Journal article
Effects of one versus two doses of prostaglandin F2alpha on AI pregnancy rates in a 5-day, progesterone-based, CO-Synch protocol in crossbred beef heifers
Theriogenology, Vol.75(8), pp.1536-1542
2011
Handle:
https://hdl.handle.net/2376/100934
PMID: 21320721
Abstract
The present study determined whether a 5-d progesterone-based CO-Synch protocol with a single dose of prostaglandin F
2α (PGF) at progesterone withdrawal on Day 5, would yield a timed AI pregnancy rate similar to two doses of PGF given 6 h apart on Day 5. Angus cross beef heifers (N = 562) at six locations were used. All heifers received 100 µg of gonadorelin hydrochloride (GnRH) and a controlled internal drug release (CIDR) insert on Day 0. Within farm, heifers were randomly allocated to receive one dose of 25 mg dinoprost (PGF) at CIDR removal on Day 5 (1 PGF; N = 264), or two doses of 25 mg PGF, with the first dose given on Day 5 at CIDR removal, and the second dose 6 h later (2 PGF; N = 298). Most heifers (N = 415) received a heat detector patch at CIDR removal. After CIDR removal, heifers were observed twice daily through Day 7 for estrus and heat detector aid status was recorded. On Day 8, heifers were given 100 µg of GnRH, heat detector aid status was recorded, and heifers were inseminated approximately 72 h after CIDR removal. Accounting for significant variables such as location (P < 0.01), heifers in estrus at or prior to AI (P < 0.001), and a treatment by location interaction (P < 0.01), two doses of PGF on Day 5 tended to have higher pregnancy rates to timed AI compared to those that received one dose of PGF (P = 0.06). In conclusion, heifers given two doses of PGF at CIDR removal on Day 5, in a 5-d CIDR-CO-Synch protocol, tended to have a higher pregnancy rate than those that received only one dose of PGF.
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Details
- Title
- Effects of one versus two doses of prostaglandin F2alpha on AI pregnancy rates in a 5-day, progesterone-based, CO-Synch protocol in crossbred beef heifers
- Creators
- C Peterson - Department of Veterinary Clinical Sciences, Washington State University, Pullman, WA 99164A Alkar - Department of Veterinary Clinical Sciences, Washington State University, Pullman, WA 99164S Smith - Washington State University Klickitat County Extension, Goldendale, WA 98260S Kerr - Washington State University Klickitat County Extension, Goldendale, WA 98260J.B Hall - Nancy M Cummins Research Extension and Education Center, University of Idaho, Carmen, ID 83462D Moore - Department of Veterinary Clinical Sciences, Washington State University, Pullman, WA 99164R Kasimanickam - Department of Veterinary Clinical Sciences, Washington State University, Pullman, WA 99164
- Publication Details
- Theriogenology, Vol.75(8), pp.1536-1542
- Academic Unit
- Veterinary Clinical Sciences, Department of
- Publisher
- Elsevier Inc
- Identifiers
- 99900546561501842
- Language
- English
- Resource Type
- Journal article