Testicular volumetry and prediction of daily sperm output in stallions by orchidometry and two- and three-dimensional sonography.

This research explores the most effective methods for determining testicular volume and daily sperm output (DSO) in stallions. It compares traditional methods using a caliper, with innovative methods using 2D and 3D ultrasound technology, concluding that 3D ultrasound offers the most accurate predictions.

Introduction

• The research aimed to provide more accurate determination of testicular volume and prediction of daily sperm output (DSO) in stallions – vital for efficient reproductive management.
• The methods used for measuring testicular volume included a caliper, and two- and three-dimensional ultrasound, with a focus on the feasibility of 3D volume analysis.

Methodology

• Initially, the volumes of 22 castrated testes were measured using these methods. The volumes obtained were then compared with actual volumes determined via displacement in a saline solution.
• Field tests were then conducted during the breeding season on 52 stallions. The volumes acquired were used to predict DSO, these projected values were then compared with actual DSO from semen evaluations.

Results

• The study found a discrepancy between volumes determined by caliper and ultrasound methods when compared to volumes from the saline solution displacement method.
• The smallest differences were noted for the 3D volume analysis, followed by the caliper and 2D ultrasound.
• Testicular volumes of breeding stallions were highest when measured by 3D ultrasound, followed by 2D ultrasound and the caliper.
• The correlation between total testicular volume (TTV) and actual DSO was high with both ultrasound methods, and moderate with the caliper.
• Linear regression analyses showed that differences in DSO could partially be explained by differences in testes volume, with the highest percentage explainable by 3D ultrasound measurements.
• 3D ultrasound also provided the best correlation between predicted and actual DSO values.

Conclusion

• The study concluded that 3D ultrasound can be effectively used to provide more accurate predictions of testicular volume in stallions.
• This technology may enhance precision when predicting breeding potential in stallions.