Efficacy of the re-utilization of an ear implant impregnated with progestogen in estrus synchronization response and pregnancy in sheep

• Published in: Tropical animal health and production Vol. 51; no. 6; pp. 1763 - 1765
• Main Authors: Bragança, José Francisco Manta, Oliveira Drissen, Raphael, Abreu Machado, Sérgio, Bennemann, Paulo Eduardo, da Rocha, Ricardo Xavier
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-07-2019; Springer Nature B.V
• Subjects: Animals; Artificial insemination; Biomedical and Life Sciences; Cattle; Chorionic Gonadotropin - administration & dosage; Chorionic Gonadotropin - pharmacology; Drug Implants - administration & dosage; Drug Implants - pharmacology; Ear; Estrus; Estrus - drug effects; Estrus Detection; Estrus Synchronization - methods; Female; Implants; Life Sciences; Pregnancy; Pregnenediones - administration & dosage; Pregnenediones - pharmacology; Progestins - administration & dosage; Progestins - pharmacology; Prostaglandins - administration & dosage; Prostaglandins - pharmacology; Rams; Random Allocation; Sheep; Short Communications; Synchronism; Synchronization; Transplants & implants; Utilization; Veterinary Medicine/Veterinary Science; Weight; Zoology; eCG; Sheep; Estrus; Prostaglandin; Norgestomet
• ISSN: 0049-4747; 1573-7438
• DOI: 10.1007/s11250-019-01853-x

The goal of this study was to assess the efficacy of the re-utilization of an ear implant impregnated with norgestomet on estrus synchronization response and pregnancy rates in sheep. Fifty-five Texel ewes were classified according to body condition (3.5) and live weight (65 kg), and randomly assigned to two experimental groups: NORN-new (
n
 = 30) and NORU-used (
n
 = 25). The dose of norgestomet used in the treatments was half of that recommended for bovine (1.5 mg). The synchronization protocol consisted of an ear implant inserted on day 0 (beginning of the experiment) and kept for 6 days. The removal of the implant on day 6 was followed by an injection of a prostaglandin analogue (0.263 mg) and eCG (250 IU). Rams with paint applied to their chest were used to facilitate estrus detection for 5 days following implant withdrawal. Estrus behavior was observed in 93.3% (28/30) and 90% for NORN and NORU, respectively. Pregnancy rates for NORN were 73.3% and for NORU were 68%. Estrus behavior and pregnancy rates between treatment groups did not differ statistically. Therefore, the re-utilization of ear implants impregnated with norgestomet, in addition to eCG and a prostaglandin analogue in short-term estrus synchronization protocols, allow acceptable estrus response and pregnancy rates in sheep.