Category: Calories

Does circadian rhythm play a role in laminitis and founder in horses?

Posted on: December 21, 2011

From left: Goldie, Angel, Robin, Stitches (lying down) and Kurt all hang out together. Wherever the mares were, the geldings were, too.

From left: Goldie, Angel, Robin, Stitches (lying down) and Kurt all hang out together. Wherever the mares were, the geldings were, too.

For years, I wondered if my second-shift schedule may have caused my horses’ laminitis and founder by messing up their circadian rhythm.

I was a journalist who worked nights and came home around 1 or 2 a.m. The horses were hungry, and I fed them when I got home. They got a handful of grain, usually because some of them needed bute, and two flakes of hay per horse.

I was more convinced of the association during Angel’s last days in May 2011, when I was spending a lot of time in the shed with her after I fed her overnight. I just sat in the shavings and hung out, looking up at the stars with her. I noticed that the boys ate a little hay and then both lied down. So, I put calories in their stomachs and then they went to bed with that sugar in their system.

In people, we know that’s a big no-no.

I’ve searched on and off since for research on a horse’s circadian rhythm to test my theory, and I have found two studies that indicate that horses actually tend to graze the most overnight when left to do whatever they want, though they also are more prone to lie down overnight than at any other time.

Over the years, my geldings probably chose to lie down in the shavings overnight because they always looked to the mares for guidance. If the mares were lying down, then they would, too. In fact, after Angel died and left the geldings alone, those two boys were so lost, they didn’t know what to do with themselves for weeks.

I now know that, if Angel hadn’t been there, they would have been off grazing, because that is what they do now. Robin Hood snorts wherever he goes. I hear him all night long. And they are on the move all night, though I limit where they can go because I don’t want them stuffing their face with grass. They tend to nap first thing in the morning.

It’s possible that the laminitic mares caused them to change their pattern of movement, leading to the boys getting fat. But, I don’t think the mares’ initial founder cases were caused by me feeding them in the middle of the night. I likely would have done more damage if I had fed them before work at 4 p.m. and then not fed them again until the next morning.

The first of the two studies I found was conducted by Cornell University in 1988. It watched a herd of eight Przewalski horses on pasture during summer around the clock and recorded their behavior. The abstract does not say how long the study lasted or where the horses were located, but I’m assuming it was New York.

The horses spent about 46.4 percent of their time feeding, .5 percent of their time drinking, 20.6 percent standing, 15.7 percent standing-resting, 1.7 percent self-grooming, 2.2 percent mutually grooming, 7.4 percent moving, 1.2 percent lying laterally and 4.1 percent lying sternally, or upright, similar to a relaxing dog. They averaged about 45 behavorial states per hour.

The study says the horses spent the greatest amount of time grazing from 8 p.m. and 4 a.m., when the temperatures were lower. They spent 68 percent of their time from 8 p.m. to midnight feeding, but only 30 percent of their time from 8 a.m to noon feeding. Recumbent rest, or lying down, was most common between midnight and 4 a.m. As it got hotter during the day, the horses spent more time standing and drinking than grazing.

The second study, by the Division of Animal Production in Australia in 2003, was a comparison of circadian patterns of sheep, cattle and horses grouped together. The abstract is brief but it notes that the horses in the study grazed extensively all night, whereas the sheep and cattle grazed more intensely during the morning and afternoon. It said horses spent only 1.1 hours lying down per day, whereas sheep and cattle spent 11.6 and 10.5 hours, respectively.

Chronically obese horses face daunting task to lose weight

Posted on: December 5, 2011

A handout titled “Assessing energy balance” by the University of Kentucky looks at the overweight horse’s nutritional needs. In the section titled “My horse is too fat,” it says quick weight gain in a horse is easier to turn around than chronic overweightness. For example, a horse whose diet wasn’t reduced when it quit exercising has an easier time losing that weight than a horse that has been obese for a long time. The chronically obese horse likely has some lameness issue that may have been caused by being fat, so it’s dietary needs are very low, meaning it’s difficult to reduce a diet enough to get this horse to lose weight.

The article gives a lot of numbers, unfortunately in kilograms, but it basically says that a normal horse should consume 1.5 percent of its body weight, or 15 pounds of food for the 1,000 pound horse. To lose weight, the horse has to cut back. We’ve done the numbers-crunching too many times, and it all comes down to how many calories are in the feed you are feeding, with hay having a lot of variables.

