Why Won't My Dog Get Pregnant?
You did your homework and have a female in her best condition and found the ideal male to mate her to. Both have passed all the health clearances recommended. But the breeding didn't work. So, what can you do to improve fertility and the chances of a successful pregnancy?
Regardless of the breed of dog, there are three categories of reasons a female fails to produce a successful litter:
- Failure of successful semen delivery
- Failure of conception
- Failure to complete a successful pregnancy
Sterility vs. Infertility in DogsIn general, reproductive failure and infertility are complex and multi-factorial. Infertility is defined as a reduced ability to produce young, while sterility is defined as a permanent inability to reproduce. If you find yourself dealing with infertility there are some important questions to ask:
- Was semen with good motility, morphology, and count deposited into the female's reproductive tract? A semen analysis should be completed prior to using the semen. A sperm count should be 10 million times the dog's weight in pounds and the semen should swim forward with vigor. Normal morphology - sperm size and shape - is required for normal fertility.
- Did the sperm successfully fertilize the egg? Did the fertilized egg implant? Did the fertilized egg survive and become an embryo? Whether you are using fresh, fresh chilled or frozen semen, ensure the right semen delivery system is used. Frozen semen must be deposited into the female's uterus, not vagina, using TCI (transcervical insemination) or surgical breeding. Fresh semen can be delivered vaginally with a natural breeding, TCI or surgical breeding. The chart below can help with this:
- Was the timing right? An ovulation detector is a portable device that helps determine the best time for breeding or when an effective progesterone draw can be done. Better yet, use progesterone testing to determine when she will ovulate. Breed two days after ovulation (progesterone of 4-8 ng/dl is when ovulation occurs) with fresh or natural breedings or three days after ovulation when using frozen semen.
- Did viable semen get to the egg? For the semen to be delivered to the egg, the stud dog must have good quality and quantity semen. Fertilization in the dog takes place in the oviduct, not the uterus, so we have to count on the semen to be capable of moving through the uterus into the oviducts in sufficient quantity for a successful fertilization.
- Did a viable egg get to the semen? This is a tough one. In veterinary medicine we don't have a way to evaluate the uterus and oviducts. If the oviduct or uterus has adhesions or other areas of constriction such as cysts, even the best semen delivered into the uterus cannot create an embryo.
- If this was a natural breeding, was there a tie? Was the breeding witnessed? Was there a normal length tie? A tie, when the male is bred to a receptive female in heat, is the time period when they are "locked" together. This may last as little as two minutes or as long as 25 minutes. Do not try to physically separate the dogs during this time or you may cause physical injury to both the male and female.
- If this was a vaginal AI or TCI, was the procedure performed correctly with no spermicidal exposure? Some lubricants and reusable equipment can have spermicidal properties. Using all disposable supplies such as the Disposable Artificial Insemination Kit is recommended. If there was a vaginal AI, was the equipment new? Latex and disinfectants can kill semen. AI collection sleeves and pipettes are inexpensive and should be discarded after one use. Syringes with latex stoppers and latex collection sleeves can kill sperm. Use latex free materials and a semen safe syringe.
- If this was a TCI, did you witness the procedure? Ask your veterinarian to show you the cervix and the passage of the catheter into the uterus.
- Does the female have a defect in her reproductive tract? Structural abnormalities can cause failure of semen passage from the vagina to the oviducts. This is not something we can assess at this time in veterinary medicine.
- Do either the male or female have brucellosis? Canine brucellosis is a bacterial disease that can be spread venereally and can cause sterility in the male or female as well as pregnancy failure and early neonatal death.
- Was the female exposed to canine herpesvirus? If a female dog has herpes for the first time, she can experience fetal loss, mummies of early fetus, as well as premature birth and loss of puppies at birth or shortly after. The dangerous window for a female is three weeks before and three weeks after whelping.
- Does the female have a bacterial infection in the vagina or uterus? Did she have another bacterial or viral disease? Does she have an illness that is affecting her entire body? For example, metritis in dogs is an infection of the uterus, during or after pregnancy. Pyometra is an infection of the uterus unrelated to pregnancy.
- Has the female aged to the point of cycling less frequently or producing fewer eggs? Females over age six have a 33 percent reduction in fertility.
- Has the male aged to the point of producing fewer sperm, producing fewer normal sperm, having abnormal prostatic fluid (BPH) or is less capable of mounting and ejaculating? Generally male dogs over age five can have a decline in prostatic fluid quality as well as semen quality. Have his semen tested prior to use.
If you have more questions, call us at 800.786.4751.
Marty Greer, DVM, Director of Veterinary Services at Revival Animal Health
The materials, information and answers provided through this website are not intended to replace the medical advice or services of your personal veterinarian or other pet health care professional. Consult your own veterinarian for answers to specific medical questions, including diagnosis, treatment, therapy or medical attention.