Morpho functional characterization and estimation of the reproductive potential of Creole goats in Santa Elena Province, Ecuador

In the arid, sun-scorched landscapes of coastal Ecuador, small-scale farming is not merely an economic activity but a lifeline for countless families. Here, the Creole goat, a hardy animal descended from strains brought centuries ago, thrives where other livestock might struggle. These animals have adapted through generations to survive with little water and sparse forage, becoming the backbone of local food security. Yet, for these herds to remain productive, the male goats, or bucks, must be fertile and capable of breeding. In the world of animal husbandry, a male's ability to reproduce is often linked to the physical development of his reproductive organs and his overall physical condition. Scientists have long known that the size of the scrotum, the pouch of skin holding the testicles, and the firmness of the testicles themselves are reliable signs of a male's fertility. Similarly, an animal's body condition—essentially a measure of how well-fed it is—plays a critical role in its ability to produce healthy sperm. Without these biological foundations, a herd cannot grow, and the families relying on it face uncertainty.

Against this backdrop, researchers set out to understand the reproductive health of Creole goats in Santa Elena Province. They focused on 190 male goats ranging from eight months to five years old, living on farms across four different parishes in the region. The scientists measured a variety of physical traits, including the animals' age, their body condition, and the precise dimensions of their testicles and scrotums. They also carefully examined the structure of the goats' legs and feet, looking for any deformities that might hinder movement. The goal was to determine if these local goats were developing normally and to identify any factors that might be limiting their ability to breed in such a harsh environment.

The results painted a clear picture of a population that is biologically capable but often held back by its environment. The average scrotal circumference for the goats was just under 22 centimeters, a measurement that generally indicates good reproductive potential. As the goats grew older, their testicular size increased significantly, with the oldest males, those four years and older, showing the most developed reproductive organs. The study found that age and body condition were the two strongest predictors of this development. Specifically, the researchers determined that for every additional month a goat lived, its scrotal size grew slightly, but a more significant boost came from better nutrition. A goat in better physical shape had a noticeably larger scrotal circumference than a thinner one, suggesting that improving the feed available to these animals could directly enhance their breeding capacity.

However, the study also uncovered a hidden challenge that goes beyond simple nutrition. While the reproductive organs were developing well, the physical structure of the goats' legs presented a serious obstacle. Nearly half of the male goats evaluated showed some form of leg or foot defect, with the most common issue being a posture known as "sickle-hocked," where the hock joint bends inward excessively. Another frequent problem involved steep angles in the lower leg joints. In the dry, thorny terrain of Santa Elena, where goats must travel long distances over rough ground to find food and locate females in heat, these structural flaws are not just cosmetic. They cause pain and fatigue, making it difficult for the males to move freely or mount females effectively. This mobility issue, combined with the seasonal scarcity of food, creates a bottleneck that prevents even healthy, fertile males from fulfilling their reproductive role.

The researchers also observed the shape of the scrotums themselves. While most goats had a standard, elongated shape, a significant portion displayed a split or cleft scrotum. In the hot climate of the region, this split is likely an evolutionary adaptation that helps cool the testicles by exposing more surface area to the air, a necessary function for maintaining sperm production in high temperatures. However, the researchers noted that if this split is too deep, it can become a liability, leaving the testicles vulnerable to injury from the sharp thorns of local vegetation. The study concluded that while the Creole goats of Santa Elena possess the biological machinery for reproduction, their potential is currently restricted by a combination of poor nutrition and structural leg defects. To improve the herd, the authors suggest a new approach to selecting breeding males: choosing those with adequate testicular size, good body condition, and, crucially, sound legs that allow them to navigate the rugged landscape without pain.