But, here’s what I found interesting in this article and not in a good way. It says a horse being given fewer calories has lower maintenance requirements because all the things associated with eating — chewing, digestion, nutrient absorption and pooping — are reduced. So, if you reduce the feed for your horse, the horse’s calorie requirements are even lower and you have to reduce the feed even more to get the weight off.

Adding insult to injury, as the horse loses weight, those needs to go down even further. So, a horse that’s on an extreme diet isn’t going to get to come off that diet if it wants to maintain that weight.

Not surprisingly, the article cautions that feeding a low enough level of food for the obese horse to lose weight might not be the best for the digestive track or the horse’s mindset.

And, it suggests rather than restricting average quality hay, feeding a low-calorie hay. A three-hour search online of “low calorie hay” will get you nowhere. Look for more material on that in the next post.

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Editor’s note on June 15, 2015:

I wrote this post before reading Juliet Getty’s post on treating the insulin resistant horse. I no longer think counting calories is a good way to treat a laminitic horse. Read Getty’s article for an excellent summary of everything that goes wrong in the insulin resistant horse and how to approach treatment.

Does using several piles of hay work for the laminitic horse?

Posted on: November 10, 2011

In 2008, a veterinarian recommended that I invite to my farm an academic scientist and horseman who had been advising people on their laminitic horses to see if he had any thoughts on why I had such a high incidence of founder.

The scientist suggested the horses were foundering from stress.

At the time, I had been trying to feed the horses as little as possible (and I now know they were still getting more calories than they should have), and the scientist said the stress might be coming from them having so little to eat.

He recommended instead that I give them all the hay that they wanted but that I spread it in the far reaches of the horses’ pastures and paddocks so they had to keep moving if they wanted to eat. I didn’t follow his recommendation to the letter because I knew my horses couldn’t consume large quantities of hay.

But for the last three years, on days when it hasn’t rained or snowed, I have taken one extra flake of hay at each meal and divided it into four tiny sections and placed it in four places in my pasture. And it has forced the horses to move around more than normal to go get that extra flake of hay.

In light of my newfound information on how many calories a flake of hay has — 2,640 at last count — I’m now interested in whether the amount of calories the horses expend to go get the hay is enough to offset the calories they get eating that extra flake. Admittedly, this is an imperfect way to figure this out.

Each horse would get an extra 1,320 calories per meal.

It takes my horses 80 seconds to walk around the back of my house and get to that pasture from their shed. They have to walk about 408 feet to do it.

The National Research Council estimate a horse burns 1,000 calories per hour walking. That would work out to 16.66 calories per minute. For my horses to walk 80 seconds is about 22 calories. They may walk out to that pasture six times in the evening to check if the flake of hay they ate has magically reappeared. So, six times out and back to their shed is 12 trips times 22 calories is 264 calories. Those 264 calories they expend can’t begin to balance the 1,320 calories each horse is taking in, so I’m going to conclude that it’s a failed strategy to try to put a little extra hay out to make the horses walk from a calorie burning standpoint.

Totaling up the caloric excess: Each horse is taking in 3,960 extra calories per day from the extra half flake per meal per horse. Each is expending 792 calories per day doing the extra walking. Maybe.

If I just take the two flakes of hay the horses get per meal and split those flakes between their pasture and shed, we’d be in better shape calorie-wise, but, as I’ve said, trying to split up two flakes into multiple piles is a bit daunting. In fact, I do split those two up already, but it makes four little piles that get scarfed down in maybe a half hour.

I feel like, if I really want to feed two overweight, insulin resistant, laminitic horses correctly, I should just walk along and sprinkle hay bits in a little trail around my farm, Hansel and Gretel-style, and make the horses walk around to get it, which would limit their eating to crumbs basically. If I lived in California, with its consistent weather, that might actually work. I don’t think it’s going to work in Missouri during the winter.

We are killing our laminitic horses with calories

Posted on: November 9, 2011

Editor’s note on June 15, 2015:

I wrote this post before reading Juliet Getty’s post on treating the insulin resistant horse. I no longer think counting calories is a good way to treat a laminitic horse. However, the included material related to calories is correct.

