Human Chorionic Gonadotropin (hCG) is a hormone used in equine reproductive management, particularly in the context of breeding. It is administered to mares to induce ovulation, facilitating more precise timing for breeding procedures. hCG mimics the luteinizing hormone surge that triggers ovulation, thereby enhancing reproductive efficiency in mares. Additionally, it is sometimes used in stallions to assess testicular function by stimulating testosterone production. This page compiles peer-reviewed research studies and scholarly articles that explore the applications, physiological effects, and implications of hCG use in equine reproductive health.
Macan RC, Camargo CE, Zielinski BL, Cardoso NGH, de Lara NSS, Bergstein-Galan TG, Weiss RR, Kozicki LE.Timed artificial insemination (TAI) has boosted the use of conventional artificial insemination (CAI) by employing hormonal protocols to synchronize oestrus and ovulation. This study aimed to evaluate the efficiency of a hormonal protocol for TAI in mares, based on a combination of progesterone releasing intravaginal device (PRID), prostaglandin (PGF2α ) and human chorionic gonadotropin (hCG); and compare financial costs between CAI and TAI. Twenty-one mares were divided into two groups: CAI group (CAIG; n = 6 mares; 17 oestrous cycles) and TAI group (TAIG; n = 15 mares; 15 oestrous cycle...
Esteller-Vico A, Ball BA, Bridges JW, Hughes SE, Squires EL, Troedsson MHT.Reproductive steroids testosterone (T) and estrone sulfate (E1S) are used as diagnostic markers for cryptorchidism in horses. The human chorionic gonadotropin (hCG) stimulation test is used as a diagnostic aid because administration of this hormone results in greater incremental differences in circulating steroid concentrations. Thoughts regarding optimal sampling times following hCG administration, however, are inconsistent. Additionally, determination of half-life of these steroids is important in postsurgical samples to confirm complete removal of testicular tissue. Objectives of this study...
Oliveira SN, Segabinazzi LGTM, Canuto L, Lisboa FP, Medrado FE, Dell'Aqua JA, Aguiar AJA, Papa FO.The goal of this study was to compare the efficiency of histrelin acetate (GnRH analog) and human chorionic gonadotropin (hCG) to hasten ovulation in Brazilian Northeastern jennies (Equus africanus asinus). Thirty cycles of ten jennies were randomly assigned in one of the three groups: G0 (control group), saline; G1, 250 μg of histrelin acetate; G2, 2500 IU of hCG. Jennies were evaluated by transrectal palpation and ultrasonography, and had the administration of an ovulation-inducing agent when a follicle measuring between 29 and 32 mm of diameter was diagnosed. Jennies were monitored every...
Toishi Y, Tsunoda N, Nagata SI, Kirisawa R, Nagaoka K, Watanabe G, Yanagawa Y, Katagiri S, Taya K.Testosterone (T) concentration is a useful indicator of reproductive function in male animals. However, T concentration is not usually measured in veterinary clinics, partly due to the unavailability of reliable and rapid assays for animal samples. In this study, a rapid chemiluminescent enzyme immunoassay system (CLEIA system) that was developed for the measurement of T concentration in humans use was validated for stallion blood samples. First, serum T concentrations were measured using the CLEIA system and compared with those measured by a fluoroimmunoassay that has been validated for use i...
Bucca S, Carli A.Human chorionic gonadotropin (hCG) and dexamethasone have a role in the reproductive management protocols of mares susceptible to persistent mating-induced endometritis (PMIE). However, it is possible that there is interference between these 2 drugs. Objective: The objective of this retrospective study was to determine the efficacy of hCG to induce ovulation in mares treated with dexamethasone at breeding time. Methods: Medical records from 152 mares and 223 cycles were analysed. In 113 cycles, mares susceptible to PMIE were treated with 1500 iu hCG and a single dose of 50 mg dexamethasone, 11...
