help ensure that your dog is in good physical condition.
.
Normal Gestation in Dogs General Information: Gestation is the period when the young are developing in the mother’s uterus. In dogs, gestation normally lasts 9 weeks (63 days). However, puppies may be delivered between 58 and 68 days.
.
There are no practical blood or urine tests available to confirm pregnancy in the dog. The earliest possible time of diagnosis may be 26-35 days after breeding, when the veterinarian may be able to detect pregnancy by feeling the abdomen. Diagnosis by radiographs (x-rays) is usually possible after 45 days.
.
During the first 5 weeks of pregnancy, there are few noticeable changes. After the fifth week, you may notice weight gain especially with large litters. If only 1 or 2 puppies are present, the mother may gain little weight until shortly before birth. Abdominal enlargement is generally obvious in the last 3 weeks.
The mammary glands may begin to enlarge as early as the 35th day, but usually development is not obvious until 45 days. Milk may be present as early as 7-9 days before delivery, but it is usually not produced until 1-2 days before delivery.
.
During pregnancy, the female dog may show a change in behavior, especially in the last few weeks. As the uterus enlarges with the developing puppies, your dog may become restless, seek seclusion and in the last few days, soil the house. She may shred papers, blankets, or bedding in an attempt at "nest building" in the last few weeks. During the last 2 weeks, your dog may become irritable and should avoid contact with small children.
.
Good nutrition is essential for healthy puppies and mothers. During the first 4 weeks of pregnancy, nutritional needs change little but feeding high-protein supplements such as eggs, lean muscle meats, or liver is a good practice. During the last 5 weeks, your dog’s nutritional needs nearly double. Feed increased amounts of food in several small meals each day. Fresh water should always be available, since fluid needs are greatly increased. The veterinarian may recommend a special diet and/or vitamins.
Moderate exercise is the proper approach. Neither forced rest nor strenuous exercise is a good idea. Short periods of gentle play and short walks are good.
.
Normal Birth in Dogs (whelping) Preparation: Begin preparations for delivery of puppies before the female gives birth. A whelping box should be provided for the mother to begin sleeping in to ensure the puppies are born in the area you have chosen. This box should be relatively small with sides 6-8 inches high to keep puppies from crawling out of the nest. Place the box in a secluded yet familiar area of the home, away from traffic, to allow the mother solitude.
.
Newspapers make excellent bedding because they can be changed easily, are absorbent, and can be shredded by the mother as she makes her "nest." If materials such as old quilts, blankets, rugs, or towels are used, they must be washed frequently.
.
If you want to know more precisely when delivery is near, check the rectal temperature of the mother twice daily starting the 58th day. Normal rectal temperature varies between 100.5 and 102 F Within 24 hours before the onset of labor, the rectal temperature drops nearly 2 degrees.
. Labor and Delivery: Labor in the bitch can be divided into 3 stages. The second and third stages are repeated with the birth of each puppy.
Stage 1: During the first stage, the mother seems extremely restless and very nervous and often seeks seclusion. She may refuse food even if offered her favorite treat. This stage may last 6-24 hours. This is a good time to exercise the mother to allow her to urinate and defecate.
Stage 2: In the second stage, contractions and expulsion of the puppies begin. Usually, a small greenish sac of fluid protrudes from the vulva. This is followed by the puppy attached to its placenta. About two-thirds of all puppies are born nose first, stomach down, and one-third are born hindquarters first. Both presentations are considered normal in dogs.
After delivery, the mother opens the sac, cleans off the pup and severs the umbilical cord. You may have to perform these functions for the mother (see Obstetric Care below). Make sure the sac is removed from the puppy immediately if it is unbroken during delivery.
Stage 3: The third stage of labor is the resting stage which follows each delivery. Mild contractions and delivery of the afterbirth occur in this phase. This stage usually lasts 10-30 minutes, but it may range from a few seconds to an hour.
. Obstetric Care: After a pup is delivered, remove all membranes covering the puppy, clean the face and remove mucus from the mouth and nose. Rub the puppy with a clean towel to dry it and to stimulate respiration and circulation. After a few minutes of rubbing, the puppy should begin to squirm and cry loudly.
.
The umbilical cord should be tied about an inch away from the puppy’s body with a fine thread and then cut on the side of the knot away from the puppy. Apply a drop of iodine or merthiolate to the cord end after it is cut.
. Assisting with the Birth: If a puppy seems to be lodged in the birth canal and the mother cannot expel it, rapid assistance is necessary. There may not be time to call your veterinarian and drive to the hospital.
.
Grasp the puppy with a clean towel and exert steady, firm traction. Do not jerk or pull suddenly. Traction may have to be applied for as long as 5 minutes. If you cannot remove the puppy, call the veterinarian.
. Behavior of the Mother: During whelping and nursing, your pet may not be her usual self. She may be very nervous and filled with a sense of protectiveness for her new family. Any aggression she may exhibit usually fades as time passes.
. Notify the veterinarian if any of the following occur:

