Please use this identifier to cite or link to this item:
http://hdl.handle.net/20.500.12188/21438
DC Field | Value | Language |
---|---|---|
dc.contributor.author | Atanasov, B | en_US |
dc.contributor.author | Dovenski, T | en_US |
dc.contributor.author | Celeska, I | en_US |
dc.contributor.author | Stevenson, J S | en_US |
dc.date.accessioned | 2022-07-21T09:58:59Z | - |
dc.date.available | 2022-07-21T09:58:59Z | - |
dc.date.issued | 2021-06 | - |
dc.identifier.uri | http://hdl.handle.net/20.500.12188/21438 | - |
dc.description.abstract | Two experiments were conducted with Holstein-Friesian cows in the Republic of North Macedonia and with Holstein cows in Kansas. We hypothesized that 1 dose of PGF2α administered on d 8 (Ov-8×1) instead of d 7 (Ov-7×1) in an Ovsynch program [GnRH-1 (d 0)-7 d-PGF2α-56 h-GnRH-2-16 h-timed artificial insemination (AI)] would increase the proportion of cows with complete luteolysis compared with controls receiving a single dose on d 7. Cows were treated with Ov-7×1 or with Ov-8×1 in experiment 1 (n = 347), using only a single dose of PGF2α. In experiment 2 (n = 452), a third treatment was added (Ov-7×2), in which a second dose of PGF2α was administered on d 8. Progesterone was measured in blood samples collected before the first or only PGF2α administration and 72 h later before insemination. Complete luteolysis was defined as having occurred when progesterone was ≥1 ng/mL before PGF2α and ≤0.3 ng/mL 72 h later (time of AI). Follicles and luteal structures were mapped before GnRH-1 and PGF2α administrations. The results of experiment 1 demonstrated a greater percentage of multiparous cows in OV-8×1 having complete luteal regression compared with multiparous Ov-7×1 cows, whereas treatments were equally effective in primiparous cows, as reflected in the concentrations of progesterone before AI. Furthermore, pregnancy per AI did not differ between treatments. Results in experiment 2 revealed that 99.3% of cows in the Ov-7×2 treatment receiving the second dose of PGF2α had complete luteolysis, regardless of parity, compared with significantly fewer cows in the Ov-7×1 and Ov-8×1 treatments (91.2 and 90.6%, respectively). Neither concentrations of progesterone, which averaged <0.4 ng/mL at AI, nor pregnancy per AI differed among the 3 treatments. In both experiments, when status of luteal function before PGF2α treatment was examined [cows with no corpus luteum (CL) before GnRH-1 but which had formed a new CL in response to ovulation after GnRH-1; cows with an older CL (the same CL that was detected before GnRH-1); or cows with both a new and an older CL], treatments did not differ in causing complete luteolysis. Furthermore, complete luteolysis in experiment 2 did not differ regardless of whether cows had 1, 2, or 3 or more CL before PGF2α administration. Pregnancy per AI did not differ among treatments, indicating that any of the 3 treatments might produce similar pregnancy outcomes with the flexibility of applying either of the 7- or the 8-d treatments. | en_US |
dc.language.iso | en | en_US |
dc.publisher | American Dairy Science Association | en_US |
dc.relation.ispartof | Journal of dairy science | en_US |
dc.title | Luteolysis, progesterone, and pregnancy per insemination after modifying the standard 7-day Ovsynch program in Holstein-Friesian and Holstein cows | en_US |
dc.identifier.doi | 10.3168/jds.2020-19922 | - |
dc.identifier.url | https://api.elsevier.com/content/article/PII:S0022030221004616?httpAccept=text/xml | - |
dc.identifier.url | https://api.elsevier.com/content/article/PII:S0022030221004616?httpAccept=text/plain | - |
dc.identifier.volume | 104 | - |
dc.identifier.issue | 6 | - |
item.grantfulltext | none | - |
item.fulltext | No Fulltext | - |
Appears in Collections: | Faculty of Veterinary Medicine: Journal Articles |
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.