The use of progesterone intravaginal devices is superior to use of the ram effect at hastening the reproductive performance in transitional Targhee ewes

Catalina Cabrera, Gabriele Maier, Matthew Cuneo, Bret McNabb

Research output: Contribution to journalArticle

Abstract

To compare the use of controlled intravaginal drug release (CIDR, EAZI-BREED™ CIDR ® Sheep, USA, Zoetis) with the ram effect, a combination of CIDR and ram effect and the addition of P.G.600 ® to each of these scenarios on their contribution to inducing the onset of cyclicity and their ability to improve reproductive efficiency in a commercial sheep flock, a randomized clinical trial was conducted. Multiparous ewes (n = 283) were randomly assigned to one of six treatments prior to intact male introduction on day 0: only CIDR devices (day −5 to day 0) (n = 40), exposure to two vasectomized rams (d-14 to d0) (n = 55), CIDR (d-5 to d0) and an intramuscular injection of P.G.600 ® (d0) (n = 40), exposure to two vasectomized rams (d-14 to d0) and treated with CIDR devices (day −5 to day 0) (n = 40). exposure to vasectomized rams (d-14 to d0), CIDR (d-5 to d0) and an intramuscular injection ofP.G.600 ® , (d0) (n = 38), and a control group, without exposure to vasectomized rams, CIDRs or P.G.600 ® (n = 70). Ewes were exposed to intact males on day 0. Days to lambing from the earliest expected lambing date at 150 days post introduction of rams was compared between groups with survival analysis. The mean survival time was significantly shorter in all groups that used CIDR compared to the control group (P < 0.003, adjusted for multiple comparisons). The addition of a teaser ram or a P.G.600 ® injection did not change survival time. In a Cox proportional hazard model for time to lambing, the use of CIDR had a hazard ratio of 1.62 (95% CI: 1.07, 2.45, P = 0.23), while other variables (teaser ram, P.G.600 ® ) were not significant. In a Poisson regression for the number of lambs born to each ewe, P.G.600 ® was not a significant variable, even when adjusted for age of ewe (P = 0.74). The combination of the ram effect and CIDRs did not have an additive effect. The use of CIDR shortened time to cyclicity in study ewes and may provide an attractive option to advance lambing season. Further studies on the economics of this method are warranted.

Original languageEnglish (US)
Pages (from-to)17-22
Number of pages6
JournalTheriogenology
Volume128
DOIs
StatePublished - Apr 1 2019

Fingerprint

ram effect
Targhee
rams
Progesterone
ewes
progesterone
reproductive performance
Intramuscular Injections
Periodicity
Equipment and Supplies
lambing
Sheep
Control Groups
controlled internal drug release devices
Survival Analysis
Proportional Hazards Models
intramuscular injection
periodicity
Survival Rate
Randomized Controlled Trials

Keywords

  • CIDR
  • Ram effect
  • Seasonality
  • Sheep
  • Transition

ASJC Scopus subject areas

  • Small Animals
  • Food Animals
  • Animal Science and Zoology
  • Equine

Cite this

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title = "The use of progesterone intravaginal devices is superior to use of the ram effect at hastening the reproductive performance in transitional Targhee ewes",
abstract = "To compare the use of controlled intravaginal drug release (CIDR, EAZI-BREED™ CIDR {\circledR} Sheep, USA, Zoetis) with the ram effect, a combination of CIDR and ram effect and the addition of P.G.600 {\circledR} to each of these scenarios on their contribution to inducing the onset of cyclicity and their ability to improve reproductive efficiency in a commercial sheep flock, a randomized clinical trial was conducted. Multiparous ewes (n = 283) were randomly assigned to one of six treatments prior to intact male introduction on day 0: only CIDR devices (day −5 to day 0) (n = 40), exposure to two vasectomized rams (d-14 to d0) (n = 55), CIDR (d-5 to d0) and an intramuscular injection of P.G.600 {\circledR} (d0) (n = 40), exposure to two vasectomized rams (d-14 to d0) and treated with CIDR devices (day −5 to day 0) (n = 40). exposure to vasectomized rams (d-14 to d0), CIDR (d-5 to d0) and an intramuscular injection ofP.G.600 {\circledR} , (d0) (n = 38), and a control group, without exposure to vasectomized rams, CIDRs or P.G.600 {\circledR} (n = 70). Ewes were exposed to intact males on day 0. Days to lambing from the earliest expected lambing date at 150 days post introduction of rams was compared between groups with survival analysis. The mean survival time was significantly shorter in all groups that used CIDR compared to the control group (P < 0.003, adjusted for multiple comparisons). The addition of a teaser ram or a P.G.600 {\circledR} injection did not change survival time. In a Cox proportional hazard model for time to lambing, the use of CIDR had a hazard ratio of 1.62 (95{\%} CI: 1.07, 2.45, P = 0.23), while other variables (teaser ram, P.G.600 {\circledR} ) were not significant. In a Poisson regression for the number of lambs born to each ewe, P.G.600 {\circledR} was not a significant variable, even when adjusted for age of ewe (P = 0.74). The combination of the ram effect and CIDRs did not have an additive effect. The use of CIDR shortened time to cyclicity in study ewes and may provide an attractive option to advance lambing season. Further studies on the economics of this method are warranted.",
keywords = "CIDR, Ram effect, Seasonality, Sheep, Transition",
author = "Catalina Cabrera and Gabriele Maier and Matthew Cuneo and Bret McNabb",
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T1 - The use of progesterone intravaginal devices is superior to use of the ram effect at hastening the reproductive performance in transitional Targhee ewes

