Science Vs Tradition: Nature Vs Nurture

NATURE

VS

NURTURE

Long winded post this week. Keep in mind this is a post on ANATOMY and how turnout and feeding practices effect the horse, not herd dynamics though they certainly are very closely tied.

Do we over think the management practices we use on our horses?
I was talking to a manager at one of my barns this week. She believes in keeping the horses in 20 hours a day. I believe keeping them out 24 hours a day.
About three years ago for a university assignment I wrote a paper on evolution and management. I called it nature VS nurture.

I found you can fit horse care into three main groups when it comes to feedings etc:
Those being stalled individually at night and out for most of the daylight hours. Those being stalled 20 or more hours a day and last but not least, horses out 24/7 allowed to just be horses.

Of course I could not get away with this unless I looked at some anatomy first.

NOTE: BCS= body condition score on a scale of 1-9, 1 being emaciated 9 being morbidly obese.Any other things you don't understand please just ask I will explain.

When we think of management, clean stalls, green pastures, and healthy horses come to mind. Sometimes what we consider convenience for us, can be disastrous for the horse. Feeding large meals infrequently, seem to suit our lifestyle; however, it is not nearly as convenient for the anatomic makeup of the horse. The horse’s lifestyle is highly dependant on what use they are to their caretakers; the humans.

The majority of horses will be on turnout during the day and stall confinement during the night. The horse would be turned out in the morning on either a grass paddock or a dry lot, depending on the land available and the horses medical history. They would be allowed to exercise and play with their paddock buddies. They would be able to graze in the paddock or be fed hay outside but the majority of the meal would be fed in the morning and at night in the stall in the form of hay and concentrates. Water is provided outside and in the stall artificially by water troughs and buckets. Hay analysis is common when hay is first cut but not on grazing pasture or grass.

The horses on this style of management would likely change significantly in the winter with the onset of snow and the loss of green nutrient rich grass. They would be turned out later and be brought in earlier and on some days not turned out at all. They would rely 100% on hay and concentrates to maintain body condition score. Grass would either not be growing or be lacking nutritional content at this time. The hay analysis would be different from the first testing in the warm weather. Many people add vitamin supplements to balance their horses rations because of hay lacking nutritional value

The other group of horses would be the racehorse, sport horse, or show horse. They are kept in stalls most of the day for various reasons, mostly because they are a financial investment. Some receive minimal turnout in dry lot paddocks, while others are in their stalls for the whole season because they are being used athletically. They are fed low forage, high concentrate diets to maintain their BCS. The feeding regime does not change very much over the course of winter except for the addition of different vitamins to balance the hay analysis for the winter. For the reason of being fed high amounts of concentrate, the horses are usually fed several times throughout the day with meals being split up into smaller portions. This helps reduce the risk of colic. Water is usually only provided in the stall when they are not turned out for very long.

The last group of horses would be 24 hour turnout. These horses are outside as

much as they want with the exclusion of, a run-in or lean-to for shelter at night or in extreme weather. There is enough land to allow the number of animals to graze without killing plants and grasses, and water is provided artificially with troughs or naturally with streams or ponds. These horses spend all day (and night) grazing. They do not have a set meal time but hay and concentrate may be offered to maintain BCS.

In the winter if snow covers the ground they might be fed hay and concentrates from mangers at timed intervals. Most horses are allowed free-range hay at this time to mimic their summer eating patterns. Others are fed at intervals like most stabled horses and receive concentrates and vitamin supplements.

The evolutionary strategy of the horses digestive system leaves us as caretakers to carefully balance their nutritional needs around our time schedule. When feeding a horse that is outside for the majority of the day and inside for major feeding times we must take care that the concentrates are not more than 0.5% of the horses total body weight (so 5 pounds of concentrate to a 1000 pound horse). It is also wise to feed these concentrates in more than one meal.

The horses digestive system is not like ours or even a dogs, yet we still seem to feed them as if they were. The size of the meal largely dictates how fast feed passes through the foregut. A horse that is fed two large meals a day passes the ingested feed quicker. The foregut emptying is influenced by how large a meal is, how much liquid it contains, and how finely ground it is. Feed that is passed quickly reduces the quality of digestion in the foregut because the feed passes rapidly(Lardy 2001). Normal passage of feed through the stomach and small intestine takes one to two hours. Once the feed reaches the hindgut it needs to be fermented. The fermentation starts in the cecum. The cecum houses a lot of bacteria responsible for breaking down the majority of plant matter. Disturbances to the cecum, such as large grain quantities or large meals can result in bulging, impaction, and rupture. This can be avoided by letting the horse graze continuously.

The large colon helps absorb most of it’s nutrients through a fermentation process that occurs many hours after the horse has ingested the feed it is digesting(Livesey). Feeding infrequent meals lets the digestive tract lay dormant. This decreases the passage of food through the digestive system and can lead to colic. If large amounts of grain are fed to a horse the acid content in the cecum can rise and create hindgut acidosis and lead to things like founder and colic. Horses are therefore better suited to smaller meals. Feeding at more regular intervals when a performance horse needs to be stalled will indeed mimic their natural habits of eating but there is one thing missing, and that is exercise.

When a horse has to eat a lot and is confined to a very small space his body does not move as much as it needs to in order to stimulate digestion and the moving of feed through the digestive system. Receiving large amounts of grain poses a big threat to the hindgut; however, when they are broken down into smaller meals the risk significantly decreases. Performance horses are expected to be able to be worked to maintain their level of fitness, and thus, to compete and win. It is a bit like eating a big dinner and going out for a sprint immediately afterwards. Your stomach would churn faster than it was supposed to, resulting in an upset stomach, or colic for the horse.

