How To Feed Broodmares Before Winter

By Dr Duncan Houston

Winter feeding for broodmares is not just about adding more hay and hoping for the best. The goal is to carry the mare into winter with enough body condition, enough forage, enough minerals, and a plan for late pregnancy and lactation.

The mare may look fine in autumn, but winter can expose weak spots quickly. Pasture drops away, weather increases calorie demand, hay quality varies, water intake can fall, and late pregnancy starts increasing the nutritional pressure. Then, once she foals, lactation becomes the most demanding stage of the whole cycle.

The real question is not simply, “What should I feed her?” It is, “Is this mare entering winter with enough reserve to stay healthy, grow the foal, foal safely, milk well, and breed back?”

Quick Answer

Broodmares should generally enter winter in a body condition score of at least 5 out of 9, with many mares doing best around 5 to 6, and a score of 6 giving a useful winter reserve. As pasture quality declines, offer good-quality hay, balance minerals properly, avoid dusty or mouldy forage, and do not feed pregnant mares endophyte-infected tall fescue unless it has been tested and confirmed safe. Late gestation and lactation increase nutrient demands, so some mares need a broodmare concentrate or ration balancer rather than hay alone. University of Kentucky guidance notes that broodmares entering late fall at BCS 6 have a useful reserve for winter, while mares below 5 are more likely to need extra calories before the next breeding and foaling season. (Equine Programs)

Why Winter Feeding Matters for Broodmares

Broodmare nutrition is a long game. What happens before winter can affect pregnancy condition, foaling strength, milk production, colostrum quality, recovery after foaling, and rebreeding.

A mare can use her own body stores to support the fetus, but that is not the ideal plan. If she starts winter thin, keeps losing condition, and then reaches late pregnancy or lactation without enough reserve, you are already behind. University of Kentucky notes that late pregnancy mares need adequate feeding because the last few months of fetal development involve major growth, and maintaining a stable body condition score is important for the mare’s own reserves. (Equine Programs)

In practice, the mare that worries me most is the one that looks “just a little light” in autumn. Owners often think there is plenty of time. Then the weather turns, pasture disappears, hay is average, she is harder to feed, and suddenly she is too lean close to foaling. That is not where you want to be making big catch-up changes.

What Body Condition Score Should a Broodmare Have Before Winter?

The Henneke body condition score system runs from 1 to 9, where 1 is extremely thin and 9 is obese. For broodmares, the practical target is usually BCS 5 to 6.

A mare around BCS 5 has ribs that are not visible but can still be felt. A mare around BCS 6 has a small amount of extra cover, which can be useful before winter and early lactation. University of Kentucky describes BCS 5 to 6 mares as having ribs that can be felt easily but not seen, with enough topline fat that the loin area looks relatively flat. (Equine Programs)

BCS 4 or Lower

This mare is too thin. You may see ribs, a sharper topline, less cover over the hips, and a generally poor reserve.

What to do: act before winter. Check teeth, parasite control, forage quality, social feeding pressure, ulcers, pain, and ration adequacy. This mare may need better forage, increased calories, and veterinary or nutrition support.

BCS 5

This is acceptable for many broodmares. She has enough cover without being fat.

What to do: maintain condition. Do not let her drift down once pasture drops away.

BCS 6

This is often a good target going into winter, especially for mares due to foal in late winter or spring. It gives a small buffer without creating an obese mare.

What to do: maintain, monitor weekly, and adjust before she starts losing weight.

BCS 7 or Higher

This mare is too heavy. She may look impressive, but extra condition is not always helpful. University of Kentucky notes that mares with high condition scores may have increased risk of limb and hoof problems, including laminitis, even though high scores have not necessarily been shown to reduce reproduction. (Equine Programs)

What to do: reduce excess calories carefully, focus on safe forage, and avoid crash dieting, especially in pregnant mares.

When Should You Start Feeding Hay?

Start feeding hay when pasture quality or quantity is no longer maintaining body condition.

