Protein for horses

Protein and energy in forage for horses

There is debate in Sweden and other countries about how much protein and energy a horse should have. This debate is also found in equestrian sport disciplines and breed societies. Exclusive Horse Feed chooses to follow science and research to arrive at protein and energy levels that correspond to the recommendations of experts in Sweden and other countries. By carefully monitoring research into forage for horses, Exclusive Horse Feed has been able to optimally develop feed suited to different types of horses and their performance levels.
Protein for horses

Daily protein requirements for horses

The protein requirement of an adult horse is 6 g of digestible crude protein/MJ. Noticeable adverse effects occur if this protein requirement goes unmet for longer periods of time. Breeding stock, growing youngstock and horses in training and competition are particularly in need of protein. Energy and protein are the building blocks of a physically sound horse.

Exclusive Horse Feed’s protein and energy recommendations for different equine categories are shown in the table (please note that these are recommendations only, and that requirements vary between individuals).

CategoryEnergy (MJ/kg DM)Digestible crude protein (DCP)
balance (g/kg DM)
Foals>10>75About 8-10
youngstock>10>75About 8-10
Heavily pregnant mares>10>75About 8-10
Lactating mares>10>75About 8-10
Performance horses>1055-60About 6
Leisure horsesAbout 945-55About 6
PoniesAbout 945-55About 6

Explanation of terms:

Crude protein: this is an expression of the nitrogen content of the feed. The nitrogen content is analysed using something called the Kjeldahl technique. This value is multiplied by 6.25, giving a result called crude protein. The average protein contains 16% nitrogen. This fraction also contains other substances than full proteins, such as amino acids, peptides, nucleic acids, ammonia, amines, amides, and so on.

Digestible crude protein: not all crude protein is equally easily digested by animals. There are different calculations for different animals (cattle, horses, etc.) to obtain what is called digestible crude protein (DCP). DCP is generally used in calculating the diet of a horse.

Energy: energy is given in Megajoules (MJ) or Megacalories (Mcals). In Sweden, energy requirements and the energy content of feed are quoted in metabolisable energy (ME) in the unit MJ. In Germany and the UK, requirements and content are quoted as digestible energy (DE) and in the unit MJ. The energy content of feed can be calculated in a number of different ways. For forage, the digestibility of the forage is used to calculate its energy value.

Gross energyMinus energy in faecesMinus energy in urine
and intestinal gases
DE, digestible energyMinus energy as heat
ME, metabolisable
NE, net energy

Studies of the reactions of performance horses to a high protein intake from forage

High protein content in the feeding

Scientist Sara Muhonen from the Swedish University of Agricultural Sciences has studied high protein content in the feeding of trotting horses in racing condition. The horses were fed with two types of forage with high energy contents (11.2 MJ/kg DM). One forage had a high level of crude protein (16.6%), i.e. more than is normally recommended by the NRC, and one within the recommended guidelines (12.5% crude protein). The study also involved abrupt changes in feed to study the horses’ adaptability to a greater protein intake.
Energizing horses

Faeces and urine were collected for measurement of water intake, and at the end of each feeding period a work test was carried out, on a treadmill as well as on the track, so that the drivers could subjectively judge how the horses had been affected by the high protein levels in their feed. Were the horses more, or less energetic? The results of the study showed that the drivers did not notice any difference between the horses fed high-protein haylage (160% of the recommended intake) and those fed lower-protein haylage.

The result of research

The horses had no problems maintaining their body weight, which showed that forage with a high nutritional content can be sufficient for the working horse’s energy needs. What was noted, however, was that the horse’s fluid balance was affected when they were eating the high-protein feed, with the horses drinking an average of 4 liters a day more when they were eating the high-protein feed. The pH of the blood did not change, but the pH of the urine fell, showing that hydrogen ions had been excreted. The results showed that horses that carry out short intense bursts of work can easily manage the excess protein. One interesting fact of note however is that the effects on fluid balance may be disadvantageous for horses that lose a lot of fluid, such as endurance horses.