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Comparison of Gonadotropin-Releasing Hormone versus Estrogen-Based Fixed-Time Artificial Insemination Protocols in Grazing Bos taurus Suckled Beef Cows
被引:1
|作者:
Ferre, Luis B.
[1
]
Jaeschke, Julian
[2
]
Gatti, Juliana
[2
]
Baladon, Gerardo
[2
]
Bellocq, Ezequiel
[3
]
Fernandez, Gustavo
[4
]
Rearte, Ramiro
[5
]
Kjelland, Michael E.
[6
]
Colazo, Marcos G.
[7
]
Thomas, Jordan M.
[8
]
机构:
[1] Natl Inst Agr Technol INTA, Chacra Expt Integrada Barrow MDA INTA, RA-B7500 Tres Arroyos, Buenos Aires, Argentina
[2] Dept Tecn Biogenesis Bago SA, RA-B1619 Garin, Buenos Aires, Argentina
[3] Serv Tecn Biogenesis Bago SA, RA-B1619 Garin, Buenos Aires, Argentina
[4] Private Vet Practice, RA-B7501 Indio Rico, Buenos Aires, Argentina
[5] Univ Nacl La Plata, Fac Ciencias Vet, Inst Invest Reprod Anim INIRA, RA-B1900 La Plata, Buenos Aires, Argentina
[6] Mayville State Univ, Mayville, ND 58257 USA
[7] Univ Alberta, Dept Agr Food & Nutr Sci, Edmonton, AB T6G 2P5, Canada
[8] Univ Missouri, Div Anim Sci, Columbia, MO 65211 USA
来源:
关键词:
estrus synchronization;
intravaginal progesterone device;
prostaglandin;
presynchronization;
cattle;
POSTPARTUM BEEF;
INTRAVAGINAL PROGESTERONE;
CONCEPTION RATES;
OVULATORY FOLLICLE;
EMBRYO-TRANSFER;
BODY CONDITION;
ESTRUS;
CATTLE;
GNRH;
AI;
D O I:
10.3390/ani13172803
中图分类号:
S8 [畜牧、 动物医学、狩猎、蚕、蜂];
学科分类号:
0905 ;
摘要:
Fixed-timed artificial insemination (FTAI) protocols for beef cattle in South America are primarily based on estradiol esters and intravaginal progesterone-releasing devices (IVPD). The objective of this study was to determine the optimal gonadotropin-releasing hormone (GnRH)-based protocol as an alternative to the use of estrogen-based protocols in grazing Bos taurus suckling beef cows. All cows received an IVPD on the day of protocol initiation and prostaglandin F-2 alpha (PG) plus equine chorionic gonadotropin (eCG) treatments at the time of IVPD removal. In Experiment 1, cows (n = 235) were randomly assigned to one of four treatments: (i) 7-day estradiol = 2 mg of estradiol benzoate (EB) at IVPD insertion on Day 9 and 1 mg of estradiol cypionate (ECP) at IVPD removal on Day 2; (ii) 7-day GnRH = 10 mu g of GnRH at IVPD insertion on Day 10, IVPD removal on Day 3 and GnRH at FTAI; (iii) 7 & 7 estradiol = PG at IVPD insertion on Day 16, EB on Day 9 and ECP at IVPD removal on Day 2; (iv) 7 & 7 GnRH = PG at IVPD insertion on Day 17, GnRH on Day 10, IVPD removal on Day 3 and GnRH at FTAI. In Experiment 2, cows (n = 462) were randomly assigned to one of four treatments: (i) 6-day estradiol = EB at IVPD insertion on Day 9, IVPD removal on Day 3 and GnRH at FTAI; (ii) 7-day estradiol; (iii) 7-day GnRH; (iv) 7 & 7 GnRH. In Experiment 1, plasma progesterone concentrations and percentage of cows with a corpus luteum (CL) at IVPD removal, and pregnancy per AI (P/AI) were greater for cows subjected to GnRH-based protocols compared with cows subjected to estrogen-based protocols (p < 0.01). In Experiment 2, cows subjected to the 7 & 7 GnRH protocol had the greatest P/AI (p < 0.01). In summary, GnRH-based FTAI protocols resulted in similar or greater P/AI compared to estrogen-based FTAI protocols in grazing postpartum Bos taurus suckled beef cows. The greatest P/AI was attained with the 7 & 7 GnRH protocol.
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页数:15
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