Plasma progesterone levels in ewes treated with progesterone-controlled internal drug-release dispensers, implants and sponges

Hamra, A.H.; Massri, Y.G.; Marcek, John; Wheaton, J. E.

doi:10.1016/0378-4320(86)90120-x

Cited by 37 publications

(23 citation statements)

References 11 publications

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“…Serum P4 concentrations have been found to increase rapidly after CIDR insertion, levels peak after 3 d and serum concentrations of P4 begin to decline gradually thereafter (Ainsworth and Downey, 1986;Wheaton et al, 1993). Hamra et al (1986) reported similar findings after treatment with CIDRs for 13 d in which P4 concentrations increased to near maximum levels within 24 h, reached peak levels 4 d after insertion and then declined gradually. Keeping in mind the CL produces P4 throughout its lifespan (10 to 14 d); no treatment protocols are recommended over 14 d.…”

Section: Controlled Internal Drug Releasing Insertssupporting

confidence: 66%

“…The assay kit was validated for ovine serum using an assay volume of 100 µl (Hamra et al, 1986;Schneider and Hallford, 1996). Assay tubes for the standard curve contained 0.1, 0.25, 0.5, 1.0, 2.0, 5.0, 10.0, and 20 ng/ul.…”

Section: Blood Collection and Analysismentioning

confidence: 99%

“…Serum samples were assayed for circulating P4 using a solid-phase, no-extraction RIA (Coat-a-Count Progesterone, Diagnostic Products Corporation, Los Angeles, CA; Stevenson et al, 2011). The assay kit was validated for ovine serum using an assay volume of 100 µl (Hamra et al, 1986;Schneider and Hallford, 1996). Assay tubes for the standard curve contained 0.1, 0.25, 0.5, 1.0, 2.0, 5.0, 10.0, and 20 ng/ul.…”

Section: Blood Collection and Analysismentioning

confidence: 99%

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Efficacy of various five-day estrous synchronization protocols in sheep

Jackson

Neville

Mercadante

et al. 2014

Small Ruminant Research

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The objective of this study was to determine the effects of various estrous synchronization protocols utilizing the five-day controlled internal drug releasing (CIDR) In Experiment 1, overall days to estrus were greater (P ≤ 0.01) in U and P compared with C. In Experiment 2, overall days to estrus were greater (P ≤ 0.02) in U and P compared with G. In summary, the 5 d CIDR reduces the number of days required to bring ewes into estrus when compared to untreated ewes. iv ACKNOWLEDGEMENTS

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Section: Controlled Internal Drug Releasing Insertssupporting

confidence: 66%

Section: Blood Collection and Analysismentioning

confidence: 99%

Section: Blood Collection and Analysismentioning

confidence: 99%

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Efficacy of various five-day estrous synchronization protocols in sheep

Jackson

Neville

Mercadante

et al. 2014

Small Ruminant Research

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“…Treatment with eCG is known to enhance the recruitment of small follicles [28], to improve the synchrony of estrus [29,30], to increase ovulation rates during the breeding season [28,29,31], and to enable the induction of estrous activity during the anovulatory season [32]. In this study, lambing rates (1.8-1.9) and litter sizes (1.9-2.0) were higher than those reported in previous investigations (0.7-1.1 and 1.1-1.7, respectively) [20,27,33]. The main reason for the high prolificacy achieved even without eCG treatment was probably that this experiment was performed only with multiparous and well-managed and conditioned ewes.…”

Section: Discussionmentioning

confidence: 46%

Reproductive performance of Lacaune dairy sheep exposed to artificial long days followed by natural photoperiod without and with additional progestagen treatment during the nonbreeding season

