The project has been funded by SLU, the World Wildlife Fund, Helge A:son Johnsson, and contributions from the general public (crowdfunding).
The quality of autumn and winter grazing in year-round grazing for horses
Page reviewed:
11/10/2025
In a 2.5-year study in which Gotland ponies were used for year-round grazing, we collected grazing samples once a month to analyze how the quality of the grazing varied throughout the year.
About this project
In this study, Gotland ponies were kept in three enclosures 25 km northwest of Arlanda. Each enclosure contained four ponies and covered an area of approximately 10 hectares (3 ha of meadow and 7 ha of forest). Grazing samples were collected once a month from the meadows. Samples were taken where the horses were seen grazing.
No samples were taken during the months when the ground was covered with snow and ice (but the horses still grazed on both the meadows and forest land by scraping away the snow). In autumn and winter, parts of the meadows were heavily grazed, but a layer of vegetation always remained. The meadows also had large areas of overgrown grass where the horses avoided grazing.
Results
High protein concentration
In the period from October to February, the ratio between digestible crude protein (DCP) and energy varied on average between 9 and 10 g DCP/MJ. This is a very high ratio and corresponds to the needs of the most demanding horses (lactating mares). The requirement for an adult horse that is not pregnant or lactating is 6 g CP/MJ. The pasture therefore does not appear to have a limited protein content, even though there were a few samples that were low. At the lowest smb rp content measured, 30 g/kg dry matter (DM), an adult 500 kg horse would need to consume 12 kg DM of pasture to meet its maintenance requirements, which is within the horse's consumption capacity.
Low energy content
There was therefore no significant limitation in protein concentration, but the energy content varied between October and February, averaging between 5-9 MJ/kg DM. At an energy content of around 5 MJ/kg DM, some horses will not have the consumption capacity to meet their entire energy requirement. This means that an energy supplement needs to be given (unless the horse has extra body fat to burn). If the pasture contains >8 MJ/kg DM, this energy concentration is sufficient for most adult riding horses. However, there may be a limitation in that the availability of pasture (both in terms of time and quantity) is too small for the horse to consume its entire energy requirement every day. If the pasture is very short, each mouthful will not be very large. If the horse is not fat and would therefore benefit from burning some fat, it will need to be supplemented with energy.
If you keep horses on pasture, you can of course also take a sample of the pasture to get an idea of its energy and nutrient content. The sample should be taken close to the ground on patches of grass where you see the horses grazing frequently. You can also take a manure sample and analyze it for crude protein content (at a regular feed lab) because there is a certain correlation between the crude protein content in the manure and the crude protein content in what the horse has eaten. The crude protein content in the manure (g/kg DM) corresponds to approximately 70% of that in the pasture (g/kg DM), but the variation can be significant.
In years of feed shortage, based on the study, we can recommend that horses be fed pasture even during the winter months, at least up to the Uppsala region. The conditions that must be met for the above description to be relevant are that there is sufficient land area for vegetation to cover the ground at all times (no clay pastures) and that the grass has been grazed short during the summer and autumn. Pasture that has not been grazed during the summer (overgrown) can have a very low protein and energy content if there has not been some regrowth under the withered grass. To get an idea of the quality of this type of pasture, a feed sample must be taken. This is done by walking diagonally across the field and cutting a sample about 5 cm from the ground every 15-20 meters.
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