Equine Energy Nutrition: Concepts, Requirements, and Feeding Decisions

Energy (in equine nutrition)

A property of feed describing usable fuel obtained after digestion and metabolism.

Nutrients

Parts of the diet that can be turned into usable energy, including carbohydrates, fats, and proteins.

Energy requirement

What the horse's body needs in terms of energy.

Energy supply

What the ration provides in terms of energy for the horse.

Calorie (cal)

A small unit of energy, often too small for practical feeding.

Kilocalorie (kcal)

Equivalent to 1000 calories, commonly used in nutrition.

Megacalorie (Mcal)

Equivalent to 1000 kilocalories, commonly used unit in horse feeding.

Digestible energy (DE)

Gross energy minus energy lost in feces; widely used for ration formulation.

Gross energy (GE)

Total energy in the feed, measured by burning it.

Metabolizable energy (ME)

Digestible energy minus energy lost in urine and gases.

Net energy (NE)

Metabolizable energy minus heat produced during digestion.

Maintenance energy

Energy needed for basic life functions, normal movement, and thermoregulation.

Production energy

Energy needed for growth, pregnancy, lactation, and exercise beyond maintenance.

Hindgut fermentation

Process that breaks down fiber through microbial action in the cecum and colon.

Volatile fatty acids (VFAs)

Products of fiber fermentation in the hindgut used as energy.

Starch

A carbohydrate that's broken down into glucose for immediate energy use.

Fat

Energy-dense nutrient that does not rely on hindgut fermentation.

Body weight (BW) in maintenance equation

Used to estimate daily digestible energy needs in horses.

DE from feed calculation

DE concentration multiplied by amount fed per day.

Energy density

Amount of digestible energy per unit weight of feed.

Forage quality

Impacts digestible energy and overall energy intake of the horse.

Maintenance DE equation

$\text{DE}_{\text{maintenance}} = 1.4 + 0.03 \times \text{BW}_{\text{kg}}$.

BCS (Body Condition Score)

Standardized method for evaluating fat cover on a horse.

Underfeeding energy

Leads to mobilization of body fat and can even break down muscle for energy.

Overfeeding energy

Can lead to obesity, which increases metabolic risks and joint stress.

High-starch feeding risk

Can disrupt hindgut fermentation and lead to digestive upsets.

Practical feeding adjustments for lactating mares

Prioritize very high-quality forage and increase energy density.

Track weight trends

Focus on gradual weight change over weeks—not single measurements.

Fat as an energy source

Increases calorie intake without significantly increasing meal volume.

Protein's role in energy

Primarily needed for tissues; not an efficient energy source.

Energy surplus interpretation

Indicates the horse may be gaining weight or has higher activity levels.

Energy deficits signs

Body fat and muscle loss, leading to potential health issues.

Digestive health importance

Focus on maintaining gut stability while increasing energy intake.

Feeding concentrates correctly

Split into smaller meals to prevent digestive disturbances.

Calories in forage

Not all hays are low energy; some can be quite calorie-dense.

Regular monitoring of body condition

Helps justify ration changes with objective observations.

Maintaining energy balance

Through adequate ration adjustments based on activity levels and physiological state.

Hard keepers feeding strategy

Use higher-energy, more digestible fiber sources rather than simply adding grain.

Effect of low-quality forage

May struggle to meet energy needs, impacting condition and health.

Daily energy requirement computation

Using maintenance DE equations and adjusting for work or physiological state.

Gaining weight management

Must increase energy intake slightly positive above maintenance.

Safe energy increase strategy

Maximize forage quality before adding concentrates.

Assessing forage intake

Recognizing pasture can sometimes exceed calorie intake of hays.

Avoiding drastic ration changes

Prevent behavioral and digestive problems.

Fostering gradual dietary adjustments

To align with horse's energy needs effectively.

Recognizing over-reliance on grain

As a solution to energy deficiencies.

Cautions with protein supplements

May fail to address primary issues of energy deficit and increase nitrogen waste.

Assessing energy sources systematically

For effective ration formulation and analysis.

Calculating additional DE from supplements

Using provided energy values to guide feeding adjustments.

Evaluating energy sources effectively

In the context of specific horse performance goals.

Feeding solutions for easy keepers

Focus on reducing calorie density without limiting forage intake.

Interpreting ration calculations versus horse condition

Always check practical responses against numerical calculations.