Do not wait until the mare is already losing weight. A simple practical test is to put hay in the pasture. If mares ignore it, pasture may still be meeting forage needs. If they eat some, pasture is starting to fall short. If they devour it quickly, the pasture is not keeping up. University of Kentucky recommends using the mare’s condition and pasture response to guide when hay should be added, and notes that feeding hay can also help reduce overgrazing damage to pasture. (Equine Programs)

The important bit: feed the mare in front of you, not the calendar. Some farms need hay early. Some have good autumn pasture. Some mares hold weight easily. Some drop weight if the weather even thinks about becoming cold.

How Much Hay Does a Broodmare Need?

Most horses need forage as the foundation of the diet. Merck Veterinary Manual states that current recommendations are for horses to receive around 1.5 to 2% of body weight per day in forage on a dry matter basis. That can include pasture, hay, haylage, hay cubes, or other high-fibre forage substitutes. (Merck Veterinary Manual)

For a 500 kg mare, that is roughly 7.5 to 10 kg of forage dry matter daily as a starting point. In winter, many mares need more than the minimum, especially if living outside, exposed to cold wind, pregnant, lactating, thin, older, or competing with other horses.

University of Kentucky reported that mares in a hay feeding study consumed about 2 to 2.25 pounds of hay per 100 pounds of body weight. For a 1,250-pound mare, that was around 25 to 28 pounds of hay consumed daily, not including wastage. (Equine Programs)

That distinction matters. The amount you put out is not always the amount she eats. Wind, mud, trampling, herd competition, poor hay racks, and fussy mares all change the real intake.

What Type of Hay Is Best for Broodmares?

The best hay is safe, clean, consistent, and matched to the mare’s needs.

Good broodmare hay should be:

• Free from mould

• Low in dust

• Free from toxic weeds

• Appropriate in energy and protein

• Consistent from batch to batch

• Tested when possible

• Fed in enough quantity to maintain body condition

Alfalfa or Lucerne Hay

Alfalfa, also called lucerne in many countries, is higher in protein and calcium than most grass hays. It can be very useful for pregnant and lactating mares, especially when forage quality is otherwise limited. University of Kentucky notes that good-quality alfalfa hay can reduce the amount of concentrate needed compared with lower-nutrient grass hay. (Equine Programs)

The mistake is assuming alfalfa fixes everything. It may provide more protein and calcium, but the full diet still needs to be balanced for energy, phosphorus, copper, zinc, selenium, and vitamins.

Grass Hay

Grass hays such as timothy, orchardgrass, meadow hay, Rhodes grass, or Bermuda grass can work well, depending on region and quality. Lower-quality grass hay may not meet the needs of late gestation or lactation by itself.

What to do: test the hay if possible. Then decide whether the mare needs a ration balancer, broodmare concentrate, or additional calorie source.

Mixed Hay

Mixed grass and legume hay is often a good middle ground. It can provide better protein and mineral content than plain mature grass hay without being as rich as straight alfalfa.

Tall Fescue

This is the big warning for pregnant mares.

Endophyte-infected tall fescue can cause serious late-pregnancy problems in mares, including prolonged gestation, dystocia, thickened placenta, premature placental separation, poor milk production, weak foals, and increased foal or mare losses. University of Georgia guidance states that pregnant mares should be removed from infected tall fescue pastures during the last trimester, with veterinarians recommending removal 45 to 90 days before the expected foaling date. (CAES Field Report) (CAES Field Report)

If tall fescue hay or pasture is part of the system, do not guess. Test it, replace it, or manage it with your vet.

Do Broodmares Need Grain or Concentrate Before Winter?

Some do. Some do not.

If the mare is holding good condition on quality forage and a properly balanced mineral program, she may not need much concentrate. If she is losing condition, entering late pregnancy, living outside in cold weather, eating lower-quality hay, lactating, or heading into the breeding season thin, she may need more.

University of Kentucky notes that pregnant mares should be maintained at BCS 5 or higher, and when forage quality or quantity is not enough to maintain condition, concentrate should be added. A commercial concentrate formulated for broodmares is a practical option when extra feed is needed. (Equine Programs)

When a Ration Balancer Makes Sense

A ration balancer is useful when the mare is getting enough calories from hay or pasture but still needs vitamins, minerals, and sometimes protein.