Hedberg Y, Dalin AM, Santesson M, Kindahl H.Strong oestrous symptoms in the mare can cause problems with racing, training and handling. Since long-acting progesterone treatment is not permitted in mares at competition (e.g. according to FEI rules), there is a need for methods to suppress unwanted cyclicity. Spontaneous dioestrous ovulations in the late luteal phase may cause a prolongation of the luteal phase in mares. Methods: In this preliminary study, in an attempt to induce ovulation during the luteal phase, human chorionic gonadotropin (hCG) (3000 IU) was injected intramuscularly in four mares (experimental group) in the luteal pha...
Veronesi MC, Battocchio M, Faustini M, Gandini M, Cairoli F.The aim of this study was to evaluate the possible relationship of pharmacological induction of estrous and/or ovulation with the occurrence of twin pregnancies in Thoroughbred mares. Out of 680 mares, 356 received one of the following treatments during the estrous cycle in which they became pregnant: injection of 0.5mg of cloprostenol at the ultrasonographic detection of a CL (n=86); injection of 5000 IU human chorionic gonadotropin (hCG) immediately before mating (n=221); injection of 0.5mg of cloprostenol at the ultrasonographic detection of a CL plus injection of 5000 IU hCG immediately be...
Silberzahn P, Pouret EJ, Zwain I.Androgen (testosterone and androstenedione) and oestrogen (oestradiol -17 beta and oestrone) concentrations were measured by radio-immunoassay in the peripheral plasma of two geldings (five-years-old), three bilateral cryptorchids (two, two and a half, and five-years-old) and three normal intact stallions (four, five and five and a half-years-old) before and after a single injection of 10,000 iu human chorionic gonadotrophin (hCG). In the stallions, hCG administration resulted in an immediate sharp increase of conjugated oestrogens and a more gradual increase of unconjugated androgens. In the ...
Woods GL, Ginther OJ.The efficacy of an equine pituitary extract for induction of multiple ovulations during the ovulatory season was studied in 112 horse mares in four experiments. Combined for all experiments, 70% of the mares (78/112) had multiple ovulations for an average of 3.0 ovulations per mare. The interval between first and last ovulation was decreased (P<0.01) when human chorionic gonadotropin (hCG) was included in the treatment regimen (0.0+/-0.0 versus 1.6+/-0.4 days). Ovulation rate was lower (P<0.01) when extract treatment was initiated at day 19 (1.3+/-0.2) than when initiated at day 15 post-...
Veronesi MC, Battocchio M, Faustini M, Gandini M, Cairoli F.The aim of this study was to evaluate the possible relationship of pharmacological induction of estrous and/or ovulation with the occurrence of twin pregnancies in Thoroughbred mares. Out of 680 mares, 356 received one of the following treatments during the estrous cycle in which they became pregnant: injection of 0.5mg of cloprostenol at the ultrasonographic detection of a CL (n=86); injection of 5000 IU human chorionic gonadotropin (hCG) immediately before mating (n=221); injection of 0.5mg of cloprostenol at the ultrasonographic detection of a CL plus injection of 5000 IU hCG immediately be...
Bucca S, Carli A.Human chorionic gonadotropin (hCG) and dexamethasone have a role in the reproductive management protocols of mares susceptible to persistent mating-induced endometritis (PMIE). However, it is possible that there is interference between these 2 drugs. Objective: The objective of this retrospective study was to determine the efficacy of hCG to induce ovulation in mares treated with dexamethasone at breeding time. Methods: Medical records from 152 mares and 223 cycles were analysed. In 113 cycles, mares susceptible to PMIE were treated with 1500 iu hCG and a single dose of 50 mg dexamethasone, 11...
Woods GL, Ginther OJ.The efficacy of an equine pituitary extract for induction of multiple ovulations during the ovulatory season was studied in 112 horse mares in four experiments. Combined for all experiments, 70% of the mares (78/112) had multiple ovulations for an average of 3.0 ovulations per mare. The interval between first and last ovulation was decreased (P<0.01) when human chorionic gonadotropin (hCG) was included in the treatment regimen (0.0+/-0.0 versus 1.6+/-0.4 days). Ovulation rate was lower (P<0.01) when extract treatment was initiated at day 19 (1.3+/-0.2) than when initiated at day 15 post-...
