Just as spring brings its own hormonal rollercoaster for mares, autumn has it’s equivalent, and it can catch owners off guard. If your mare has suddenly become unpredictable, tense, or "not herself" as the nights draw in, her hormones could be behind it.

What’s happening inside your mare’s body during the autumn transition and what you can do to help her through it comfortably?

Your mare’s reproductive cycle is switched on and off by daylight length, not the calendar. Through spring and summer, most mares cycle roughly every 21 days. As the days shorten heading into autumn, her body begins winding down but this can cause irregular and erratic bursts of hormones, known as the autumn transition.

Autumn transition is essentially a mirror image of the more talked-about spring transition. Mares typically go through several prolonged spells of "heat-like" receptivity, often lasting a week or two at a time, much as they do during the spring transition into the breeding season.

It all comes down to daylight. Your mare's year often has four reproductive phases:

• September/October/November - The autumn transition as daylight hours start to shorten
• December/January - Winter anoestrus, the rest phase
• February/March - The spring transition as daylight hours start to lengthen
• April to August/September - Approximate 21-day oestrus cycling
  
  During this current autumn transition, ovarian activity can become erratic rather than settling smoothly. This hormonal turbulence can result in localized ovarian pressure or ovulation pain, and can present similarly to a dull back ache.

For you as an owner, the autumn transition often shows up as a run of frustrating, seemingly random behavioural changes. Typical pain points include:

• Unpredictable moods – anxious, reactive, clingy, irritable, moody or uncooperative
• Reduced focus - resistance, spookiness, or stubbornness to work
• Increased sensitivity - grooming, tacking up, around the girth, flanks, or hindquarters
• Squealing, kicking, tail swishing or pinning ears back - around other horses she's normally settled with
• Longer or more erratic "heat-like" behaviour - than during her regular summer cycles

It's worth remembering that mood swings alone aren't a diagnosis. If your mare's behaviour is genuinely out of character, or comes with signs of pain, it's always worth ruling out other causes such as gastric ulcers, back pain, or low-grade lameness. Always consult your vet or chat to us if you’re unsure.

• Changes in appetite or subtle weight fluctuations as her body adjusts
• A duller coat or slower start to her winter coat coming through
• Stiffness or tension through her back and hindquarters
• General changes in energy levels, some mares become flat, others unusually reactive

The good news: while you can't stop the transition happening, there's plenty you can do to help her feel more comfortable through it.

• Keep a behaviour diary - Note timings, patterns, and any triggers. This helps you spot whether her behaviour genuinely lines up with hormonal shifts or if something else is going on.
• Support her routine - Consistency in turnout, feeding, and exercise helps reduce additional stress on top of what her body is already managing.
• Review her diet - As grazing quality drops off during the autumn, make sure her daily feed is balanced to fill any nutritional gaps while also supporting her hormonal health. A good quality feed balancer such as Blue Chip Happy Mare is a simple way to do this.
• Provide targeted nutritional support - Happy Mare has been formulated specifically with mares in mind, to help support them through their ever-changing hormonal fluctuations.
• Warm her up properly - With stiffness more noticeable as temperatures drop, a longer than usual warm up or a few minutes of lunging before riding can make a real difference.
• Talk to your vet if necessary - Persistent, severe, or pain-associated behaviour changes deserve veterinary attention rather than being managed through nutrition and management alone.

When your mare isn't quite herself; tense, sensitive, or unpredictable, it affects both of you.

Happy Mare was developed as the UK's first dedicated feed balancer built specifically around this problem, formulated by mare owners, for mare owners.

Rather than treating mood as separate from nutrition, Happy Mare is built on the idea that digestive health and hormone function are closely linked. When the gut is out of balance, hormones often are too. It combines three targeted botanical ingredients with a complete daily balancer, all in one tasty pellet:

• Chaste tree berry - helps maintain natural hormone signalling, supporting a more even temperament through seasonal cycle changes
• Raspberry leaf - traditionally used to support reproductive comfort
• Dandelion root - supports liver function, which plays an important role in processing hormones out of the body

Alongside these herbs, Happy Mare still delivers everything you'd expect from a Blue Chip balancer: a full spectrum of essential vitamins, minerals, micronutrients and probiotics to support digestion, nutrient absorption, and overall condition.

Because it's fed as a small daily pelleted serving rather than a bulky powder, it's easy to feed accurately, harder for a fussy mare to leave behind in the bottom of the bucket, and simple to hand-feed if needed.

Do you have a mare going through her autumn transition? Our team is always happy to help you find the right balance for her. Call us on 0114 266 6200, email info@bluechipfeed.com, or drop us a message on social media.