164 Effect of dissolving solution on embryo recovery results of superovulation with FSH single subcutaneous injection
T. Maeda A , A. Katae A , T. Terashima A , A. Yokota A , M. Sugawara A , H. Sekizawa B , T. Nishisozu C and O. Dochi CA North Bull Inc., Sendai, Miyagi, Japan
B Sekizawa Animal Clinic, Nasushiobara, Tochigi, Japan
C Department of Dairy Science, Rakuno Gakuen University, Ebetsu, Hokkaido, Japan
Reproduction, Fertility and Development 34(2) 320-320 https://doi.org/10.1071/RDv34n2Ab164
Published: 7 December 2021
© 2022 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of the IETS
Efficient embryo recovery is important for genetic improvement of beef cattle by embryo transfer. In this study, we examined the effect of FSH dissolving solution on superovulation in Japanese black cow. Three hundred thirty-two Japanese black cows were superovulated from April 6, 2019, to October 2, 2020 (aluminium hydroxide gel, AHG group, n = 137; saline solution, SS group, n = 195). In the AHG group, a CIDR device was inserted into the vagina at a random stage of the oestrous cycle (Day 0), and 2 mg oestradiol benzoate (EB) was injected intramuscularly (IM) 24 h later. On Day 6, 30 AU of FSH was dissolved in 2.5 mL of SS, which was then mixed with 0.5 mL of AHG solution and subcutaneously injected in the neck. Simultaneously, PGF2α was introduced by injecting 0.5 mg of cloprostenol (PGF). The CIDR device was removed 60 h after FSH injection, and GnRH (47.5 μg of fertirelin) was injected 36 h after removing the CIDR device. AI was performed 12 h after injecting GnRH. In the SS group, CIDR was inserted into the vagina at a random stage of the oestrous cycle (Day 0), and 2 mg of EB was injected IM on Day 2. On Day 6, 20 AU of FSH was dissolved in 30 mL of SS and subcutaneously injected in the neck. PGF was injected at the same time as FSH injection. The CIDR device was removed 60 h after FSH injection, and AI was performed 48 h after removing the CIDR device. Ova/embryo collection was performed nonsurgically using a balloon catheter, and the quality evaluation of the embryo was done based on the manual from IETS. Data were analysed by ANOVA for the number of collected ova/embryos and number of transferrable embryos, and the chi-squared test was used for the proportion of transferrable embryos. The numbers of ova/embryos, number of transferrable embryos, and proportion of transferrable embryos in the AHG and SS groups were 14.5 ± 13.3 vs. 8.1 ± 8.9, 6.7 ± 7.4 vs. 4.7 ± 6.1, and 49.5 ± 33.6 vs. 59.1 ± 34.6, respectively. The number of ova/embryos and number of transferrable embryos were significantly higher in the AHG group than in the SS group (P < 0.01). The AHG group had significantly higher number of ova/embryos and transferable embryos than the SS group (P < 0.01). However, SS group had a significantly higher proportion of transferable embryos than the AHG group (P < 0.01). These data show that 30 AU of FSH dissolved in 2.5 mL SS and 0.5 mg of AHG decreased the percentage of normal embryos compared with 20 AU of FSH dissolved in 30 mL of SS alone, but increased the number of ova/embryos and the number of normal embryos. These results also show that AHG is a suitable dissolving medium for FSH to induce superovulation by a single hormone injection.