Silberzahn P, Pouret EJ, Zwain I.Androgen (testosterone and androstenedione) and oestrogen (oestradiol -17 beta and oestrone) concentrations were measured by radio-immunoassay in the peripheral plasma of two geldings (five-years-old), three bilateral cryptorchids (two, two and a half, and five-years-old) and three normal intact stallions (four, five and five and a half-years-old) before and after a single injection of 10,000 iu human chorionic gonadotrophin (hCG). In the stallions, hCG administration resulted in an immediate sharp increase of conjugated oestrogens and a more gradual increase of unconjugated androgens. In the ...
Oliveira SN, Segabinazzi LGTM, Canuto L, Lisboa FP, Medrado FE, Dell'Aqua JA, Aguiar AJA, Papa FO.The goal of this study was to compare the efficiency of histrelin acetate (GnRH analog) and human chorionic gonadotropin (hCG) to hasten ovulation in Brazilian Northeastern jennies (Equus africanus asinus). Thirty cycles of ten jennies were randomly assigned in one of the three groups: G0 (control group), saline; G1, 250 μg of histrelin acetate; G2, 2500 IU of hCG. Jennies were evaluated by transrectal palpation and ultrasonography, and had the administration of an ovulation-inducing agent when a follicle measuring between 29 and 32 mm of diameter was diagnosed. Jennies were monitored every...
Toishi Y, Tsunoda N, Nagata SI, Kirisawa R, Nagaoka K, Watanabe G, Yanagawa Y, Katagiri S, Taya K.Testosterone (T) concentration is a useful indicator of reproductive function in male animals. However, T concentration is not usually measured in veterinary clinics, partly due to the unavailability of reliable and rapid assays for animal samples. In this study, a rapid chemiluminescent enzyme immunoassay system (CLEIA system) that was developed for the measurement of T concentration in humans use was validated for stallion blood samples. First, serum T concentrations were measured using the CLEIA system and compared with those measured by a fluoroimmunoassay that has been validated for use i...
Hedberg Y, Dalin AM, Santesson M, Kindahl H.Strong oestrous symptoms in the mare can cause problems with racing, training and handling. Since long-acting progesterone treatment is not permitted in mares at competition (e.g. according to FEI rules), there is a need for methods to suppress unwanted cyclicity. Spontaneous dioestrous ovulations in the late luteal phase may cause a prolongation of the luteal phase in mares. Methods: In this preliminary study, in an attempt to induce ovulation during the luteal phase, human chorionic gonadotropin (hCG) (3000 IU) was injected intramuscularly in four mares (experimental group) in the luteal pha...
Esteller-Vico A, Ball BA, Bridges JW, Hughes SE, Squires EL, Troedsson MHT.Reproductive steroids testosterone (T) and estrone sulfate (E1S) are used as diagnostic markers for cryptorchidism in horses. The human chorionic gonadotropin (hCG) stimulation test is used as a diagnostic aid because administration of this hormone results in greater incremental differences in circulating steroid concentrations. Thoughts regarding optimal sampling times following hCG administration, however, are inconsistent. Additionally, determination of half-life of these steroids is important in postsurgical samples to confirm complete removal of testicular tissue. Objectives of this study...
Macan RC, Camargo CE, Zielinski BL, Cardoso NGH, de Lara NSS, Bergstein-Galan TG, Weiss RR, Kozicki LE.Timed artificial insemination (TAI) has boosted the use of conventional artificial insemination (CAI) by employing hormonal protocols to synchronize oestrus and ovulation. This study aimed to evaluate the efficiency of a hormonal protocol for TAI in mares, based on a combination of progesterone releasing intravaginal device (PRID), prostaglandin (PGF2α ) and human chorionic gonadotropin (hCG); and compare financial costs between CAI and TAI. Twenty-one mares were divided into two groups: CAI group (CAIG; n = 6 mares; 17 oestrous cycles) and TAI group (TAIG; n = 15 mares; 15 oestrous cycle...
