Menopause in horses refers to the cessation of reproductive cycles in older mares, although it is not as clearly defined or commonly observed as in humans. Unlike humans, most mares continue to exhibit estrous cycles throughout their lives, but reproductive efficiency can decline with age. This topic explores the physiological changes and potential health implications associated with aging in equine reproductive systems. Research in this area investigates hormonal fluctuations, fertility patterns, and the overall impact of aging on mare reproductive health. This page compiles peer-reviewed research studies and scholarly articles that examine the occurrence, characteristics, and clinical considerations of reproductive aging in horses.
Zeng Z, Jiang X, Li X, Wells A, Luo Y, Neapolitan R.By the 1990s it became popular for women to use hormone therapy (HT) to ease menopause symptoms. Bioidentical estrogen and progesterone are supplements whose molecular structures are identical to what is made in the human body, while synthetic supplements are ones whose structures are not. After the Women's Health Initiative found that the combined use of the synthetics conjugated equine estrogen (CEE) and medroxyprogesterone acetate (MPA) increased breast cancer risk, prescriptions for synthetic HT declined considerably. Since then there has been an increased interest in bioidentical HT; toda...
Maldonado PA, Montoya TI, Acevedo JF, Keller PW, Word RA.Although the positive effects of vaginal estrogens and the selective estrogen receptor modulator, ospemifene (OS), on the vaginal epithelium are well recognized, less is known regarding the effects of these therapies on the lower urinary tract or vaginal muscularis. Clinical evidence suggests that vaginally administered estrogen may improve overactive bladder-related symptoms. The objective of this study was to compare the effects of OS, vaginal conjugated equine estrogens (CEE), or both on the vaginal wall and lower urinary tract in a rat model of menopause. Contractile force of the bladder n...
Talboom JS, Engler-Chiurazzi EB, Whiteaker P, Simard AR, Lukas R, Acosta JI, Prokai L, Bimonte-Nelson HA.In women, ovarian hormone loss at menopause has been related to cognitive decline, and some studies suggest that estrogen-containing hormone therapy (HT) can mitigate these effects. Recently, the Women's Health Initiative study found that conjugated equine estrogens, the most commonly prescribed HT, do not benefit cognition. Isolated components of conjugated equine estrogens (tradename Premarin(®)) have been evaluated in vitro, with delta(8,9)-dehydroestrone (∆(8)E1) and equilin showing the strongest neuroprotective profiles. It has not been evaluated whether ∆(8)E1 or equilin impact cogn...
Guvenal T, Durna A, Erden O, Guvenal F, Cetin M, Cetin A.The purpose of this study was to compare the effects of different postmenopausal hormone therapy regimens, namely conjugated equine estrogens (CEE), CEE plus medroxyprogesterone acetate (MPA), tibolone, and raloxifene on cerebral blood flow and cognitive functions. Methods: A total of 64 healthy postmenopausal women admitted to the Department of Obstetrics and Gynecology, Cumhuriyet University, Turkey were included in this study. Patients were divided into five groups with respect to the treatment protocols: CEE 0.625 mg/day (n=13); CEE 0.625 mg/day + MPA 2.5 mg/day (n=14); tibolone 2.5 mg/day...
Smith NL, Heckbert SR, Lemaitre RN, Reiner AP, Lumley T, Weiss NS, Larson EB, Rosendaal FR, Psaty BM.Clinical trial evidence indicates that estrogen therapy with or without progestins increases venous thrombotic risk. The findings from these trials, which used oral conjugated equine estrogens, may not be generalizable to other estrogen compounds. Objective: To compare risk of venous thrombosis among esterified estrogen users, conjugated equine estrogen users, and nonusers. Methods: This population-based, case-control study was conducted at a large health maintenance organization in Washington State. Cases were perimenopausal and postmenopausal women aged 30 to 89 years who sustained a first v...
Clarkson TB.Clearly, a new era has begun, with increasing numbers of the scientific/medical community asking whether estrogens have any cardiovascular benefits. Doubts have arisen from two randomized prospective trials. The Heart and Estrogen/progestin Replacement Study (women who were generally beyond 65 years of age with preexisting coronary heart disease) found no benefit in reducing coronary events by a combination of estrogens and a progestin. Later, the Estrogen Replacement Atherosclerosis Trial reported that no benefit could be shown for either conjugated equine estrogens only or the combined thera...
Velasco-Murillo V.It exists controversies about if the effects and benefits of the esterified estrogens could be similar to those informed for equines, because its chemical composition and bioavailability are different. Esterified estrogens has not delta 8,9 dehydroestrone, and its absorption and level of maximum plasmatic concentrations are reached very fast. In United States of America and another countries, esterified estrogens has been marketed and using for treatment of climacteric syndrome and prevention of postmenopausal osteoporosis, based on the pharmacopoiea of that country, but the Food and Drug admi...
