Anti-quality factors associated with alkaloids in eastern temperate pasture

Abstract

The greatest anti-quality associated with eastern temperature pasture grasses is the result of ergot alkaloids found in endophyte-infected (Neotyphodium ceonophialum) tall fescue (Festuca arundinacea Schreb.) The relationship between the grass and the endophyte is mutalistic with greater persistence and herbage mass as a result of the endophyte. Ergot alkaloids reduce growth rate, lactation, and reproduction in livestock. Significant effects are the result of elevated body temperature and reduced peripheral blood flow such that necrosis may result. Perturbations also occur in a variety of body systems. Planting new pastures with seed containing a "non-toxic" endophyte appears to be a potential solution. Ergotism results from the ingestion of the scelerotia of Claviceps purpurea containing ergot alkaloids found on seed heads. Ergotism resembles the effects of endophyte-infected tall fescue. Endophyte-infected perennial ryegrass (Lolium perenne L.) contains ergot and lotirem alkaloids that result in reduced growth and tremors. Reed canarygrass (Phalaris Anundinacba L.) contains tryptamine, hordenine and gramine alkaloids that reduce growth. Annual ryegrass (Lolium multiplorum L. may contain galls with cornetoxins which result in neurological signs.

Molecular characterisation and interpretation of genetic diversity within globally distributed germplasm collections of tall fescue (Festuca arundinacea Schreb.) and meadow fescue (F. pratensis Huds.)

“…), an outbreeding allohexaploid (2n = 6x = 42) which is cultivated world-wide for pasture and turf. Tall fescue is the predominant pasture grass grown in the United States of America, where it is cultivated on greater than 14 million hectares (Buckner et al 1979; Thompson et al 2001). Climatic changes are also leading to increased cultivation of tall fescue within cooler temperate regions such as Europe and southern Australia, where the less drought tolerant species perennial ryegrass (Lolium perenne L.) has traditionally been preferred due to ease of grazing management and palatability (Rognli et al 2010).…”

Fescue toxicosis

“…Ruminant species have a placental lactogen that can overcome this initial lack of prolactin stimulation of the mammary gland prior to and at birth (Cross, 1997). However, lower prolactin concentrations in dairy and beef cows consuming E fescue, as well as diminished feed intake associated with the ingestion of E fescue, can be reflected by decreased milk production (up to 50%) observed after the perinatal period (Schmidt and Osborn, 1993;Thompson et al, 2001;Evans et al, 2004b).…”

“…New, novel endophyte varieties of fescue that lack ergovaline, but not other types of fescue endophytic toxins, do not cause fescue toxicosis (Roberts and Andrae, 2004). Syndromes similar to fescue toxicosis are seen when ergotized grains infected by C. purpurea are ingested by livestock (Thompson et al, 2001;Evans et al, 2004a). Finally, it has been shown that D 2 dopamine antagonists, which stimulate prolactin secretion, are able to alleviate most of the toxic effects of fescue (Lipham et al, 1989;Cross, 1997;Evans et al, 1999).…”

“…Altered luteal function in heifers grazing E fescue can result in reduced progesterone. Consumption of E fescue and ergopeptide exposure have been associated with low progesterone production in both cows and horses, diminished progestagens in late-gestational mares (5α-pregnanes rather than progesterone normally predominate the last two trimesters of equine pregnancy), suppressed relaxin associated with possible impaired placental function, and, somewhat more variable, alterations in estrogen concentrations in pregnant mares (Cross, 1997;Evans et al, 1999;Thompson et al, 2001;Evans, 2011). These imbalances of reproductive hormones lead to early pregnancy problems in cattle and late pregnancy problems in horses.…”

“…The tall fescue plant and its endophyte enjoy a mutualistic or symbiotic relationship (Thompson et al, 2001). Each benefits from the survival of the other.…”