Induction of accessory corpus luteum by gonadorelin in relation to the time of treatment and the follicle size in inseminated cows

Abstract

Doležel R., Chambert C., Musilová D., Čech S., Páleník T. (2017): Induction of accessory corpus luteum by gonadorelin in relation to the time of treatment and the follicle size in inseminated cows. Czech J. Anim. Sci., 62,[195][196][197][198][199][200] This study evaluated the occurrence of two corpora lutea (CL) and the pregnancy rate in cows treated with gonadorelin on days 5, 6 or 7 after insemination in relation to the day of treatment and the size of the largest follicle on the ovaries at the time of treatment. Cows bearing one CL on days 5 (n = 40), 6 (n = 48), and 7 (n = 47) after insemination with defined size of the largest follicle on the ovaries (small ≤ 9 mm, n = 34; medium 10-14 mm, n = 59; large 15-20 mm, n = 42) were included in the study. Gonadorelin was administered after examination (day 0) and ultrasonographic examination was repeated on days 14, 28, and around day 90. The occurrence of 2 CL vs 1 CL was higher in pregnant cows on day 14 as well as on day 28 (86 vs 14% and 82.5 vs 14%, n = 57). Pregnancy rates on day 28 and around day 90 were higher in cows bearing 2 CL (n = 57) vs cows bearing 1 CL (n = 54) (82.5 vs 18.5% and 79.0 vs 18.5%, P < 0.001). The occurrence of 2 CL on day 28 was higher in cows treated on day 5 compared to cows treated on day 6 or 7 after insemination (60.0 vs 33.3 or 36.2%, P < 0.05). No significant differences in the number of CL and pregnancy rate were found in relation to follicle size at the time of treatment. Our results showed the higher efficiency of accessory CL induction by gonadorelin administration in cows treated on day 5 vs those treated on day 6 or 7 post insemination, however efficiency of the treatment was not influenced by the size of the largest follicle on the ovaries.

Reproductive Outcomes in High-Yielding Holstein Cows Following Administration of GnRH on Day 5 After Artificial Insemination

“…In our previous study, we confirmed that administering GnRH between 7-14 days after artificial insemination (AI) can increase the number of aCL and improve reproductive performance in repeat-breeder dairy cows [1]. According to the results of Doležel et al, [17], inducing aCL through gonadorelin administration was found to be more efficient in cows treated on day 5 following insemination, as compared to cows treated on days 6 or 7. A study conducted by Cunha et al [6] Disclaimer/Publisher's Note: The statements, opinions, and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s).…”

Effects of apoptosis by 20α-hydroxysteroid dehydrogenase activity on corpus luteum formation during early pregnancy in cattle

“…Few studies have been conducted on changes in the corpus luteum tissue during pregnancy, and most suggest that 20α-HSD-mediated apoptosis during early pregnancy may indicate abortion (Naidansuren et al 2012). However, the corpus luteum undergoes active tissue reorganisation during pregnancy and the functional activity of the corpus luteum changes accordingly (Kim et al Supplement of 20α-HSD protein 0.5 μg/ml 1 μg/ml 1.5 μg/ml 0.5 1 1.5 (μg/l) 2014; Dolezel et al 2017). The process of reconstitution of the corpus luteum is accomplished by transforming growth factor-beta (TGF-β) signalling, T cell receptor signalling/Ilyushin-2 (IL2) signalling, which is a luteinising enzyme, and the activity of matrix metalloproteinases by extracellular matrix collagen (ADAMTS1) affects the extracellular matrix, resulting in the overall degeneration of the corpus luteum tissue (Kim et al 2014;.…”