Re: Vitex/Chasteberry study #Vitex_CHB_Chasteberry
After you earn all the subtle and not-so-subtle signs of uncontrolled PPID, you can decide to check ACTH, insulin and glucose based on your observations.
The best time to test, assuming Shifty is comfortable and doing well on his current dose, is before the seasonal rise really get going, in late June or very early July. That's early enough to check that his ACTH and insulin levels are within normal ranges and, if not, quickly make adjustments to his pergolide dose before the seasonal rise really ramps up. The collective experience here is that increasing pergolide dose before the seasonal rise works much better than chasing out-of-control PPID in September or October. Learning to monitor the symptoms of uncontrolled PPID will help you through this.
Read about the seasonal rise and its annual effect on ACTH here: https://www.ecirhorse.org/seasonal-rise.php If you like to read charts, you can see the how the seasonal rise increases ACTH week by week: https://www.thelaminitissite.org/ppid-faq/acth-interpretation
With a newly diagnosed PPID horses, it's a learning experience to manage pergolide dosage during the seasonal rise. It's common for horses to need an additional 1-1 ½ mg of pergolide (or more!) to keep ACTH from an exaggerated increase August through November. If you see signs that PPID is not well controlled during the rise (or any time of year!), increased urination, lethargy, depression, muscle loss, more of a pot belly, and especially if Shifty becomes tender footed, it's wise to check ACTH, insulin and glucose. And even if PPID seemed well controlled, I've seen bruising at the toe during trims in early January or hoof abscesses, indicating uncontrolled insulin some time within the previous few month. We become really alert to the subtle signs of uncontrolled PPID.
Some members can slowly reduce the pergolide dose after the seasonal rise, in late December or early January, assuming you see no signs of poorly controlled PPID. Other members have not such luck.
Cass, Sonoma Co., CA 2012
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