"COMPLETE RIDER" YOUR #1 HORSE DESTINATION




Additives for Horse Feeds

Bob Coleman
Horse Specialist
Alberta Agriculture, Food & Rural Development now professor University of Kentucky
reprinted with permission of the Horse Branch Alberta Agriculture

Table of Contents

Horse owners use a variety of feeding practices to meet the nutrient needs of their horses. The basis for all feeding programs is good quality forage which is supplemented with concentrate feeds to ensure the diets are nutritionally adequate. These concentrate feeds can range from grain mixes prepared on the farm with local grains, to custom grain mixes, or commercial horse feeds. Horse owners want the best for their horses. Because of this, they are continually looking for new supplements or feed additives that will improve their horses health, or give them a competitive edge in the performance arena.

Many products are available and making the correct decision regarding the use of these additives can be a challenge.

YEAST CULTURES

While yeast products have been around for many years being added quite regularly to beef, dairy and poultry feed, it is only recently that the use of yeast culture has been considered for addition to horse feeds.

What is yeast culture? Yeast culture by definition is the dried product composed of yeast, and the media it was grown on, dried in such a manner as to preserve the fermenting activity of the yeast. The benefit of the yeast culture comes from the metabolites produced during the fermentation process. It is suggested that the metabolites stimulate the bacteria in the hind gut of the horse, increasing their activity which results in an increase in digestion of feeds by the bacteria. The increase in activity is a result of changes in the bacteria population found in the hind gut. Moore et al, (1994) found that the bacteria which digest fiber in the hind gut of the horse increased in numbers when the horses were supplemented with yeast culture. This increase in numbers can result in more nutrients from the feed being available to the horse. Research has shown that horses fed diets supplemented with yeast culture digested more of the dry matter and fiber than did unsupplemented horses. The digestion of fiber in the horse results in the production of volatile fatty acids which the horse uses as a source of energy.

In addition to increasing the digestion of dietary fiber, Glade & Biesik (1986) noted a positive effect of yeast supplementation of protein digestion in the young growing horse.

The other significant effect from yeast culture supplementation is the improvement in phosphorus digestibility. Pagan (1990) reported that the digestibility of phosphorus improved an average of 22.3% when horses were fed yeast culture.

The addition of yeast culture in feeding programs for young growing horses, broodmares and performance horses has been evaluated. While not all research has shown statistically significant improvements a number of positive results have been found when yeast culture was fed.

Young Growing Horses

A study in 1983 with weaned foals fed for 120 days found a significant increase in daily gain and wither height when foals were supplemented with yeast cultures (Table 1).

Table 1

                         DAILY GAIN   WITHER HEIGHT   FEED/GAIN
                           kg/day    INCREASE INCHES    RATIO

Ration & Yeast Culture      0.45*          3.50*        9.84*
Ration Control              0.27           2.25        16.11

*P < 0.01                                               Mason 1983

In an on farm demonstration, Standardbred weanlings were fed a foal ration supplement with a yeast culture or the same foal ration without yeast culture. The supplemented foals gained 0.93 kg per day vs. 0.75 kg for the unsupplemented foals. Unfortunately this study did not record changes in wither height to allow one to determine if the growth was skeletal growth or if the foals were just gaining weight.

A study with Warmblood weanlings fed a high forage diet plus 1.5 kg of concentrate with or without yeast culture found that the yeast culture foals had a 10% greater weight gain and an approximately 2% greater gain in wither height, (Ciro 1991).

A Missouri study using yearlings found no difference in daily gain, or wither height with yeast culture supplemented diets, however they noted a 10% improvement in feed efficiency, (Bennett-Wimbush, 1991).

The research suggests that modest improvements in growth are possible with the addition of yeast culture to the diet of the young growing horse. It appears that the level of improvement will be affected by the level and duality of forage in the diet, and the age of the horse when it is fed the yeast culture. If horses are fed high forage diets where the quality of the forage is questionable, a greater response may be expected.

Broodmares

In the mature horse, studies have shown improved fiber, protein and phosphorus digestibility due to enhanced microbial fermentation in the hind gut. Lactating broodmares fed a yeast culture supplemented diet showed a short term increase in milk production. This increase while significant persisted only for the first two weeks of lactation. However, analysis of the milk noted significant improvements in the nutrient content of the milk for the first 8 weeks of lactation.. The gross energy content, protein level and other nutrient in the milk were increased as a result of the yeast culture supplementation. The increased nutrient content of the milk from supplemented mares resulted in improved growth of the foals during the first 8 weeks of life. It is important to note that while there was an improvement in foal growth rate, the trial only measured the affects of supplementation up to the 8th week post foaling.

Performance Horse

The effect of yeast culture on the performance horse is not clear. In one study where the horses were worked intensively there was a trend for a reduction in the lactic acid levels in blood during the recovery period but no significant differences due to diet during the exercise bout were noted, (Biel et al, 1990). However, in a study where the horses were lightly worked there was a reduction in blood lactate for those horses to receiving yeast culture, (Glade & Campbell, 1990).

In the performance horse it appears that the level of conditioning, the intensity of the activity and length of time the supplement is fed will affect the results obtained from feeding yeast cultures.

