Normal fertility in a cat, and the ability to reproduce kittens, requires a normalestrous cycle, with a healthy reproductive tract, normal ova (eggs), normal and stable levels of reproductive hormones, fertilization by normal spermatozoa, implantationof an embryo in the lining of the uterus (endometrium), normal placenta placement, and stable levels of progesterone concentration. These conditions must be maintained for the entirety of the two month gestational period, or the process of reproduction will be altered, with resultant infertility.
Some of the common symptoms that appear in cats that are unable to reproduce are abnormal cycling, failure to conceive, failure to copulate/mate, normal copulation without subsequent pregnancy, and/or pregnancy loss.
Infertility can affect cats of all ages, but tends to be more common among older cats. Cats that have had previous uterine infections can also have subsequent difficulties with implantation. However, one of the most causes of seeming infertility is insemination during the improper time in the estrous cycle.
Other conditions that may play a role in the cat's ability to reproduce include:
- Male infertility factors
- Sub-clinical uterine infections
- Toxoplasmosis/protozoal infection
- Abnormal ovarian functions
- Chromosomal abnormality
- Systemic viral or protozoal infection
- Lack of sufficient copulatory stimulus in order to induce ovulation
Your veterinarian will perform a thorough physical exam on your cat, taking into account the background history of symptoms and possible incidents that might have led to this condition. There are several diagnostic tests that can be conducted in order to find out if the symptoms are related to the infertility disorder.
Some of the basis for the diagnosis will be related to whether your cat has conceived or given birth in the past. If she has reproduced successfully before, your veterinarian will consider whether the male mate that has been chosen for breeding is of proven fertility, or whether the timing for the breeding was scheduled in accordance with your cat's ovulation cycle.
Your cat's hormone levels will be analyzed, to be sure that she has the required levels for conception and a following pregnancy. Progesterone concentration must remain steady throughout the pregnancy for it to be successful.
A complete blood profile will be conducted, including a chemical blood profile, a complete blood count, and a urinalysis. These tests will show evidence of infections, either bacterial, viral, or parasitic. Viral infections that will be tested for include toxoplasmosis, protozoal parasite infection, herpesvirus, feline leukemia virus (FeLV), feline immunodeficiency virus (FIV), and hypercorticolism. In addition, your doctor will be checking your cat's body thoroughly for any other chronic disease conditions.
Imaging techniques may be used to look for any abnormalities in the uterus, such as masses (indicating tumors), and anatomic abnormalities that would interfere with conception. In a healthy cat, the ovaries and uterus will not be visible on X-ray imaging. If your veterinarian is able to view the ovaries or uterus, this would suggest that there may be an underlying condition of ovarian cysts, ovarian cancer, or uterine cysts. If it appears, on examination, that your cat has cysts or other masses of tissue in the uterus or reproductive tract, your veterinarian will need to take a sample of tissue from the uterus for biopsy.
Improper breeding is most often at the root of the perceived infertility. To prevent this, the male tom cat may be bred to another queen to test his ability to impregnate. Your doctor may also advise you to change the amount of light your cat receives, including natural or artificial light, since cats' estrous cycles are heavily influenced by season light changes. Another alternative may be the use of gonadotropin, a hormone which induces ovulation in animals unable to do so normally.
If improper breeding does not seem at fault, your veterinarian will begin treatment for other underlying causes for infertility. For example, antibiotics are given if a uterine infection is suspected. Some of the surgical considerations include surgical repair of the obstructed reproductive tract, surgical correction of abnormalities in the vagina, removal of a cancerous ovary, and either draining or surgically removing the ovarian cysts.
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Your veterinarian will schedule a follow-up exam to test your cat's progesterone hormone levels, and to perform an ultrasonography exam to confirm a healthy pregnancy and placental position.