Tall fescue has become the most predominate pasture grass in the US due to its wide range of adaptation, ease of establishment, persistency of stand, tolerance of poor soil, insect and nematode resistance, long grazing season with superior winter growth, and forage quality.  Unfortunately, with these superior forage qualities come animal performance problems, which have plagued cattle on fescue since its wide acceptance in the 1940s and 1950s.  Light calf weaning weights, lower gains, lower milk production, and reproductive problems account for millions of dollars in losses to producers each year.

Fescue toxicosis is often referred to as “summer slump” or “summer syndrome” because it is most commonly observed during warmer months of the year.  The causative agent is a fungus (Neotyphodium coenophialum formerly Acremonium coenophialum) called an “endophyte.”  Endophyte-infected fescue cannot be determined visually because the endophyte does not affect the plant’s appearance as it lives within the plant.  Animals grazing endophyte-infected fescue may exhibit the following signs:

• Reduced weight gains

• Reduced feed intake

• Intolerance to high environmental temperatures

• More time spent in the water or shade and less time grazing

• Excessive salivation

• Rough hair coats

• Elevated body temperatures

• Faster respiration rates

• Reduced reproductive performance

• Hormonal imbalances

Consumption of endophyte-infected fescue results in the animal’s inability to properly regulate body temperature due to vasoconstriction of peripheral blood vessels and disfunction of the thermoregulatory and hormonal centers in the brain.  Inability to dissipate heat is why cattle suffering from fescue toxicosis often spend more time standing in water and under shade rather than grazing.  The real culprits in fescue toxicosis are the ergot alkaloidal compounds (toxins), which are converted in the rumen from ergovaline, produced by the endophytic fungus.  While fescue toxicosis is most severe during warm seasons, performance of cattle consuming fungus-infected fescue hay is also adversely affected.

Fescue Toxicosis Relief

Pasture Management

The effects of fescue toxicosis are more pronounced when cattle graze fescue with a seed head as the endophyte concentrates in the seed head.  Several methods of pasture management have been suggested to alleviate the effects of fescue toxicosis in grazing cattle.  These include interseeding a companion forage such as clover, prevention of seed head formation by clipping or continuous grazing, or pasture renovation. 

Interseeding a companion forage will dilute the consumption of the endophyte-infected fescue.  Heavy continuous grazing or clipping is probably the best preventative method because the fungus is most concentrated in the seed head.  A high stocking rate or clipping not only eliminates the formation of seed heads, but also maintains the grass in a more vegetative stage of higher nutritive value.  Likewise, if hay is to be harvested, it is suggested that it be baled in a more vegetative stage as well.  Pasture renovation with endophyte-free varieties of fescue have been used with limited success, especially in southern climates. 

The presence of the endophyte imparts specific advantages to the plant agronomically, which explains why fescue was so widely cultivated.  A new variety of fescue has recently been commercially released.  This new variety contains a novel endophyte that retains the agronomic advantages of endophyte-infected fescue, but does not produce the poor animal performance associated with toxic endophyte-infected fescue.  Use of new endophyte-free varieties requires re-seeding of pastures, an investment that some producers are reluctant to pursue.

Nutritional Management

Controlled supplementation with grain or grain byproducts and the use of creep feed for calves may help alleviate the effects of the endophyte toxins.  Producers should limit the amount of non-structural carbohydrates (such as grain) given to grazing cattle as over supplementation with grain can reduce efficiency of forage fiber digestion.  Feedstuffs with sufficient structural carbohydrate content can be fed at higher amounts and will not compromise the rumen’s ability to efficiently utilize forages.

