Winter is a time when we have to pay special attention to all stock, including our equine friends. Even the transition period between the seasons needs special attention to ensure they are getting the best out of the feed available.
It’s useful to start by considering how a horse’s nutrient requirements change depending on the season. Energy is a fundamental requirement for all living things, and its release and use depend on the environmental conditions the animal experiences. We can all relate to the fact that the more exercise we do, the more energy we need, or we lose weight. In colder weather, a horse will use more of the energy generated from its feed to keep warm, leaving less for maintaining the tissue reserves that keep its body in good condition. This is why so many horses lose weight during winter. Those most at risk include any which already have problems getting the best from their feed (eg. older animals), those prone to colic or other digestive disorders, the highly strung and the naturally skinny ones. There are two ways to counter weight losses: increase feed and use covers or provide shelter to maintain body heat.
The big cover-up
When using covers, it is important to check your horse at least once a week and monitor their body condition score. I always get a flood of enquiries following the winter season with the same story of an owner who hasn’t taken off the cover for months, and is now faced with a mount that resembles a toast rack with a triangular rump. In these situations it can take many months for the horse to regain condition and top line, leading to big feed bills at the very least, as well as potential deficiency problems (especially noticeable in hooves and coat) and a reduced ability to perform.
Allowing body weight to fluctuate widely is not a good thing. It can lead to all kinds of problems that may take years to manifest. It is always important to try to keep your horse’s weight as stable and as close to optimum as possible, regardless of the season.
Mild or harsh climates
The extent that winter affects grazing animals depends on your local climate. This varies greatly between regions, of course, with some areas (eg. Northland) being warm enough to enjoy all-year-round grass growth. In this situation, it is important to remember that, just because grass grows, it isn’t always the same. The levels and forms of nutrients present within the grass vary on a daily basis, depending on sunlight strength, actual temperature, rainfall, soil conditions and soil quality. Many owners feel that they can leave their horses out to graze all year round with little additional input. This may be achievable if you pay very careful attention to the grass varieties sown and the condition of the soil, but in most cases, horses managed in this way eventually show some form of deficiency, which may be directly or indirectly manifested as a physical problem. This is why it is important to test your soil and grass regularly, and manage it accordingly if you do not wish to feed anything to your stock.
If you do not practise careful paddock maintenance, it is important to be aware that during the winter season, your horses may well be deficient in essential nutrients. At the very least you should provide them with access to vitamins and minerals. This is especially important for youngstock and pregnant broodmares, who have greater nutritional requirements necessary for growth or the correct development of their foals in utero, respectively.
In colder regions, the predominant grasses tend to be more fibrous (such as brown top) and so present less of a problem in terms of flush growth. However, as the temperature dips below 10ºC, so the grass stops growing, and horses may be left with little to eat after a while. The grass becomes metabolically dormant, which means it is not actively manufacturing any nutritionally useful compounds within its cells. If your region is prone to snow, this makes it even more difficult for them to find grazing. Hence, all ponies and horses kept in colder conditions need supplemental feed.
Transition between seasons
Most regions are at risk from the autumn flush of grass, especially on dairy pastures, as perennial rye grasses are particularly prone to this additional growth. When growing rapidly, grasses provide a good source of non-structural carbohydrate, with little of the fibre (structural carbohydrate) that the horse needs to maintain correct gut function. This is why many horses have diarrhoea that smells acidic during spring and autumn. In order to reduce this problem, a good source of dietary fibre must be fed, to balance out the sugar and re-establish hind gut fermentation. Pre- and pro-biotics are useful to rebalance severely affected individuals.
Autumn and spring are also the times where you seem to be forever changing covers – one minute it’s bright and sunny, and the next it’s cold and wet. But even in the midst of winter, if you have an occasional warm day, check your horse is not too hot under its cover, and remove or replace it with a lighter one if necessary. Many horses in New Zealand are over-covered by their owners. This can lead to chronic heat stress or depleted tissue mineral reserves from sweat losses.
Most horse owners select some kind of forage to feed out during the winter. This may be given as hay, silage, haylage (which has a higher dry matter normally than silage) chaffs or moist feeds. If you have a choice, select hay that feels hard to scrunch up, as this is a basic gauge to the level of fibre it contains. It is straightforward nowdays to have your forage tested in a lab, for minor cost. The results will tell you exactly what it contains, and can be used to identify imbalances or insufficiencies.
