Effect of reproductive methods and GnRH administration on long-term protocol in Santa Ines ewes

This study aimed to determine whether reproductive performance of ewes submitted to laparoscopic timed artificial insemination (TAI) would be similar to ante meridiem (AM)/post meridiem (PM) rule and assisted natural mating (NM), and whether GnRH may enhance the pregnancy rate in TAI. In experiment...

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Bibliographic Details
Published in:Tropical animal health and production 2017-08, Vol.49 (6), p.1303-1308
Main Authors: Biehl, Marcos V, Ferraz Junior, Marcos V C, Ferreira, Evandro M, Polizel, Daniel M, Miszura, Alexandre A, Barroso, José P R, Oliveira, Gabriela B, Bertoloni, Analisa V, Pires, Alexandre V
Format: Article
Language:English
Subjects:
Animals
Artificial insemination
Biomedical and Life Sciences
Brazil
Cattle
Design factors
Estrus
Estrus Synchronization
Experiments
Factorial design
Female
Gonadotropin-releasing hormone
Gonadotropin-Releasing Hormone - pharmacology
Insemination, Artificial - methods
Insemination, Artificial - veterinary
Laparoscopy
Life Sciences
Mating
Ovulation
Pregnancy
Pregnancy Rate
Progesterone
Random Allocation
Regular Articles
Reproduction
Reproduction (biology)
Sheep, Domestic - physiology
Synchronization
Veterinary Medicine/Veterinary Science
Zoology
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Summary:This study aimed to determine whether reproductive performance of ewes submitted to laparoscopic timed artificial insemination (TAI) would be similar to ante meridiem (AM)/post meridiem (PM) rule and assisted natural mating (NM), and whether GnRH may enhance the pregnancy rate in TAI. In experiment I, 191 non-lactating ewes were synchronized, then TAI was performed either 48 h after progesterone (P4) removal (TAI-48 h) or 12 h after estrus detection (AM/PM); moreover, some ewes were submitted to NM (NM) as control treatment. In experiment II, 247 non-lactating ewes were allocated in five treatments, a control (no-GnRH on protocol) and four treatments arranged in a factorial design 2 × 2. The factors were time and dose of GnRH: ewes that received either 10 μg (TAI-10 μg-36 h) or 25 μg of GnRH (TAI-25 μg-36 h) 36 h after P4 removal and ewes that received either 10 μg (TAI-10 μg-48 h) or 25 μg of GnRH (TAI-25 μg-48 h) at time of insemination, 48 h after P4 removal. In experiment I, pregnancy rate in TAI-48 h was lower ( P  = 0.03) than AM/PM and NM. Moreover, the probability of pregnancy in TAI-48 h was higher ( P  = 0.06) in ewes detected in estrus early. In experiment II, the use of GnRH in TAI protocols increased ( P  
ISSN:0049-4747
1573-7438
DOI:10.1007/s11250-017-1329-1