Diseases of the Reproductive System

Chapter 68 Diseases of the Reproductive System


Sheep and goats are seasonally polyestrous. Most are short-day breeders, although there are breeds that will cycle year-round. Normal gestation length is approximately 153 days. The doe has an estrous cycle length of 21 days, and she stays in estrus for an average of 36 hours. The ewe has an estrous cycle length of 18 days, and she stays in estrus for an average of 30 hours.



DYSTOCIAS


Dystocia, or difficult parturition, can be a major cause of losses in a small ruminant operation. If a female animal starts contraction and no progress is made within 30 minutes, then a veterinarian should be called. If the dam is clinically normal, the vet may elect to wait 30 minutes before any intervention. Female animals should be examined 30 minutes after parturition to determine whether there are any more fetuses in the uterus. Dystocias are most commonly caused by fetal malpresentation, dam/fetus size mismatch, and occasionally ringwomb, a condition where the cervix fails to dilate. If the veterinarian’s hands are small enough, and copious amounts of lubricants are used, many dystocias may be corrected manually. Otherwise, a Cesarean section must be performed.




TECH ALERT


Be sure to check the dam for a second or third fetus because multiple births are not uncommon in these species.



VAGINAL AND UTERINE PROLAPSES


Vaginal prolapses are not uncommon in sheep. Uterine prolapses, and vaginal prolapse in goats, fortunately are quite rare. Nutritional factors have been implicated in vaginal prolapses, whereas many uterine prolapses are due to hypocalcemia. The tissue that is prolapsed should be scrubbed and replaced. Raising the hindquarters of the doe or ewe facilitates the process, as does an epidural. Hyperosmotic solutions can be applied to shrink the mass of tissue. After the tissue is replaced, sutures can be applied to retain the tissue. There are also specific devices designed to retain a prolapsed vagina.



Campylobacter (Vibriosis)


Vibriosis, the condition caused by this Campylobacter, is one of the most significant causes of spontaneous abortion in sheep in the United States. Two species of Campylobacter are known to cause abortions. Infection occurs when the pregnant female sheep ingests the organism that has been in the digestive tract of another individual.



CLINICAL SIGNS



• Late-term abortions

• Stillbirths

• Weak lambs


DIAGNOSIS



• Isolation of the organism from fetal abomasums, placenta, or dam’s vaginal discharge


TREATMENT



• Penicillin, streptomycin, or tetracycline

• During an outbreak, giving tetracycline or oxytetracycline in late gestation helps to prevent abortions

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Aug 31, 2016 | Posted by in GENERAL | Comments Off on Diseases of the Reproductive System

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