You cannot remove a puppy lodged in the birth canal.
There is a strong, persistent labor without delivery of a pup.
There is weak, intermittent labor for 6 hours without delivery of a pup.
It has been more than 4 hours since the last birth and it is probable that more puppies are still inside.
There is a greenish-black discharge and no labor or puppies within 3-4 hours. The greenish-black color is normal, but such a discharge should be followed very soon by the delivery of pups.
The pregnancy lasts more than 65 days.

Care of Newborn Puppies General Information: During the first few weeks of the newborn’s life, the mother provides the necessities of warmth, nutrition, and stimulation. The owner’s responsibilities consist of careful observation to detect problems before they become serious.
.
Warmth: Room temperature should be at least 70 F. The puppies should be kept off cold floors because chilling can be fatal to young puppies.
Nursing: A well fed healthy puppy has a round stomach and seems content. Notify the veterinarian if the puppies seem uneasy or cry frequently.
Crying: Extended crying is usually a sign of trouble and should be reported to the veterinarian immediately.
Tail docking/dewclaw removal: Puppies of breeds in which these procedures are done should be presented at 2-5 days of age.
Eyes: The puppies’ eyes should open at 10-14 days of age.
Weaning: Soon after the puppies’ eyes are open, pan feeding of milk may be started. Other foods may then gradually be added. More on feeding puppies: 1) Newborn 2) Weanling
.
Care of the Bitch After Whelping General Information: Pregnancy and nursing puppies constitute a severe strain on the mother’s health. Though most mothers handle the task admirably, the wise owner can take certain precautions to protect the health of both mother and puppies.
.
Physical examination: Within 48 hours after the birth, the mother and puppies should be examined by a veterinarian.
Diet: Usually no special diet is required, but the mother will require approximately twice as much food as normal.
Fluids: Provide clean, fresh water at all times.
Activity: Ordinarily the mother will spend most of the first 3 weeks with her puppies. Allow her as much exercise as she desires.
Bowel movements: Due to increased food consumption and the enlarged uterus, your pet may have to relieve herself more frequently. The stools may be soft for the first few days. If diarrhea or straining develop, call the veterinarian.
Mammary gland care: Check the nipples daily and clean with warm water if dried milk begins to accumulate. Inform the veterinarian of any discoloration of the skin, swelling, tenderness, or sores. Trim the puppies’ nails if they are scratching the mammary glands.
Vaginal discharge: A reddish vaginal discharge, with clotted blood, is normal for the first few days. This may occur intermittently for several weeks.
Behavior: Call the veterinarian if the nursing mother appears nervous, restless or uncomfortable, or refuses to nurse the puppies.
General effects: Normally the mother experiences heavy coat shedding during the nursing period. Brush her regularly, and call the veterinarian if any bald spots develop. A slight weight loss is normal, but consult the veterinarian if the mother appears overly thin.
Estrus (heat period): Pregnancy should have no effect on the next heat period. This period should occur within 6 months after birth of the puppies.
Spaying (ovariohysterectomy): If you desire surgical sterilization for your pet, an appointment should be scheduled after the puppies are weaned and milk production has ceased, but before the next heat period.
.

