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Follicular dynamics, circulating progesterone, and fertility in Holstein cows synchronized with reused intravaginal progesterone implants that were sanitized by autoclave or chemical disinfection.
Melo, L F; Monteiro, P L J; Nascimento, A B; Drum, J N; Spies, C; Prata, A B; Wiltbank, M C; Sartori, R.
Afiliação
  • Melo LF; Department of Animal Science, University of São Paulo, Piracicaba, SP 13418-900, Brazil.
  • Monteiro PLJ; Department of Animal Science, University of São Paulo, Piracicaba, SP 13418-900, Brazil.
  • Nascimento AB; Department of Technical Services, ABS Global Inc., De Forest, WI 53532.
  • Drum JN; Department of Animal Science, University of São Paulo, Piracicaba, SP 13418-900, Brazil.
  • Spies C; Department of Animal Science, University of São Paulo, Piracicaba, SP 13418-900, Brazil.
  • Prata AB; Department of Animal Science, University of São Paulo, Piracicaba, SP 13418-900, Brazil.
  • Wiltbank MC; Department of Dairy Science, University of Wisconsin-Madison, Madison 53706.
  • Sartori R; Department of Animal Science, University of São Paulo, Piracicaba, SP 13418-900, Brazil. Electronic address: robertosartori@usp.br.
J Dairy Sci ; 101(4): 3554-3567, 2018 Apr.
Article em En | MEDLINE | ID: mdl-29428754
This experiment aimed to compare circulating progesterone (P4), follicular dynamics, and fertility during reuse of intravaginal P4 implants that were sanitized by autoclave or chemical disinfection in lactating Holstein cows submitted to fixed-time artificial insemination (FTAI). For this, 123 primiparous and 226 multiparous cows from 2 farms, averaging (mean ± standard deviation) 163.9 ± 141.9 d in milk, 35.7 ± 11.3 kg of milk/d, and a body condition score of 2.9 ± 0.5, were enrolled in the study. Cows were randomly assigned to 1 of 2 treatments using a completely randomized design and each cow received a reused implant (1.9 g of P4; previously used for 8 d) that was either autoclaved (AUT; n = 177) or chemically disinfected (CHEM; n = 172) on d -10. Also on d -10, cows received 2 mg of estradiol benzoate and 100 µg of GnRH. On d -3, cows received 25 mg of dinoprost (PGF2α). A second PGF2α was given on d -2, along with 1 mg of estradiol cypionate and P4 implant removal. Cows received FTAI on d 0. A subset of cows (n = 143) was evaluated by ultrasound on d -10, -8, -6, -3, -2, 0, and 5 to identify ovarian structures, and blood was sampled on d -10, -3, and -2 for P4 concentrations by RIA. Pregnancy diagnoses were performed at d 32 and 60. Statistical analyses was performed using PROC-MIXED for continuous variables and PROC-GLIMMIX of SAS 9.4 (SAS Institute Inc., Cary, NC) for binomial variables. The treatments did not differ in circulating P4 on d -10 or -3, but P4 was greater on d -2 in CHEM cows. Ovulation to the treatments on d -10 was associated with lower circulating P4 on d -10 (2.0 vs. 3.1 ng/mL) and resulted in greater P4 on d -3 (4.0 vs. 2.4 ng/mL) and more cows with a corpus luteum on d -3 (100 vs. 40%) than nonovulating cows. Cows that ovulated to d -10 treatments were more likely to have a synchronized new follicular wave (97.9 vs. 63.2%) and had an earlier wave emergence (1.9 vs. 2.6 d), resulting in less cows ovulating a persistent follicle (0.0 vs. 35.7%). Type of P4 implant, corpus luteum presence on d -10, and ovulation to d -10 treatments did not affect fertility (pregnancy per AI; P/AI). However, P/AI on farm A was greater than on farm B at 32 (40.8 vs. 27.8%) and 60 d (35.8 vs. 24.3%), independent of treatment. In conclusion, P4 implants with different P4 release patterns did not produce detectable differences in follicular dynamics, synchronization rate, or P/AI. Nevertheless, presence of corpus luteum or ovulation at the beginning of the FTAI protocol affected reproductive variables, such as timing and synchronization of follicular wave emergence, and size of the ovulatory follicle. Beyond that, more overall synchronized cows became pregnant to the FTAI protocol.
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Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Progesterona / Bovinos / Desinfecção / Reutilização de Equipamento / Implantes de Medicamento / Sincronização do Estro / Fertilidade Tipo de estudo: Guideline / Prognostic_studies Limite: Animals / Pregnancy Idioma: En Revista: J Dairy Sci Ano de publicação: 2018 Tipo de documento: Article País de afiliação: Brasil País de publicação: Estados Unidos

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Progesterona / Bovinos / Desinfecção / Reutilização de Equipamento / Implantes de Medicamento / Sincronização do Estro / Fertilidade Tipo de estudo: Guideline / Prognostic_studies Limite: Animals / Pregnancy Idioma: En Revista: J Dairy Sci Ano de publicação: 2018 Tipo de documento: Article País de afiliação: Brasil País de publicação: Estados Unidos