Efficacy of Yeast Products in Equine Diets

In the past several years, multiple sources have recommended yeast products for inclusion in equine diets for many purposes, including improving fiber and phosphorus digestibility, increase feed efficiency, support hindgut bacteria, and even prevention and cure of gastric ulcers. However, a close look at the published data available on the efficacy of supplementing yeast culture in the diets of horses does not support the claims of positive effects in horses fed quality diets that meet nutritional requirements.

AAFCO defines a number of yeast products as feed ingredients, including dried yeast, yeast culture and yeast extract. Dried yeast may be either active or nonfermentative. Yeast culture is a dried product composed of viable yeast cells and the media on which it was grown. Yeast extract is a dried or concentrated product of cell contents from ruptured yeast cells.

Studies in ruminants suggest that addition of yeast products to ruminant diets promote bacterial growth in the rumen. It is generally believed that yeast additives either directly facilitate fiber digestion and dry matter intake, or contain metabolites or compounds that stimulate bacterial growth to facilitate fermentation and animal performance in ruminants. Since horses have fermentative capability in the hindgut, it has long been proposed that yeast products may have beneficial effects on digestion/fermentation in the hindgut, resulting in enhanced fermentation and increased fiber and/or nutrient digestibility.

According to the 2007 National Research Council’s Nutrient Requirements of Horses, “Unlike observed effects in ruminant studies, supplementation of yeast in horse diets tended to show some beneficial effects on fermentation, but results were equivocal across studies.” There is great variation in published results of feeding yeast products to horses – most studies report minimal to no increase in cecal or colonic bacterial cultures as a result of feeding yeast products, although a few studies have reported beneficial effects when yeast products were fed with very high starch diets, or with low quality forages. Some studies have reported no improvement in nutrient apparent digestibility when yeast products were fed to mature horses, but others have reported some improvements in fiber and nutrient digestibility. However, the reports of improved digestibility of nutrients with the addition of yeast products are most often seen when yeast products are added to nutritionally deficient diets. The Purina Equine Research team recently completed a thorough, long-term study that looked at the efficacy of yeast in enhancing fiber digestion in horses, as well as several other parameters, and the data indicated no effects of yeast on fiber digestion. This data is currently being prepared for submission for publication in a scientific journal.

Yeast products can be a source of quality nutrients, including essential amino acids and B-vitamins, so adding yeast products to a nutritionally deficient diet will result in improved performance in horses, just as addition of any ingredient that supplies deficient nutrients to a ration will result in improvement in performance. However, when yeast products are added to diets that are nutritionally balanced and fortified to meet a horse’s nutrient requirements, the additional nutrients provided by the yeast products will be of no benefit. At this time, there is insufficient data to support the inclusion of yeast products in horse feeds for benefits other than those simply provided by the nutrient content of the yeast products, and there are many other feed ingredients that provide quality nutrients for optimal nutrient content in horse rations. Purina Premium Horse Feeds are nutritionally fortified and balanced with quality protein sources as well as specific essential amino acids, minerals and vitamins to meet horses’ nutritional requirements when fed as recommended.

Gastric Ulcers - a pain in the stomach

I received several requests this week for help with horses suffering from gastric ulcers. Unfortunately, performance horses are especially prone to developing ulcers because of the way they are fed and managed. Even exercise itself can contribute to ulcer formation. We know from previous research that horses maintained on full-time pasture have almost no incidence of gastric ulcers. If a horse has been diagnosed with ulcers, they must be treated with medication such as ranitidine or omeprazole in order to allow the gastric mucosa to heal. There are also several feeding and management practices that can help prevent ulcers from returning or occurring in the first place. Below is an excerpt from an email I sent to a horse owner looking for help with a horse suffering from ulcers.

For a horse with gastric ulcers, one of the best things you can do is to allow constant access to forage. Not only does this keep some quantity of feed in the stomach at all times, but also the act of chewing produces saliva which can buffer the stomach contents. Allowing 24/7 access to pasture is the optimal scenario, but if this is not possible, then the use of hay nets that slow down the rate of intake to more closely mimic natural grazing behavior can help. One such hay net that I like and recommend is the “Nibble Net”. The type of forage is also important, and including alfalfa hay in the ration has been shown to decrease ulcer incidence. Some horses can tolerate 100% alfalfa hay with no problem while others may do better with a 50:50 grass/alfalfa mix. I would recommend slowly replacing some of the timothy hay with alfalfa. Depending on how he tolerates the alfalfa (maintains normal fecal consistency, no undesirable changes in attitude under saddle), you may even replace all of the timothy and consider replacing some of the chopped forage with alfalfa. This would increase the amount of “chew time” he has, as horses usually consume chopped forages fairly quickly. I do not expect him to have trouble with alfalfa hay, as long as it is introduced slowly.

For the concentrate portion of the diet, a high fat/high fiber feed is recommended. We have had very good luck with Purina Ultium in ulcer-prone horses, especially those which are in regular work. Ultium is also very calorie dense and will help with weight gain. The fiber level in Ultium is actually higher than most Senior feeds, and because this horse can also consume some forage, a senior feed is not necessarily required.