AU - Cabrera, Catalina

AU - Maier, Gabriele

AU - Cuneo, Matthew

AU - McNabb, Bret

PY - 2019/4/1

Y1 - 2019/4/1

N2 - To compare the use of controlled intravaginal drug release (CIDR, EAZI-BREED™ CIDR ® Sheep, USA, Zoetis) with the ram effect, a combination of CIDR and ram effect and the addition of P.G.600 ® to each of these scenarios on their contribution to inducing the onset of cyclicity and their ability to improve reproductive efficiency in a commercial sheep flock, a randomized clinical trial was conducted. Multiparous ewes (n = 283) were randomly assigned to one of six treatments prior to intact male introduction on day 0: only CIDR devices (day −5 to day 0) (n = 40), exposure to two vasectomized rams (d-14 to d0) (n = 55), CIDR (d-5 to d0) and an intramuscular injection of P.G.600 ® (d0) (n = 40), exposure to two vasectomized rams (d-14 to d0) and treated with CIDR devices (day −5 to day 0) (n = 40). exposure to vasectomized rams (d-14 to d0), CIDR (d-5 to d0) and an intramuscular injection ofP.G.600 ® , (d0) (n = 38), and a control group, without exposure to vasectomized rams, CIDRs or P.G.600 ® (n = 70). Ewes were exposed to intact males on day 0. Days to lambing from the earliest expected lambing date at 150 days post introduction of rams was compared between groups with survival analysis. The mean survival time was significantly shorter in all groups that used CIDR compared to the control group (P < 0.003, adjusted for multiple comparisons). The addition of a teaser ram or a P.G.600 ® injection did not change survival time. In a Cox proportional hazard model for time to lambing, the use of CIDR had a hazard ratio of 1.62 (95% CI: 1.07, 2.45, P = 0.23), while other variables (teaser ram, P.G.600 ® ) were not significant. In a Poisson regression for the number of lambs born to each ewe, P.G.600 ® was not a significant variable, even when adjusted for age of ewe (P = 0.74). The combination of the ram effect and CIDRs did not have an additive effect. The use of CIDR shortened time to cyclicity in study ewes and may provide an attractive option to advance lambing season. Further studies on the economics of this method are warranted.

AB - To compare the use of controlled intravaginal drug release (CIDR, EAZI-BREED™ CIDR ® Sheep, USA, Zoetis) with the ram effect, a combination of CIDR and ram effect and the addition of P.G.600 ® to each of these scenarios on their contribution to inducing the onset of cyclicity and their ability to improve reproductive efficiency in a commercial sheep flock, a randomized clinical trial was conducted. Multiparous ewes (n = 283) were randomly assigned to one of six treatments prior to intact male introduction on day 0: only CIDR devices (day −5 to day 0) (n = 40), exposure to two vasectomized rams (d-14 to d0) (n = 55), CIDR (d-5 to d0) and an intramuscular injection of P.G.600 ® (d0) (n = 40), exposure to two vasectomized rams (d-14 to d0) and treated with CIDR devices (day −5 to day 0) (n = 40). exposure to vasectomized rams (d-14 to d0), CIDR (d-5 to d0) and an intramuscular injection ofP.G.600 ® , (d0) (n = 38), and a control group, without exposure to vasectomized rams, CIDRs or P.G.600 ® (n = 70). Ewes were exposed to intact males on day 0. Days to lambing from the earliest expected lambing date at 150 days post introduction of rams was compared between groups with survival analysis. The mean survival time was significantly shorter in all groups that used CIDR compared to the control group (P < 0.003, adjusted for multiple comparisons). The addition of a teaser ram or a P.G.600 ® injection did not change survival time. In a Cox proportional hazard model for time to lambing, the use of CIDR had a hazard ratio of 1.62 (95% CI: 1.07, 2.45, P = 0.23), while other variables (teaser ram, P.G.600 ® ) were not significant. In a Poisson regression for the number of lambs born to each ewe, P.G.600 ® was not a significant variable, even when adjusted for age of ewe (P = 0.74). The combination of the ram effect and CIDRs did not have an additive effect. The use of CIDR shortened time to cyclicity in study ewes and may provide an attractive option to advance lambing season. Further studies on the economics of this method are warranted.

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