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PRE-BREEDING EXAM FOR THE BITCH

A few procedures performed before the bitch comes in heat may make all the difference in producing a litter of live healthy puppies. These procedures will contribute to the continued good health of your bitch. Also, they ensure the safety of the stud dog if a natural breeding should desired, and they can help protect the stud dog's reputation by preventing unnecessary breeding failures. We like to start about one month before the coming heat, in order to have time to treat any problems found.

The most common factor in missed litters is the condition of the uterus. Changes to the uterus occur because of low grade bacterial infection, and the progesterone stimulation that occurs in the 'false pregnancy' experienced by every bitch following her heat. Progesterone causes changes in the uterine lining and additionally lowers resistance to bacterial infections. The full breeding cycle in the bitch not 3 weeks, but 4 months, due to the hormonal false pregnancy. Some bitches show outward physical and behavioral signs of a false pregnancy, others don't, but they all have elevated progesterone levels that affect disease resistance and the uterine lining. If a bitch cycles once a year, every 8 months, or every 6 months, she has time for the uterine lining to rest and normalize. Bitches that cycle every 4 months have no such rest period. These short-cyclers, therefore, are more likely to have the condition known as cystic hyperplasia. They are also, for the same reasons, more likely to suffer chronic low grade infection and inflammation in the uterus. The result of these latter two conditions is a build up of diffuse scar tissue in the endometrium. It also follows that every year older the bitch is, the greater the build up of damage from these causes.

Bitches that short-cycle should have periodic white blood counts, and possibly mibolerone treatment (formerly 'Cheque Drops') to monitor for the development of pyometra and to limit ongoing endometrial damage.

CULTURE, SENSITIVITY, AND WHITE BLOOD COUNT

No matter how clean the environment, there will be a continual supply of bacteria (mostly of fecal origin), present where the bitch sits. Every time she has a heat, her cervix opens and bacteria can move into the uterus. In humans, upright posture and gravity tend to work against infections ascending from the external genitalia. Dogs don’t have this asset. If ‘vaginitis’ (an infection in the vagina) is present and fairly well established in the bitch when her cervix opens, the infection may gain entry to the uterus where it may become an ‘endometritis’ or a ‘pyometritis’. An endometritis is an inflamed uterus, and a pyometritis is the condition of frank pus in the uterus.

The factors that cause a uterus to become an unsuitable place for puppy development are scar tissue, inflammation and continual stimulation of the uterine lining. The causes of scar tissue and inflammation are low grade bacterial infections. So, while the developing puppy may not be literally attacked by harmful bacteria residing in the uterus, bacteria can contribute significantly to the deterioration of the uterine environment. Any bacteriologist will tell you that any organism can be pathogenic in large numbers. On the other hand, we don't really need or expect to wipe all bacteria with antibiotic treatment, but we hope to keep the numbers of these bacteria below the level where it would be expected to interfere with conception and gestation. Some especially dangerous bacteria we do try to eliminate. Additionally, some bacteria can contribute to neo-natal puppy death (as opposed to puppy loss during gestation).

In order to gauge whether a positive bacterial culture means a vaginitis, an endometritis, or a pyometritis, we must always do a white blood count. The culture-and-sensitivity, and the white count work together to generate information in a useful form. Keeping in mind that the entire animal must be evaluated for other reasons for an elevated WBC, in intact bitches in otherwise good health, a normal to mildly elevated count with a positive culture usually indicates a vaginitis. A moderately elevated white count implies a severe vaginitis or an endometritis, and a white count of 30,000 and above is a severely affected uterus; in this last condition, the uterus may be distended with pus which can be felt by palpation and may be visualized on ultra sound or x-ray exam. This is then known as pyometra.

NOTE: bitches with pyometra will either exhibit no signs at all, or mild depression and perhaps some loss of appetite. There may be a thick creamy discharge, but just as often there is not. If the disease has progressed to the pyometritis point, it is well beyond the point we like to have caught it. One way to monitor your bitch and avoid such an extreme problem is to do a white blood count about 3 weeks after each heat period whether or not she has been bred.

