Mud ’n’ glory Managing your pasture over winter is a daunting task, but your horses will be the better for it, as Dr Lucy Tucker PHD explains
Many horses and ponies in New Zealand are kept out at pasture all year round – we are fortunate our climate allows us to do this, although it is not always without problems. Hardy ponies often do not need covering, and most horses are fine with a winter cover on to keep the worst of the weather out.
Understanding how to get the best out of your paddock during the winter is important in terms of feeding your horse and making sure you have good grass available coming into the spring. This month, I want to look at the dynamics of horse paddocks in winter, what nutrition you can expect from them to provide to your horse, and some idea of how to manage grassland in the coldest and wettest months.
Location matters
Firstly, where you live and your local climate will dictate how useful your grassland is through the winter. In the ‘winterless north’, grass will keep growing all year round.
However, wherever the temperature falls below 10°C, grass will stop growing. The fertility of soil will also change depending on the season, as the biological cycles in the soil, as well as issues like water-logging, will affect the availability of nutrients such as nitrogen and minerals to the plant, and may also inhibit root activity.
In winter, grass is in its mature phase and not rapidly growing. In this situation, certain nutrients (eg. protein) become bound to structures in the plant, making them less digestible. So even though chemical analysis may show these nutrients are present, they may not be available for digestion.
These winter factors combine to affect the relative amounts and nutritional value of grass, which is why we typically have to supply preserved forages and extra hard feed to horses and ponies in the cold months. The data in Table 1 show the variation in grass nutritional composition and digestibility, based on US trials, between spring (actively growing) and winter (dormant) periods in a mixed horse pasture made up of 50% smooth meadow grass (Kentucky blue grass), 30% tall fescue and 20% orchard grass.
These numbers illustrate how much the nutritional situation changes from season to season, and explain why horses often lose weight in winter.
Grass nutrient content and digestibility by season (Lewis, 2005)
Nutritional value Spring Winter
Digestible energy (Mcal/kg) 2.57 2.44
Protein (%) 14.7 13.8
Digestibility*
Dry matter digestibility (%) 60 18
Digestible protein (%) 14 7
*Orchard grass and clover
Remember to keep a close eye on your horse’s condition score during the winter months, so you can feed more or less as they require to make sure their correct weight is maintained. I recommend checking your horse at least once a week – without his cover on! And remember to use your hand to ‘feel’ the amount of cover over the ribs – long, thick coats can hide the fact the horse is getting skinny.
If you have a late-weaned foal, he or she will need feeding a balanced hard feed in order to maintain growth and development, if they only have access to winter grass.
Mud, glorious mud!
As a grazing animal, horses are not very kind to pasture. Their body weight to hoof size ratio makes them very heavy on the ground, causing the soil to become churned into mud. The fact that they enjoy galloping around, regardless of ground conditions, adds to this problem.
Their ability to make holes in pasture causes the sward (grass cover) to become very open, allowing airborne weed seeds access to fresh soil in which to take root and flourish. Constant ‘ploughing’ by horses’ hooves turns the soil over, exposing previously dormant weed seeds, which then actively grow. This is why poorly managed horse paddocks become full of weeds and bald areas very rapidly.
Areas with particular ‘wear’ or boggy problems in horse paddocks include gateways, water troughs and feeding areas.
It is possible to improve these areas by putting down stone or other materials (eg. wood peelings) to reduce the muddy mess. Alternatively, move troughs regularly to reduce damage, or strip-graze horses using a back tape as well as a front tape fence, as this will spread the load evenly over the paddock, allow grazed areas to recover and will make sure the paddock is grazed evenly.
Feeding out
When feeding out supplemental forage, such as hay or silage, it is important to make sure these areas are rotated and cleaned up and the animals are encouraged to ‘eat up’ each feeding area (or wasted forage must be scraped up and disposed of) to prevent the forage creating a thick ‘thatch’ over the grass, which will smother its subsequent growth.
Dried forages, in particular, contain seeds, which will become scattered within the feeding area and will take root in the spring, so harrowing to spread these seeds evenly across the ground is important to prevent the development of patchy areas of new grass appearing.
If you are feeding silage, make sure you have enough horses per bale or feed out small enough amounts to last for about a week, as potentially toxic moulds will start to grow if you leave it exposed for longer periods of time.
Coping strategies
As for strategies to help overcome the winter mud blues, if you are in a very wet area, you could try to rent some winter grazing on, for example, sand country, to prevent your horses damaging your own grassland.
My own paddocks are loam over clay, which is great in summer, as the clay keeps the moisture in, allowing grass growth in dry weather.
However, in winter it can all become rather messy, especially when it has rained non-stop for the past three weeks!
In these situations you can always nominate a ‘sacrifice paddock’, ie. one that may be scheduled for resowing in spring, so the horses can make a mess in it without you worrying about pasture recovery.
We are lucky to have a large paddock with big trees at one end which do a fabulous job of sucking the moisture out of the ground, leaving a dry area for feeding out forage and as shelter in poor weather. If you are planning to plant any trees on your paddocks, do think about where to put them where you could create dry areas in winter for your horses.