Acute Metritis General Information: Acute metritis is a rapidly developing infection of the uterus, usually occurring at the time of birth. It may be a result of abortion, retained placenta, or a mild infection in the uterus. Bacteria may also enter the uterus during attempts by owners to help the mother during delivery.
.
A vaginal discharge is often mixed with blood and pus. The patient is feverish and depressed, loses her appetite, and refuses to care for her young. The puppies or kittens cry excessively and seem restless even after nursing.
.
Acute metritis may be considered an emergency and requires immediate medical attention. Your veterinarian may recommend that your pet not be used for future breeding. Spaying may be necessary.
Laboratory tests may be required to evaluate your pet’s condition and her ability to undergo possible surgery (spay). If babies are still nursing, they may need to be taken from the mother and fed by hand to prevent their being contaminated by the vaginal discharge.
. Notify your veterinarian if any of the following occur:

Your pet refuses to eat or seems depressed.
Your pet repeatedly vomits.
Your pet seems unusually thirsty.
The babies become weak or die.

.
Artificial Insemination General Information: Artificial insemination may be advisable if the male dog and bitch are incompatible for some reason or when either or both dogs are sexually inexperienced. Performed under proper conditions by a qualified veterinarian, the procedure is safe and conception rates are good.
.
Artificial insemination involves three basic procedures:
1. Detecting the time of ovulation by vaginal smears.
2. Collection of semen from the male dog.
3. Insemination of the bitch.
. Recommendations Both the male and female should have a thorough physical examination before breeding. This includes laboratory examination of the feces for internal parasites and a blood test for heartworms. All vaccinations should be current.
.
Important: If you plan to register the litter of an artificially inseminated bitch with the American Kennel Club, you should obtain AKC approval before breeding.
.

.
Birth Control in Dogs:
Cheque: General Information: Cheque is a highly effective drug for birth control in female dogs. It must, however, be used as directed. The following precautions must be heeded:

Cheque should not be given to dogs that have not cycled for the first time.
Cheque should not be given to dogs that are pregnant or lactating, have reproductive tract disease or tumors, or have tumors of the anal area.
Cheque should not be given to dogs with a history of liver or kidney disease.
Cheque should not be given to Bedlington Terriers.
Cheque should not be given for more than 24 consecutive months.

A physical examination and vaginal smear should be performed before treatment to determine the dog’s health status and stage of the reproductive cycle. Cheque is not intended for female dogs kept primarily for breeding purposes.
.
After stopping treatment, most dogs will come into heat in 2-3 months. A heat period can occur anytime from 1 week to 8 months after treatment is stopped.
. Notify your veterinarian if any of the following occur:

Your pet develops a vaginal discharge.
A pink, fleshy mass protrudes from the vaginal opening.
Your pet comes into heat while taking Cheque.
Your pet becomes aggressive.
Your pet becomes lethargic or reluctant to eat.

Ovaban General Information: Ovaban is a highly effective drug for birth control in female dogs. It must, however, be used as directed. The following precautions must be heeded:

Ovaban should not be given to dogs that have not cycled for the first time.
Ovaban should not be given to dogs with mammary tumors or reproductive tract disease.
Ovaban should not be given to pregnant dogs.
Ovaban should not be given for more than 2 consecutive heat cycles. Treatment can be resumed after one cycle without treatment.

A physical examination and vaginal smear should be performed before treatment to determine the dog’s health status and stage of the reproductive cycle.
. Notify your veterinarian if any of the following occur:

Your pet’s mammary glands enlarge or produce milk.
Your pet seems listless or drinks or urinates excessively.
Your pet’s temperament or appetite changes.
Your pet develops a vaginal discharge.

.
Cesarean Section General Information: A cesarean section is a procedure to surgically remove puppies or kittens from the uterus when natural (unassisted) delivery of the young is impossible or potentially harmful to the mother or babies.
.
The reasons for a cesarean section are numerous and varied. The female may be too sick to deliver the young. Mechanical obstructions in the birth canal, caused by such things as old fractures, tumors, or abdominal masses, may prevent normal passage of babies. Or the babies may be unusually large.
.
Sometimes this surgery is planned well in advance because of known problems. At other times, difficulties develop at the time of birth, and the decision to perform surgery must be made immediately.
After full recovery from a cesarean section, the mother usually assumes her normal maternal duties. The incision and sutures from surgery rarely interfere with nursing. If problems arise, the veterinarian will advise you regarding proper action.
.
The mother may be treated as usual, but her activity should be moderately restricted. The abdomen and mammary glands may be cleaned with a warm, damp cloth as needed. The nest should be kept dry and clean. If the mother is still showing signs of sedation from surgery, she should not be left alone with her puppies until she regains her normal attitude and behavior. Some dogs may kill their pups while under the influence of sedatives.
. Notify your veterinarian if any of the following occur:

Your pet is weak and depressed.
Your pet vomits, has diarrhea, or refuses to eat.
The babies cry frequently.
Your pet refuses to care for the babies.
Fluid or pus drains from the incision or the vagina.

