Case Report: Infertility in bitches at a German Shepherd breeding center and nutritional management

Inadequate nutrition of the dams, even if recognized as a possible cause of infertility, it is usually underestimated during the common diagnostical procedures (i.e., clinical examination, vaginal cytology, ultrasound, blood and urine analysis). Although the diet may meet adult maintenance requirements, several nutrients can be suboptimal during the pre-gestation period and may influence reproductive performance. This case report describes the use of an oral supplement to increase fertility in a German Sheperd breeding center experiencing prolonged secondary anoestrus.

Fifteen German Shepherd bitches with secondary anoestrus (>12 months) underwent standard reproductive workup (vaginal cytology, hormone assays, ultrasound, and semen testing of sires). Abdominal ultrasound of the bitches did not present any signs of cystic endometrial hyperplasia (CEH). Similarly, metabolic disorders (hypothyroidism and Cushing's disease) were ruled out. It was hypothesized that the kennel diet might have provided suboptimal bioavailability of nutrients; as such the nutritional plan was reviewed, and a multi-component "fertility mix" (liquid and powder phases dosed daily at 0.8 g/kg^0.75 and 0.4 g/kg^0.75, respectively) was added to the usual complete maintenance ration.

Within 6 months of supplementation, 12/15 bitches resumed cyclicity and were confirmed pregnant or gave birth; whereas three underweight bitches with chronic enteropathies did not resume cyclicity.

The diagnostic approach to infertility is complex and involves both male and female factors, while dietary adequacy is often overlooked. Nutrients such as eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), arachidonic acid, folic acid, vitamin E, selenium, and zinc may influence ovarian steroidogenesis and antioxidant systems, and maintenance diets may not always be optimal for bitches intended for reproduction. These observations are hypothesis-generating; baseline and follow-up nutrient biomarkers were not obtained and no untreated control group was available, precluding causal inference.