Most horse owners know that forage should make up the bulk of their horse’s diet, but knowing how much exactly to feed can cause confusion.
Feeding rates for hay can range from 1.0 to 3.0% of the horse’s BW*, but it is important to note that feeding forage at a rate less than 1.5% BW should only be done under the recommendations and supervision of a veterinary professional.
*on a dry matter (DM) basis, which excludes the weight of moisture within the hay.
When allowed free-choice hay, voluntary hay intake is often around 2.0-2.5% of their BW DM, which is why feeding 2.0% BW DM is often the recommended starting point for your horse’s diet.
Factors to Consider When Determining the Appropriate Feeding Rate for Your Horse
Current body condition score
The hay you’re feeding
Management practices
Available pasture
Climate
Dentition
Meeting voluntary intake rates can help satisfy natural behavioural and physiological needs, and depending on forage quality, can meet a large portion of your horse’s requirements. That said, determining how much hay you should feed your horse depends on numerous factors, which will be explored in more detail below.
Body Condition Score
Body condition scoring measures fat cover and storage on the body, and is a great indication of energy level suitability in the diet. Excess energy will lead to weight gain, while insufficient energy can contribute to weight loss.
Horses who need to gain weight and are currently eating 2.0% BW in hay can be increased to 2.5% BW in hay, or fed ad lib hay, to help increase calorie intake.
Horses who need to drop weight and have had calories reduced in other areas of the diet (ie concentrates) can be fed hay at 1.5% BW to reduce calorie intake.
Unfortunately, simply feeding more or less hay is not always the answer, due to variations in hay nutrient profiles.
The Hay’s Nutrient Profile
The amount of hay that you feed will also depend on the hay you’re feeding, and on factors such as maturity level and type of hay fed.
Maturity level will have a significant impact on the nutrient profile of your hay. Nutrients and energy content are higher in the leaf portion of hay, but as plant maturity increases, leaf matter decreases as the stem increases.
Note: monitoring consumption is also important. A horse may be fed 2.0% BW in hay, and may maintain that intake even if more hay is provided. When the horse is in otherwise good health, this is likely a reflection of the hay’s maturity level making it unpalatable.
Hay that is cut before maturity and has a high leaf-to-stem ratio will have higher energy and protein, and can be a great choice for horses with higher requirements, but may drastically oversupply energy for easy keepers even at reduced feeding rates.
The type of plants within the hay can also alter the nutrient profile, with legumes such as alfalfa or trefoil having higher protein than grass plants.
TIP: Hay analysis can help you have a better picture of the nutrient profile of your hay.
Remember, the best hay for YOUR horse is the hay that allows them to eat lots of it, while staying healthy and at a good BCS, whether that means feeding free-choice high quality hay to a performance horse or feeding 1.5-2.0% BW of a very mature hay to an easy keeper.
Management practices
Your feeding practices may also dictate how much hay you feed. Horses should not go longer than 4-5 hours without hay due to constant acid secretion in their stomach.
So, if hay provision practices cannot ensure that horses have hay throughout the day, you can use strategies such as slow feeding devices (like hay nets) or feeding more of a less nutritious hay to maximize chew time and slow intake!
If feeding a horse who needs controlled calories who can only get tossed hay once or twice a day, feeding more of a mature hay in a slow feeder is better than feeding less of a more energy-dense hay.
Supplying multiple slow feed stations in your turnout field can also promote energy expenditure, mimic natural foraging behaviours, and be a useful strategy to slow intake without frustrating the horse.
Pasture availability (a pasture with dense grass (6-8 inches tall) can replace some hay inclusion in the diet at estimated intakes of 0.6 kg per hour), but horses in a dry lot or overgrazed pasture will require hay to supplement their grazing time.
Climate
Climate can also impact your horse’s energy needs, and as such, how much hay they should eat. Thermoregulation expenditure in cold weather can increase maintenance energy needs by 25%, and all horses should be fed extra hay when temperatures fall below a horse’s lower critical temperature.
Lower Critical Temperature (LCT): The minimum temperature that metabolic heat production can function to maintain core body temperature (Morgan, 1998; Novak, Shoveller and Warren, 2008).
A horse’s LCT ranges between -15°C to 5°C when their winter haircoat is dry, depending on age, precipitation, season, body condition and hair coat (DeBoer et al, 2020), but increased dry matter provision and will be required to support each horse when the temperature is below their lower critical temperature. It is estimated that at maintenance, a mature horse’s energy requirement increases 2.5% per degree Celsius below LCT (Cymbaluk, 1994).
Horses who are not blanketed in the winter have been reported to increase their hay intake to 2.51% BW, compared to blanketed horse intake of 2.3% BW (DeBoer et al, 2020).
Note: some horses may need additional sources of energy added to the diet during sustained cold. Consider adding easily digestible fibers such as beet pulp, which can help promote hydration and digestive health during winter months as well.
Dentition
Senior horses or horses who cannot handle long-stem forage due to other health issues may require for their long-stem forage ration to be replaced with feed that is safer for them to consume.
When using commercial hay replacers or products such as hay cubes/pellets, they need to be fed to replace hay in a 1:1 ratio - for instance, if you are replacing 1 kg of hay, feed 1 kg of hay replacer, keeping total forage intake above 1.5% BW as a minimum.
Note that feeding management of these hay replacer meals is also incredibly important. As these rations are easier to chew than hay, horses will eat them faster, which can increase time spent without feed. Using slow feed buckets or feeding smaller meals throughout the day to minimize time spent without feed can help maintain normal digestive processes.
Some Tips When Feeding Hay
Feed by weight: While it may not be practical to weigh every hay ration you toss to your horse, if you feed square bales, we recommend weighing a couple flakes to get an idea of the average weight per flake. Fish hanging scales are an economical option for a more accurate barn feeding program.
Gain some geographical accuracy: If not testing your hay, look for average hay nutrient data based on your geographical area. These reports can often be found online via “[your area] forage summary [year]”. We are always happy to help you find this information if you need a hand!
Still need help figuring out how much hay to feed your horse? Let’s connect!
References
Cymbaluk, NF., Christinson, GI. 1990. Environmental Effects on Thermoregulation and Nutrition of Horses. Veterinary Clinics of North America: Equine Practice 6(2): 355-372.
DeBoer, M., Konop, A., Fisher, B., Martinson, K. 2020. Dry Matter Intake, Body Weight, and Body Condition Scores of Blanketed and Nonblanketed Horses in the Upper Midwest. Journal of Equine Veterinary Science 94(2000): 103239.
Cymbaluk, NF. 1994. Thermoregulation of horses in cold, winter weather: A review. Livestock Production Science 40(1): 65-71
Novak, S., Shoveller, AK., Warren, LK. 2008. Nutrition and Feeding Management for Horse Owners. Alberta Agriculture and Rural Development.
NRC. 2007. Nutrient Requirements of Horses: Sixth Revised Edition. Washington, DC: The National Academies Press. 2007. https://doi.org/10.17226/11653
Morgan, K. 1998. Thermoneutral zone and critical temperatures of horses. Journal of Thermal Biology 23(1): 59-61.