et al. 2015

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This study compared the reproductive performance of Lacaune dairy ewes exposed to a light program and subsequent male introduction without (n = 36) or with (n = 36) an additional 6-day progestagen treatment during the nonbreeding season. All ewes were exposed to extended day length (16 hours light and 8 hours darkness) for 77 days during winter (December 15 until March 2) followed by increasing natural photoperiod. At the end of the photoperiodic treatment, three blood samples were collected 6 days apart for progesterone (P4) analysis to determine cyclic activity. One half of the ewes were additionally subjected to a 6-day progestagen treatment in combination with PGF2 and eCG at insert withdrawal. Rams fitted with marking harnesses were introduced to females for 45 days and marked ewes recorded. Ewes exposed to the light program only were joined 40 days after the end of photoperiodic treatment, and ewes with additional progestagen treatment were joined 1 day after insert removal (40-44 days after the end of photostimulation). Lambing data were recorded and fertility (percentage of ewes lambing, lambing rate, and litter size) assessed to the first service period and overall. Mean serum P4 concentrations were similarly (P > 0.05) low in both groups (0.4-0.7 ng/mL vs. 0.4-0.6 ng/mL). On the basis of elevated P4 levels (>1 ng/mL), evidence of luteal activity was found in 27.8% of the ewes at the end of the light program. Estrus response was equally high (97.2%) and estrus distribution highly synchronized in progestagen-treated ewes (91.7% within 4 days). In ewes exposed to the light program only, estrous activity was recorded within 4 days (six ewes), from Day 8 to Day 17 (17 ewes) and from Day 19 to Day 25 (12 ewes) after joining. The percentage of ewes that lambed to the first service period was higher (P < 0.05) in ewes exposed to the light program only than that in the group additionally treated with progestagen/PGF2 /eCG (94.4% vs. 69.4%). Overall, the percentage of lambing ewes was similar in both groups (97.2% and 94.4%), and lambing rates (1.4-1.9) and litter sizes (1.9-2.1) were high and not influenced (P > 0.05) by the treatment. In conclusion, this study reports that exposition of Lacaune ewes to artificial long days followed by natural day length and male introduction is highly effective to induce fertile estrous activity during the nonbreeding season and offers a reliable and practical alternative to hormonal manipulation for out-of-season breeding in sheep. a b s t r a c tThis study compared the reproductive performance of Lacaune dairy ewes exposed to a light program and subsequent male introduction without (n ¼ 36) or with (n ¼ 36) an additional 6-day progestagen treatment during the nonbreeding season. All ewes were exposed to extended day length (16 hours light and 8 hours darkness) for 77 days during winter (December 15 until March 2) followed by increasing natural photoperiod. At the end of the photoperiodic treatment, three blood samples were collected 6 days apart for progesterone (...

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“…Initially, a supraluteal effect is expected, which means that an increase in follicular renewal may occur. In the end, however, a subluteal effect may happen and decrease the speed of follicular renewal (Hamra et al, 1986). The use of progestagen during a short time would be an alternative solution because it could improve estrus synchronization in ewes (Husein et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Ovarian response of Suffolk ewes to estrous synchronization using short-term protocol

et al. 2012

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-The efficacy of estrus synchronization using short-term protocol was evaluated by ultrasound exams in Suffolk ewes during the pre-breeding season. The control Group (n = 12) was synchronized by treatment for 12 days with vaginal sponges impregnated with medroxyprogesterone acetate, and 400 IU eCG at sponge withdrawal. Experimental groups I, II and III kept the sponge in place for 4 days, and 100 μg of PGF 2α was administered at sponge withdrawal. Additionally, Group I (n = 12) had 0.1 mg of estradiol benzoate (EB) administered during sponge placement and 50 μg of GnRH 48 hours after sponge removal. Group II (n = 6) had 35 mg of progesterone (P4) injected, and 0.1 mg of EB administered during sponge placement, 400 IU eCG at withdrawal and 48 hours after, 50 μg GnRH were administrated.Group III (n = 12) had 35 mg of P4 and 0.2 mg of EB administered at sponge placement, 400 IU eCG at withdrawal, and 50 μg of GnRH was administrated after 56 hours. Ovaries were monitored through ultrasound scanning. Concerning the first wave, no difference was detected between the control group and the experimental groups. However, the characteristics of ovulatory wave were significantly different between the groups. The duration of the follicular wave was shorter for Group III than for Group II. The follicle in Group I reached its maximum diameter before the Group II. The diameter of the follicle at the sponge withdrawal in the control group was larger than in Group I. After sponge withdrawal, the follicular growth rate was smaller in the control group than in Group III. The maximum diameter of the follicle in Group II was larger than in the other groups. The short-term protocol in which estrogen was used did not synchronize the emergence of the wave of follicular development.

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Plasma progesterone levels in ewes treated with progesterone-controlled internal drug-release dispensers, implants and sponges

Cited by 37 publications

References 11 publications

Efficacy of various five-day estrous synchronization protocols in sheep

Efficacy of various five-day estrous synchronization protocols in sheep

Reproductive performance of Lacaune dairy sheep exposed to artificial long days followed by natural photoperiod without and with additional progestagen treatment during the nonbreeding season

Ovarian response of Suffolk ewes to estrous synchronization using short-term protocol

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