If an infection exists and the white count is high, the pyometra is treated with the administration of prostaglandin therapy to open the cervix and empty the uterus in order to get the infection under control, along with concurrent antibiotic therapy. Those bitches with a frank pyometra and an extremely high white blood count may become septicemic, toxic, shocky and die if not caught in time. Bitches that are followed in a routine manner are caught before they become too toxic and can be treated effectively, and at least 85% should be able to return to normal fertility.

To determine if a uterine infection exists, a bacterial culture and sensitivity should be done using a ‘guarded culture instrument’. The culture is taken high in the vagina, near the cervix, and is termed a ‘high culture’ or a ‘cervical culture’. We find that sometimes even young bitches that have not been bred before may have significant numbers of bacteria that are capable of being uterine and reproductive pathogens, as well as very elevated white blood counts indicating a uterine infection. We always tell people that the reason we have to check on even maiden bitches, is that the bitches don’t wear panties (and the dogs aren’t circumcised)!

The use of a guarded culture instrument or a sterile stainless steel speculum will ensure that the organisms come from the area near the cervix, rather than the area around the vulva. If a guarded culturette or a stainless speculum is not used, the culture will be contaminated by the organisms the bitch last sat on, rather than those that are actually in residence near the cervix. Using proper instrumentation and technique, there is virtually no possibility of introducing bacteria from the lower vagina to the area near the cervix; those who claim this will happen, probably do not have the instrumentation and know-how to perform the procedure properly, and a qualified reproductive practitioner should be located.

A sensitivity is performed along with the culture. This is done in a petri dish filled with a culture medium which will support the growth of most bacteria. The culture swab is swept evenly over the medium, to provide a solid growth pattern. Then, small discs of blotter paper, each impregnated with a different antibiotic, are placed on this surface. Where the growth of bacteria is prohibited in a circle around the disc it is said that that organism is ‘sensitive’ to that antibiotic. Where there is no interruption in the growth of the bacteria around the disc, the organism is said to be ‘resistant’ to that antibiotic. This gives us our third item of useful information; what antibiotic to chose to treat the infection.

Many breeders who aren't exactly certain of what each of these procedures are, think that a vaginal swab, used by some to evaluate breeding readiness, means a culture has been taken. The vaginal swab us used to transfer the epithelial cells lining the vagina to a slide. These cells are stained and examined for the amount of keratinization they exhibit. This has nothing to do with a culture/sensitivity.

If an infection is found that warrants antibiotic therapy, four to seven days after treatment has been completed, a follow-up culture is necessary to be sure the organism has been eliminated, or reduced in numbers below an acceptable level. It is important to obtain the actual report of the lab on the culture and sensitivity, as many labs are incorrect in which organisms they identify as ‘significant’ in a reproductive infection. A report of ‘clean’ or ‘no significant organisms’ is not sufficient.,/P>

The organisms we generally feel are significant in a properly obtained cervical culture are : beta Strep, E. coli, Pseudomonas spp., and Staph aureas, as well as several others if they are found in large numbers.

Additionally, we check for Mycoplasma, an organism that is cultured in a different manner. Mycoplasma is responsible for kennel wide sterility is some instances. In other examples, a bitch may whelp a litter even though she has Mycoplasma in residence. In fact, it is a 'normal inhabitant' in the reproductive tract. However, normal does not mean desirable, and if the culture comes back with a moderate or heavy growth report, we treat for it to reduce the level of organisms. There is controversy about just how important a pathogen it is, but years of clinical experience and sterility in dogs that have been infected suggest that it is not prudent to neglect this organism. Mycoplasma cultures are processed differently than the standard aerobic cultures and take a bit longer to grow. We prefer to obtain cultures about a month before the bitch is expected in heat, which gives us time to get all of the necessary information, and to give antibiotics if necessary without having to worry about getting it done before the time for breeding.

THYROID

Thyroid is the basic ‘trophic’ hormone in the body; trophic means promoting or supporting growth. In order for all of the more specific reproductive hormones to play their proper role in the very complex series of events resulting in successful production of a litter, thyroid must be present at an adequate level.

