AR37 endophyte research - project comes to a close

Errol Thom,
Senior Scientist, DairyNZ

Overall conclusions

  1. AR37 ryegrass was clearly more persistent than either AR1 or Standard (HE) ryegrass. This supports findings from previous work.
  2. The greater persistency translated into a reduced need for renovation of AR37 pastures after the 2008 drought, but in the three years before that time there was no difference in total pasture yield.
  3. There was no sign of ryegrass staggers or any other animal health issues in cows grazing AR1 or AR37 pastures – even at times when cows grazing HE were affected by ryegrass staggers.
  4. With ryegrass/white clover pastures, there was a trend for slightly lower milksolids (MS) production over summer from cows grazing AR37 or HE compared with AR1. With pure ryegrass pastures there were no significant differences in MS production. These results suggest that the higher clover content of the AR1 mixed pasture was a contributing factor to the observed MS production differences.
  5. Where pasture persistence is the top priority then AR37 will clearly deliver benefits. Where persistence of AR1 ryegrasses is not a problem, continuing to sow AR1 is advised.