This is common in:

• Easy keepers

• Mares on good pasture

• Mares on alfalfa or mixed hay

• Mares that become overweight on full concentrate feeds

• Mares that need minerals without extra calories

University of Kentucky describes balancer pellets as concentrated sources of minerals and vitamins, fed in small amounts, and useful when calories are adequate but trace nutrients need support. It also notes that salt or mineral blocks are used inconsistently by many horses, so they may not reliably meet every mare’s mineral needs. (Equine Programs)

When a Broodmare Concentrate Makes Sense

A broodmare concentrate is more appropriate when the mare needs extra energy, protein, and minerals.

This may apply to:

• Thin mares

• Hard keepers

• Late gestation mares

• Lactating mares

• Mares on lower-quality hay

• Mares living outside in cold conditions

• Mares recovering after nursing a foal

• Mares that need to regain condition before breeding

The key is not to dump grain into the bucket suddenly. Feed changes should be gradual. Merck notes that dietary changes in horses should occur slowly over about 10 to 14 days to reduce disruption of gut microbes and digestive upset. (Merck Veterinary Manual)

How Do Nutritional Needs Change in Late Gestation?

Early pregnancy does not usually require dramatic feeding changes if the mare is already in good condition. The mistake is thinking this stays true all the way to foaling.

Nutrient requirements increase as pregnancy progresses. University of Kentucky notes that NRC recommendations show pregnant mare nutrient requirements begin increasing above maintenance from the fifth month of gestation, with demands rising further in later months. (Equine Programs)

In late gestation, the mare may also have less room in the abdomen as the foal grows, so large feeds may be harder for her to manage. Smaller, more frequent meals can be useful where concentrate intake is needed.

Decision point: if a mare is losing condition in late pregnancy, do not wait until after foaling to fix the diet. Lactation will make the problem harder.

Why Lactation Is the Hardest Nutritional Stage

Lactation is the monster stage. A mare can look fine in late pregnancy and then melt after foaling if the diet is not ready for milk production.

University of Kentucky notes that a 1,200 to 1,300-pound mare may produce about 40 pounds of milk per day in early lactation, and that lactation is more nutritionally demanding than gestation. The same guidance says lactating mares may consume more than 30 pounds of hay daily, and many need broodmare concentrate, often around 5 to 12 pounds per day depending on mare size and forage quality. (Equine Programs)

Merck’s nutrient table also shows the scale of the change: for a 500 kg mare, estimated digestible energy requirements rise from maintenance levels of 16.7 Mcal per day to 31.7 Mcal in the first month of lactation, with major increases in protein, lysine, calcium, and phosphorus needs. (Merck Veterinary Manual)

This is why the pre-winter diet matters. You are not just feeding for today. You are preparing the mare for the most demanding part of the reproductive cycle.

Do Broodmares Need More Water in Winter?

Yes, and this is often overlooked.

Cold weather, dry hay, frozen troughs, and reduced drinking can increase the risk of poor feed intake and impaction colic. Merck Veterinary Manual states that horses eating only dry hay may nearly double their water intake compared with some mixed forage situations, and that lactating mares need approximately 12 to 14 litres per 100 kg body weight to support health and milk production. (Merck Veterinary Manual)

Practical winter water rules:

• Keep water clean

• Prevent freezing

• Check troughs twice daily in cold weather

• Consider warmed water where appropriate

• Do not rely on snow as water

• Monitor manure moisture

• Watch for reduced appetite when water intake drops

A mare can have beautiful hay and still run into trouble if she is not drinking.

Severity and Risk Framework

Low Risk: Mare in Good Condition With Good Forage

This mare is BCS 5 to 6, eating well, drinking well, on clean hay or pasture, and has a balanced mineral program.

What to do: maintain the plan, monitor weekly, and adjust before winter weather or late gestation increases demand.

Medium Risk: Mare Starting To Lose Condition

This mare still looks acceptable but is slowly dropping weight, eating hay quickly, or entering winter with limited pasture.

What to do: increase hay, test forage if possible, add a ration balancer or broodmare feed where needed, and reassess in 2 to 3 weeks.

