Ryegrass endophyte and cattle growth in Northland

Abstract

Perennial ryegrass pastures infected with or free of the endophyte (Neotyphodium lolii) were compared for growth and health of young grazing cattle. Heat stress, indicated by excessive salivation, was observed on several occasions among cattle grazing endophyte-infected ryegrass, but there were no differences between groups in body temperature. Liveweight gains were generally slow and inconsistent. During one period of rapid liveweight gain in March-April 1997, heifers grazing endophytefree pastures gained 7 kg more than heifers grazing infected pasture. Taking data from three four-week grazing periods in summer and autumn, liveweight change of cattle grazing endophyte-free pastures showed a consistent advantage over cattle grazing endophyte-infected ryegrass. Significant differences in serum prolactin were recorded on two occasions, and on one day in February 1998 weaner bulls grazing infected ryegrass were breathing significantly faster than their counterparts on endophyte-free pasture. These results can be compared with previous reports that endophyte status of ryegrass pastures has little effect on grazing cattle, and contrast with the published literature for tall fescue. Keywords: liveweight gain, Neotyphodium lolii, perennial ryegrass, ryegrass endophyte

The impact of a forage plant breeder – the story of Herrick Sydney (Syd) Easton (1946 - 2023)

“…Syd made an important contribution to understanding the genetics of the interaction between the host plant and the endophyte, and the importance of Epichloë endophyte for ryegrass survival when predated by a number of introduced insect pests (Easton 1999). The host plant genotype is now understood to regulate the extent of alkaloid expression (Fletcher and Easton 1997;Easton et al 2002a;Easton 2007a and b;Fletcher et al 2006;Popay and Easton 2006) as well as the ease of seed transmission (Gagic et al 2018).…”

“…Endosafe ® had been identified as a strain that produced peramine to control Argentine stem weevil (Fletcher et al 2006) but did not produce lolitrem B and so was presumed safe for use with animals because it would not cause ryegrass staggers ). However, another alkaloid was associated with the Endosafe ® strain, ergovaline and which when expressed at high levels can cause heat stress in animals 1996;Easton and Couchman 1999). This led to it Endosafe T® being withdrawn from the market except in the hybrid ryegrass Grasslands Greenstone where the level of ergovaline was relatively low, and no livestock health problems had been encountered .…”