February 1994

AKC Gazette

February 1994

Ray Knudson

INFERTILITY IN THE BITCH

 

 

This month’s columnist, Dr. Nancy Rose, is a veterinarian and Bulldog breeder in Craigsville, West Virginia. Her Ask the Vet column in published regularly in the Bulldog Club of America, Division II newsletter.

 

Infertility In the Bitch

In my opinion, 90 percent of those bitches that are bred to proven sires but do not become pregnant do not have an infertility problem. Their only problem is that they are not bred at the correct time during their cycle.

Progesterone level tests, such as Target or Status Pro, performed by a competent veterinarian to determine the bitch’s fertile period will take care of the problem. (I prefer the Target test made by Biometallics.) The following discussion is for the other 10 percent. For simplicity I will divide these bitches into two categories: those that cycle normally and those that do not.

A normal heat cycle should occur at regular intervals and be of predictable duration. It may vary in length, but should be predictable for a particular bitch. A normal bitch must have a minimum of four months, between cycles. This is the time it takes for the uterus to recover from estrus or pregnancy and be able to accept the next pregnancy.

If your bitch falls into the normal-cycle category but cannot be successfully bred, discuss these options with your veterinarian.

q       A blood test for Brucella canis.

q       Explatory Iaparotomy, which includes careful examination of the reproductive tract, culture and sensitivity tests of the uterine lumen and biopsy of the uterus and ovary. Some problems may be encountered that are beyond repair and the bitch can be spayed during the procedure.

q       Surgical insemination, where the semen is injected directly into the uterine body via an abdominal incision. Do not inject more than 12 ml. This procedure may be performed during the course of an exploratory laparotomy, but I do not recommend taking cultures and/or performing a biopsy at the same time. Surgical insemination should be performed 48 hours after the bitch’s progesterone level reaches 5 ng/ml. This procedure is also recommended for increasing the chance of a fertile breeding using frozen semen.

If you have reason to believe your bitch has been pregnant but has reabsorbed the fetus, then an exploratory laparotomy will help rule out anatomical defects or infectious agents as the cause of fetal reabsorption. Ultrasound is also very helpful in this situation. Other causes of fetal reabsorption are progesterone insufficiency and hypothyroidism. These may be identified by blood work and corrected as necessary.

For hypothyoidism, use Soloxine – I do notrecommend the use of generics – 0.1 mg/10 lbs. Twice daily, I have experienced excellent results with thyroid supplementation, even when the bitch’s T3 and T4 levels were normal.

Progesterone Therapy is more complicated. Replacement therapy (Regumate, 1 cc/50 lbs., orally once a day) must be monitored closely with ultrasound and blood tests. An accurate due date must be calculated to avoid prolonged gestation and fetal death (a side effect of prolonged administration of progesterone).

The other group, bitches with abnormal cycles, fall into four categories (an exploratory laparotomy may be indicated with these bitches, too).

q       Shortened interestrus period (less than four months). You can prolong this period by using Cheque drops for five or six months. Therapy is begun 30 days before the next expected estrus. This condition tends to appear each time, so you must plan to breed her on her next heat.

q       Prolonged interestrus period. The most likely cause is hypothyroidism or Cushing’s disease. These causes may be ruled out by blood work.  Such a bitch may be experiencing a “silent heat,” where she is cycling normally but detection is difficult to impossible. Try wiping the vulva daily with a tissue or weekly vaginal smears. Also, using a more experienced stud dog may help.

q       Split heat, sometimes called “wolf heat.” The bitch appears to have a normal cycle but will be in heat again in two to six weeks. This is considered a normal variation in the canine estrus cycle. The second heat is the fertile heat, but use progesterone testing to determine the time of ovulation.

q       Persistent or very frequent estrus. The most common causes are ovarian tumors or cysts. Exploratory laparotomy and/or ultrasound are the diagnostic tools. If a tumor is found involving only one ovary, that ovary may be removed. The test treatment for ovarian cysts is surgical exposure and manual rupture of the cysts. Hormonal Therapy (HCG) for ovarian cysts may cause pyometra.

Unfortunately, most of these procedures are quite expensive and time-consuming. You may choose to spay your bitch unless you have

that special girl whose contribution to our breed would be worth the extra effort and expense.—NR

            We are happy Dr. Rose shared this article with us.

Ray Knudson, 4300 Town Road, Salem, WI 77024-5120.