Horses – how they graze and how they digest their feed must be considered when talking about methods of producing stored forage and how it is to be fed.
The horse is a grazing animal and in the wild spends little time in one place. He is constantly eating and walking, only taking time to drink and rest. Horses have adapted their muzzle to be used as a sorting device to separate what they want to eat from the rest. They use their teeth to grasp the grass, and with a sharp sideways motion the grass is torn and moved into the mouth to be chewed. After several bites, the head comes up and the chewing continues until the feed is swallowed.
This is important for several reasons: 1) the grass is torn into relatively short pieces 2) the head is moved away from the ground frequently and 3) the horse is moving for the majority of the time he is eating.
Ruminants (such as cows) have evolved to have 4 stomachs which they use to “pre-digest” the forages they eat. They largest of the 4 stomachs is the rumen. It is host to hundreds of organisms that break the forages down into digestible forms on which the rest of the gut can do the real job of digestion. At the same time the rumen acts as a buffer removing many of the toxins and contaminants from the feed before they enter the “real” digestive system. Also, the cow has the ability to regurgitate the forage so that very coarse feeds can be chewed, swallowed and then regurgitated to be re-chewed into more digestible sizes.
The horse has a very different system, and may have been the original hybrid. It starts with a simple stomach (very similar to man’s) which starts the breakdown of the non forage part of the ration – grains/starches – and continues until it reaches the cecum and large colon which are completely redesigned – enlarged and elongated. This area receives the forages largely unchanged where it undergoes a similar type of digestion that occurs in the cow - the “fermentation” releases the nutrients from the forage in a form that can now be absorbed.
What this means is that the horse has to be careful of what it eats and how much it is broken down so that it can pass through the stomach to get to the cecum and large colon. Also, the quality of the feed is much more important since there is no fore stomach to remove contaminants and toxins before they enter the digestive system. In addition, the horse has problems with extremely coarse feeds which cannot be re-chewed and fermented like the cow does before having it enter the smaller areas of the digestive system.
These basic differences in two types of animals that on the outside appear to be eating the same types of feeds lead to vast differences between what is acceptable/desirable for each. That being said, I will now focus on the types of forage and the way they are produced that are best for use in horses.
ROUND BALES
Round bales are arguably easier and more efficient to harvest, cheaper to purchase, and less labor intensive to feed; but the trade off is the increased chances of spoilage and contamination that can occur.
Since cattle are much less sensitive to spoilage that can occur due to fungus and moulds, there is often less attention paid to the readiness (% moisture) of the hay before baling. The outside of the bales may appear of good quality only to find severe dust and mould problems inside.
Round bale production is much faster than square bales which can lead to the increased possibility of the hay becoming contaminated with wildlife caught up in the bales. These small creatures can contaminate the hay with the byproducts of the spoiling of the carcasses in the hay.
Also, the speed and volume with which the hay is fed into the round baler does not filter out foreign substances like sticks and plastics that become part of the bale.
Special equipment is needed to handle and store the bales because of their size. Often storage of the bales is less than ideal – being left out in the environment to suffer repeated exposure to rain and sun damage.
Square bales have become a thing of the past for most cattle operations. The majority of the square bales put up are usually specific for horses. Since horses are much less tolerant of the poor hay quality, producers often try to take extra care in baling at the optimum time – avoiding rain damage at all costs and trying to insure the hay is free of contaminants.
These bales are easier to handle and store – requiring little equipment or special storage buildings.
Small bales allow for easy inspection of one of a group to check for quality before investing in larger numbers. It is also often easier to determine contamination and spoilage simply by inspecting (visually and nasally) the outside of the bales.
METHODS USED TO FEED HAY
As much as I have appeared negative on round bales they can be used successfully in horses provided the following conditions are met:
1) The hay is properly stored and free from obvious signs of weathering – grey/black mould growing on the outside.
2) The hay is of horse quality – free of dust, moulds and foreign substances
3) The population of horses eating the round bale is such that it can be completely consumed in less than 3 days. Once opened the bale becomes subject to weathering just as it was before baling – rain will cause the same fungus/mould growth as when in the field.
4) The area of feeding the horses is free of structures that may result in injury to the horses. Round bale feeders may work for cattle, but horses can suffer terrible injuries from these after catching their legs or heads in the structures, sometimes even leading to the deaths of these individuals. In addition, baler twine and wraps must be removed from the area since they can be ingested with the hay and causing colic or becoming wrapped around legs and causing serious injury.
5) When the round bale itself becomes storage area for the hay – with the hay being removed from the bale and fed to the horses while taking care to store the remainder in such a way that it will not be ruined by elements of the environment.
Square bales need special consideration when they are fed as well. Each bale should be inspected when it is opened to be fed – moldy, dusty, “off” smelling or colored bales should be discarded. Again, it is important to remove the baler twine from the feeding area for the same reasons as with the round bales.
In feeding either type of bales, be sure to keep the area clean from waste contamination. Horses do not normally eat where they poop – you know those grassy areas in the pasture are not areas of exceptional growth, that’s the area the horses use for the bathroom and hence do not like to eat there. Also remember that it is in the feces that the worm eggs that infect your horse come from.
HAY RELATED HEALTH CONCERNS
Botulism is a condition caused from ingesting a toxin produced by a bacteria found in spoiling meat. The toxin is deadly in incredibly small doses and has no cure. It occurs most commonly when small animals are caught up in the baling process (usually round bales), and after death the carcass spoils and leaks into the surrounding hay spreading the toxin which is inadvertently eaten in the hay. Each year there are several reported deaths from horses eating contaminated round bales. The toxin causes paralysis and death so quickly the affected animals are found dead near the round bale containing the toxin. There is a vaccine available to prevent these deaths.