It can be misleading to consider a 'lab normal’ range for T4 as the appropriate range for successful pregnancy. In terms of reproduction, we are not interested in what is a normal level for an aged animal. We need to know normal T4 for a bitch of 1.5 to 5 years of age when trying to judge if there is a sufficient thyroid level to support pregnancy. We have no breed and age break-downs in those lab normal ranges. Even though the labs have been computerized for a long time, most submitting veterinarians neglect to note down the breed when they submit their samples. Thyroid requirements vary with age and with stress and disease demands. Thyroid normals from labs will include unhealthy dogs, and not reflect the 'euthyroid' of those included in the range.

The best way to generate normal thyroid levels for your breed is to organize a blood clinic at a national specialty; in this way, we can obtain thyroid levels of healthy dogs of ages ranging from 6 months to veterans. When the values obtained are sorted by age, you will have a good idea of normal thyroid for a dog of your breed and age.

The bitch for which we may recommend l-thyroxine supplementation to assure that this is not the factor preventing a breeding from being successful, is not a bitch that we would say had abnormal thyroid function. If the dog were exhibiting clinical signs of a true thyroid deficiency, she would not be the one you would be proposing to breed anyway. She would be an unthrifty and unhealthy looking animal. Many of the normal breeding animals I check have a T4 in the low normal range. Many of them are older than 5 years of age; some of them also have Lyme disease. I feel, and this is an opinion I have discussed with several endocrinologists, that we should try to have bitches in the upper third of the normal range to assure that thyroid is not a limiting factor for pregnancy. Almost every bitch of 5 years or more will have a relatively low thyroid, when compared to her thyroid (T4) at a younger age. This a normal sign of aging. As human women should reproduce before 40, bitches should reproduce before 5. Yet through the simple act of supplementing l-thyroxine, we are most often able to extend that breeding range to 9 years, all other things being equal. The argument as to whether we should be breeding bitches with low thyroids is, in my mind, totally useless until we take a better look at the validity of published ranges.

A thyroid panel, such as the OFA panel, should be obtained on a young healthy bitch in order to reflect the true euthyroid condition of the animal. Thyroid varies just like body temperature throughout the day; for a normal appearing and functioning animal, the ball park T4 is all we need to evaluate before breeding.

In a younger bitch that has had trouble conceiving and has a low (or low normal) T4, often once a successful pregnancy has been established and the bitch is checked again after she has finished with weaning and shedding, she may be able to go off supplementation and maintain higher levels of T4 on her own. Again, rechecks are necessary to determine needs, if any as the bitch’s age and circumstances change. It is not a certainty that a bitch with a low normal T4 can’t have a normal heat, become pregnant and whelp a litter; rather, it is a matter of trying to cover the bases and eliminate areas where potential problems can occur in order to enhance our chances of producing the litter.

BRUCELLA

The owner of the stud dog should always require that a Brucella titer be done within the month or so prior to a breeding. Unless artificial insemination is a certainty, or even if just normal courtship behavior is anticipated, it is necessary to protect the male, and any future bitches that might come to him. It is contagious, and will render dogs and bitches infected with it totally sterile. Brucella is a true venereal disease, whereas the infections we have discussed previously arise from the environment. It is likewise reasonable that the stud dog owner request that all of the tests we have discussed should be done, to protect the stud dog’s health and fertility, and to protect his reputation as a sire.

LYME DISEASE, MONTHLY HEARTWORM AND PREGNANCY

Click here for a complete discussion of the influence of Lyme disease and monthly heartworm medication on pregnant bitches. Suffice to say here, no breeding animal, whether dog or bitch, should ever be on any monthly or injectable heartworm medication. Daily preventives such as Filaribits or Nemacide are safe to use.

The following tests are reasonable for the stud dog owner to request the bitch owner to do before a breeding. Even if artificial insemination is used, no stud dog owner wants her dog's reputation for producing puppies to suffer because the bitch wasn't worked up. These same tests will help ensure the breeder of a normal healthy litter.

  • LYME WESTERN BLOT OR IDEXX SNAP-3D LYME TEST (differentiates between vaccinal and natural Lyme exposure)
  • BRUCELLA TITER
  • CULTURE AND SENSITIVITY (aerobic)
  • CULTURE (Mycoplasma)
  • WHITE BLOOD COUNT
  • THYROID TEST (T4)
    If the bitch is over 4 or has had a 'miss' on a prior breeding

Mary C. Wakeman, D.V.M.
©2000-2003 for BREEDERVET
Revised 3/28/03

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