In the 1970's an historic experiment was conducted on Auburn University 's Black Belt Substation near Marion Junction. This study was the first experiment that linked the disorder commonly referred to as fescue toxicity with a fungus (endophyte) that is usually present inside 'Kentucky 31' tall fescue, the variety that occupies the majority of the fescue acreage in the United States.

It was later learned that this fungus also causes the cattle disorders called fat necrosis and fescue foot. In addition, it can reduce reproductive efficiency of cattle, sheep, and other animals, it drastically reduces milk production of several species of grazing animals, and it causes foaling problems in horses. All of these were important findings that might be thought of as breakthroughs" regarding our understanding of fescue and the fescue endophyte.

Soon after the fungus was linked to fescue toxicity, there were additional important findings. These included learning that: (1) the fungus is transmitted only through seed; (2) the vast majority of fescue plants in most fescue fields contain this fungus; and (3) it is a simple matter to eliminate the fungus from breeding lines and thus make fungus-free seed commercially available (which happened quickly thereafter). Thus, it appeared that livestock producers would be able to greatly increase animal productivity and avoid disorders by using fungus-free seed to establish fungus-free fescue fields.

Unfortunately, another finding soon greatly dampened enthusiasm for establishing fungus-free fescue stands. Specifically, it was learned that when the fungus is removed from fescue, the plants are more likely to be attacked by insects and nematodes, they are less agronomically fit (lower seed production, slower germination, etc.) and the grass is not as stress tolerant as when the fungus is present. Because of the reduced hardiness and pest resistance, many producers who planted fungus-free fescue soon lost their stands.

Another Breakthrough

In the 1990's there was yet another breakthrough regarding the fescue fungus situation. This interesting and potentially extremely important development requires a bit of background information and explanation in order to be fully understood and appreciated.

Scientists learned that the fescue endophyte produces a number of different alkaloids (a large and diverse class of naturally-occurring chemical compounds). Among the many alkaloids that are known to exist, some (including cocaine, heroine, and nicotine) are widely known to have powerful effects on living things. Various other alkaloids cause certain plants to be poisonous. The alkaloids produced by the fescue fungus are different from these, but nonetheless are also powerful.

The fescue fungus alkaloid situation is complex and not well understood at present, but it has become clear that there are "good" and "bad alkaloids produced by the endophyte in Kentucky

31 fescue, which is why it results in both desirable and undesirable effects. Though some of the alkaloids produced by the fungus in fescue (such as one named ergovaline) result in fescue toxicity and other animal disorders, other fungus-generated alkaloids (such as peramine) may be responsible for enhancing stress tolerance, and certainly are involved in increasing pest resistance in tall fescue.

Additional studies revealed another interesting and important fact. Namely, that there are different strains of the fescue fungus and, more importantly, that some strains produce greater or larger amounts of various particular alkaloids (which likely explains why some fields of fungus-infected fescue seem to be much more harmful to livestock than others).

Once this was understood, scientists began to wonder if it might be possible to find a fungus that produces a particular spectrum of alkaloids that could result in producing the good effects (the effects we want fescue to express) without causing the bad effects (poor animal performance and disorders). Several research groups pursued this line of study, and workers in AgResearch, an agricultural research organization in New Zealand , were the first to identify such a fungus.

They worked with faculty at the University of Georgia to insert this fungus strain in two fescue varieties, Jesup and Georgia 5, both of which are now marketed under the name "MaxQ."

It should be noted that MaxQ is actually the name of the special endophyte; the name of the variety (Jesup or Georgia 5) is provided on the seed tag. However, the general term that scientists are using to refer to such a special-purpose fungus is "novel endophyte." Thus, Max Q became the first commercially-available novel endophyte.

In testing done to date by University of Georgia personnel, the MaxQ fungus has lived up to expectations. In grazing trials done with lambs and steers, it produced gains similar to fungus-

free fescue, but has persisted more like infected fescue. Additional research trials and on-farm demonstrations are underway in a number of states, including Alabama .

In addition to the exciting animal performance data generated in Georgia, the ergovaline production by both Jesup and Georgia 5 MaxQ fescue was similar to non-infected fescue (virtually zero), while toxic Jesup produced substantial quantities of this undesirable alkaloid. Furthermore, peramine levels in Jesup MaxQ and Georgia 5 MaxQ were similar to that produced by toxic Jesup.

Finally, many livestock producers who have planted fungus-free fescue and lost their stands will be especially interested in learning that stand evaluations have been extremely encouraging. In multiple years of continuous grazing of MaxQ fescue seeded into bermudagrass at Eatonton, Georgia, the persistence of Jesup MaxQ and Georgia 5 MaxQ was been similar to that obtained with toxic Jesup and toxic Georgia 5, while endophyte-free Jesup and endophyte-free Georgia 5 stands declined dramatically.

Conclusion

The potential importance of this development can hardly be overemphasized. If novel endophyte fescue continues to consistently and dependably result in high animal gains without causing animal disorders, yet will persist similarly to "toxic" endophyte infected fescue varieties such as Kentucky 31, it constitutes an extremely important development for forage/livestock agriculture.