Endophytes are a naturally living organism that lives in the plant and dies in the plant. They are an important part of the plants ability to survive; they protect the plant by producing alkaloids (some toxic to animals) and in return feed off the plant and live (in most cases) quite happily inside the plant.
Endophytes are important as they are essential for enhancing the persistence and productivity of ryegrass and in summer active tall fescue.
There are different types of endophytes available in ryegrass and these include Standard Endophyte (SE) which is a naturally occurring endophyte which is in older ryegrass pastures. SE produces Lolitrem B compound which can cause ryegrass staggers and Ergovaline which causes heat stress, therefore can be an animal health risk.
Since endophytes were discovered in 1982 there has been some advancement with the introduction of novel endophytes that include:
AR1 endophyte is known as an 'animal safe' endophyte that produces only the compound peramine, but in turn the endophyte does not protect the plant from insect attack as well as SE or AR37.
Endo 5 endophyte does not cause ryegrass staggers and has low levels of Ergovaline. Endo 5 persists better than AR1 endophyte and is a better option than SE.
NEA endophyte produces chemical compounds of Peramine, Ergovaline and low levels of Lolitrem B. It is unlikely to cause ryegrass staggers but can cause heat stress to animals.
MaxP® is a novel endophyte for tall fescue. MaxP produces peramine and loline chemical compounds, but no ergovaline or lolitrem B the toxins that impact on animals. There have been no animal health issues identified to date for cattle (beef or dairy) or sheep grazing tall fescue with MaxP, or without endophyte in Australia, New Zealand or the USA. MaxP novel endophyte also improves the persistence of tall fescue in regions that experience long dry summers, particularly in winter rainfall regions.
The major insect pests known to be deterred by MaxP are Argentine stem weevil, black bettle and pasture mealy bug.
AR37 endophyte is the new novel endophyte that currently provides the best balance of pasture production and persistence in ryegrass with limited animal health issues. Animal performance of both sheep and milk production in dairy cows is the same when animals are fed with AR1 or Nil endophyte. (Grasslands, NZ) The combination of insect tolerance and persistence advantages makes AR37 a valuable technology for many farmers.
AR37 can cause staggers, trials have shown that on average the frequency, duration and severity of ryegrass staggers is less than standard endophyte. After many years of use on commercial dairy farms, ryegrass staggers have not been observed in dairy cows on farm to date. AR37 varieties should not be used on properties grazing either deer or horses.
AR37 novel endophyte provides the greatest form of protection in ryegrass from insects including root aphid, black bettle, argentine stem weevil, and pasture mealy bug.
For more information on AR37 visit www.AR37.com.au