PS7-28. Impact of Sire and Donor on in vitro Embryo Production Efficiency in Small Ruminants: A Large-scale Commercial Analysis.

Abstract The objective of this retrospective study was to evaluate and quantify the direct impact of sire (semen source) and donor (oocyte competence) effects on cleavage rates, Embryo Development Rate (EDR), and final embryo yields in a commercial small ruminant in vitro embryo production (IVP) program. Data from 1,800 Laparoscopic Ovum Pick-Up (LOPU) followed by in vitro fertilization (IVF) sessions, conducted throughout 2025 across multiple sheep and goat breeds, were analyzed. A total of 21,347 oocytes were recovered, of which 18,201 were morphologically classified as viable. Cleavage and embryo development outcomes were recorded per session. Statistical analyses included Pearson and Spearman correlation coefficients to assess relationships between cleavage and final embryo production. The Kruskal-Wallis H-test was utilized to determine variance among individual sires and donors (restricted to animals with a minimum of 5 LOPU sessions). The fertilization process resulted in 11,455 cleaved oocytes and a total production of 7,308 viable embryos. This reflects an overall EDR of 40.1% relative to viable oocytes and a 63.8% conversion rate from cleaved oocytes. A moderate to strong positive correlation was observed between the number of cleaved oocytes and total embryos produced (Pearson r = 0.58; Spearman r = 0.50). A highly significant sire effect on the final embryo yield and EDR was identified (H = 250.81, P < 0.0001), with top-performing sires averaging up to 8.60 embryos per session. Furthermore, the individual donor female effect was statistically significant (H = 53.53, P < 0.001), with elite donors yielding up to 7.00 embryos per LOPU. In conclusion, individual genetic variance, particularly the sire effect, significantly impacted embryo developmental competence in large-scale LOPU-IVF programs. Pre-screening and rigorous selection of sires based on IVF kinetic data are indispensable strategies to maximize EDR, embryo yields, and program profitability.