How to use the lactating mare nutrients calculator
- Enter the mare's weight.
- Choose the stage of lactation.
- Press Calculate.
Worked example
A 500 kg mare in the first 3 months of lactation.
- Mare weight (200–900 kg)
- 500 kg
- Stage of lactation
- First 3 months of lactation
- Weight
- 500 kg (1,102 lb)
- Stage
- First 3 months of lactation
- Crude protein
- 1,468–1,535 g
- Calcium
- 55.9–59 g
- Phosphorus
- 36–38.3 g
Estimated average minimum requirements for the mare (NRC 2007), shown as a low–high range. Not a feeding plan: ask your vet or an equine nutritionist.
Example values are illustrative; this result is produced by the same calculator above.
How we calculate it
Sources: Merck/MSD Veterinary Manual · NRC
Understanding your result
A mare that is nursing a foal needs much more energy and protein than a mare at maintenance. The NRC (2007) table, reprinted by the Merck/MSD Veterinary Manual, gives requirements for the first three months of lactation and for the period from three months to weaning.
Because needs change over time, the table gives a low and a high value. At 500 kg, a mare in the first three months needs at least about 30.6 to 31.7 Mcal of digestible energy and 1,468 to 1,535 g of protein a day, compared with 16.7 Mcal and 630 g at maintenance.
The calculator returns the published values at 200, 500 and 900 kg and interpolates in a straight line for weights between them. The figures cover the mare only, are minimums, and are not a feeding plan.
Common mistakes
- Feeding a lactating mare as if she were at maintenance.
- Using the maintenance calculator for a mare with a foal.
- Treating the low end of the range as the amount to feed.
- Forgetting that pregnant mares have different needs.
- Changing her diet suddenly.
Good to know
- Ask your vet about body condition scoring during lactation.
- Good-quality forage supplies part of the requirement.
- Foals need their own feeding plan.
When to talk to your vet
- Your mare is losing condition
- Before changing a lactating mare's diet
- Your mare is pregnant
Frequently asked questions
Why is the result a range?
The published requirement changes during lactation, so the table gives a low and a high value. The calculator shows both.
Does it include the foal?
No. It covers the mare's own needs during lactation. Foals are fed and managed separately; ask your vet.
Can I use it for a pregnant mare?
No. Pregnant mares have different requirements, so ask your vet or an equine nutritionist.
Which stage should I choose?
Choose the first 3 months for a mare nursing a foal under three months, and 3 months to weaning after that.
Is the foal included?
No. Only the mare's needs are shown.
Why do the numbers rise so much compared with maintenance?
Producing milk takes a lot of energy and protein, so the published requirements are much higher than for a mare at maintenance.
Sources
- Merck/MSD Veterinary Manual — Estimated Average Minimum Daily Nutrient Requirements of Mature Horses and Ponies (table adapted from NRC 2007)
- NRC (2007) Nutrient Requirements of Horses, 6th ed., National Academies Press
Related calculators
- Horse Maintenance Nutrients CalculatorSee the daily minimum energy, protein, calcium, phosphorus and vitamin A a mature horse needs for maintenance, from its weight.
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- Horse Weight CalculatorEstimate your horse's weight from its heart girth and body length with a tape measure.
- Horse Hay Cost CalculatorWork out how long a bale lasts and what hay costs per day, month and year.
Estimated average minimum requirements from published tables, not a feeding plan. Ask your veterinarian or an equine nutritionist. If your pet may have eaten something harmful, contact your vet or an animal poison helpline now.