Follicle stimulating hormone, luteinising hormone and progesterone concentrations in the blood of Thoroughbred mares exhibiting single and twin ovulations

Urwin, Valerie E.; Allen, W. R.

doi:10.1111/j.2042-3306.1983.tb01813.x

Cited by 14 publications

(8 citation statements)

References 14 publications

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“…The lower LH likely reflected, at least in part, the greater concentrations of progesterone on the corresponding days. Previous reports have documented higher concentrations of progesterone during dioestrus in mares that had multiple ovulations (Henry et al 1982;Urwin and Allen 1983;Squires et al 1987) but did not indicate that the higher progesterone in doubleovulating mares begins immediately after the ovulations. Support for the interpretation that the lower postovulation LH in the group with multiple ovulations results from higher progesterone is the demonstration of a negative effect of exogenous progesterone on LH (Gastal et al 1999a(Gastal et al , 2000.…”

Section: Discussionmentioning

confidence: 89%

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Development of One vs Multiple Ovulatory Follicles and Associated Systemic Hormone Concentrations in Mares

Ginther

Jacob

Gastal³

et al. 2009

Reprod Domestic Animals

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Ablation of follicles > or = 6 mm in diameter and treatment with PGF2alpha 10 days after ovulation were used to induce the development of ovulatory waves. Comparisons were made between induced waves with one (33 waves, 72%) and multiple (13 waves, 28%) ovulatory follicles. Diameter deviation was defined as the separation of follicles into dominant and subordinate categories. Multiple ovulatory follicles were preceded by more (p < 0.001) follicles > or = 20 mm at the beginning of deviation, higher LH preceding deviation (approached significance, p < 0.08), lower (p < 0.05) concentrations of FSH on the day of deviation and thereafter, and higher (p < 0.0003) oestradiol by 2 days after deviation. During the peri-ovulatory period, systemic hormone concentrations for waves with multiple ovulations involved higher oestradiol before ovulation (approached significance, p < 0.07), lower FSH (p < 0.04) before and after ovulation, and both higher progesterone (p < 0.05) and lower LH (p < 0.05) beginning the day after ovulation. Results indicated that by the beginning of deviation there were more follicles > or = 20 mm and subsequently greater oestradiol production in waves that led to the development of multiple ovulatory follicles, and during the peri-ovulatory period differences between one and multiple ovulations were consistent with the negative effects of the ovarian hormones on the gonadotropins.

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Section: Discussionmentioning

confidence: 89%

“…Previous reports have documented higher concentrations of progesterone during dioestrus in mares that had multiple ovulations (Henry et al. 1982; Urwin and Allen 1983; Squires et al. 1987) but did not indicate that the higher progesterone in double‐ovulating mares begins immediately after the ovulations.…”

Section: Discussionmentioning

confidence: 90%

Development of One vs Multiple Ovulatory Follicles and Associated Systemic Hormone Concentrations in Mares

Ginther

Jacob

Gastal³

et al. 2009

Reprod Domestic Animals

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“…Furthermore, heritability is also unlikely as a full sister and a half sister to the mare in question both showed normal ovulatory patterns. Circulating FSH and LH concentrations in double ovulating mares have not been found to differ from those in mares with single ovulations (Urwin and Allen 1983;Squires et al 1987). However, in a case like the present mare, which showed extreme deviations from the normal, physiological ovulation rate, hormonal aberrations, either at the production or receptor levels, is very likely to underlie the phenomenon.…”

Section: Discussionmentioning

confidence: 98%

“…In the mare, circulating progesterone concentrations have been reported to be higher after double ovulations than after a single ovulation (Palmer and Jousset 1975;Henry et al 1982;Urwin and Allen 1983;Squires et al 1987). In the present case, plasma progesterone concentration reached only 14 ng/ml during the first week of pregnancy and was therefore no higher than the levels reported in previous studies (Squires eta/.…”

Section: Discussionmentioning

confidence: 99%

Spontaneous multiple ovulation and development of multiple embryonic vesicles in a mare

Brück¹,

Lehn-Jensen²,

Yde

1997

Equine Veterinary Journal

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Summary A Warmblood mare was observed to ovulate spontaneously 12 follicles within 2 days, none of which exceeded 22 mm in diameter. On Days 13 and 17 after ovulation, 6 embryonic vesicles were identified in the uterus by ultrasonography but by Day 26, 5 of the vesicles had disappeared. Development of the surviving conceptus was monitored until Day 42. Plasma progesterone concentrations rose to 14 ng/ml on Day 7, decreased over the next 8 days and then plateaued to around 4–6 ng/ml until Day 70. The occurrence of multiple spontaneous ovulations was diagnosed repeatedly in this mare. However, the developmental competence of the ovulated oocytes seemed to be impaired.

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“…The higher plasma progesterone concentration in mares with twins in comparison to mares carrying singletons is consistent with findings from other studies. Urwin and Allen demonstrated that higher levels of progesterone were observed in mares with double ovulations. Ginther showed that progesterone was significantly higher in mares with multiple ovulations compared with single ovulations beginning Day 1 post ovulation to Day 4 post ovulation.…”

Section: Discussionmentioning

confidence: 98%

Factors affecting live foal rates ofThoroughbred mares that undergo manual twin elimination

Schnobrich

Riddle

Stromberg

et al. 2013

Equine Veterinary Journal

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SummaryReasons for performing study: Mares diagnosed with twin vesicles at 13-17 days after ovulation commonly have one of 2 vesicles manually reduced. It is not known whether vesicle location (adjacent vs. nonadjacent), mare age, mare reproductive status, parity, month of breeding or mare plasma progesterone concentration affects live foal rates. Objectives: To determine factors associated with a positive outcome (live foal) in mares undergoing manual twin reduction between 13 and 17 days post ovulation when performed by a single operator. Study design: Retrospective case-control study. Methods: Breeding records and the Jockey Club records of registered Thoroughbreds were used to evaluate factors affecting the outcome of pregnancies in mares undergoing twin elimination and mares with singleton pregnancies. Thoroughbred mares with twin pregnancies (n = 129) were matched by age, parity, farm location and month bred with mares diagnosed with a singleton pregnancy (n = 127). The effects of location of embryonic vesicles, mare age, reproductive status, parity, month of breeding, vesicle size and plasma progesterone concentration at pregnancy diagnosis on live foal rate were examined. Results: Position of embryonic vesicles at time of manual elimination, parity and month bred had no effect on live foal rate. Live foal rates in mares >9 years of age were lower (71.8%) than in all mares Յ9 years (87.1%; P<0.05). Mares >9 years of age that had a twin reduced lost more pregnancies (34.8%) than age-matched control mares (20.0%; P<0.005). Mean plasma progesterone concentration of twin-reduced mares was greater than in control mares when compared on the same day post ovulation. Plasma progesterone concentrations did not differ between mares that lost their pregnancy and those that delivered a live foal. Conclusions: Mare age of >9 years is associated with decreased pregnancy rate after twin reduction. Potential relevance: Furthering the understanding of factors that affect live foal outcome following manual twin elimination in mares.

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Follicle stimulating hormone, luteinising hormone and progesterone concentrations in the blood of Thoroughbred mares exhibiting single and twin ovulations

Cited by 14 publications

References 14 publications

Development of One vs Multiple Ovulatory Follicles and Associated Systemic Hormone Concentrations in Mares

Development of One vs Multiple Ovulatory Follicles and Associated Systemic Hormone Concentrations in Mares

Spontaneous multiple ovulation and development of multiple embryonic vesicles in a mare

Factors affecting live foal rates ofThoroughbred mares that undergo manual twin elimination

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