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We are killing our laminitic horses with calories.

That’s my conclusion. I had been thinking I had been starving my chronically laminitic horses for years only to discover I wasn’t even close.

I spent some time on the phone in November 2011 with an expert in equine nutrition, Dr. Scott King, a veterinarian who is now the equine products manager at Bayer Healthcare in the Animal Health Division. He used to be in charge of new product development at the Purina division that overseas equine feed and before that he was a practicing large and small animal veterinarian, who happened to be my vet.

He was doing me a favor in answering a question on a topic unrelated to calories, but that was all that was on my mind that week, and the conversation eventually turned to the appropriate amount of calories, officially kilocalories, that a horse should eat.

He said he believes that a maintenance horse needs fewer calories than the NRC recommendation of 15,000 calories that I’ve been quoting. He says the maintenance calorie requirement is 13,000, and he studied low-calorie diets for horses extensively, so he should know.

Prior to this conversation, I had taken my hay into my local feed store to make sure I had the weight correct. Using a USDA-calibrated scale, my flake was about 2 14/16 pounds, and I rounded up to 3 pounds for ease of doing the math, since flakes vary in size anyway.

Dr. King said brome hay tends to average 800 calories per pound. My brome was a bit more at 880 calories. Alfalfa is 900 calories.

If I multiplied 880 calories by 3 pounds, I got 2,640 calories for one flake.

I told Dr. King I thought that was impossible, adding: “That means that, if it’s raining and I decide to throw my horses an extra flake of hay to keep them busy while they stand in their shed, I’ve just given them several thousand extra calories.”

He said that’s right. Referring to horse obesity, he said: “I believe it’s all about the calories.”

As noted previously, each of my two horses had been getting six flakes of hay per day, or 15,840 calories a day.

They also had been getting a total of 1 pound of Purina’s Nature’s Essentials Enrich 32 (I weighed that, too), which has 1,100 calories per pound.

And the horses got a carrot a day, which was roughly 50 calories.

For a grand total of 16,990 calories.

If a pound of fat is equivalent to 3,500 calories, and the horses were getting 3,990 extra calories a day by Dr. King’s standards, it didn’t take much to figure out why the 14-2 hand pony looked wide enough to be two ponies.

Dr. King recommended that I ride one at a walk and pony the other, since my efforts to make them do real exercise had failed due to mobility issues.

Note that all my horses foundered while in work, and a horse in work gets to eat considerably more calories..

Once a horse is foundered and cannot work, you definitely are dealing with a whole new meal plan, and likely most of us are overfeeding our laminitic horses immensely once they turn into lawn ornaments, thus cementing their fate as chronically laminitic horses for the rest of their lives.

Knowing what I’ve learned about how many calories are packed into a flake of seemingly harmless hay — what I once equated to a bowl of salad for humans — I now have to believe overeating played a major role in these recurring founder cases, even if I find out that excess iron or some other environmental factor gave the horses a big push.

Calories in hay and feed for laminitic and foundered horse

Posted on: November 7, 2011

A typical hay sample report shows the hay’s megacalories per pound in addition to the sugar and starch content. A megacalorie is 1,000 kilocalories, and a kilocalorie is what we know as a calorie. The rest of this article will use the familiar term of calorie.

My recent hay sample of brome hay says it has .88 megacalories, or 880 calories, per pound. If my horses are eating 20 pounds per day, they are getting 17,600 calories a day from their hay, which is wee bit over the 15,000 calories a day that the National Research Council is suggesting for a sedentary 1,000-pound horse, which might explain the big rolls of fat on my horses’ sides. For years with these hay results, I’ve been looking at the sugar and starch content to determine if I had the right hay. But, now I’m taking into consideration the calorie content, and the horses are getting too many calories. Reviewing my hay tests going back to 2004, the calories per pound all fall within a similar range. This particular hay is not extreme.

As for feed, the Animal Health Foundation, a laminitis research foundation, compiled the calorie amounts of many common equine feeds and distributed the list in 2007. I’m attaching a copy of that here since I can’t find it online. Most feeds have 1,000 to 1,500 calories per pound. My horses are getting a pound each of forage supplement.

