Pasture Research Illustrates Benefits of Endophytes to Grass and Animal

Introduction: Demonstrating the benefit of non-toxic endophyte-infected pasture grasses on animal performance is well documented and is equal to that of non-infected tall fescue.  However, it is more difficult to demonstrate that which the endophyte imparts on the grass.  Research conducted by the University of Georgia, in collaboration with Agrinostics Ltd. Co., is demonstrating endophyte value to both plant and animal. 

Setup: The experiment began with fall planting of toxic endophyte infected, novel (non-toxic) endophyte infected, and endophyte free (E-) tall fescue in October 2020.  Each seed type was planted into 3 pastures (9 total pastures).  All seed were produced in certified fields located in the Oregon and harvested in July, 2020.  The seeding rates were 15 lbs/A for endophyte infected seed and 25 lbs/A for the E- seed.  Annual ryegrass from soil-borne seed germinated and competed with the establishing pastures.  Pastures were mowed to minimize the ryegrass competition in winter and spring of 2021.  Pastures were harvested for hay in May and September 2021.  The pastures regrew for 32 days in October, 2021 after which they were stocked with 2 steers, each weighing approximately 570 lbs.  Animals remained on pasture for 28 days.  Forage yield was measured before and after grazing, and again 37 days after the last grazing day.

Table.  Mean forage yield of pasture treatments, differences in yield vs. E- tall fescue, and potential extra grazing days that endophyte-infected tall fescue provided.

Results: The E- pastures were more adversely affected by the ryegrass competition than were the toxic or novel endophyte-infected pastures (see table).  There was over a ton of added forage in the endophyte infected pastures compared to the E- pastures over the 3 sampling dates.  The added number of grazing days afforded to the endophyte-infected pastures was calculated assuming steers consumed 3% of their body weight.  The number of added grazing days were 133 for novel pastures, and 150 for toxic pastures. The short-term grazing still enabled us to document steers grazing E- and novel tall fescue gained twice as much as those on toxic tall fescue. 

In addition, pastures planted to E- tall fescue had more winter weeds than those planted to endophyte-infected tall fescue (see picture below).  The primary weed was chickweed (Stellaria media) which livestock tend to avoid.  This means the chickweed will provide added competition and tend to further reduce stands of the E- paddocks.

(Pictures) from left to right: Pastures of toxic endohyte-infected, novel-endophyte, and E- tall fescue.  Note the weeds in the E- stand.

Summary: Pasture establishment conditions during winter of 2020/2021 challenged E- tall fescue because of annual ryegrass competition.  Endophyte-infected (toxic and novel) tall fescue had better competitive traits and improved stands compared to E- pastures.  This meant that the infected pastures had more grazing days than E- tall fescue.  Animal gains for novel and E- pastures were the same and twice that of toxic endophyte-infected tall fescue.  Winter weeds in winter of 2021/2022 will continue to reduce stands of E- tall fescue.  Endophytes (toxic AND novel) provide competitive advantages that will prolong pasture persistence.

~ Dr. Nick Hill, Agrinostics Ltd. Co.

The Alliance for Grassland Renewal is a national organization focused on enhancing the appropriate adoption of novel endophyte tall fescue technology through education, incentives, self-regulation and promotion.  For more resources or to learn more about the Alliance for Grassland Renewal, go to

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