The use of yeast culture to supplement your horses diets has a number of benefits. The improved digestibility of the fiber portion of the diets is especially important for those horses that are fed high forage diets. The improved protein digestion is important for those horses (ie. young growing horse and the lactating mare) which have higher protein requirements and the improved phosphorus availability is useful since phosphorus can be deficient in many feeds and meeting phosphorus requirements is always a challenge.

CHELATES

The level of chelated products in livestock feeding is typically added at 25-30% of the total mineral in a feed. If the chelated product enhances absorption why not use 100% of the mineral from chelates? Price becomes a factor as chelated minerals are expensive.

Chelated mineral products have been available for many years and more recently have seen increased usage in horse feeds. What is a chelated mineral? In very simple terms, a chelated mineral is a mineral such as copper, zinc, manganese, cobalt or iron (there are others) that is bonded to "small proteins", peptides or amino acids.

The process of chelating improves the absorption of the mineral from the digestive tract. How this improvement is actually achieved is unknown at this time but it has been suggested that the chelated mineral is more soluble and can cross the intestinal wall more easily, (Rompala & Halley, 1995).

Jackson (1991) reported the differences in absorption of chelated trace minerals in comparison to the inorganic form. This information is summarized in Table 2.

Table 2

         RELATIVE AVAILABILITY OF MINERAL PROTEINATES COMPARED TO
                     TYPICAL INORGANIC MINERAL SOURCES

                           Copper         Zinc      Manganese

Inorganic Form              100            100        100
Chelated Form               140            125        121

                                                   Jackson 1991

The benefits of using chelated minerals for livestock has received a great deal of research interest. The areas that have been studied are reproduction, health, soundness and growth.

Research into chelated minerals for horses has focused on the broodmare and the young growing horse.

Much of the research on feeding chelated minerals to horses has shown varied results. Researchers in Florida found that mares receiving trace mineral supplementation in a combined inorganic/chelated product had a tendency for a reduction in the number of cycles bred and in the number of services per mare. However, there was no effect in conception rate, (Ott & Asquith, 1994). Other researchers have suggested improvements in reproductive performance in barren or open mares by reducing time to first cycle or reducing early embryonic loss when chelates were fed. However these studies have included other management practices which may have affected the improvement in reproductive efficiency, (Ley et al, 1990, Roble & Farfa, 1987).

In the growing horse limited research has been published. In 1995 Ott & Johnson reported that using chelated minerals in diets for yearling did not improve weight gain or wither height. However that study did show some very interesting results related to hoof growth. The addition of a chelated mineral product (which supplied a portion of copper, zinc and manganese as chelates) resulted in an improved hoof growth for the yearlings receiving that diet. There was no increase in strength of the hoof wall but growth was enhanced. Similar results have been reported with dairy cattle fed chelated products.

The other area where chelates have received some attention is related to the immune system. It is well known that providing adequate levels of trace minerals is required for proper immune function. Because of the increased availability of chelated products it is thought that their use will enhance immune function, (Vandergrift, 1993).

Chelates have been recommended for enhanced reproduction, growth, soundness and immune function. While the addition of a chelated product to a feeding program will improve the availability of the mineral to the horse it is unclear how this improved availability will affect production. In situations where it is critical that the horse's requirements for a particular mineral or minerals be met, the addition of a chelated product may be beneficial. It is important for horse owners to realize that while the use of a chelated mineral product may provide a benefit it should only be used as part of a good farm management program not a replacement.

OTHER ADDITIVES

Many other products are added to horse diets to enhance the horse's performance. It is difficult to evaluate many of these products and their potential usefulness because no factual information is available to describe their function. It is not uncommon to see anecdotal information used to promote the use of these products; or conclusions on their use drawn from non horse information. An example of this is blood builders which show some benefit in human athletes but it is difficult to draw the same conclusion for the equine athlete, (Lawrence, 1992).

A number of feed additives have been looked at recently to evaluate their effect on performance horses. Products like trimethylglycine (TMG) was found to improve the clearance of blood lactate following intensive activity in the untrained horse but was of no benefit to the trained horse (Warren et al, 1995). NN dimethylglycine (DMG) a product which may reduce lactate build up in performance horses has also shown results which would suggest that when fed to a properly conditioned horse there is no benefit (Moffitt et al, 1985). If the only information you have to make a decision with is anecdotal it will be next to impossible to determine how useful many of these products really are.

As a horse owner how can you decide what to use? Selecting products based on scientific evidence is the only way to make your choice. Products like yeast culture and chelates have been evaluated scientifically and do show promise in providing beneficial effects for the animals receiving them. These products are additions to programs that enhance proper management and feed selection they will not replace good feed or good management. If you are unsure, ask a nutritionist for some help.

REFERENCES

Bennett-Wimbush, K., 1991. Yeast Culture Research Report. 1994-1, Effect of Yeast Culture
     on Growth in Yearling Horses. Diamond V Yeast, Cedar Rapids, Iowa.

