Animal Safety & Production

Pastures with AR37 produce more drymatter and through better persistence, pasture quality should be higher meaning stock have a better feed supply on offer. With its improved persistence, the risk of feed deficits should also be reduced. For areas such as Northland and Waikato, ryegrass with AR37 provides the ideal option for superior pastures, where ryegrass pastures with current endophyte options struggle against insect and weed invasion.

Ryegrass with AR37 has been tested by AgResearch for liveweight gain in sheep, and animal performance was the same as ryegrass without endophyte, and AR1 ryegrass. Sheep performance is considerably better with AR37 than standard endophyte. The incidence of dags is as low with AR1.

Growth rates of lambs grazing various endophyte type ryegrasses (mean of 3 years)

Standard endophyte association grams/dayAR37 association grams/dayEndophyte free ryegrass grams/day
44 129 131

DairyNZ have completed a four year trial looking into dairy performance on AR37, click here for more information.

Although AR37 can cause ryegrass staggers. Trials have shown that on average the frequency, duration and severity of ryegrass staggers is less than for standard endophyte. However on occasions, sheep (and potentially other animals) grazing AR37 ryegrass may be severely affected.

After many years of use on commercial dairy farms, ryegrass staggers have not been observed in dairy cows on-farm to date. For information specific to Italian ryegrasses with AR37 click here. AR37 varieties should not be used on properties grazing either deer or horses.

Another key benefit of AR37 is that it does not cause heat stress or flystrike, which can be associated with other endophytes that hold high levels of ergovaline.

Endophyte animal safety & production (Ryegrass, Festulolium & Continental Tall Fescue)

These ratings are indicative. Animal performance and health can vary under different management systems and between seasons.

These tables were compiled by AgResearch, DairyNZ and NZPBRA. 

Table 5 - Livestock performance – sheep & lambs

Table 5 2019

Table 6 - Livestock performance – dairy cows & beef cattle

Table 6 2019 b

Key to tables 5 - 6

diam.png Poor animal production and/or health: This endophyte is known to regularly cause significant problems.
diam.pngdiam.png Moderate animal production and/or health: This endophyte is known to regularly cause significant problems.
diam.pngdiam.pngdiam.png Good animal production and/or health: This endophyte can cause problems from time to time
diam.pngdiam.pngdiam.pngdiam.png Very good animal production and/or health

NB – All trialling for ryegrass staggers occurs under simulated worst case scenario management, and does not represent normal farm practice.

() Provisional result: Unlikely to be tested on, or negatively affect cattle production.

Notes on Table 5

  1. Standard endophyte can cause severe ryegrass staggers, can significantly decrease lamb growth rates in summer and autumn, and significantly increase dags.
  2. Ryegrass containing AR37 endophyte can cause severe ryegrass staggers, but the frequency of ryegrass staggers is much lower than for ryegrass with standard endophyte.  One50 AR37, Asset AR37, and Ohau AR37 may give rise to higher instances of ryegrass staggers than other AR37 cultivars in some situations.
  3. Lambs grazing ryegrass containing AR37 endophyte can have reduced LWG during periods of severe staggers.

Notes on Table 6

  1. Standard endophyte can cause ryegrass staggers, and has been shown to depress milksolids (MS) production through summer and autumn.
  2. While ryegrass staggers has not been observed on cattle and dairy cows, it could occur on rare occasions.
  3. In dairy trials overall MS production from ryegrass containing AR37 endophyte is not significantly different from that with AR1. A small reduction in MS was observed over summer on ryegrass containing AR37. A contributing factor to this was the lower clover content in AR37 pastures.