Sodium Caseinate and Cholesterol Improve Bad Cooler Stallion Fertility.

This research investigates the influence of sodium caseinate and cholesterol additives on the fertility preservation of cooled stallion semen. It found that the combination of sodium caseinate and cholesterol significantly improved the fertility of stallion semen characterized as “bad cooler” when stored at 5°C for 24 hours.

Introduction

• The study was targeted at evaluating how sodium caseinate, a milk derivative, and cholesterol could enhance the preservation of stallion semen when used as additives in extenders during the cooling process.

Methodology

• The stallion semen samples obtained from 19 stallions were divided into four extenders: E1 – a commercially available skim-milk based extender; E2 – similar to E1 but with the milk component replaced by sodium caseinate; E3 – E1 formula with added cholesterol; E4 – a combination of E2 and cholesterol.
• These extended semen samples were subsequently cooled and stored at 5°C for 24 hours. Semen from one “bad cooler” and one “good cooler” stallions, divided into the four extenders, were also used to inseminate 30 light breed mares (30 estrous cycles per extender).

Results

• After 24 hours of cooling, the semen’s motility parameters, plasma membrane stability, and mitochondrial membrane potential were assessed.
• The sperm kinetics in milk-based extenders (E1 and E2) were found to be superior to E3 and E4. However, plasma membrane stabilization was significantly higher in E4 than E1, with E2 and E3 having intermediate values.
• There was a lower mitochondrial potential intensity in E2 and E4 compared to E1 and E3.
• The “good cooler” stallion had approximately 80% fertility in all extenders, while for the “bad cooler” stallion, fertility varied: E1 had 40% fertility, E2 had 45%, E3 had 55%, and E4 had the best performance with 85% fertility.

Conclusion

• The study concluded that adding sodium caseinate and cholesterol to the extender significantly boosted the fertility of “bad cooler” stallion semen cooled for 24 hours. This suggests that these additives could be used to enhance the effectiveness of semen preservation for stallions identified as “bad coolers”.