No-CL Superstimulatory Protocol: Developing a New Superovulation Treatment Initiated in the Absence of Corpus Luteum (CL) and Compared with D1 and Traditional Superovulation in Cattle

ABSTRACT

The objective of this study was to investigate the effectiveness of superovulation under a complete absence of the Corpus luteum (CL) and compare it with D1 protocol and traditional superovulation in cattle. Animals were divided into three groups as following; 1- D1-protocol: Animals (n= 7) were leaved to get natural ovulation (D0), then received FSH for the next 4 days of the cycle. GnRH was given 12h after the last dose of FSH. 2- No-CL superovulation protocol: Animals (n=10) were synchronized and received PGF2α at D9 or D10 then classified to two subgroups (D9-sub-group and D10-sub-group). After 36 h, all follicles (≥ 5 mm) were aspirated (D0). 3- Control: Animals (n=3) were submitted to the conventional superovulation protocol. Blood samples were collected daily for 13 days. Progesterone (P4) and Estradiol (E2) in plasma were measured by Enzyme immune assay (EIA). The results showed that the number of growing follicles was significantly (P< 0.05) higher in both D9 and D10 subgroups in comparison to the D1 protocol (25.8 ± 4.3 and 20 ± 1.9 vs. 10.9 ± 1.9 respectively). While the number of ovulated follicle was higher in D9 sub-group than D10 sub-group, D1 protocol and control (13.8 ± 4.4 vs. 7.6 ± 3.5, 6.8 ± 1.5 and 9.7±0.9). In conclusion, the superovulation protocol with complete absent of the CL produced high number of growing follicles, decreased variability and considered as a promising superovulation protocol.