High Risk: Thin Mare, Poor Hay, or Late Gestation Without a Plan

This mare is BCS 4 or lower, heavily pregnant, on poor forage, competing in a herd, older, dentally compromised, or already losing topline.

What to do: involve your vet or equine nutritionist. Check teeth, parasites, disease, ulcers, pain, and feed access. This mare needs a targeted plan, not just another scoop of whatever is in the shed.

Critical Risk: Fescue Exposure, Laminitis, Colic, or Rapid Decline

This includes late-pregnant mares on possible endophyte-infected fescue, mares with sudden severe weight loss, colic signs, laminitis signs, refusal to eat, dehydration, or late pregnancy udder and foaling concerns.

What to do: contact your vet promptly. These are not situations to manage by feed changes alone.

What Else Can Cause Poor Condition Before Winter?

Do not assume a thin broodmare simply needs more feed.

Important rule-outs include:

Dental Disease

Sharp enamel points, loose teeth, wave mouth, missing teeth, or painful chewing can reduce hay intake. Older mares are especially at risk.

Parasites

A mare with a heavy parasite burden may lose condition despite adequate feed. Use a targeted parasite control plan based on veterinary advice and faecal egg counts where appropriate.

Poor Hay Quality

Hay can look acceptable and still be low in energy, protein, or key minerals. Testing is the only way to know properly.

Herd Competition

Some mares are pushed away from hay or feed by more dominant horses. Feeding in a group can hide individual underfeeding.

Chronic Pain

Arthritis, hoof pain, back pain, or chronic disease can reduce appetite and condition.

Gastric Ulcers

Poor appetite, weight loss, irritability, and poor performance can sometimes be linked with ulcers, especially in stressed or recently transported mares.

Pregnancy Problems

A mare that is unwell, developing abnormal udder changes, leaking milk early, losing condition rapidly, or showing discharge needs veterinary assessment. Nutrition is not always the primary problem.

When Is This an Emergency?

Feeding decisions are usually planned, not emergency work. But some broodmare situations need urgent veterinary attention.

Call your vet promptly if:

• A pregnant mare stops eating

• She shows colic signs

• She has signs of laminitis

• She is rapidly losing weight

• She is late pregnant and exposed to possible infected fescue

• She develops abnormal vaginal discharge

• She leaks milk well before foaling

• She has no udder development close to foaling

• She is dehydrated or not drinking

• She has diarrhoea or fever

• She is weak, dull, or separated from the herd

• She is unable to chew hay properly

• She is late pregnant and seems painful or distressed

The fescue point deserves extra respect. University of Georgia lists fescue toxicosis signs in mares including prolonged gestation, dystocia, agalactia, thickened placenta, premature placental separation, weak foals, and foal mortality. (CAES Field Report)

What Should You Do Next?

1. Body Condition Score Every Mare

Do this before winter, then repeat every 2 to 4 weeks. Use your hands, not just your eyes. Winter coats lie. Ribs under fluff are sneaky little traitors.

2. Separate Mares by Need

Do not feed every broodmare the same way. Thin mares, easy keepers, late gestation mares, lactating mares, older mares, and young mares may all need different plans.

3. Assess Pasture Honestly

If mares are eating hay immediately, pasture is no longer enough. If pasture is overgrazed, feeding hay also helps protect paddock recovery.

4. Test Hay Where Possible

A forage analysis gives you energy, protein, calcium, phosphorus, and other useful values. Without testing, you are guessing.

5. Choose the Right Supplement Type

Use a ration balancer when calories are adequate but minerals are not. Use a broodmare concentrate when the mare needs calories plus nutrients.

6. Avoid Unsafe Forages

Do not feed dusty, mouldy, weed-contaminated, or unsafe fescue forage to pregnant mares.

7. Make Feed Changes Slowly

Introduce new hay, concentrate, or supplements gradually over 10 to 14 days where possible. Sudden changes can increase digestive upset risk. (Merck Veterinary Manual)

8. Protect Water Intake

Check water daily, prevent freezing, and remember that dry hay and lactation increase water demand. (Merck Veterinary Manual)

9. Plan for Late Gestation Before It Arrives

Do not wait until the last month to realise the mare is thin. The final months increase nutrient demand, and lactation is even harder.