I would NOT recommend that this horse receive oral paste electrolyte preparations, as these can exacerbate ulcers.

Minimizing stress in the horse’s environment is also something that should not be overlooked; this may include increasing turnout time, insuring the horse is not isolated from other horses, and/or preventing “overtraining” (strenuous exercise on a regular basis without adequate rest periods).

As far as dietary supplements go, most of them are untested and unproven in the horse to improve gastric ulcers.

Following some of these suggestions can really make a positive difference for those horses that suffer from ulcers.

Another Friday Funny...

We have had a crazy busy week (and spring for that matter) here at the farm. I found it amusing this morning when the first thing I found pulling into the farm was a lot of water in place where there should be none! Happy Friday morning! Looks like we get to dig up our pasture and try to find the leak and repair it before the sun gets up far enough to really get hot.

Lola was fascinated by the bubbling water coming out of the ground in her pasture, she was having a good time pawing and playing in it!

Friday Funny - O Lord, Won't You Buy Me.....

Someone sent this to me in an email, and I wish I knew who to give credit for these lyrics because I think they are great. Enjoy!

Sung to the tune of Janis Joplin's "O Lord Won't You Buy Me a Mercedes Benz"

Oh Lord won't you buy me a horsey that bends
My friends all ride warmbloods, I must make amends
I practice my leg yields each evening 'til ten
Oh Lord, won't you buy me a horsey that bends

Oh Lord, won't you buy me a horse that won't buck
I'm tired of trying to land standing up
I spend all my time brushing dirt off my butt
Oh Lord won't you buy me a horse that don't buck

Oh Lord, won't you buy me a horse that won't bite
I count all my fingers and toes every night
I feel like a carrot when I'm in his sight
Oh Lord won't you buy me a horse that won't bite

Oh Lord, won't you buy me a horse that stays clean
I brush him, I groom him, I've considered chlorine
His colour's too chestnut for a horse with grey genes
Oh Lord won't you buy me a horse that stays clean

Oh Lord won't you buy me a horse with some guts
This spooking and shying is driving me nuts
And while you are at it make me less of a klutz
Oh Lord, won't you buy me a horse with some guts

Oh Lord, won't you give him some hindquarter drive
This horse is soooo lazy, not sure he's alive
We bend and we circle 'til way way past five
Oh Lord won't you give him some hindquarter drive

Oh Lord, won't you give me a mule that gaits well
No trotting, no pacing...he four beats like h***
Lop eared and no withered; man it'd be swell
Oh Lord if you'd give me a mule that gaits well

Oh Lord, won't you give me a mare with a brain
One that keeps working when hormones are strained
The gelding's in therapy, the stallion is drained,
Oh Lord won't you give me a mare with a brain

Oh Lord won't you buy me a horse that don't eat
No grass or no hay, now that would be neat
No rain means no pasture, my wish I'll repeat
Oh Lord won't you give me a horse that don't eat

Oh Lord, won't you give me a horse with no bills
My vet and my farrier are first in my will
Work hard all day long just to pay for his pills
Oh Lord, won't you give me a horse with no bills

Oh Lord-please-make his IQ just a 3
The horse I got now thinks he's smarter than me
Well, he doesn't just think it, he's right, don't you see
Oh Lord-PLEASE-make his IQ just a 3

Oh Lord, won't you buy me a horse with some spots
I'm bored with the bay ones and chestnuts and such
Leopards or snow flakes or peacocks with socks
Oh Lord won't you buy me a horse with some spots

Oh Lord, won't you buy me a horse with good feet?
No head bob or hip hitch, no screwed up right lead
I could finally ride more than I soak, wrap and knead
Oh Lord, my achin' backside would rejoice, INDEED

Oh Lord won't you buy me a horse with a saw?
One who can measure and manage an awl
A horse that can eyeball and set a post straight;
drill holes, screw hinges and hang a tube gate
Oh Lord, won't you buy me a horse with good tools?
These crooked fences make us all look like fools!

Oh Lord, won't you buy me a saddle that fits
My arse is so tender I can't hardly sit
Something soft to my tushy and wide for his back
Maybe deep seated, cushioned and in shiny black
Ooooh, Lord, won't you buy me a saddle that fits

Fireworks and Horses

The 4th of July is just days away. If you are like me, you dread nightfall, because that is the time when your crazy neighbor decides it is time to shoot off a truckload of fireworks in the field next to your horse pasture. The first time my horses heard fireworks, I thought they were going to run through the fence. Now I've learned to bring them in the barn and turn up volume on the barn radio to help keep them safe. I came across this article from The Horse with some good tips on how to prepare your horses for a fireworks display:

The Horse | Fireworks and Horses: Preparing for the Big Boom

I think the key is to know your horse so that you can predict where he will feel most comfortable and secure. For some, that may be in the barn with their buddies, while others may prefer to be out in their pasture. Making sure that your fences are in good repair and there is nothing that a scared horse may run into is a good idea. And if your horse truly can become a danger to himself, consider talking to your vet about whether or not it is safe to administer sedatives.

Enjoy your 3-day weekend everyone, and stay safe! Happy 4th of July!