Senior Feeds and the Unthrifty Horse

As horses get older even previously easy keepers can suddenly become hard to maintain for a variety of reasons.

Photo: iStock

Q. My Arabian/Quarter Horse trail horse is 20-plus years old. He got very skinny two winters ago, and it’s taken me until now to get his weight back to where it should be. He’s always been an easy keeper, and usually we’ve had to watch what he’s eaten so he didn’t get fat. We were very concerned when he lost weight. I’ve been lucky enough to have good hay and grass over the last 18 months, and I’ve been feeding him 10 pounds of a 10% fat beet-pulp-based senior feed each day, divided into two or three feedings.

Now that he’s gained weight, I’m wondering if I need to take him off the senior feed and offer him a low-carb performance feed that also has 10% fat, which is what I feed my horses that are in work. I’m concerned about the sugar causing problems for my senior horse, such as Cushing’s disease. Do I need to worry about that? I don’t want him to get skinny again!

He doesn’t quid or have other health problems we’re aware of. He hacks out maybe once or twice a week; he’s primarily a pasture ornament.

Diane Fanta, Virginia

A. As horses get older even previously easy keepers can suddenly become hard to maintain for a variety of reasons, such as:

  • Dentition can cause issues. This isn’t always directly related to teeth— a reduction in muscular strength associated with chewing can also cause problems. This can result in hay being less well chewed, which makes digestion harder.
  • Internal parasites. Certain older horses are more prone to worms, which can cause weight loss. Fecal egg counts are a useful tool for assessing this and deworming protocols can be adjusted accordingly.
  • Pituitary pars intermedia dysfunction (PPID, or equine Cushing’s). This disease can lead to weight loss. In some cases it seems the digestive tract just doesn’t function as effectively as it once did.

Owners should always consult their veterinarian to assess weight loss in a senior horse.

Most senior feeds employ very digestible ingredients, with some relying heavily on easily fermentable fiber sources such as beet pulp. Senior feeds generally provide slightly higher crude protein and trace mineral levels  than other feeds for adult horses due to the fact that some research suggests senior horses absorb these nutrients less efficiently.

While it’s not completely necessary to keep your senior horse on a low non-structural carbohydrate (NSC) feed if he doesn’t have any metabolic issues that require a low-NSC diet, nutritionists and veterinarians generally support controlling the NSC amount fed whenever possible, especially in nonworking horses.

The thing to remember here is that you are maintaining your horse’s weight and body condition on 10 pounds of this senior feed a day. To maintain his weight and body condition as you are now, you need to ensure that the calorie intake stays as it is and that the source of those calories is as digestible as the diet you are feeding now. Given that the feeds you mention are 10% fat and also have a similar crude protein content, I would expect that they have similar calorie levels.

Not all senior feeds are low-NSC, which is the combination of water soluble sugar and starch in the feed. Additionally, not all senior feeds are as high in fat as the one you are feeding. While the number of manufactures sharing information about their feeds’ NSC content is increasing, not all provide it. While in theory changing feeds to reduce NSC intake might be a good idea, you must be careful to maintain the current calorie intake and ensure that the feed being fed is easily digestible.

As it turns out the senior feed you’re using is less than 12% NSC, which is quite low and might be somewhat surprising given how sticky it is. Stickiness in feed is often associated with molasses however, in this case it is due to the oil used to bring up the fat content. In comparison the high-fat, low-carb performance feed you’re considering has a combined starch and sugar content of 20%. So as it turns out if you switched feeds in order to reduce starch and sugar intake you would in fact do the exact opposite and inadvertently increase it!

This is a great example of why looking for the details on feed labels or calling the feed company for information on a feed is so important. Feed names alone cannot always be relied upon.

You might be wondering how this feed can be called “low-carb” with an NSC of 20%. As it turns out, 20% NSC is low when you compare it to the traditional grains and sweet feeds that we used to feed. Oats have a starch content of over 40% and corn can be as high as 60% starch, so in comparison 20% NSC is a significant reduction over traditional concentrate feeds.

While the industry has shifted toward reducing NSC intake in performance horses, many athletes still need some NSCs, because the body only carbohydrates during anaerobic work. Performance feeds with around 20% NSC are a great way to ensure there is some starch in the ration for those anaerobic work moments, while at the same time insuring that the amount of starch fed is being controlled.

If your senior horse has no metabolic issues, a performance feed could be a good choice but if your goal is to keep NSC as low as possible then the senior feed you are on is the better choice. Going forward always check the fine print and details on the feeds you are considering and don’t rely solely on the feed name.


About the Author

Clair Thunes, PhD

Clair Thunes, PhD, is an independent equine nutrition consultant who owns Summit Equine Nutrition, based in Sacramento, California. She works with owners/trainers and veterinarians across the United States and globally to take the guesswork out of feeding horses. Born in England, she earned her undergraduate degree at Edinburgh University, in Scotland, and her master’s and doctorate in nutrition at the University of California, Davis. Growing up, she competed in a wide array of disciplines and was an active member of the United Kingdom Pony Club. Today, she serves as the regional supervisor for the Sierra Pacific region of the United States Pony Clubs. As a nutritionist she works with all horses, from WEG competitors to Miniature Donkeys and everything in between.

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