Functional and Fertility Outcomes of Two Milk-Based Extenders for Short-Term Storage of Ram Semen at 15°C.

The efficiency of AI in sheep depends partly on maintaining sperm function during storage. This study compared INRA 96 and a skim milk-based formulation for storing ram semen at 15°C for 6 h, evaluating sperm quality and IVF and field fertility outcomes. INRA 96 showed higher VCL, ALH, and sperm viability after 6 h of storage. However, cleavage rate, blastocyst rate, and blastocyst cell number after IVF, as well as field fertility and prolificacy, did not differ between extenders. These results indicate that the skim milk-based formulation preserved reproductive outcomes at levels comparable to INRA 96, supporting its suitability as a cost-effective alternative for routine AI programs.