Autumn P. Davidson

Reproductive Ultrasound of the Bitch and Queen

Ultrasonographic evaluation of the reproductive tract is an important component in the evaluation of the bitch and queen. Information is obtained concerning normal events involving the reproductive system (eg, ovulation, pregnancy) as well as pathologic conditions (eg, ovarian cysts, metritis). The appearance of the female reproductive tract normally changes with phases of the cycle; these changes need to be interpreted with knowledge of the ovarian cycle. Serial ultrasonographic evaluation of the diseased reproductive tract can be very helpful in evaluating response to therapy.

Increasing Age Influences Uterine Integrity, But Not Ovarian Function or Oocyte Quality, in the Cheetah (Acinonyx jubatus)

Although the cheetah (Acinonyx jubatus) routinely lives for more than 12 yr in ex situ collections, females older than 8 yr reproduce infrequently. We tested the hypothesis that reproduction is compromised in older female cheetahs due to a combination of disrupted gonadal, oocyte, and uterine function/integrity. Specifically, we assessed 1) ovarian response to gonadotropins; 2) oocyte meiotic, fertilization, and developmental competence; and 3) uterine morphology in three age classes of cheetahs (young, 2–5 yr, n = 17; prime, 6–8 yr, n = 8; older, 9–15 yr, n = 9). Ovarian activity was stimulated with a combination of equine chorionic gonadotropin and human chorionic gonadotropin (hCG), and fecal samples were collected for 45 days before gonadotropin treatment and for 30 days after oocyte recovery by laparoscopy. Twenty-six to thirty hours post-hCG, uterine morphology was examined by ultrasound, ovarian follicular size determined by laparoscopy, and aspirated oocytes assessed for nuclear status or inseminated in vitro. Although no influence of age on fecal hormone concentrations or gross uterine morphology was found (P > 0.05), older females produced fewer (P < 0.05) total antral follicles and oocytes compared to younger counterparts. Regardless of donor age, oocytes had equivalent (P > 0.05) nuclear status and ability to reach metaphase II and fertilize in vitro. A histological assessment of voucher specimens revealed an age-related influence on uterine tissue integrity, with more than 87% and more than 56% of older females experiencing endometrial hyperplasia and severe pathologies, respectively. Our collective findings reveal that lower reproductive success in older cheetahs appears to be minimally influenced by ovarian and gamete aging and subsequent dysfunction. Rather, ovaries from older females are responsive to gonadotropins, produce normative estradiol/progestogen concentrations, and develop follicles containing oocytes with the capacity to mature and be fertilized. A more likely cause of reduced fertility may be the high prevalence of uterine endometrial hyperplasia and related pathologies. The discovery that a significant proportion of oocytes from older females have developmental capacity in vitro suggests that in vitro fertilization and embryo transfer may be useful for “rescuing” the genome of older, nonreproductive cheetahs.

Ultrasonographic Evaluation of the Thyroid Gland in Healthy, Hypothyroid, and Euthyroid Golden Retrievers with Nonthyroidal Illness

Ultrasound evaluation of the thyroid gland was performed in healthy, hypothyroid, and euthyroid Golden Retriever dogs with nonthyroidal illness (NTI) to determine the diagnostic usefulness of ultrasound for differentiating between euthyroid and hypothyroid dogs. Thirty-six healthy, 11 hypothyroid, and 35 euthyroid dogs with NTI were evaluated. Each thyroid lobe was examined ultrasonographically for size, shape, echogenicity, and homogeneity. Thyroid lobe volume was estimated by using the equation for an ellipsoid: pi/6(length X height x width). No differences were found between healthy dogs and euthyroid dogs with NTI. In the majority of euthyroid dogs, the thyroid lobes were fusiform and triangular in shape in longitudinal and transverse planes, respectively. The thyroid capsule appeared smooth. The thyroid parenchyma had a homogeneous echogenic pattern and usually was hyperechoic or isoechoic compared with the surrounding musculature. Ultrasound findings in hypothyroid dogs were more variable, including a greater frequency of round to oval-shaped thyroid lobes in the transverse imaging plane (P < .05), hypoechogenicity of the thyroid parenchyma compared with surrounding musculature (P < .001), and a decrease in the size and volume of the thyroid lobes and total volume of the thyroid gland (P < .05) compared with euthyroid dogs. Other findings in hypothyroid dogs included an irregular surface to the thyroid capsule, a heterogeneous pattern to the thyroid parenchyma, and differences in the echogenic pattern between the left and right thyroid lobes. Results suggest that determination of thyroid size and volume by ultrasound may be a useful adjunctive test for differentiating between hypothyroid and euthyroid dogs with NTI.

