Vaginal parameters during the 24-hour preceding insemination in Bunaji cows under three standard synchronization protocols

Abstract

Introduction: The criticalness of the point at which inseminations are carried out at breeding stations to pregnancy rates perhaps contributed to the emergence of timed artificial insemination (TAI) protocols. Methods: Vaginal mucus resistivity (VMR), temperature (VT) and cytology (VC) were investigated using cows (Bunaji, n = 75, >2 parities) that were equally randomized to TAI protocols: CoSynch (100µg Gonadotropin-Lecirelin® IM on d0, d10; 500µg Clorprost 1® IM on d7), OvSynch (100µg Le-cirelin® on d0, d9; 500µg Clorprost 1® on d7) and Prostaglandin (500µg Clorprost 1® on d0, d11). VMR, VT and VC (superficial-epithelia-cells %) were monitored on d9, d10 (Gonadotropin-group) and d13, d14 (Prostaglandin-group) using Draminski® bovine Estrous probe, SK-SKATO® thermometer and standard procedures, respectively. Results: From d9 to d10, VMR declined by 22.40% to 260.06±44.27Ω (range 250-270), VT rose by 1.43% to 35.50±0.71°C while VC declined by 69.57% to 14% for CoSynch-group. Similarly, VMR declined by 13.04% to 245.12±12.91Ω (range 240-250), VT rose by 2.86% to 36.00±0.00°C while VC increased by 52% to 52% for OvSynch-group. From d13 to d14, VMR declined by 2.90% to 335±28.87Ω (range 330-340), VT rose by 1.43% to 35.50±0.71°C while VC declined by 76% to 0% for Prostaglandin-group. These findings suggest that the 24-hour preceding insemination were associ-ated with VMR: 240 to 270Ω, VT: 35 to 36°C, VC: 14 to 52% and VMR: 330 to 340Ω, VT: 35 to 35.5°C, VC: 0% for Gonadotropin-based and Prostaglandin protocols, respectively. Significance: Vaginal-mucus resistivity, temperature and cytology are thus described to better define insemination time and improve pregnancy rates at cattle breeding stations.