The study of a hermaphroditic sheep caused by a mutation in the promoter of SRY gene

Clinical, Histological and Genetic Characterisation of a Disorder of Sexual Development in a Pygmy Goat

A 10-month-old pygmy goat was examined at the Royal (Dick) School of Veterinary Studies at the University of Edinburgh in January 2022, having been referred with a suspected diagnosis of a disorder of sexual development (DSD). The animal displayed a predominantly female phenotype (vulva with enlarged clitoris and vagina) but some male external characteristics such as a beard, larger body size, and larger horns. It also typically exhibits male behaviours such as mounting, aggression, and flehmen response. Computed tomography (CT) detected a bicornuated tubular fluid-filled structure connected to bulbous soft tissue masses. Subsequent exploratory laparotomy and reproductive tract removal identified underdeveloped uterine horns connected to ductus deferens and gonads, which were confirmed as testicles by histological examination. No spermatogenesis was detected, and no ovarian tissue was apparent. Blood levels of testosterone showed a marked decrease post-surgery (2.10 nmol/L to <0.03 nmol/L). Whole genome sequencing suggested that the patient may have an XY male karyotype, although cytological analysis was not possible to confirm the XY karyotype.

Maternal nutrition and fetal imprinting of the male progeny

The global population as well as the demand for human food is rapidly growing worldwide, which necessitates improvement of efficiency in livestock operations. In this context, environmental factors during fetal and/or neonatal life have been observed to influence normal physical and physiological function of an individual during adulthood, and this phenomenon is called fetal or developmental programming. While numerous studies have reported the impact of maternal factors on development of the female progeny, limited information is available on the potential effects of fetal programming on reproductive function of the male offspring. Therefore, the objective for this review article was to focus on available literature regarding the impact of maternal factors, particularly maternal nutrition, on reproductive system of the male offspring. To this end, we highlighted developmental programming of the male offspring in domestic species (i.e., pig, cow and sheep) as well as laboratory species (i.e., mice and rat) during pregnancy and lactation. In this sense, we pointed out the effects of maternal nutrition on various functions of the male offspring including hypothalamic-pituitary axis, hormonal levels, testicular tissue and semen parameters.

Developmental programming of the ovarian reserve in livestock

Mammalian females are born with a finite number of follicles in their ovaries that is referred to as the ovarian reserve. There is a large amount of variation between females in the number of antral follicles that they are born with, but this number is positively correlated to size of the ovarian reserve, has a strong repeatability within a female, and a moderate heritability. Although the heritability is moderate, numerous external factors including health, nutrition, ambient temperature, and litter size influence the size and function of the ovarian reserve throughout life. Depletion of the ovarian reserve contributes to reproductive senescence, and genetic and epigenetic factors can lead to a more rapid decline in follicle numbers in some females than others. The relationship of the size of the ovarian reserve to development of the reproductive tract and fertility is generally positive, although some studies report antagonistic associations of these traits. It seems likely that management decisions and environmental factors that result in epigenetic modifications to the genome throughout life may cause variability in the function of ovarian genes that influence fecundity and fertility, leading to differences in reproductive longevity among females born with ovarian reserves of similar size. This review summarizes our current understanding of factors influencing size of the ovarian reserve in cattle, sheep, and pigs and the relationship of the ovarian reserve to reproductive tract development and fertility. It provides strategies to apply this knowledge to improve diagnostics for better assessment of fertility and reproductive longevity in female livestock.