Given the vast acreage in fescue production and time-consuming alternatives to management of endophyte-infected fescue pastures, feed manufacturers have sought to develop supplements designed to counter the effects of the toxin.  Considerable research by ADM Alliance Nutrition has resulted in the development of a nutritional mineral supplement that counters the negative effects of the fescue fungus toxin on production.  Research and field results from the use of MasterGain® Fescue Endo-Fighter™ have yielded positive results.  Research has shown MasterGain Fescue Endo-Fighter attacks the problem with a patent-pending combination of four complimentary functions:

• Believed to have a positive effect on combating toxins

• Helps dissipate heat

• Support for proper rumen function

• Immune system support

Possible Toxin Binding

Certain compounds have been shown to have the ability to bind ergovaline (produced by the fescue endophyte), which prevents or greatly reduces the amount of ergovaline available for conversion to ergot alkaloids.  These toxic substances are readily absorbed across the rumen wall into the circulatory system.  Methods designed to halt conversion of ergovaline to ergot alkaloids markedly reduce the amount of toxins entering the blood stream.  The result is fewer toxins are absorbed by the cow, and the negative effects on hormones, blood flow, behavior, and performance are reduced.

Using an in vitro research study, ADM Alliance Nutrition demonstrated the ability of certain ingredients in Endo-Fighter to bind ergovaline.  This binding results in less ergovaline (toxin) being available for conversion to the easily absorbed and highly toxic ergot alkaloids.    The prevention of ergovaline conversion to the alkaloid favors cattle production.

Heat Dissipation

The ability of cattle to dissipate heat is vital to cattle production during hot summer months.  Vasoconstriction that results from consumption of endophyte-infected fescue hay during the winter also has serious consequences.  Lack of blood circulation to ears, tails, and hooves makes cattle more susceptible to frostbite and similar conditions, which lead to a gangrenous condition that can result in loss of hooves and the tips of tails and ears.

Studies with humans and rats suggest botanicals may have beneficial effects on thermoregulation.  A select, naturally-occurring botanical’s potential to positively effect thermoregulation and vasodilation was evaluated by ADM Alliance Nutrition research scientists.  The select, naturally-occurring botanical was fed over a 57-day trial to growing cattle (steers and heifers) on fescue pasture containing a low amount (110 ppb) of ergovaline.  (Signs of fescue toxicosis are typically prevalent above 600 ppb ergovaline.)  Core body temperatures were measured rectally and vasodilation was evaluated using an infrared thermometer to determine ear, hoof, and surface body temperatures.   

Overall a reduction in ear, body surface, and hoof temperatures and an increase in rectal temperature occurred in the control cattle.  This occurrence is consistent with vasoconstriction resulting in a reduced ability to dissipate heat.  The consumption of the naturally-occurring botanical improved blood flow to the ear, body surface, and hoof and lead to a slight reduction in rectal temperature.  The benefits of the naturally-occurring botanical on thermoregulation may be even more pronounced in cattle faced with fescue toxicosis.  The four-way approach that Endo-Fighter uses to approach fescue toxicity allows the botanical to have a maximal effect in the field.  The bottom line is comfortable cattle spend more time grazing, leading to weight gain and/or more milk production rather than standing in ponds or shade.

Rumen Function

The incorporation of ingredients to support proper and efficient rumen function offer additional benefits to MasterGain Fescue Endo-Fighter. Research-proven ingredients have been selected based on their ability to improve fiber digestion, nutrient utilization, and help maintain optimum function even when the cow is stressed.  Improved fiber digestion allows the animal to get more nutrition from the feed that is consumed.  Research has documented improved gains in growing beef cattle using this technology alone.  When combined with the fescue-specific actions of Endo-Fighter, cattle are better prepared to perform on fescue pastures.

Immune System Support

Highly bioavailable antioxidants have been documented to support and enhance proper immune function.  Antioxidants are required when immune cells attack invading bacteria. The pairing of these antioxidants with highly purified ingredients help improve gastrointestinal tract health and subsequent health and productivity of cattle, especially when consuming endophyte-infected fescue.  The use of a vasodilator improves blood flow, allowing the potent antioxidants easier access to the sites where infection or challenges occur.  When these effects are combined with the improved rumen function and resulting nutrient availability, the cow has more energy available to support a strong immune system.  Data supports the concept that when brood cows are fed the compounds in Endo-Fighter, they raise heavier calves.  A heavier calf is associated with a healthier and more mature immune system.

