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TRAC Dairy Tech Tip - Summer 2017/18

Updated: May 20, 2020


Endophytes are fungi that grow in pastures. While they produce a range of alkaloid products that aid in protecting the plant from insect attack, they can also cause considerable problems within your stock, namely Perennial Ryegrass Toxicosis (PRGT) also known as Staggers. These endophytes can also be present in Tall Fescue.


The fungi (endophytes) build up in the plant stems, crown, seed heads and leaves, however it is at lower levels in the leaf. When the plant is stressed it releases the toxins and problems can occur. Firstly, to those eating long stalky ryegrass with lots of stem and seeds and secondly to those eating right down to the crown of the plant. Those grazing the plant optimally (neither too rank nor too short) are much less effected.

Classic cases of PRGT occur when we see a summer rain on well eaten pasture… you get a regrowth that then either rapidly gets cropped down to the crown, or rapidly goes to head… both can present issues. In lactating cows milk can be reduced because of PRGT, in the last couple of weeks alone we have seen losses of 3 litres plus in some areas, particularly when paired with the sudden bursts of high humidity and heat as well. When endophytes are impacting cattle they will experience an increase in body temperature, causing a double whammy of heat stress on the days we have been having over 25 degrees. Clinical signs & symptoms

  • Vaso Constriction = heat stress

  • Reduced feed intake

  • Reducde hormone Prolactin = deacreased milk yield

  • Increased nervousness

  • Scouring

  • Reduced fertility

  • Death - primarily from misadventure

If you notice any of these signs, call one of our ruminant experts to discuss adjusting the pasture rotation or including a toxin binder into your ration


We have seen many farms suffer with heat stress over the last few weeks. Keeping cows cool is top priority to maintain appetite and production. And don't forget to CHECK water troughs frequently! Click here for information on heat stress and some consequential impacts on dry cows and heifers from research out of the USA.


Find out protein, energy, sugar, NDF and much more to meet your summer growth targets. With the price spike of cereal grain, knowing the silage quality means we can better tailor grain usage. Send a silage sample into Forage Lab Australia for quick and accurate results.


Our Consultants:


Tom Thorn 0427 243 319

Owen Rees 0429 437 823


To download our key TRAC Dairy Tech Tip - Summer 2017/18 Edition, please click the link below...

Download PDF • 518KB

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