Academic Journal
292 Evaluation of two Beef cow Fixed-Time AI Protocols That Utilize pre-Synchronization
| العنوان: | 292 Evaluation of two Beef cow Fixed-Time AI Protocols That Utilize pre-Synchronization |
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| المؤلفون: | Ketchum, Jaclyn N, Quail, Lacey K, Epperson, Kaitlin M, Guy, Chloey, Rich, Jerica J J, Zoca, Saulo Menegatti, Kline, Adalaide, Andrews, Taylor, Walker, Julie, Fontes, Pedro, Johnson, Sandy, Owen, Megan P, Harvey, Kelsey M, Summers, Adam F, Perry, George A |
| المصدر: | Journal of Animal Science ; volume 100, issue Supplement_3, page 139-140 ; ISSN 0021-8812 1525-3163 |
| بيانات النشر: | Oxford University Press (OUP) |
| سنة النشر: | 2022 |
| مصطلحات موضوعية: | Genetics, Animal Science and Zoology, General Medicine, Food Science |
| الوصف: | Pre-synchronization has been evaluated as a method to improve synchrony of ovulatory follicles before fixed-time AI (FTAI). The objective was to compare FTAI results in beef cows from two protocols that utilize pre-synchronization. Blood samples were collected on d-14 (d0=CIDR removal) to determine progesterone concentration at the start of synchronization (P4start: ≥1ng/mL=high, < 1ng/mL=low). In a subset (n=1,032), an additional blood sample was taken between d-21 and -29 to determine cyclicity. Cows (n=1,119), from 21 herds, were grouped by days postpartum and age and randomly assigned to one of two protocols. Cows assigned to the PG 6-day CIDR protocol (PG6d) received prostaglandin F2α (PG) on d-9, CIDR insertion and GnRH on d-6, and CIDR removal and PG on d0. Cows assigned to the 7&7 Synch protocol (7&7) were administered PG and CIDR insertion on d-14, GnRH on d-7, CIDR removal and PG on d0. For both protocols, FTAI occurred coincident with GnRH 66 h after second PG. Pregnancy was determined by transrectal ultrasonography 30-40 d following FTAI. The GLIMMIX procedure of SAS (9.4) was used to detect differences in estrus response and pregnancy success with herd included as a random variable. Estrus response (0 to 66 h) was influenced by treatment (P< 0.01; PG6d=60±5% and 7&7=74±4%), Body Condition Score (P< 0.01), cycling status (P=0.03), P4start (P< 0.01), and a P4start by treatment interaction (P< 0.001; PG6d-highP4=62±6%, PG6d-lowP4=58±6%, 7&7-highP4=84±3%, 7&7-lowP4=60±6%). Pregnancy success was influenced by estrus expression (P< 0.01; estrus=38±4% and no estrus=62±6%), and a treatment by P4start interaction (P=0.04; PG6d-highP4=58±5%, PG6d-lowP4=39±7%, 7&7-highP4=49±5%, 7&7-lowP4=55±8%) but was not influenced by treatment (P=0.45; PG6d=49±4% and 7&7=52±4%). In conclusion, effectiveness of pre-synchronization method depends on a cows’ physiological status at the beginning of the protocol. The 7&7 protocol increased ... |
| نوع الوثيقة: | article in journal/newspaper |
| اللغة: | English |
| DOI: | 10.1093/jas/skac247.257 |
| الاتاحة: | http://dx.doi.org/10.1093/jas/skac247.257 https://academic.oup.com/jas/article-pdf/100/Supplement_3/139/45963287/skac247.257.pdf |
| Rights: | https://academic.oup.com/pages/standard-publication-reuse-rights |
| رقم الانضمام: | edsbas.38C43EE0 |
| قاعدة البيانات: | BASE |
| DOI: | 10.1093/jas/skac247.257 |
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