The influence of chlormadinone acetate treatment on the concentration of some steroids in the blood, on the ovarian activity, and on the sexual behaviour of the mare.
Abstract: The effect of orally administered chlormadinone acetate (CAP), 10 mg daily for a period of 16 days, was investigated in the case of four mares with an irregular oestrous pattern accompanied by low ovarian activity (group 1), four mares which did not show oestrous symptoms at all and which had also low ovarian activity (group 2), and two ovariectomized and two ovario-hysterectomized mares (group 3). In all mares of group 1 and in the two ovariectomized mares of group 3 oestrus symptoms became apparent during treatment. Two mares of group 2 came into heat 8 and 11 days after the cessation of treatment. The two other mares of group 2 and the ovario-hysterectomized mares of group 3 showed no oestrous symptoms at all. In all except the two ovario-hysterectomized mares the progesterone concentration was found to increase in the peripheral blood from less than 1 ng/ml up to at least 4-6 ng/ml. In the mares which came into oestrus this progesterone increase occurred about three days before symptoms of heat became apparent. It is assumed that the uterus played an important role in the increase of the progesterone concentration in the blood during or after CAP treatment. A similar rise of the progesterone level was also found in the ovariectomized mares, indicating that this progesterone did not originate in the ovaries.
Publication Date: 1977-07-15 PubMed ID: 70082
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- Journal Article
Summary
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The research investigates the effects of chlormadinone acetate (CAP), a hormonal treatment, on ovarian activity, blood steroid concentration, and sexual behavior of mares with different levels of ovarian activity.
Research Setup
- The study involved 12 mares divided into three groups, each presenting different levels of ovarian activity. Group 1 comprised four mares with irregular oestrous patterns and low ovarian activity, group 2 had four mares with no visible signs of oestrous and low ovarian activity, and group 3 consisted of two mares with removed ovaries and two mares that also had their uterus removed.
- The mares were treated orally with 10mg of CAP daily for a span of 16 days.
Findings
- Group 1 mares and the two ovariectomized mares of group 3 showed signs of oestrous during the CAP treatment. Among group 2, two mares displayed signs of heat 8-11 days after treatment was discontinued.
- Group 2’s two remaining unresponsive mares and group 3’s two ovariectomized mares showed no signs of oestrus throughout.
- Excluding the two ovariectomized mares, all mares exhibited an increase in progesterone concentration in their blood, from less than 1 ng/ml to at least 4-6 ng/ml. In those that manifested oestrus, the rise in progesterone occurred about three days before the onset of heat symptoms.
Takeaway
- The rise in progesterone concentration during or after CAP treatment, the researchers conjecture, may involve the uterus. This is also suggested by the fact the same rise in the progesterone level was observed in ovariectomized mares, indicating that the increased progesterone does not originate from the ovaries.
- The information from this study could be beneficial for understanding and managing the reproductive cycle and fertility of equine species. The hormonal reactions to CAP have shown potential in controlling oestrous and ovarian activity in mares.
Cite This Article
APA
Nitschelm D, van der Horst CJ.
(1977).
The influence of chlormadinone acetate treatment on the concentration of some steroids in the blood, on the ovarian activity, and on the sexual behaviour of the mare.
Tijdschr Diergeneeskd, 102(14), 805-816.
Publication
Researcher Affiliations
MeSH Terms
- Anestrus / drug effects
- Animals
- Castration
- Chlormadinone Acetate / pharmacology
- Estrus / drug effects
- Female
- Horses
- Hysterectomy
- Ovary / drug effects
- Ovary / physiology
- Pregnancy
- Pregnenolone / blood
- Progesterone / blood
- Sexual Behavior, Animal / drug effects
- Uterus / drug effects
Citations
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