Nevada County Picayune and Gurdon Times Newspaper Archive

Farm and Home News

Tall fescue is grown on more than 35 million acres in the southeastern United States. Its rapid acceptance since the 1930's was due to many attributes, including ease of establishment, wide adaptation, long grazing seasons, tolerance of environmental stress and pest resistance.

Chemical measures of forage quality such as digestible dry matter, crude protein and mineral levels suggest that tall fescue forage has potential for high quality and good animal performance.

Unfortunately, fescue is not without its shortcomings. Cattle grazing fescue often develop a chronic, unthrifty condition, especially apparent during the summer months. In addition, some cattle occasionally develop lameness and lose portions of their feet and tails during fall and winter. Some mares grazing fescue have reproductive problems during the last trimester of pregnancy.

In the mid-1970's, USDA scientists discovered an endophytic fungus that infects the fescue plant. New technology has allowed scientists to study the DNA composition of the endophyte and classify it as Neotyphodium coenophialum.

Two characteristics of the endophyte have great practical importance. First, the organism does not affect either the growth or the appearance of the grass, and it requires a laboratory analysis to detect its presence. Second, it is seed transmitted and apparently not transmitted in any other way. Ergot alkaloids produced by Neotyphodium coenophialum infected fescue has been implicated as the source of adverse physiological effects in cattle and horses.

In cattle there appears to be three separate syndromes associated with tall fescue: fescue foot, bovine fat necrosis and summer slump. Fescue foot clinical signs are rough hair coat, loss of weight, elevated body temperature and respiration rates, tenderness of legs and loss of hooves and/or tail switch.

Fescue foot occurs mainly in the winter. It is a serious syndrome, but its occurrence is relatively low in relation to the large acreage of tall fescue.

Bovine fat necrosis is characterized by the presence of hard masses of fat in the adipose tissue, primarily in the abdominal cavity. This syndrome, which results in digestive upsets and difficult births, has been associated with high rates of nitrogen fertilization from either chemical fertilizers or from poultry litter.

Fescue toxicity or summer slump is by far the most common syndrom in cattle on tall fescue. It is characterized by poor animal gains, reduced conception rates, intolerance to heat, failure to shed winter coats, elevated body temperature and nervousness. While this syndrome is most noticeable in summer, adverse effects occur throughout the year.

In horses the most pronounced problems of endophyte infected fescue are seen in pregnant mares, although some problems may be observed in all classes of horses.

Abortions may occur during late pregnancy or stillborn foals may result at the time of parturition. Mares may carry their foals for 30 to 40 days longer than normal, resulting in a difficult birth due to the increased size of the foal. Foal deaths may increase due to difficult births associated with increased foal size.

Thickened placentas and/or retained placentas are common. This may cause excessive hemorrhaging, resulting in mare death. Uterine infections may increase, thus causing a delay in rebreeding.If these are not problems enough, mares on fescue may have reduced milk production or no milk at all. Colostrum production may be decreased or nonexistent.

The first step in managing fescue toxicity is to know for certain that the pasture is indeed infected and at what level. For specific sampling procedures, cost and shipping requirements, contact the Extension office at 887-2818.

There are several management options to choose once infection levels are known.

1.Remove pregnant mares from endophyte infected tall fescue fields 45 to 90 days before foaling. This is really not an option, but a necessity.

2.Manage pastures to maintain other grasses to dilute the toxic tall fescue.

3.Close grazing of tall fescue in spring will reduce seedhead production.

4.Seeding of legumes will greatly dilute the toxic fescue and often overcome any problems with animal gain.

5.Replant infected tall fescue with endophyte-free seed. (Possibility of reinfection.)

6.Kill infected stands and replant with another plant species.