10. Review the Plan With Your Vet

This is especially important for mares that are thin, obese, older, pregnant with twins previously, exposed to fescue, lactating, laminitis-prone, or difficult to keep in condition.

Common Mistakes Owners Make

Waiting Until the Mare Is Thin

It is much easier to prevent weight loss than to rebuild condition in late pregnancy or early lactation.

Feeding by Scoop Instead of by Need

One scoop means nothing unless you know the feed weight, forage intake, mare size, body condition, and nutrient profile.

Assuming Hay Is Always Enough

Some hay is excellent. Some is mostly expensive bedding with ambition. Test it where possible.

Relying on Mineral Blocks Alone

Some horses do not consume blocks consistently. A ration balancer or measured mineral supplement is often more reliable.

Overfeeding Easy Keepers

Obese mares are not automatically healthier. Overconditioned mares may have higher limb, hoof, and laminitis risk.

Ignoring Fescue

Pregnant mares and endophyte-infected fescue are a dangerous combination. This is one of the big broodmare nutrition traps.

Making Sudden Feed Changes

Abrupt hay or concentrate changes can disrupt the hindgut and increase digestive upset risk. Make changes gradually.

Prevention: A Better Broodmare Winter Feeding Plan

A strong winter broodmare plan should include:

• Body condition scoring before winter

• Individual feeding groups

• Hay testing where possible

• Clean, safe forage

• Adequate hay before pasture fails

• Balanced minerals

• Salt access

• Clean unfrozen water

• Regular dental checks

• Parasite control based on risk

• Hoof care and laminitis monitoring

• Safe fescue management

• Gradual feed transitions

• Late gestation diet review

• Lactation feeding plan before foaling

• Weight and condition checks every few weeks

The best broodmare feeding plans are boring in the right way. No panic changes, no mystery supplements, no winter rescue mission. Just steady condition, good forage, clean water, balanced minerals, and enough adjustment before the mare starts telling you the plan has failed.

FAQ

What body condition score should a broodmare be before winter?

Most broodmares should enter winter around BCS 5 to 6 out of 9. A BCS of 6 can provide a useful reserve before winter and early lactation, while mares below 5 need attention before nutritional demands increase. (Equine Programs)

Can a pregnant mare live on hay alone?

Some can, if the hay is high quality and the mare is holding condition. Many still need a ration balancer for minerals and vitamins. Late gestation and lactation often require additional nutrition, especially if hay quality is moderate or the mare is losing condition.

Is alfalfa good for broodmares?

Good-quality alfalfa can be very useful because it is higher in protein and calcium than many grass hays. It may reduce the amount of concentrate needed, but the full ration still needs to be balanced. (Equine Programs)

Should pregnant mares avoid fescue?

Pregnant mares should avoid endophyte-infected tall fescue, especially in late pregnancy. If fescue is present, test it and work with your vet. Many recommendations advise removing pregnant mares from infected fescue 45 to 90 days before foaling. (CAES Field Report)

When do broodmares need the most feed?

The highest nutritional demand is usually early lactation. Late gestation increases requirements, but milk production after foaling is even more demanding. Merck’s lactating mare nutrient table shows major increases in energy, protein, calcium, and phosphorus needs during early lactation compared with maintenance. (Merck Veterinary Manual)

Final Thoughts

Feeding broodmares before winter is about preparation, not panic. The aim is to keep mares in steady condition, support pregnancy, avoid unsafe forage, prepare for late gestation, and prevent the dramatic weight loss that can hit during lactation.

The key decision points are simple: score the mare, check the pasture, feed enough safe forage, balance the minerals, protect water intake, avoid infected fescue, and adjust the diet before she starts losing condition.

A broodmare does not need to be fat going into winter. She needs to be prepared.

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If you are unsure whether your broodmare is too thin, too heavy, getting enough hay, or safe on her current pasture, ASK A VET™ can help you work through body condition, feeding changes, and when veterinary support is needed.