When a horse eats small, frequent meals the food is passed continually, he drinks more and everything is passing like a smooth assembly line through his body. The horses stomach can only hold approximately 18 liters and empties every one or two hours and when he is eating small meals it will empty and refill in time, instead of emptying and staying empty, as with infrequent meals. When the horse is continually grazing he is walking around churning all these contents and allowing them to be digested more thoroughly and effectively, absorbing nutrients as he munches away.

The best feeding regime in mind of the horse is the continual 24 turnout. He can eat as much as he wants, when he wants, and allow nature to take its course. Concentrates that would be added to maintain BCS could be ingested and then followed by many more hours of grazing, allowing the rate of passage through the body to be more fluent and thorough. Colic’s would likely be less frequent (some horses excluded in that cribbers being one example) because the ingested food would be passing in and out of each digestive organ relative to the natural time-phase it takes to extract the nutrients needed.

When the horse is eating continually there would not be this time-phase where nothing is ingested. The stomach and small intestine are designed to allow constant entry of small amounts of food, therefore leaving it empty. The stomach also continually produces gastric acid that helps break down food. Continually grazing reduces the instances of gastric ulcers because the acid has ingested matter to break down, not the stomach lining. The hindgut is reliant on an adequate supply of dietary fiber for fermentation and preventing digestive upset.

A horse that is outside all the time with his herd-mates also has a big impact not on anatomy but his emotional structure. Often times horses that are turned out for the day and inside at night lack the bond and herd structure that horses turned out 24/7 have.

Horses that are together all the time can bond, are constantly touching each other, and communicating freely. This is not the case when a horse is confined to a stall for a portion of the day and has walls or bars between the contact with it’s other herd mates.

The upside of turnout/stall management would be mostly convenience on the owners part. Horses that are turned out in paddocks after hours in a stall confinement, can later be brought back in and fed individual concentrates and hay rations to their own body condition, training level, and individual needs. These horses can receive a more accurate feeding regime. It is also more convenient for most of us humans in our busy lifestyle.

The downside of this management practice would be leaving a big time gap when the horse is not fed. Acids build up in the stomach and eat the lining, creating gastric ulcers. The whole digestive system is left empty when the horse has nothing to eat creating a vast array of problems during post-meal time.(Geror) The horse can get bored when not eating anything and will usually begin chewing on things, cribbing, stall kicking, etc.

The upside of the horse that is stall bound for most of the day on a high concentrate diet would be, the ability to create a ration good for an individual performance horse. You would be able to feed them to maintain their BCS and it is extremely convenient for the person working the horse to access them from their stalls.

The downside of this feeding management would be the horses’ inability to move around and graze. The feeding practices may be split up into small, frequent meals; however, a diet consisting of such a high energy level can lead to a bored, extremely high strung animal, that gets minimal turnout and intense exercise.

The upside of the 24/7 turnout management practice would be allowing the horse to roam and graze as he sees fit. Ingested matter is constantly being consumed, therefore it is constantly moving through the digestive system smoothly. He can play and socialize as much as he wants. In the winter, if and when, the snow covers the ground the horse would have to be fed hay to maintain BCS. This would closely mimic how and what the horse ate during times of drought or harsh weather in the wild. He would be eating older, denser herbage, and rate of passage through the digestive system would slow(Janis, 1967)

The downside of this management practice would be the inability to regulate what your horse eats, thus having to provide supplemental grains and hay to keep BCS optimal. The horse has a short supply of amylase in its body(Geror). Amylase helps digest starch. In our artificial grassed paddocks we may plant several types of grasses. Some will be higher in a starch called fructan. Fructan is the carbohydrate-like starch responsible for grass founder. Not being able to limit when a horse eats grass can increase his chances of grass founder, especially if he is overweight, insulin resistant or other high risk candidates. When a horse eats grass on a cloudy day, fructan production ceases because growing time is not optimal for the plant. When a horse eats the grass on these days he is ingesting a higher amount of fructan or a higher starch level.

In conclusion, it is far better to let the horse be. If the land is available and you want happier, healthier horses, let them roam in a grassy paddock that is more suited to their evolutionary needs.

So lets discuss this. What category does your horses management fit into?

Mine are out 24/7. They will behave and be fine in stalls if I need them to be but they are generally not too happy about it as expressed by the next day when I turn them out and they barrel around like idiots for about five minutes screaming their heads off and bucking and acting goofy, which they normally never do (FYI Indigo, stop requiting medical attention and you wont have to be stalled ever again, promise).
The reason why they like going into the stall if they have to is because they have been conditioned. What do I mean by that? They get to eat grain by themselves where normally they share their grain being fed for the average of the group, though all ours are easy keepers. They know when we open that door and allow them into the one stall we have they get their own grain at meal time. Simple as that. They are greedy, no matter how well they all get along.

The barn manager mentioned said to me "After four hours all the horses are waiting at the gates to come in. They don't want to be out, they like the barn."
I thought about this for a minute and asked her when she fed them. Put two and two together.

As any horse owner knows a horse has a clock in his head that says an hour before feeding time that he has to start announcing to the world that he is starving and would like his meal, like now!
The time in which she turned her horses out and the time they wanted to come in coincided with their meal time. Their little horsey lunch time brain clocks kicked in and they knew if they were at the gates they got to be the first ones in to eat their lunchtime ration. Smart horses.

Of course sometimes 24/7 turnout is not ideal for our sake. Busy lifestyles, keeping certain horses weight on, exercise, weather etc can put a damper on management.

I enjoy reading my nature vs nurture paper every time. I ended up with a 97 on it. It reminds me, along with the barns I work at that I am glad to be able to keep my horses outside all the time.

So again, what category does your horses fit into? Why do you use that management practice and if you could change the way it is right now what would you change?