Yesterday it was good, today it is bad,
keep your fingers crossed for tomorrow!
By Tracy Powell, DVM
The question posed to me was “Why does it seem that years ago it was rare to hear about bitches missing and sterile dogs, but today we hold our breath with every collection and breeding?”. I can empathize with this question as I recently bred my own bitch and held my breath until I ultrasounded her. Years ago we pretty much assumed that when we bred a bitch she was pregnant, and for the most part she usually was. I think there are many factors that play a role in sterility and pregnancy - way too many reasons to cover in this article and many reasons yet to be scientifically proven. I will share some thoughts with you from patients I have seen at my veterinary practice.
The rise in artificial insemination vs. natural breeding is one reason. There are bitches that have been properly timed, vaginal culture was clear, normal thyroid level with a clean bill of health that when bred via surgical, transcervical or vaginal insemination do not conceive. I recommend that those bitches be bred naturally on their next heat and they will then often conceive. There are many reasons why this may be the case, but I think the big reason is because there are many things that happen during natural breeding which do not happen during artificial breeding. The bulb of the penis swells (causing them to tie) and prevents semen from back flowing out of the vagina. The tie also stimulates contractions of the uterus to help bring the semen to the oviducts. The urethral opening on the penis is angled up, towards the opening of the cervix, so when he ejaculates the semen is forced in the direction of the cervix. After the semen has been ejaculated, prostatic fluid is ejaculated in high velocity spurts, pushing the semen through the cervix and into the uterus. Until recently, there has not been a good way to mimic natural breeding with vaginal artificial insemination. Minitube has recently developed a vaginal insemination catheter called MAVIC. It is a catheter that has a balloon that blows up inside of the vagina, simulating a tie. It prevents back flow of semen and stimulates uterine contractions. After the semen is injected through the catheter and into the vagina, an extender is used to flush the remaining semen out of the catheter and push the semen into the cervix (what prostatic fluid would do). The catheter is left in the bitch for 5-15 minutes and the bitch does not need to be elevated because the balloon prevents the semen from back flowing out of the vagina, while mimicking a natural tie. Have you ever seen a bitch stand on her front legs with her rear end up in the air for 5-15 minutes after she is bred naturally?!?! Me neither!
Another reason is a rise in vaginal infections in the bitch. When I breed a bitch and she does not conceive, I recommend a deep guarded vaginal culture 1 month prior to her next heat. I would estimate 90% of those bitches come up positive for bacteria, mycoplasma or ureaplasma. When treated with the appropriate antibiotics for 2-3 weeks prior to breeding, the majority of the bitches conceive. The reason why you want to test 1 month prior to their heat is because sometimes the best antibiotic to kill the bacteria are not safe to use during pregnancy. You want to make sure that you have enough time to use the antibiotic for 2-3 weeks before breeding her. Also, if the culture comes up with many bacteria, mycoplasma or ureaplasma, you can treat for 3 weeks and then re-culture before the breeding to make sure all the organisms have been killed. Another big problem I have seen is the use of prophylactic antibiotics prior to breeding. I get calls all of the time asking for amoxicillin or cephalexin because their bitch just came into season and they will be breeding her. While this may or may not do harm, you never know which antibiotic to put them on because you don’t know if or what bacteria they have and what antibiotic it is sensitive to. Many times we start them on one antibiotic and then culture her and it comes back that the drug you chose will not kill the bacteria present in the vagina. Then you are switching antibiotics days before or even after the breeding or you don’t have enough time to use the appropriate antibiotic because she has already been bred and the best drug is not safe to use during pregnancy.
Hereditary issues also play a role. Males with poor quality sperm can sometimes be traced back to fathers and grandfathers with poor sperm. The same is true for bitches. The bitch is born with a set number of eggs that will have the ability to be fertilized. How many eggs are released during ovulation determine litter size (along with the quality of the sperm). I see bitches that were singletons or from small litters then going on to have small litters themselves. The other thing that I believe is likely hereditary is primary uterine inertia. This is when the bitch does not go into labor and needs a caesarean section to deliver the puppies. I often see bitches for c-sections because of uterine inertia whose mothers also had inertia. I cannot believe this is purely coincidence when I see it so often.
Diet may also play a role. This can be an emotional topic for breeders. Raw vs. kibble – let the battle begin! My experience is that in some cases, fertility does change with diet. I have some breeders that have switched from kibble to raw diets and went from high to low fertility and some breeders that went from low to high fertility. Many kibbles are loaded with byproducts, fillers and poor sources of protein. Most of us know to avoid those foods, as they certainly can affect everything from fertility to obesity and skin problems. There are some great kibble diets out there now that are balanced and have wonderful sources or protein. As for raw diets, some are balanced and some are not. People that make their own raw diets, instead of buying pre-made complete raw diets, sometimes get into trouble with calcium and phosphorus ratios and making a truly complete and balanced meal. It takes a lot of homework and preparation time to make your own balanced raw diet. I applaud those that do it. Those that feed raw must be very careful to avoid salmonella. I have seen dogs get salmonella from improperly prepared or handled raw diets. This will certainly affect fertility. Some breeders feed both raw and kibble. I think this is becoming more common. Keep in mind one rule of thumb if feeding both raw and kibble - you should not feed raw and kibble at the same time. The diets are processed by the dogs in different ways. So feed one in the morning and the other in the evening. Another diet related factor that affects conception is obesity. Obesity has been shown to decrease fertility in bitches. So if your bitch is overweight, get the excess weight off of her prior to breeding. Read your labels, stay informed, keep them in good shape, and if something isn’t working for your dogs, consider trying something new.
Poor semen count and quality can occur for so many reasons. Heredity, primary testicular problems, prostate infections, retrograde ejaculation (when they ejaculate into the bladder instead of out the urethra opening of the penis), temperature, diet, stress, drugs, endocrine diseases, etc. The list goes on and on. There is too much to cover for this article and so much we are still learning. I will however mention that temperature has been shown to affect semen count and quality. In general, a dog’s semen is better in the cooler months then the warmer months. So if your dog collects poorly in the summer, try again when it is cooler out. Also try not to house him outside in warmer weather when he needs to be used for stud.
With so many factors affecting pregnancy and semen, it seems we are lucky to get a bitch pregnant at all! When we spend so much time researching pedigrees and spend many sleepless nights deciding on a stud, it is so disappointing to not have a litter. Keep your dogs in good condition, do the appropriate health tests, and do the appropriate fertility tests as needed. Stay strong and persevere….it is for the future of our breed.
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