Effect of GnRH and hCG on ovulation and pregnancy in mares

Kiliçarslan, Mehmet; Horoz, Huriye; Şenünver, Adem; Konuk, Suat; Tek, Çağatay; Carioğlu, B

doi:10.1136/vr.139.5.119

Cited by 11 publications

(8 citation statements)

References 4 publications

(3 reference statements)

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“…The total and per cycle pregnancy rates obtained in this retrospective study are similar to those previously reported using frozen/thawed equine semen (Pickett et al 1993;Metcalf 1995;Samper 1995;Barbacini et al 1999). Routine use of hCG did not affect fertility in our artificial insemination programme, confirming previous reports of the use of fresh semen or with natural mating (Loy and Hughes 1966;Voss et al 1975;Michel et al 1986;Kilicarslan et al 1996).…”

Section: Discussionsupporting

confidence: 89%

“…Human chorionic gonadotropin (hCG) was the first drug used to induce ovulation in the mare (Day 1939) and, at the moment, it is probably the most widely used worldwide by equine practitioners. The efficacy of hCG to induce ovulation in cycling oestrous mares with at least one 35 mm ovarian follicle has been previously demonstrated by many authors (Day 1939;Loy and Hughes 1966;Voss et al 1975;Webel et al 1977;Driancourt and Palmer 1982;Michel et al 1986;Wilson et al 1990;Kilicarslan et al 1996;Rossdale and Lambrecht 1998).…”

Section: Introductionmentioning

confidence: 88%

See 1 more Smart Citation

Retrospective study on the efficacy of hCG in an equine artificial insemination programme using frozen semen

Barbacini¹,

Zavaglia²,

Gulden³

et al. 2000

Equine Veterinary Education

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Section: Discussionsupporting

confidence: 89%

Section: Introductionmentioning

confidence: 88%

Retrospective study on the efficacy of hCG in an equine artificial insemination programme using frozen semen

Barbacini¹,

Zavaglia²,

Gulden³

et al. 2000

Equine Veterinary Education

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“…The injection of prolan on the first day of estrous in mares caused ovulation 24 to 48 h after injection. Several experiments have been conducted to test the efficacy of hCG on inducing ovulation (Duchamp et al, 1987Kilicarslan et al, 1996Roser et al, 1979Sullivan et al, 1973Voss et al, 1974Weissman et al, 1996Wilson et al, 1990. The results of these studies was that 1500-3300 i.u.…”

Section: Hcgmentioning

confidence: 49%

The Estrous Cycle and Induction of Ovulation in Mares

Yoon¹

2012

Journal of Animal Science and Technology

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For horse breeders or managers, it is critical to understand the estrous cycle of mares. Breeding of mares cannot be successfully achieved throughout the whole year as mares breed seasonally. Mares are only able to breed when day length is more than 16 h, and this period is known as the breeding season. Their estrous cycle is approximately 21 days with 5-7 days of estrus and 14 to 15 days of a diestrus period. The estrous cycle of the mare is mainly controlled by gonadotropins, which control follicular development and ovulation. Mares exhibit unique ovulatory events which are not observed in other species. A LH surge occurs for several days, with levels of LH reaching their peak after ovulation. The LH level at the time of LH peak is lower than most other species. The unique anatomical structure of the ovaries of mares is known to limit the number of eggs ovulated. Several attempts have been made to develop chemical/hormonal agents which might be used to manipulate the timed ovulation of mares. Agents that have been tested include hCG, native GnRH, Deslorelin (Ovuplant, GnRH-agonist), Buserelin (GnRH analogue), equine pituitary extracts and equine chorionic gonadotropin (eCG or PMSG). However, the function, purity or stability of these agents is not reliable. Recombinant equine LH, an alternative agent for the timed ovulation, has been developed and tested for its biological activities, through the use of both in vitro and in vivo experiments. The reLH was suggested to be a reliable agent in inducing ovulation within 48 h after being administered through injection, when the size of dominant follicle is 35 mm in diameter.

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“…In mares, analogues of hCG and GnRH are widely used for stimulation [14][15][16] . For controlling the time of ovulation, the use of hCG more than once has led to lower activity of ovarium due to corresponding antibody formation.…”

Section: Introductionmentioning

confidence: 99%

Short-acting Deslorelin Implant (Ovuplant®) could not Sufficiently Induce Fertile Cycles of Coloured Mohair Goats in Suckling (Anoestrous) Season

Uslu¹,

Şendağ²,

Taşal³

et al. 2012

Kafkas Univ Vet Fak Derg

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It is known that the pituitary FSH and LH stores are dramatically depleted during the anoestrous in seasonal breeders. Hence, the aim of this study was to evaluate the effect of deslorelin implant (a GnRH analogue) to induce oestrus in suckling goats. Suckling goats (n=21) of coloured Mohair breed were randomly assigned into two trial groups: Goats in Group I (n=11, Ovuplant®) received subcutaneously the implant (2.1 mg deslorelin), while animals in Group II (n=10, control) received no treatment. Along with the implant administration, serum progesterone (P4) concentrations were determined (every other day up to 12 d) by RIA method. Within 4 days of implant administration, there were significantly higher (P<0.001) rates (100%) of pro-oestrus signs (attractiveness without mating) in Group I, than those in controls (zero %). The signs sustained for 9 days without oestrus (mating) in the vast majority (10/11) of implanttreated animals. But, an exceptional goat was in receptive oestrus commenced from the third day following the onset of pro-oestrus. Even so, there was no pregnancy post-mating. The P4 concentrations between the groups remained below 1 ng/ml, regardless of implant treatment. Findings suggest that; i) for the P4 concentrations, there was no marked difference between implant-treated and control groups, as remaining below 1 ng/ml all, and ii) short-acting deslorelin implant could not induce fertile oestrus cycles in coloured Mohair goats during the suckling (anoestrous) season.

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Effect of GnRH and hCG on ovulation and pregnancy in mares

Cited by 11 publications

References 4 publications

Retrospective study on the efficacy of hCG in an equine artificial insemination programme using frozen semen

Retrospective study on the efficacy of hCG in an equine artificial insemination programme using frozen semen

The Estrous Cycle and Induction of Ovulation in Mares

Short-acting Deslorelin Implant (Ovuplant®) could not Sufficiently Induce Fertile Cycles of Coloured Mohair Goats in Suckling (Anoestrous) Season

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