Frequently Asked Questions

Be assured that your Histrelin formulation left BET Pharm with a frozen ice pack which goes on to melt over a period of 12-24 hours. This is normal and your formulation is in good condition. We have performed stability studies that demonstrate that Histrelin is stable for at least 7 days at 40 C (greater than 100 F).

The low dose Histrelin is used by most veterinarians to stimulate follicular development in mares that have 15 to 25 mm follicles that appear to be static and not growing as expected.

It is also used in mares that are anovulatory due to PPID. Even after 90 days of appropriate Pergolide/Cabergoline treatment ovarian follicles may only attain a diameter of 20 to 30 mm and then regress.

Histrelin at 50ug IM BID will often recruit these follicles to grow and ovulate. The Histrelinis continued until ovulation occurs. This formulation should not be used in stallions as it may cause down regulation followed by significant declines in both estrogen and testosterone serum concentrations.

BioRelease Histrelin LA is formulated to stimulate maximal LH release and is released over approximately a 24-hour period whereas Histrelin in saline is released over a much shorter period (3 to 5 minutes). Research trials over the last decade strongly suggest the slower release (LA) formulations are more effective at ovulating smaller follicles (28 to 35mm) and all follicles during early spring (February thru April.) We offer both formulations in our pharmacy but BioReleaseHistrelin is preferred by > 99% of our clients even though it costs nearly four times more. Multiple research studies have shown that doses as low as 0.25 or 0.5 mL are clinically effective (>90% Ovulation in 48 hours) from mid May thru September.

Field studies have suggested that IM administration of 50 to 100 mg of Estradiol-17 β given between days 5 and 7 post partum may improve uterine tone. Acupuncture may also be of benefit.

Poor uterine tone and fluid retention is often associated with PPID (Cushing’s Disease) and these cases respond well to Pergolide and/or Cyproheptadine. If PPID is not present, acupuncture and exercise in the form of using a pony to force the mare to exercise are very helpful. As an adjunct to this, high doses of Estradiol-17 β given IM when the mare is anovulatory have been reported to be effective. Usually a single dose of 10 – 20 mg Estradiol-17 β followed by a single dose of BioRelease Estradiol-Cypionate 30- 50 mg is the protocol followed.

The most commonly used drug is Altrenogest. Doses of 44 mg per day orally have been used or more recently veterinarians have been using compounded Altrenogest in BioRelease vehicle at a dose of 225 mg IM once per week to reduce studdish behavior. Other options (not presently available) include long acting GnRH antagonist/agonist to down-regulate intact stallions so they are temporarily biochemically castrated.

Studies in Brazil have demonstrated that 10 mg Estradiol–Cypionate (single dose IM) given when follicles are 25 to 35 mm will delay ovulation by approximately 24 hours. The Estradiol-Cypionate treated mares will respond to Deslorelin LA if the need to delay ovulation changes. This treatment needs to be explored in foal heat where small delays in days to ovulation can greatly enhance pregnancy rates.

Most often veterinarians are using Testosterone in oil or Estradiol-Cypionate in BioRelease vehicle to maintain gelded teasers. Generally a dose of 100 mg Testosterone IM two to three times each week are effective. Estradiol-Cypionate can usually be given at a dose of 10 mg per day or 50 mg twice per week. Doses will vary from animal to animal depending on their sensitivity to the steroid.

Historically, Veterinarians have used the synthetic Estrogen Dinestrol to treat urine pooling. However, this Estrogen is no longer available. Therefore, vets are now using a compounded concentrated Estradiol-17 β (50mg/ml) to treat the condition. Usually doses of 100 mg IM q 48 hrs or 50 mg intravaginally q 24 hrs are used. This may be done in conjunction with acupuncture or forced exercise.

The compounded double anthelmentic can be top dressed on feed and the two actives work synergistically to eliminate more parasites when given in a strategic deworming program for three consecutive months in the Spring and three months in the Fall. Some parasitologists hypothesize that this combination will decrease the likelihood of parasite resistance. The cost per dose is very competitive.