Influence of semen placement location and other factors on the number and morphological status of obtained embryos from donor cows

The aim of the study was to analyze the effectiveness of embryo collection depending on where semen in superovulation cow-donors in heat is deposited. Research was carried out on 44 embryo donors, including 26 heifers and 18 cows of the Polish Holstein-Friesian breed. Manipulations were carried out with the participation of veterinary doctors who specialize in embryo transfer. The estrus cycle of the future donors was synchronized with the double intramuscular injection of 2 ml Cloprostenol (Oestrophan, Biofaktor Company), Dinolytic (Pfizer Polska Sp. z o.o.) 5 ml or Bioestrovet (0.5 mg of Cloprostenol - active substance) (Vetoquinol, Biowet Sp. z o.o.) 2 ml administered for 11 days. Superovulation was initiated at day 10th of an estrus cycle - administered by injection of 10 ml of FSH (Pluset) during 4 consecutive days (in the morning and in the evening). Estrus was induced on the 3rd day of the superovulation treatment by providing 500 mu g and 250 mu g of Cloprostenol (Bioestrovet) twice - 2 ml in the morning and 1 ml in the evening. Subsequently, 25 donors were inseminated three times, another 19 were inseminated twice with single or double doses of semen deposited at different locations inside the uterus. Donors were inseminated with frozen semen which is used for standard AI. Obtained results showed a significant influence of placement location of semen on the efficiency of embryos' collection. The highest ratio (40.4%) of embryos and oocytes was obtained in the case when semen was itself placed in the uterine horn. The lowest ratio (16.2%) was observed in the case when semen was placed in the uterus. Moreover, a difference in the number of obtained oocytes and embryos depends on the sequence of semen placement locations. In the case of location in the uterus body versus uterine horn 0.6 more embryos and oocytes were collected. The number of embryos suitable for transfer was the highest when semen was placed in the uterine horn. Concluding, the uterine horn appeared to be the best place for semen location.