Understanding Grass

I was asked an interesting question by a new horse owner last week.

“How much grass is enough grass?”

The million dollar question.

To me, and to many other horsey peoople, the answer comes from observation, and instinct. To explain our reasoning, however, requires a degree.

Here I`m going to try to explain the elements that we consider when looking at paddock use, rest, and rotation.

The Horse

Different horses need different amounts of food; a native will survive from lower quality, or quantity, of grass than a finer horse of a similar size. Does the horse suffer from laminitis? This will affect the amount of grass they should be permitted for health reasons. Other factors such as their age, body condition, size, and workload, will have an impact on their dietary requirement. 

The Time of Year

Grass is more nutritious in spring and autumn, with higher levels of carbohydrates, and when the temperature is above six degrees celsius grass grows. This means that horse`s need less grazing space when the grass is growing quicker otherwise they risk being overfed. At different times of the year horses are on the pasture for different lengths of time; in winter most horses are stabled at night, and in the summer many live in the field all day. 

The Land

Take a look at the actual grass and weeds that grows in the field; this will give a clue to the pH of the soil (acidic soil gives rise to buttercups, docks, and dandelions). Different grasses grow at different rates in different types of soil and be of a varying nutritional level, and the type of herbs that grow will also be affected. Herbs are beneficial to the horse`s diet but, for example, clover is high in protein and will encourage weight gain. This means that each pasture is different, and it`s makeup needs to be considered when determining how much grass is there. Additionally, different soils cope with adverse weather in different ways – clay soil retains moisture so is harder to manage in the winter. The length of time that a pasture has been there influences it`s durability as the grasses have a more established root structure, so will survive wet conditions better as the soil is less likely to wash a way. If the soil is well draining grass will begin growing earlier in the year, which will affect the time of year and amount of grass growth. It is quite easy to have a soil analysis test taken, and professional advice sought to help manage the grasses on your particular field. Weeds inhibit the growth of grass, so the quality of the grass in a field with a large number of dock leaves will be of a lower quality.

Pasture Management

How you care for the paddock on a day to day basis affects it`s sustainability and how quickly it recovers when it is rested. A pasture that is poo-picked daily will have a lower worm burden, and the grass will grow more evenly; not generating patches of long, sour grass which is not eaten by horses. Over stocking a pasture will lead to the grass being eaten down very quickly  and becoming too short, which inhibits it`s ability to regenerate. Additionally, leaving horses on a pasture for too long will mean that the grass is eaten too close to the root and the root and structure is disturbed. The usual pasture management, such as harrowing or fertilising, will affect the quality of the grasses. It can be useful to fertilise the land to ensure that there is sufficient levels of nitrogen, phosphorus, and potassium to ensure that the quality of the grass is suitable for horses. Excessive, or incorrect type of fertiliser, can produce rich grass, which puts horses at risk of colic and laminitis.

This list of factors is by no means exhaustive, and over a year or two horse owners begin to know their land, the weeds that tend to grow, how the grass recovers, and it`s rate of growth during the year. By poo-picking daily you have the opportunity to study the ground beneath your feet and the amount of grass there. It is allso useful to assess your horse`s weight and body condition on a weekly basis, as weight gain in spring suggests that the grass is growing too quickly for the horse to eat, and the horse needs less grazing.