But the reality is in many places, low availability and high cost of forage sources, plus a lack of suitable storage, means many horse owners have to use what forage they can find or afford. This is a worrying situation, as affordable sources may be poorer quality. Horses are more adversely affected by dusty or mouldy forages compared to cattle or sheep. Older bales, especially made with very leafy plants, such as clover, become dustier than newer hay made with fibrous grass varieties.
If you find yourself faced with using poor quality forage, remember to counteract the damaging effects of dust by soaking it. Soaking doesn’t need to be for a long time; a good dunking will often suffice, or tip buckets of water over the forage balanced on a grill of some sort to allow draining. Over-soaking causes the loss of water soluble nutrients.
If you are using a tub for soaking, remember to change the water regularly to prevent it becoming a soup of fermenting and rotting material, which will be a source of further contamination for your horse!
Check each section of bales and remove obviously mouldy areas by hand (wear a dust mask for your own protection). You can feed a proven mycotoxin binder to limit the risk from potential exposure to the toxins.
Be aware that preserved grasses, especially the dried forms such as hay, contain lower levels of antioxidant vitamins compared to fresh grass. This is because the vitamins are degraded by UV during the curative process of drying. In New Zealand, where antioxidant mineral levels in the soil are already low and UV is high, this can become a major problem, leading to many different types of oxidative disease, including cancers, infertility and neurological damage. Additional supplementation will insure against long-term problems.
If you supply your horse with a complete and balanced compound feed at the correct amount for its body weight, then the horse should be receiving sufficient nutrients to sustain it. This assumes that the feed has been formulated to the latest requirements of horses (according to the published research).
During your weekly condition score check, you may well observe a drop in weight as winter progresses – perhaps through a slight prominence of the spine at the rump or more noticeable ribs. In this case, increase the feed until the horse is back to an optimal condition, and then reduce levels gradually until you reach a steady state in condition score.
Don’t forget the good doers
Some owners are lucky enough to own good doers who winter-out with no problems. Do be aware that these horses will still need a regular supply of vitamins and minerals at the very least, as the levels in the grass will be low. Many good doers are left to their own devices and can be rather neglected during the winter if they are not being ridden. Remember, they still need to be checked on a daily basis.
Water, not ice!
Water is an essential nutrient that is often overlooked. Always keep an eye on the water supply, especially in very cold weather. Keep a ball floating in the trough to make a ‘nose hole’ if ice formation is likely in your area, and remember to ensure all automatic filling systems are operational in freezing conditions.
Areas around water troughs and feeding areas are prone to becoming very muddy, so moving them around is good if you are set up to do this. Mud fever thrives in these circumstances, and animals with inadequate antioxidant intakes are more prone to developing these and similar skin conditions due to their lower immune status.
Some horses, such as hunters, work their hardest during the winter, and have extra nutritional requirements as a result. Remember to feed according to the amount of work done, and keep a careful look out for any condition loss. If your horse is fit and clipped, then make sure it has a good enough cover to maintain its body heat. I have seen some hunters turned out on hills fully clipped without covers and with very little body fat immediately after the season has finished. This practice is pretty much guaranteed to cause major weight loss, cold shock and poor circulation, leading to poor welfare.
Irrespective of the season, you should allow your horse to cool down to a good, resting temperature after strong exertion. In colder weather, many owners forget the large change in the horse’s body temperature that occurs following exercise if not cooled down correctly. The blood supply to the gut must be fully re-established before feeding, and during hard work (especially where the horse is excited), this flow is preferentially directly to the muscles.
Walk back to the truck quietly, and allow the horse to stand for at least another 30 minutes before offering any feed, and use suitable covers to prevent cold shock. These actions will help to prevent certain colics and will maximise the horse’s ability to extract nutrients from the feed, replacing those lost during the day.
Always make sure your horse is well hydrated following any major exercise.
Basically, our horses are very like ourselves in their winter needs – give them enough grub and wrap them up warmly and they should be fine!
- This article was first published in the June 2008 issue of NZ Horse & Pony
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