Spring and the Mare: Understanding Her Season

There's a certain kind of horse owner who will read the title of this post and immediately nod. They know. They've stood at the stall door in March watching their sweet, steady mare turn into someone unrecognizable — pinning ears, swishing tail, sensitivity through the roof — and wondered what happened to the horse they knew in November.

The answer, in most cases, is spring. And understanding what's actually happening to your mare this time of year can make the whole season feel a lot less personal.

Her Body Is Working Overtime

As daylight hours increase, mares transition out of winter anestrus — the period of reproductive dormancy that gives their hormonal system a rest. Come late February through April, that system kicks back into gear. Progesterone and estrogen begin cycling again, and with that comes the full behavioral picture most of us recognize:

• Touchiness along the topline and flanks
• Irritability or tension under saddle
• Unpredictable energy and focus
• A general sense that she would rather you didn't exist today

This isn't a character flaw. It's her endocrine system doing exactly what it's designed to do. The challenge for us as riders and handlers is learning to work with that — not against it.

What's Actually Driving the Behavior

The hormonal fluctuations of estrus affect far more than reproductive function. Progesterone and estrogen influence mood, pain sensitivity, and stress response throughout the body. A mare who is sharp and reactive in spring may genuinely be feeling more uncomfortable in her own skin — more sensitive to the pressure of a girth, more reactive to leg aids, more easily overwhelmed in situations that wouldn't have bothered her in the fall.

It's also worth noting that the transition period — those early spring cycles before her rhythm fully establishes — can be particularly unpredictable. Irregular cycling is common in late winter and early spring, which means her hormonal landscape may be shifting frequently rather than following a predictable pattern. That inconsistency is often what makes spring the hardest season to manage.

What You Can Do Right Now

Track the cycle. If you haven't started keeping a simple log of her behavior relative to her cycle, now is a good time. Note her demeanor, her responsiveness under saddle, and any physical signs of estrus each day. After a few weeks, patterns usually emerge — and patterns give you something to work with. What looks like random bad behavior often turns out to be very predictable once you have the data.

Adjust your training expectations during peak estrus. This isn't about letting her off the hook — it's about being strategic. Many riders find their mares are more than willing to work hard in the days following ovulation when progesterone is higher and the body is calmer. Saving technically demanding or high-pressure work for those windows, and keeping estrus days lighter, can do a lot for both the horse's wellbeing and the partnership.

Don't dismiss behavioral changes as "just her being a mare." Hormonal cycling is the most common cause of spring behavioral shifts, but it's not the only one. Watch for signs that something more may be going on:

• Extreme behavior that's consistent regardless of cycle phase
• Physical symptoms like decreased appetite, girthiness, or changes in manure
• A sudden shift in personality that feels out of character even for spring

If any of these ring true, it's worth a conversation with your vet to rule out pain or underlying imbalance before defaulting to management tactics alone.

Support her from the inside out. How a mare feels physically has a direct impact on how she handles the hormonal demands of cycling. A well-nourished horse with a supported immune system tends to move through these transitions more smoothly than one who is nutritionally deficient or under chronic stress.

A Note on Natural Support

For mares whose cycles create significant disruption — either to the horse or to the partnership — there are options worth exploring before jumping to more aggressive interventions.

Oxy-Gen's PMP (Performance Mare Product™) was formulated specifically with this in mind. Rather than suppressing the cycle, PMP works to support the systems that cycling puts under pressure — the endocrine and immune systems — using patented beta glucan technology alongside vitamins and antioxidants. Here's what that looks like in practice:

• Helps mares maintain a normal, relaxed disposition through hormonal fluctuations
• Supports physical and mental well-being throughout the cycle
• Maintains normal reproductive function — without disrupting it

It's the kind of product that works best as a foundation — something you're giving consistently before things get hard, rather than reaching for reactively once the season is already in full swing. If your mare has struggled in past springs, now is a good time to get ahead of it.

The Bigger Picture

Spring is a season of change, and mares feel that more acutely than most horses. She isn't trying to make your life difficult. She's navigating a significant physiological shift — and the way she comes through it says a lot about how well her body is supported to handle it.

The horse owners who tend to have the smoothest springs are the ones who approach this season with curiosity rather than frustration. They observe, adjust, and meet the mare where she is. Which, honestly, is pretty good advice for horsemanship in general — not just in March.

Have questions about whether PMP might be a good fit for your mare? We're always happy to talk through what might work for your horse's specific situation. Reach out anytime.