Publikationsdatenbank

Effect of dose and timing of prostaglandin F2α treatments during a 7-d Ovsynch protocol on luteal regression and pregnancy outcomes in lactating Holstein cows (2023)

Art

Poster

Autoren

Hölper, Marvin (WE 19)

Bretzinger, Lukas (WE 19)

Randi, Federico

Heuwieser, Wolfgang (WE 19)

Borchardt, Stefan (WE 19)

Kongress

European Buiatrics Congress and ECBHM Jubilee Symposium

Berlin, 24. – 26.08.2023

Quelle

Kontakt

Tierklinik für Fortpflanzung

Königsweg 65
Haus 27
14163 Berlin
+49 30 838 62618
fortpflanzungsklinik@vetmed.fu-berlin.de

Abstract / Zusammenfassung

Objectives
Incomplete luteolysis after a single prostaglandin F2α (PGF2α) treatment can lead to suboptimal fertility in cows submitted to an Ovsynch protocol. Our objective was to evaluate the effect of 3 different Ovsynch protocols on progesterone concentration and pregnancies per artificial insemination (P/AI), where all cows received a P4 releasing intravaginal device (PRID) from d 0 until d 8. We hypothesized that (1) both modified PGF2α treatments lead to decreased P4 at the second GnRH treatment (G2), resulting in greater P/AI, (2) the treatment effect is influenced by the presence of a corpus luteum (CL) at the beginning of the protocol, and (3) potential vaginal discharge caused by the PRID does not have a negative influence on fertility

Material and Methods
Lactating Holstein cows from one commercial farm (n = 1,056) were randomly assigned to 1 of 3 treatment groups on a weekly basis (n = 356; control: d 0, 100 µg of GnRH + PRID; d 7, 25 mg of dinoprost; d 8, PRID removal; d 9, 100 µg of GnRH). Cows in the second group (n = 353) received an Ovsynch protocol with a double dose of PGF2α (DoubleDose: d 0, 100 µg of GnRH + PRID; d 7, 50 mg of dinoprost; d 8, PRID removal; d 9, 100 µg of GnRH). Cows in the third group (n = 347) received an Ovsynch protocol with a second PGF2α treatment 24 h after the first one (2PGF: d 0, 100 µg of GnRH + PRID; d 7, 25 of mg dinoprost; d 8, 25 mg of dinoprost and PRID removal; d 9, 100 µg of GnRH). All cows had their ovaries scanned to determine the presence of a CL at the beginning of the Ovsynch protocol. Vaginal discharge score (VS) was evaluated at PRID removal. All cows received timed artificial insemination approximately 16 h after G2. Pregnancy diagnosis was performed via transrectal ultrasonography (d 38 ± 3 after timed artificial insemination) and rechecked on d 80 ± 7 after timed artificial insemination. Blood samples were collected on d 0, 7, and 9 of the protocol to determine P4 concentrations.

Results
Progesterone at G2 was lower for 2PGF and DoubleDose cows compared with cows in the control group (control 0.35 ± 0.02 ng/mL; DoubleDose 0.29 ± 0.02 ng/mL; 2PGF 0.30 ± 0.02 ng/mL). Overall, P/AI did not differ among treatments. We found, however, an interaction between treatment and CL at the first GnRH treatment. Cows lacking a CL at the first GnRH treatment in the 2PGF group had greater P/AI (47.9%) compared with the same type of cows in the DoubleDose group (32.7%). We observed an effect of VS on P4 concentration at d 7. We found an increase in P4 with greater VS. Vaginal discharge score at PRID removal tended to have a positive effect on P/AI at d 38 (VS0: 36.5%; VS1: 41.3%; VS2: 49.7%).

Conclusions
The addition of a second PGF treatment on d 7 and 8 of a 7-d Ovsynch protocol increased luteal regression and decreased mean P4 at G2. Cows without a CL at G1 treated with PGF2α twice 24 h apart showed greater P/AI.