Biel, M., L.M. Lawrence, J. Novakofski, K. Kline, D. McLaren, L. Moss, D. Powell, 1990.
     Effect of Yeast Culture Supplementation on Exercising Horse. Journal Animal Science,
      68 (supp) 375.

Ciro, T.T., 1 99 1 . The Effect of Yea Sacc (1026) on Growth Rate & Wither Height of Colurnbian
     Warmblood Weanlings. Biotechnology Briefs in Alltech 7th Annual Symposium :
     Biotechnology in the Feed Industry. Lexington, Kentucky. p. 355.

Glade, M.J., 1 99 1 a-c. Dietary Yeast Culture Supplementation
     of Mares During Late Gestation and Early Lactation.
     a)       Effect of Dietary Nutrient Digestibilities and Fecal Nitrogen Partitioning. Journal
                of Equine Vet Science 1 1:10.
     b)       Effects ofMilk Production, Milk Composition, Weight Gain and Linear Growth
                of Nursing Foals. Journal of Equine Vet Science 1 1 :89.
     c)       Effects on Mares and Foals Plasma Metabolite, Amino Acid and Endocrine
                Profiles. Journal of Equine      Vet Science 1 1:1 67.

Glade, M.J. and M. Campbell-Taylor, 1990. Effects of Dietary Yeast Culture Supplementation
     During the Conditioning Period on Equine Exercise Physiology. Journal Equine Vet. Science 10.434.

Glade, M.J. and L.M. Biesik, 1986. Enhanced Nitrogen Retention in Yearling Horses
     Supplemented with Yeast Culture. Journal Animal Science 62. 1635

Jackson, S.G., 1993. Mineral Proteinates Applications in Equine Nutrition. Proceedings of the
     9th Annual Symposium : Alltech Biotechnology in the Feed Industry. Lexington, Kentucky. p.91.

Lawrence, L.M., 1992. The Use of Nutritional Ergogenic Aids in Horses. In Proceedings
     for the 1992 Kentucky Equine Research. Short course Feeding the Performance Horse.

Ley, W.B., C.D. Thatcher, W.S. Swecher, P.N. Lessard, 1990. Chelated Mineral
     Supplementation in the Barren Mare : A Preliminary Trial. Equine Vet. Science 10(3) p. 176.

Mason, T.R., 1 993. Effect of Tall Oil and Yeast Culture on Growth Rate of Wild Horses. Res.
     Bull McNeese Slate Univ., Lake Charles, L.A.

Moffitt P.G., G.D. Potter, J.L. Kreider and T.M. Moritani, 1985. Venous Lactic Acid Levels in
     Exercising Horses Fed NN Dimethylglycine. In the Proceedings of the 9th Equine
     Nutrition & Physiology Symposium, p. 248.

Moore, B.E., K.E. Newman, P. Spring, V.E. Chandler, 1994. The Effect of Yeast Culture (Yea
     Sace 1026) in Microbial Populations and Digestion in the Cecum and Colon of the
     Equine. Abstract #969. Journal of Animal Science. Vol 72 Supp (1).

Ott, E.A. and R.L. Asquith, 1994. Trace Mineral Supplementation of Broodmares. Journal
     Equine Vet. Science, No. 14(2) p. 93.

Ott, E.A. and E.L. Johnson, 1995. Effect of Trace Mineral Proteinates on Growth Skeletal
     Development and Hoof Development of Yearling Horses. 14th Proceeding of Equine
     Nutrition and Physiology Symposium, Ontario, California, p.3.

Pagan, J.D., 1 990. Effect of Yeast Culture Supplementation on Nutrient Digestibility in Mature
     Horses. Abstract 340, Journal of Animal Science, Vol. 68, Supp. 1.

Roble, M.G. & R.J. Farfa, 1987. Effects of Metalosates on Conception Rates of Thoroughbred
     Mares. 10th Proceeding of the Equine Nutrition & Physiology Symposium. Ft. Collins,
     CO., p. 637.

Rompala, R.E. and J.T. Halley, 1995. The Trojan Horse of Nutrition. Feed Management, Vol.
     46(4) p. 52.

Vandergrift, B., 1993. The Role of Mineral Proteinates in Immunity and Reproduction - What
     Do We Really Know About Them. In Proceedings of Alltech's 9th Annual Symposium:
     Biotechnology in the Feed Industry. P. 27.

Warren L.K., K.N. Thompson, L.M. Lawrence, and T. Brewster Baines, 1995. The Influence of
     Trimethylglycine in the Trained, Untrained Horse Exercising to Fatigue. In the
     Proceedings for the 14th Equine Nutrition & Physiology Symposium. Ontario,
     California, January 15-21, 1995, p. 123.

Mr. Coleman is a former Equine Nutritionist and Horse Specialist with Alberta Agriculture Food and Rural Development. Now with U of K

 

E-Mail info@completerider.com

E-Mail | TV Show | Features | Horse Play | Learning Center |Contact Us | Advertise
designed for grasslands entertainment group by webSlave Mara all rights reserved

Suppiments:GAGs?|MSM?|Herbals?|Vitamins and Minerals?|Electrolytes?|
Other articles on nutrition |Forages|Water&Electolytes with the Exercising Horse|