The hay is particularly frustrating because my horses go through two flakes of hay at each of their three meals in no time and look at me as if I’m starving them. And, my strategy for exercising them has been to spread the hay out in several areas so they have to walk to get it. I can’t leave much of a pile in each place if I’m trying to stick to the two flakes per horse rule. And if I leave too small of a pile on a windy day, it just blows away. To find out that I’m 2,600 calories over their limit while struggling to stick to two flakes per horse per meal makes it all feel a little hopeless.

How many calories does your laminitic or foundered horse burn exercising?

Posted on: November 6, 2011

Editor’s note on June 15, 2015:

I wrote this post before reading Juliet Getty’s post on treating the insulin resistant horse. I no longer think counting calories is a good way to treat a laminitic horse. However, the included material related to calories is correct.

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The National Resource Council’s equine nutrition report, released in 2007, provides information on how much energy horses expend during exercise in addition to giving dietary requirements.

The NRC says that an 1,100 pound horse burns 5,000 calories if it trots for two hours. And the horse burns 2,000 calories if it walks for two hours.

Breaking that down a little bit, a horse trotting for one hour burns 2,500 calories. Trotting for 10 minutes works out to 417 calories. That’s pretty good for 10 minutes of work.

A horse walking for one hour burns 1,000 calories, and a horse walking for 10 minutes burns 167 calories.

By contrast, the average male running for an hour burns about 940 calories or 157 calories in 10 minutes, according to NutriStrategy.

Ten minutes is important in looking at laminitic horses, because some research suggests that 10 minutes of exercise a day is enough to lower a horse’s insulin level.

In 1992, researchers at the School of Veterinary Medicine at Louisiana State University reported that 10 minutes of exercise significantly reduced insulin resistance and helped ponies lose weight in as little as six weeks. The ponies were put on a treadmill and required to walk for one minute, trot for one minute and canter for eight minutes (hard to imagine making a pony canter on a treadmill). This was their only exercise. The rest of the time, they were stalled. The ponies lost a significant amount of weight during this time, changing body shape, losing girth size and seeing more muscle definition. Researchers noted that improved insulin sensitivity was maintained in the six weeks after exercise was stopped.

If your horse burned 417 calories in that 10 minutes, and everything else were kept equal, the horse would burn 2,919 calories a week.

To lose a pound of body fat, a horse must create a deficit of 3,500 calories, either from eating less or exercising more. If the horse burned an additional 2,919 calories a week trotting for 10 minutes every day, the horse would be pretty close to losing that pound.

If your horse needs to lose 200 pounds, 1 pound a week may not sound very helpful, but every diet has to start somewhere.

How many calories should you feed your insulin-resistant laminitic horse?

Posted on: November 5, 2011

Most owners of laminitic horses that have the insulin form of the disease are willing to move mountains to help their horse, but they don’t know where to turn. Often, they bring in the best farrier possible to try new shoeing techniques.

But the problem at least in part is related to the horse’s diet. Fix the dietary problem, and you have a much better chance of saving the feet.

Figuring out the content of what you’re feeding a horse is not an easy challenge. But some of this information is available. The process does require having your hay tested for content, as well as your grass, if your horses are on pasture.

The National Resource Council of the National Academies (top scientific minds in the country) released updated horse nutrition recommendations in 2007.

Horses’ food usually is assessed in megacalories. A megacalorie is 1,000 kilocalories, or calories as we refer to kilocalories in the human world.

The NRC says a 1,000-pound sedentary horse needs 15,000 calories a day of digestible energy, plus 1.2 pounds of crude protein, 18 grams of calcium and 13 grams of phosphorus. The numbers go up for a 1,200-pound horse to 18,000 calories, 1.5 pounds crude protein, 22 grams calcium and 15 grams phosphorus.

To lose a pound of body fat, an individual, including a horse, must create a deficit of 3,500 calories, either from eating less or exercising more. Generally, health officials suggest a person do this by reducing caloric intake by 500 calories a day for a loss of a pound a week. It seems reasonable that a horse could do the same since a horse gets a much bigger allotment of calories. But there are many challenges in pursuing that goal. There is no easy way to figure out how many calories a horse is eating. And a horse that is chronically obese apparently has a much more difficult time losing that weight than a horse that put on exess weight recently.