.
Cryptorchidism (undescended testicles)
. General Information: During growth of a male fetus, the testicles develop in the abdominal cavity, pass through an opening in the body wall called the inguinal canal, and descend into the scrotum. Normally both testicles have descended into the scrotum at or shortly after birth. Occasionally descent is not complete until 5-6 months of age.
.
In some individuals, however, one or both testicles fail to descend into the scrotum. Dogs with both testicles undescended are usually sterile while those with only one testicle undescended are fertile.
.
Undescended testicles are most common in small or toy breeds.
.
Dogs with undescended testicles should be castrated, since the condition is hereditary, the dogs are not eligible for show, and the incidence of testicular tumors in undescended testicles is 14 times greater than descended testicles.
.

.
Hypocalcemia in Lactating Bitches (milk fever, eclampsia, puerperal tetany)
. General Information: Hypocalcemia (milk fever) occurs in female dogs of all breeds, but most frequently in smaller breeds. Females with a heavy milk production and a large litter of actively nursing puppies are most likely affected. The exact cause is unknown, but there appears to be an imbalance between calcium uptake from the digestive tract and calcium outflow in milk, bone, urine, and feces. Because the level of calcium in the blood is reduced, replacement of calcium is essential. Without prompt treatment, the condition can be fatal.
.
Milk fever may recur in later pregnancies. The veterinarian will discuss prevention if you plan to breed your dog again.
.
Initial treatment consists of intravenous calcium until signs are relieved.
. Notify your veterinarian if any of the following occur:

Your dog staggers or has a stiff gait.
Your dog has a muscle tremor or rigid limbs.
Your dog acts restless or anxious.
Your dog pants excessively.

.
Pyometra General Information: Pyometra is a severe bacterial infection with accumulation of pus within the uterus. Though it often occurs in middle-aged or older females that have never had puppies, younger dogs are sometimes affected. The condition most commonly develops a few weeks after a heat period.
.
Pyometra results from hormonal influences that decrease the normal resistance to infection. Bacteria enter the uterus when the cervix is open during the heat period and infection results. If the cervix closes after infection, large volumes of pus can accumulate.
.
Signs of pyometra include loss of appetite, excessive thirst, depression, and vomiting. Sometimes there is a discharge of pus from the vagina. The disease may develop very slowly over several weeks.
.
Medical and surgical treatments are available, but surgical treatment is more common. The advantages of surgery are that the condition cannot recur, and there will no longer be bothersome heat periods. Medical treatment is most often performed in young animals intended for breeding or when surgery seems too risky. In some cases, medical treatment is used until the animal is strong enough for surgery. Surgery consists of removal of both ovaries and the uterus. Because the patient is ill and the uterus is infected, the surgery is more complicated and carries a higher risk than routine spaying in a healthy animal. Postoperative treatment includes antibiotics and intravenous fluids. Blood tests are useful in both diagnosing the condition and monitoring the response to treatment.
. Notify the veterinarian if any of the following occur:

Your dog is reluctant to eat or seems depressed.
Your dog vomits or has diarrhea.
Your dog has excessive thirst or urination.
Your dog removes or otherwise endangers the sutures.

.
Termination of Pregnancy General Information: An early or unwanted pregnancy is best ended by ovariohysterectomy (spaying). This is an irreversible operation to remove both ovaries and the uterus. The pet is then permanently sterile and will no longer experience the heat cycle.
.
If permanent sterility is not desired, hormone treatments can be given to block implantation of fertilized eggs within the uterus. The eggs then leave the uterus with the uterine secretions, and the pregnancy ends. In a small number of cases, hormonal termination of pregnancy causes some undesirable side effects. Your veterinarian will discuss the risks in this type of treatment.
.
Hormonal treatments are only successful if begun within a few days after mating. Ordinarily such treatment extends the heat period. The animal will continue to attract males, and another mating may occur. The drugs given will usually prevent pregnancy should another mating occur within a few days of the injection.