Effect of pre-synchronisation with progestogen and eCG on reproductive activity in synchronised ewes during anoestrous season.

The objective of the study was to investigate the effect of pre-synchronisation on the occurrence of the oestrus and pregnancy rate after fixed time artificial insemination (FTAI) in synchronised ewes during the anoestrous season. Kivircik ewes ( = 84) were randomly assigned to one of the two treatment groups with (PRE;  = 42) or without (SYN;  = 42) pre-synchronisation. In the SYN group, the ewes were subjected to a 7-d short-term protocol (P4 insertion-6d-PGF2α-1d-P4 removal + eCG).

Effect of One-Day Delaying CIDR Administration in 5-Day Cosynch Protocol in Dairy Heifers.

Effect of one-day delaying progesterone administration at the beginning of 5-day Cosynch protocol was investigated in Holstein heifers for the first artificial insemination (AI). Heifers received a synchronized ovulation and timed AI (TAI) with CIDR inserted on day (d) 0 (CIDR-5; = 206) or d 1 (CIDR-4; = 192). In both group, GnRH was administered on d 0 followed by a single PGF injection and CIDR removal five days later from GnRH.

Nitric oxide concentrations, estradiol-17β progesterone ratio in follicular fluid, and COC quality with respect to perifollicular blood flow in cows.

The objectives were to investigate relationships among concentrations of nitric oxide (NO), estradiol 17 beta (E2), and progesterone (P4) in follicular fluids (FF), and quality of cumulus oocyte complexes (COCs) with respect to perifollicular blood flow (FBF). In Experiment I, follicles (138) were classified according to the presence or absence of FBF (assessed with transvaginal Doppler ultrasonography) and diameter of follicles (small, 2-4 mm; medium, 5-8 mm; and large, ≥9 mm). Concentrations of NO in FF did not differ significantly among these size categories.

Changes in follicular blood flow and nitric oxide levels in follicular fluid during follicular deviation in cows.

Two experiments were conducted to test the hypothesis that there are dynamic changes in follicular blood flow during follicular deviation and that nitric oxide (NO) in follicular fluid (FF) plays a role in regulation of follicular blood flow. In Experiment I, follicular blood flow of the two largest follicles was monitored by using Power Doppler ultrasonography during follicular deviation in sixteen follicular waves during eight estrous cycles in eight cows. Blood flow did not differ (P>0.

Reproductive responses following postpartum suppression of ovarian follicular development with a deslorelin implant during summer heat stress in lactating dairy cows.

The objective was to evaluate pregnancy rate to a timed artificial insemination (TAI) protocol in the autumn for cows treated with a non-degradable GnRH agonist implant (Deslorelin [DESL], 5mg) during the summer heat stress period compared with non-treated controls (CON). Cows were randomly assigned to receive or not a DESL implant within 1-4 days postpartum (dpp) twice weekly, from 25 June through 8 August 2001. All cows in DESL implant and CON treatments were injected with PGF(2alpha) 7 days after enrollment.