Fat Horse on Free Choice?

You’ve read all the articles about having food in front of your horse at all times. You’ve read about allowing the horse to eat as much as they want and that eventually they will self-regulate. Yet, your horse gains massive amounts of weight when you don’t tightly control his intake. Are you a failure? No. This article and the subsequent one will discuss why free choice strategies don’t work for every horse.

 

Dietary factors

To understand dietary needs and intake, it’s important to reflect on the dietary habits of feral horses. Feral horses eat a large portion of the day because that’s what is necessary to consume sufficient calories for existence. A large portion of the horse’s energy comes from fermentation in the hindgut. This takes time and is not “instant energy”. Additionally, the horse is walking and moving all day, expending energy, while they are grazing.

Moisture content: Pastures have a moisture content of approximately 90%. Hay, in comparison, is rarely above 15% moisture. A horse that usually eats 18 lbs of hay would need to consume about 90 lbs of grass to eat the same number of calories.

Quality of feed available: Horses have not evolved to eat the enriched pastures that we have today. The pastures that we currently have are more caloric and nutrient dense than pastures the horses have had through the last centuries. We use fertilizers and irrigation to stimulate growth, reseeding pastures for greater uniformity, and selective breeding of plant cultivars to obtain higher yields.

The vegetation that we feed our horses is of a higher quality, more caloric and nutrient dense, than the vegetation that the horses evolved with.

Annual rhythms of horses (called circannual rhythm)

Horses have also adapted to have annual rhythms. Examples include growing a heavy coat for winter or mares turning off their hormonal cycles for breeding in the winter time.

In many areas of the country and world, vegetation is sparse in the winter, at the same time that energy requirements for heat production are increased. Many species, including deer and elk, are known for eating enough in the summertime to add a significant layer of body fat prior to winter.

Similarly, horses may lose weight in the wintertime. Their energy requirements are increased in winter. This is due to the increased amount of energy necessary for heat production. Body stores may suffer due to this increase in energy requirements. It’s not unusual for the horses to shed out in the springtime and the owner thinking that the horse has lost topline or is a little ribby. The loss of topline frequently is a reduction in the size of the fat layer that runs along the spine and not really loss of muscle.

In the summertime, when food sources are more available, horses may gain weight to replenish what they lost the previous winter. This is an example of a survival mechanism, not necessarily a homeostasis of the amount consumed.

Body type:

Some horses are “easy keepers”. This refers to the horse that seemingly gains weight on little feed. Inherited body metabolism makes a difference in how efficiently a horse stores energy (think “gains weight”). Hormonal switches exist to regulate food intake.

 What you can do:

Knowing that horse husbandry in today’s day and age is not like it was centuries ago, we can still help our horses maintain a healthy weight by monitoring and controlling the food intake. A common rule of thumb on the amount of feed is 1.5% of the current weight or 2% of the horse’s ideal body weight, whichever is greater. However, each horse is unique and it’s important to monitor a horse’s weight and feed accordingly. An important caveat to weight loss in the horse is that if you restrict calories too severely, the horse will actually slow their metabolism to expend less energy. By doing this, you may not see the desired results.

How can you control a horse’s intake?

➡ For grazing, you can use a grazing muzzle.

➡ And for hay amounts, you can use an inexpensive luggage scale and a hay net or garbage bag, to weight your horse’s hay.

Of course, if your horse is able, and not foot sore nor lame, the addition of exercise to the routine is helpful to maintain good body weight.

Next week: We’ll continue to explore this topic, focusing on some of the hormonal mediators of appetite, as well as some of the best practices for horse husbandry.

Disclaimer: Statements regarding dietary supplements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease or health condition.

©Joan Kulifay 2024

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