“Heaves” or COPD (which could be called the asthma of horses) occurs over time due to the constant inhaling of dust and moulds found in spoiled or poor quality hay. This leads to an allergic reaction to these substances. The affected horses have extreme difficulty breathing, often accompanied by wheezing and severe coughing. Once this occurs, the problem will not simply go away. It is there to stay, and for the rest of the horse’s life, extreme care will be needed to keep these agents from the horse’s environment. What makes matters worse is that there are often cross reactions to similar agents in the environment such that the horse may start to have attacks when there is high pollen counts, etc. There are treatments for these conditions, but no cure. This means that the horse will likely need treatment on and off for the rest of its life.
Fescue toxicity occurs when a specific organism or endophyte grows in the fescue – it does not harm the grass but produces a substance that disrupts the hormone flow of the pregnant mare. There are no obvious outward signs that this has occurred. The following are the problems that can be caused by the endophyte:
2) Premature placental separation and infection of the placenta – weakening of the cervix for hormone imbalance
puts the fetus in peril due to the infection it is recognized quickly enough it can be successfully treated.
3) Prolonged gestational length which leads to oversized foals and difficulty foaling.
These can all be avoided by removing pregnant mares from ANY exposure to fescue – neither pasture nor hay - for the last 3 months of gestation. Often this means moving the mares to a dry lot and feeding alfalfa cubes or hay that one is SURE is not fescue (i.e. orchard grass, timothy, etc.).
DENTAL HEALTH AND HOW IT RELATES TO A FORAGE DIET
They start their lives with two upper and lower incisors and two upper and lower premolars which are not well suited to eating forage, but by 3 to 4 months the teeth have progressed enough to start seriously eating on their own. Since the majority of foals are born early in the spring, the soft summer grasses are easy for them to consume. By fall the teeth have matured enough to eat the coarse and tougher fall/winter grasses or hay. For these reasons, most recommend some of the better hay for younger and weanling horse to insure they will be able to consume it successfully.
As the horse grows they develop a full complement of teeth by 2 to 3 years. At this time, these adolescent horses start to shed their “baby teeth”. So at between 2 and 5 years they lose one set per year (3 sets total). These deciduous teeth loosen and may even fracture into pieces as they are lost. Owners report that the horse is eating sideways and dropping feed. If the symptoms become exaggerated, swelling and/or a foul smell is noted, these teeth may have to be extracted by your veterinarian.
The horse’s teeth are built the opposite of human teeth with the outside made up of cementum and dentin, while in the center are enamel scrolls. All of these materials are strong but it is enamel which is the strongest. This allows the softer outside of the teeth to wear leaving raised enamel scrolls in the center of the teeth. The rows of teeth are sloped as well – taller on the outside of the upper teeth and on the inside of the lower teeth. When the horse chews, it is in a rotary motion, allowing the raised enamel scroll and the sloping tables of the teeth to cut the tough grasses into manageable pieces.
This system leads to the next dental issue – the formation of dental spurs. Although the material on the outside of the molars is very strong, it is not brittle. Instead of breaking as it wears it tends to flare out on the taller sides of the teeth. These flares can progress to the point that these razor sharp edges cut into the cheek and tongue to the point that eating is impaired. Suddenly an otherwise healthy horse starts losing weight and dropping grain while eating. This problem is easily corrected by “floating” the teeth which means using grinding instruments to remove these edges. For this reason it is recommended that a dental exam is performed yearly to prevent these issues from becoming problems.
Lastly, and what I think may be the most important problem is dental loss in the geriatric horse. When horses reach their twenties, the molars stop growing. But instead of just wearing down, the spent teeth are forced out until they loosen and fall out. During this time all sorts of disasters can strike. The spent teeth start to have different rates of growth, so that the opposing tooth can grow into the opposite arcade and stop the rotary motion needed to chew. Also as these spent teeth reach the gum line the old roots become exposed and feed material packs in the spaces. This leads to severe infections of the teeth, gum and can even extend into the sinuses. One can see swelling of the cheeks, jaws or sinus areas but the diagnosis is most often made by the smell (which, unfortunately, is unforgettable). These problems are corrected by removing the spent teeth and grinding the opposing teeth to allow for chewing to resume.
The loss of these molars is not always associated with clinical problems but their loss definitely affects the horse’s ability to chew. Along with the obvious signs of weight loss and difficulty chewing most people notice the horse begins to quid. Quiding is when the horse takes the hay or grass into their mouths, chew it and then spit out a ball of hay or grass. This happens because the horse cannot cut the forage into the size need to be swallowed.
The problem for the geriatric horse is how then to replace the forage in the diet. There are any number of senior feeds on the market – many of which are complete feeds (can be fed as the sole source of feed). There are other methods such as “equine soup” in which pelleted feed, alfalfa cubes and rehydrated beet pulp are mixed into a mash and fed in a large container. This usually means separate feeding since it takes time to consume the quantities needed.
All this being said – the bottom line is that geriatric horses cannot eat hay or grass in the same manner as younger horses. Neither square or round bales matter. The fact is they do not have the teeth to cut the hay into digestible segments.
COLIC AS IT RELATES TO HAY QUALITY
Hay quality is often a major player in the causes of colic. It is not only the obvious problems of contamination with foreign bodies such as twine, plastic and wire but also irritants that may be included or develop in the hay.
The organisms of spoilage – fungus and moulds may contain toxins that directly affect the digestive system – causing indigestion/gas colic, diarrhea, etc.
Irritants -such as blister beetles or plants not normally eaten up - included in the hay that is ingested due to the indiscriminate consumption of hay.
Over-mature forages made into hay may not only not satisfy the nutritional needs but can often lead to impaction type colic. The horse’s less tolerant digestive system simply cannot break down these fibers and they stop the flow of feed through the cecum and large colon.