First data of multiple ovulation and embryo transfer in modicana cows.

The Modicana is one of the minor Italian cattle breeds of limited diffusion, is autochthonous of Sicily and has a prevalent dairy aptitude. Multiple ovulation and embryo transfer (MOET) is an important tool for the genetic improvement and preservation of endangered breeds. Superovulation protocols use FSH extracted from porcine or ovine pituitaries and the two commercial products approved in Italy give comparable results despite different FSH/LH ratio [1]. Despite manufacturers' recommendations, the final dose of the drug is empirically adjusted in relation to aptitude, breed and age. Aim of the study was the application of MOET in Modicana cows using a protocol based on FSH/LH (Pluset, Bio 98). A total of 9 flushings in 9 donors were performed in a Modicana cattle farm placed in Ragusa, Italy. The criteria of selection of the donors were: age of 4-5 years, 90-200 days post partum, body condition score around 3.5, free from diseases with special regard to the genital tract. The study was performed from September 2016 to June 2017. The donors were visited 10 days after the onset of standing estrus to count the antral follicles of 2-3 mm and, eventually, to aspirate dominant follicles. Superovulation was induced by 10 intramuscular injections of Pluset, at 12-hour intervals over 5 days. A total of 500 UI of FSH were administered in declining doses after 6 unsuccessful experiences in 6 different donors with the manufacturer's dose (1000 UI). On day 4, cloprostenol (Estrumate, MSD Animal Health) was given. On day 6 and 7, each cow was inseminated with frozen semen 3 times at 8 hours interval, starting 12 hours after the onset of the standing estrus. Embryos were collected 7 days after inseminations by transcervical uterine flushing using a standard protocol and commercially media. Embryo morphology was assessed under a stereomicroscope according to the International embryo transfer Society classification guidelines [2]. Embryo were transferred in Modicana heifer recipients fresh or after freezing with a standard curve for bovine embryos (from -7°C to - 35°C with a rate -0.5°C/min). All the data were presented as mean and standard deviation. Fisher's exact text was used to analyze results. The estimated count of antral follicles in the selected donors was 14±6 resulting in 12±3 corpora lutea in the study group (n=9) versus 2±1 corpora lutea in the manufacturer's dose group (n=6) (p=0.04). A total of 70 embryos were recovered, evaluated and 53 were transferred as fresh (n=18) or frozen (n=35). The number of recovered and transferable embryos for cow was: 10±1 and 8±1. First grade blastocysts (6.1) and morulae (4.1) were the most represented embryos (30 and 32%). Non-transferable embryos (24%) were mainly represented by unfertilized ova (70%). Pregnancy rates (42 day) of recipients were 50% for fresh and 48% for frozen transferred embryos (p=1). Our data suggest that a low dose of FSH is effective for MOET schedules in Modicana breed. Despite individual differences, Modicana breed is candidate to be a good embryo producer among dairy cattle breeds.