Anderson F.With the approach of the menopause and the cessation of ovarian estrogen production, a number of uncomfortable and/or dangerous conditions may be manifested, and are all indications for estrogen replacement therapy. Various routes of estrogen administration are available--oral, subcutaneous implant, intravaginal, and transdermal--each having advantages and disadvantages. There is also a choice possible among replacement hormones, which include the natural estrogens, such as estradiol and estropipate; synthetic estrogens, for example, ethinyl estradiol and diethylstilbestrol; and conjugated equ...
Smith NL, Heckbert SR, Lemaitre RN, Reiner AP, Lumley T, Weiss NS, Larson EB, Rosendaal FR, Psaty BM.Clinical trial evidence indicates that estrogen therapy with or without progestins increases venous thrombotic risk. The findings from these trials, which used oral conjugated equine estrogens, may not be generalizable to other estrogen compounds. Objective: To compare risk of venous thrombosis among esterified estrogen users, conjugated equine estrogen users, and nonusers. Methods: This population-based, case-control study was conducted at a large health maintenance organization in Washington State. Cases were perimenopausal and postmenopausal women aged 30 to 89 years who sustained a first v...
Clarkson TB.Clearly, a new era has begun, with increasing numbers of the scientific/medical community asking whether estrogens have any cardiovascular benefits. Doubts have arisen from two randomized prospective trials. The Heart and Estrogen/progestin Replacement Study (women who were generally beyond 65 years of age with preexisting coronary heart disease) found no benefit in reducing coronary events by a combination of estrogens and a progestin. Later, the Estrogen Replacement Atherosclerosis Trial reported that no benefit could be shown for either conjugated equine estrogens only or the combined thera...
Guvenal T, Durna A, Erden O, Guvenal F, Cetin M, Cetin A.The purpose of this study was to compare the effects of different postmenopausal hormone therapy regimens, namely conjugated equine estrogens (CEE), CEE plus medroxyprogesterone acetate (MPA), tibolone, and raloxifene on cerebral blood flow and cognitive functions. Methods: A total of 64 healthy postmenopausal women admitted to the Department of Obstetrics and Gynecology, Cumhuriyet University, Turkey were included in this study. Patients were divided into five groups with respect to the treatment protocols: CEE 0.625 mg/day (n=13); CEE 0.625 mg/day + MPA 2.5 mg/day (n=14); tibolone 2.5 mg/day...
Zeng Z, Jiang X, Li X, Wells A, Luo Y, Neapolitan R.By the 1990s it became popular for women to use hormone therapy (HT) to ease menopause symptoms. Bioidentical estrogen and progesterone are supplements whose molecular structures are identical to what is made in the human body, while synthetic supplements are ones whose structures are not. After the Women's Health Initiative found that the combined use of the synthetics conjugated equine estrogen (CEE) and medroxyprogesterone acetate (MPA) increased breast cancer risk, prescriptions for synthetic HT declined considerably. Since then there has been an increased interest in bioidentical HT; toda...
Maldonado PA, Montoya TI, Acevedo JF, Keller PW, Word RA.Although the positive effects of vaginal estrogens and the selective estrogen receptor modulator, ospemifene (OS), on the vaginal epithelium are well recognized, less is known regarding the effects of these therapies on the lower urinary tract or vaginal muscularis. Clinical evidence suggests that vaginally administered estrogen may improve overactive bladder-related symptoms. The objective of this study was to compare the effects of OS, vaginal conjugated equine estrogens (CEE), or both on the vaginal wall and lower urinary tract in a rat model of menopause. Contractile force of the bladder n...
Anderson F.With the approach of the menopause and the cessation of ovarian estrogen production, a number of uncomfortable and/or dangerous conditions may be manifested, and are all indications for estrogen replacement therapy. Various routes of estrogen administration are available--oral, subcutaneous implant, intravaginal, and transdermal--each having advantages and disadvantages. There is also a choice possible among replacement hormones, which include the natural estrogens, such as estradiol and estropipate; synthetic estrogens, for example, ethinyl estradiol and diethylstilbestrol; and conjugated equ...
Velasco-Murillo V.It exists controversies about if the effects and benefits of the esterified estrogens could be similar to those informed for equines, because its chemical composition and bioavailability are different. Esterified estrogens has not delta 8,9 dehydroestrone, and its absorption and level of maximum plasmatic concentrations are reached very fast. In United States of America and another countries, esterified estrogens has been marketed and using for treatment of climacteric syndrome and prevention of postmenopausal osteoporosis, based on the pharmacopoiea of that country, but the Food and Drug admi...
Talboom JS, Engler-Chiurazzi EB, Whiteaker P, Simard AR, Lukas R, Acosta JI, Prokai L, Bimonte-Nelson HA.In women, ovarian hormone loss at menopause has been related to cognitive decline, and some studies suggest that estrogen-containing hormone therapy (HT) can mitigate these effects. Recently, the Women's Health Initiative study found that conjugated equine estrogens, the most commonly prescribed HT, do not benefit cognition. Isolated components of conjugated equine estrogens (tradename Premarin(®)) have been evaluated in vitro, with delta(8,9)-dehydroestrone (∆(8)E1) and equilin showing the strongest neuroprotective profiles. It has not been evaluated whether ∆(8)E1 or equilin impact cogn...
