These ratings are indicative. Animal performance and health can vary under different management systems and between seasons.
The information in this table is based on animal safety trialling protocols designed to expose animals to simulated worst-case scenario management. This involves forcing them to graze deep into the base of pure perennial ryegrass pastures that have been allowed to grow for several weeks over late spring/summer (similar to a hay crop) where they will encounter the highest concentrations of harmful endophyte chemicals if these are present.
This management does not represent normal farm practice although similar situations may arise on farms in rare circumstances. Under normal farm grazing practices, the contribution of basal pasture material to total animal drymatter intake is relatively low and therefore the intake of harmful chemicals (if they are present) is diluted. Thus, the likelihood of adverse effects on animals is reduced, but the potential for problems to occur may still exist if the endophyte brand is rated < 4-star for ‘freedom from staggers’ and/or there are comments on animal performance which flag potential issues.
Comments on animal performance have been moderated based on information from other trials (in addition to the formal animal safety testing protocols), consideration of the ‘normal’ grazing management practices implemented on farm (see previous paragraph), and recognition that animal diets are very seldom pure ryegrass. Other dietary components such as clovers or non-ryegrass grass species, crops or supplements will dilute the intake of endophyte alkaloids.
Key to Ryegrass staggers ratings:
♦ Likely to cause severe staggers in most years
♦♦ Can cause severe staggers in some years
♦♦♦ Can cause severe staggers occasionally
♦♦♦♦ Very unlikely to cause staggers
NB - All trialling for ryegrass staggers occurs under simulated worst case scenario management and does not represent normal farm practice.
Tables was compiled by the NZPBRA (correct as of print July 2023). AR1, AR37 and MaxP endophytes are used under license from Grasslanz Technology Limited. AR37 and AR584 endophytes are protected under the New Zealand Plant Variety Rights Act 1987.
It is not advisable to mix AR37 and AR1 varieties. AR1 is not recommended for areas where black beetle, porina or root aphid are common problem pests. AR37 is only suitable for sheep and cattle and not advised for deer or horses.