| Autor: |
Eduardo S, Ribeiro, Ralph G S, Bruno, Alexandre M, Farias, Juan A, Hernández-Rivera, Gabriel C, Gomes, Ricardo, Surjus, Luis F V, Becker, Alyssa, Birt, Troy L, Ott, Josh R, Branen, R Garth, Sasser, Duane H, Keisler, William W, Thatcher, Todd R, Bilby, José E P, Santos |
| Rok vydání: |
2013 |
| Předmět: |
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| Zdroj: |
Biology of reproduction. 90(1) |
| ISSN: |
1529-7268 |
| Popis: |
Objectives were to evaluate the effects of administering either one or two low doses of slow-release recombinant bovine somatotropin (bST) on hormone concentrations, conceptus development, and fertility in dairy cows. Cows from two farms were detected in estrus on or after 50 days postpartum (n = 1483), inseminated, and enrolled in the study (Day 0). Within farm, cows were blocked by parity and assigned randomly to receive a single placebo injection at insemination (control), a single injection with 325 mg of bST at insemination (S-bST), or two injections with 325 mg of bST administered on Days 0 and 14 (T-bST). From a subset of cows, blood was collected twice weekly from Day 0 to 42 for determination of hormone concentrations and on Day 19 for isolation of leucocytes and analysis of transcript abundance of selected interferon-stimulated genes. Pregnancy was diagnosed on Days 31 and 66, and ultrasonographic morphometry of the conceptus was performed on Days 34 and 48 in a subset of cows. Cows that received T-bST had increased plasma concentrations of GH and IGF1 for 4 wk, increased mRNA expression of ISG15 and RTP4 in leukocytes, earlier rise in the pregnancy-specific protein B in plasma of pregnant cows, increased conceptus size, and enhanced fertility. Cows that received S-bST had increased concentrations of GH and IGF1 for only 2 wk and it was insufficient to alter conceptus development and fertility. In conclusion, supplementation with low doses of bST during the pre- and peri-implantation periods enhanced conceptus development, reduced embryonic losses, and improved fertility in dairy cows. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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