Journal article
Fixed-time AI pregnancy rate following insemination with frozen-thawed or fresh-extended semen in progesterone supplemented CO-Synch protocol in beef cows
Theriogenology, Vol.71(7), pp.1180-1185
2009
Handle:
https://hdl.handle.net/2376/109435
PMID: 19195696
Abstract
The objective of this study was to compare fixed-time AI pregnancy rate in Angus crossbred beef cows inseminated with frozen-thawed or fresh-extended semen. Two ejaculates from each of two Angus bulls were collected by artificial vagina and pooled for each bull. The pooled semen from each bull was divided into two aliquots; Aliquot 1 was extended using Caprogen
® (LIC, Hamilton, New Zealand) to a concentration of 3
×
10
6
sperm/straw and Aliquot 2 was extended using egg-yolk–glycerol extender to a concentration of 20
×
10
6
sperm/straw. Semen extended with Caprogen
® was maintained at ambient temperature and semen extended with egg-yolk–glycerol extender was frozen and maintained at −196
°C until insemination. In each of two breeding seasons (Fall 2007 and Spring 2008), Angus-crossbeef cows (
N
=
1455) at 12 locations were randomly assigned within location to semen type [Fresh (
N
=
736) vs. Frozen (
N
=
719)] and sire [1 (
N
=
731) vs. 2 (
N
=
724)]. All cows were synchronized with 100
μg of GnRH im and a progesterone Controlled Internal Drug Release insert (CIDR) on Day 0, and on Day 7, 25
mg of PGF2
α im and CIDR removal. All cows received 100
μg of GnRH im and were inseminated at a fixed-time on Day 10, 66
h after CIDR removal. Timed-AI pregnancy rates were influenced by season (
P
<
0.05), cows detected in estrus prior to and at AI (
P
<
0.001), and dam age (
P
<
0.01). Pregnancy rates were not affected by semen type (Fresh
=
51.5% vs. Frozen
=
50.4%;
P
=
0.66) and there were no significant interactions of semen type by estrus expression, semen type by sire, or semen type by season (
P
>
0.1). In conclusion, commercial beef cows inseminated with fresh-extended semen (3
×
10
6
sperm/straw) yielded comparable pregnancy rates to conventional frozen-thawed semen in a progesterone supplemented, CO-Synch fixed-time AI synchronization protocol and may provide an alternate to frozen semen for more efficient utilization of superior genetics.
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Details
- Title
- Fixed-time AI pregnancy rate following insemination with frozen-thawed or fresh-extended semen in progesterone supplemented CO-Synch protocol in beef cows
- Creators
- A Bucher - Department of Large Animal Clinical Sciences, Virginia-Maryland Regional College of Veterinary Medicine, USAR Kasimanickam - Department of Large Animal Clinical Sciences, Virginia-Maryland Regional College of Veterinary Medicine, USAJ.B Hall - Department of Animal and Poultry Sciences, College of Agricultural and Life Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USAJ.M DeJarnette - Select Sires Inc., Plain City, OH 43064, USAW.D Whittier - Department of Large Animal Clinical Sciences, Virginia-Maryland Regional College of Veterinary Medicine, USAW Kähn - Clinic of Reproductive Medicine, Vetsuisse Faculty, University of Zurich, SwitzerlandZ Xu - Livestock Improvement Corporation, Newstead, Hamilton, New Zealand
- Publication Details
- Theriogenology, Vol.71(7), pp.1180-1185
- Academic Unit
- Veterinary Clinical Sciences, Department of
- Publisher
- Elsevier Inc
- Identifiers
- 99900547136001842
- Language
- English
- Resource Type
- Journal article