Dear Jessica, First, we would like to thank you for your great help. We have read your advices for many years and have learned a lot from you doing so. Now, we would like to ask you a question that may not be of any importance in the US (we couldn't find any answers in your archives on the subject), but it does matter to us in the Netherlands. Our horses live on a farm near the coast in Holland. The animals (cows, sheep) on this farm are kept in a natural way. But here's our question: not only the cows but also the horses on this farm are fed ensilaged grass. Now we think that this kind of grass is not healthy for horses, only for cows, but the farmer disagrees with us and keeps arguing that we should feed our horses the ensilaged grass instead of hay. One of our horses has a lung-problem and the fed adviced us to feed her wet hay. Now, our stable keeper tells us that ensilaged grass is much better for the horse because it is less dusty. Could you help us out? Thanks very much, many greetings from Holland, Anneke and Femke.
Your question is a good one, and it should interest at least some horse-owners in the USA. Silage is slowly gaining in popularity as a horse feed in the USA just as it is elsewhere in the world. There are some particular problems associated with silage, though, and you have brought up some of them in your letter.
Silage - preserved, high-moisture forage - can provide grazing animals with nutrition and bulk. It can be an excellent feed for cattle. It can also be used as a supplementary feed for horses, under very specific conditions.
Although silage can be an excellent feedsource for cattle, it isn't quite as useful for horses. Horses have different needs, and very different digestive systems. Cattle can digest and benefit from feed that a horse could not eat and survive, and if you are going to feed your horses any silage, you will need to manage them, and the silage, carefully.
The management begins with the process of making the silage. This process needs to be a little different if the silage is intended as horse feed instead of cattle feed. The forage should be left to grow for a week or ten days longer than it would be if it were intended for cattle; for horses, it's best if the forage is allowed more growth for stem development. This is something that your farmer may already be doing - talk to him about it.
Here's my advice.
If you are going to feed your horses silage:
1. Feed only the very best silage, preferably silage prepared specifically for horses.
2. Feed the silage as a PART of the horses' diet, not all of it - perhaps one-third silage to two-thirds hay. Their diet should certainly contain no more than half silage. You can figure that one pound of dry hay is the equivalent of about three pounds of silage. (see #3)
3. Know the moisture content of your silage, so that you will know how much actual feed your horses are getting. Silage has a high moisture content, so horses consuming a diet of two-thirds hay, one-third silage, or of half hay, half silage, will require a good deal more feed (in terms of weight) than horses consuming hay/dry matter only. In other words, don't forget that twelve pounds of dry hay is twelve pounds of hay; twelve pounds of silage may be four pounds of hay and eight pounds of water.
4. Be sure that the moisture content of the silage is consistent - and that it is always moist. Too-wet silage may ferment for too long and lose some nutrients, which will make it less than ideal feed, but too-DRY silage will quickly mold and spoil - and this will make it dangerous for horses to eat.
5. Feed silage as small "meals" - not as large amounts provided free-choice. Silage should be fed to horses only in amounts that they will eat immediately - it can't be left exposed to the air, as it will become dry. When silage is exposed to air and begins to dry out, it can become very dangerous to horses. Exposure to air results in the development of molds and toxins, and sometimes of mycotoxins. This isn't usually a problem for cattle, but it can kill horses. Botulism, for example, is a serious problem associated with silage (and, in some cases, haylage). Botulism is usally not a problem for cattle, thanks to their special digestive systems, but it is very dangerous and often fatal to horses. Horses, unlike cattle, are extremely susceptible to botulism. If symptoms of botulism are noticed very early, and if horses are given prompt medical attention, they may survive, but only if they haven't been exposed to a great deal of the toxin. If you are going to feed silage, be prepared: Talk to your veterinarian and ask about a vaccine to protect your horses from botulism. You may also want to ask about an anti-toxin, which, IF your veterinarian can get it, may be helpful if it is used immediately upon the appearance of symptoms.
I hope this helps you decide how to feed your horses. Please talk to your veterinarian about this question, and ask him to look at this particular farmer's silage and at the conditions of management. If he thinks that it would be safe for your horses to consume SOME silage as part of their daily diet, then it may be worth trying. My guess, however, is that your horses would be healthier on a normal diet of grazing and hay. Since one of your horses needs to have its hay soaked, and since at best, silage can make up only part of a horse's diet, you will find that you are still soaking hay in any case. If your horse becomes unable to eat even soaked hay without a recurrence of its lung problem, you may need to change that horse's feed completely, perhaps to a combination of a nutritionally-complete feed and beet pulp (as a ource of roughage).
I suspect that your vet will agree with the following:
When the forage is suitable for horses, AND when the forage is ensilaged in a way that excludes air and results in a clean, low pH silage, AND when the silage is kept clean and uncontaminated, with the same moisture content and the same low pH, AND when horses are managed in such a way that (a) only top-quality silage is fed, (b) the silage makes up only one-third to one-half of their diet, the rest being hay, and (c) the amount of silage fed to the horses at any one time is just enough for them to consume promptly and completely, THEN silage can be useful as horse feed.
Back to top.
Jessica Jahiel's HORSE-SENSE is a free, subscriber-supported electronic Q&A email newsletter which deals with all aspects of horses, their management, riding, and training. For more information, please visit www.horse-sense.org
Please visit Jessica Jahiel: Holistic Horsemanship® [www.jessicajahiel.com] for more information on Jessica Jahiel's clinics, video lessons, phone consultations, books, articles, columns, and expert witness and litigation consultant services.