Using Estrous Behavior to Time Initiation of Oxytocin Administration to Prolong Luteal Function in Mares.

Autor: Manning HS; Department of Veterinary Clinical Sciences, The Ohio State University College of Veterinary Medicine, Columbus, OH., Runcan EE; Department of Veterinary Clinical Sciences, The Ohio State University College of Veterinary Medicine, Columbus, OH. Electronic address: Runcan.1@osu.edu., Dias de Moraes CR; Department of Veterinary Clinical Sciences, The Ohio State University College of Veterinary Medicine, Columbus, OH., Coutinho da Silva MA; Department of Veterinary Clinical Sciences, The Ohio State University College of Veterinary Medicine, Columbus, OH.
Jazyk: angličtina
Zdroj: Journal of equine veterinary science [J Equine Vet Sci] 2019 Apr; Vol. 75, pp. 78-81. Date of Electronic Publication: 2019 Feb 06.
DOI: 10.1016/j.jevs.2019.01.012
Abstrakt: The objective of this study was to use estrous behavior alone to determine the appropriate time for beginning an oxytocin treatment protocol for estrus suppression. We hypothesized that administration of oxytocin beginning 8 days after the onset of estrus will prolong the luteal phase in mares. Twenty-three light breed mares (aged 4-20 years) were exposed to a stallion and observed for signs of sexual receptivity. Mares not displaying signs received 250 μg of cloprostenol intramuscularly (IM) and were teased again 3-4 days later. On the day that estrous behavior was observed (Day 0), mares were randomly divided into two groups: oxytocin (n = 11): oxytocin (60 IU, IM) was administered once daily from Day 8-17; control (n = 12): did not receive treatment. Blood was collected from all mares every 4 days throughout Day 17, and every 7 days thereafter until Day 45. Serum progesterone concentrations >1.0 ng/mL were indicative of a functioning corpus luteum. Interestrus interval was defined as the period between Day 0 and the day when progesterone next reached <1.0 ng/mL. The average interestrus interval was higher for treated mares compared with control mares (32.4 ± 4.2 vs. 21.8 ± 1.5 days, respectively, P = .01). In the oxytocin group, the interestrus interval was longer than 31 days in 6 of 11 (54.5%) mares and up to 45 days in 5 of 11 mares (45.5%). We conclude that luteal maintenance beyond 30 days was attained by once-daily oxytocin administration beginning 8 days following behavioral estrus in a majority of mares.
(Copyright © 2019 Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
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