Field Trials

MasterGain Fescue Endo-Fighter Mineral was evaluated in brood cows pastured on farms with a history of fescue toxicity.  Trials were conducted in Missouri between August and October of 2004.  Treatment groups were compared to control groups, which were offered the same mineral formulation minus the “fescue toxicosis ameliorator” component.  Mineral intake exceeded target intakes. Although mineral intake calculation was only based on cows consuming the minerals, it is likely that calves also consumed some mineral.  The trials occurred later in the year when it is not uncommon for mineral intake to exceed target.  Early season mineral consumption is not expected to be as high.  Trial results are given in Table 1.

Table 1  Growth of Cattle Consuming MasterGain Mineral (control) Versus MasterGain Fescue Endo-Fighter Mineral Formulation (experiment)
	Farm A		Farm B
Cow Data	Control	Experiment	Control	Experiment
No. cows	29	26	33	34
Starting wt, lb	1114	1077	1351	1276
Ending wt, lb	1090	1102	1397	1381
Wt. change, lb	-24	25	46	105
ADG, lb	-0.24	0.25	0.36	0.81
Avg. daily mineral intake, lb	0.55	0.61	0.26	0.43
Calf Data
No. calves	22	26	30	34
Starting wt, lb	275	268	342	388
Ending wt, lb	419	470	618	687
Wt. change, lb	144	202	276	299
ADG, lb	1.44	2.02	2.53	2.74
Source: ADM Alliance Nutrition research trial B05301

Trial conclusion: The MasterGain Fescue Endo-Fighter formula produced better gains compared to the standard MasterGain formula.  Producers observed marked improvements in cattle appearance and time spent grazing.  One producer stated, “I was very impressed with this new product.  Cattle appearance was improved.  They milked better, which means the calves did better.  They were grazing more and had a better hair coat.  They just looked like they felt better and more healthy than cattle not on this product.  This all means more money in my pocket.

Competitor Product Trial

ADM Alliance Nutrition’s “fescue toxicosis ameliorator” – Endo-Fighter – was compared to the major competitor fescue product.  At ADM Alliance Nutrition’s Decatur, IN research center, calves were subjected to a standard fescue toxicity model.  During the fescue toxicity period, the basal diet contained endophyte-infected fescue seed.  The content of seed used in the experiment was designed to mimic the amounts seen in field conditions.  Room temperature was elevated to simulate summertime conditions and allow assessment of the thermoregulatory effects of the additive on fescue toxicity.

Calves were individually housed and all feed intake was measured.  Calves were fed Endo-Fighter or the competitive product at the beginning of the meal and the amount consumed was controlled for all calves.  Clinical signs of fescue toxicity, such as elevated heart rate, respiratory rate, and rectal temperature, indicated that heat stress and fescue toxicity did occur in all calves.  Rectal temperature was near normal at the onset of the trial; however calves fed the competitor product had lower rectal temperatures before consuming any of the competitor product.  This is noteworthy as by the end of the trial these calves had significantly greater rectal temperatures.  Trial conclusion: Research demonstrates Endo-Fighter repeatedly reduces body temperature (up to 40% lower body temperature increase) compared to the leading competitor product in cattle maintained in closely controlled fescue toxicity conditions. Bottomline – Cattle consuming Endo-Fighter are better equipped to handle the heat stress associated with fescue toxicosis.

Conclusion

While fescue has many favorable characteristics that make it an excellent forage, production losses associated with its use are prevalent.  Pasture management and nutritional management may help curb the effects of fescue toxicosis in cattle consuming fescue.  MasterGain Fescue Endo-Fighter is comprised of a patent-pending combination of components specifically selected and research-proven to support production of cattle on endophyte-infected fescue pastures.  Research trials confirmed cows and calves consuming MasterGain Fescue Endo-Fighter Minerals gained more weight than controls.  Cattle have also been shown to be better able to handle heat stress associated with fescue toxicity when consuming MasterGain Fescue Endo-Fighter Minerals.  Endo-Fighter is no substitute for good management, but is a useful tool to help producers unlock the potential of their cattle grazing fescue pastures.

MasterGain Fescue Endo-Fighter Minerals . . .
It’s a combination of research and technology at work.