Reproductive Ultrasound of the Dog and Tom

Ultrasonographic evaluation of the reproductive tract is an important component in the evaluation of the dog and tom with reproductive disorders. Information is obtained confirming normal anatomy as well as pathologic conditions (eg, testicular neoplasia). Serial ultrasonographic evaluation of the diseased reproductive tract can be very helpful in evaluating progression of disease (eg, testicular atrophy) and response to therapy (eg, benign prostatic hyperplasia).

Uterine and Fetal Monitoring in the Bitch

The use of uterine and fetal monitoring improves the outcome of canine obstetrics. Much of the guesswork of managing whelping can be eliminated. At normal term, absolute indications for cesarean section are detected with monitoring, before multiple fetal deaths or any serious maternal compromise occurs. Bitches with previous history of cesarean section may be able to whelp vaginally successfully, having medical intervention based on monitoring. The anxiety level of owners during whelping is diminished, and the level of participation of the veterinarian improves.

Serum 17α-hydroxyprogesterone concentrations during the reproductive cycle in healthy dogs and dogs with hyperadrenocorticism.

OBJECTIVE To determine concentrations of 17alpha-hydroxyprogesterone (17OHP) in serum of healthy bitches during various stages of the reproductive cycle and in bitches with hyperadrenocorticism and to compare the dynamics of 17OHP with those of progesterone. DESIGN Prospective evaluation study. ANIMALS 15 healthy sexually intact bitches and 28 spayed bitches with hyperadrenocorticism. PROCEDURES 11 healthy bitches were evaluated during estrus, nonpregnant diestrus, and anestrus (group 1); 4 other healthy bitches were evaluated during pregnancy and after ovariohysterectomy (group 2). Cycle stages were determined via physical examination, vaginal cytologic evaluation, and serum progesterone concentration. Bitches with hyperadrenocorticism were evaluated once at the time of diagnosis (group 3). Serum hormone concentrations were determined with immunoassays. RESULTS In group 1, the serum 17OHP concentration was significantly higher in diestrus (median, 1.8 ng/mL) than in estrus (median, 1.1 ng/mL) and anestrus (median, 0.2 ng/mL) and higher in estrus than in anestrus. Changes in serum progesterone concentrations accounted for 22% (estrus) or 23% (diestrus) of the variation in serum 17OHP concentrations. In group 2, 17OHP and progesterone concentrations were significantly higher during pregnancy than after ovariohysterectomy. The serum 17OHP concentration in group 3 was significantly lower (median, 0.2 ng/mL) than in group 1 in estrus and diestrus and in group 2 during pregnancy (median, 0.7 ng/mL) but was not different from 17OHP concentrations in anestrus or after ovariohysterectomy (median, 0.2 ng/mL). CONCLUSIONS AND CLINICAL RELEVANCE Serum 17OHP concentrations in healthy bitches increased during estrus, diestrus, and pregnancy and at those times were higher than in spayed bitches with hyperadrenocorticism.

Advanced small animal reproductive techniques.

Small animal reproductive techniques have become quite advanced in recent years. Techniques described in this paper include transcervical catheterization for the purpose of insemination and intrauterine diagnostics (e.g., cytology, culture, and/or biopsy), and semen cryopreservation that allows international shipping of valuable semen and preservation of reproductive capacity. The use of uterine and fetal monitoring devices that enable intervention and mediation of dystocia is also described.

Primary Uterine Inertia in Four Labrador Bitches

Uterine inertia is a common cause of dystocia in the bitch and is designated as primary (i.e., uterine contractions fail to ever be initiated) or secondary (i.e., uterine contractions cease after a period of time but before labor is completed). The etiology of primary uterine inertia is not well understood. The accurate diagnosis of primary uterine inertia requires the use of tocodynamometry (uterine monitoring). Primary uterine inertia has been postulated to result from a failure of luteolysis resulting in persistently elevated progesterone concentrations. In this study, primary uterine inertia was diagnosed in a series of four bitches in which luteolysis was documented suggesting some other etiopathogenesis for primary uterine inertia.

Reproductive Causes of Hypocalcemia

Reproductive causes of hypocalcemia include puerperal tetany (eclampsia) and mild hypocalcemia during whelping. This article reviews the pathophysiology, signalment, clinical signs, and treatment of eclampsia in the bitch and queen. The second part of the article focuses on the consequences and treatment of hypocalcemia prior to and during whelping in dogs and cats.

Adult-Onset Lymphoplasmacytic Orchitis in a Labrador Retriever Stud Dog

A formerly fertile 5-year-old 45-kg Labrador retriever was evaluated for azoospermia noted during routine semen collection for an artificial insemination. Over the past 3 years, the dog had sired 4 litters of anticipated size for the breed out of 5 breedings, the most recent a litter of 10 conceived and whelped 2 months previously. Physical examination findings were normal with the exception of bilaterally small and soft testes. An open excisional wedge biopsy of the right testis was performed under general anesthesia. Histopathology findings supported an immunologic, autoimmune pathogenesis that had resulted in infertility over the previous 4 months.