Is there glyphosate in my hay?

Glyphosate, also known by its trade name Round Up, seems to be quite the buzz word in hay lately. You will even find hay advertised as glyphosate free. Do you really need to be concerned about glyphosate contamination in the hay you feed your horses?

I recently tested 5 stacks of hay we happen to have on hand here at the farm. I didn’t choose this hay because I thought it was more or less likely to have glyphosate on it, I simply used what I had on hand. I took 500 g samples from 6 different kind of hay originating from 3 different farmers in 3 different towns in Alberta. As you can see from the results below, all 5 samples tested below 0.01 ppm (parts per million.) According to the lab this mean no glyphosate was detected. No lab can guarantee any crop to be 100% free as there could possibly be minute traces below detection levels, however, the information provided to me by the lab indicates that all the hay I tested is free of glyphosate.

These results came as no surprise to me. I did not expect to find glyphosate residue in my hay. Glyphosate is a non-selective herbicide meaning it will kill most plants to which it is applied, the exception being black berries of course, nothing kills those. This is unlike the broad leaf class of herbicides which generally do not affect grass but will kill broad leaf weeds (and other broad leaf plants) such as dandelions and buttercups. Grazon is a popular broad leaf herbicide often used here on the west coast for the control of buttercups in pasture and hay fields. Glyphosate, on the other hand, kills everything, any plant it comes in contact with. It stops the shikimic pathway, a specific enzyme pathway, which prevents the plant from making certain proteins required for growth. Glyphosate kills plants from the root up preventing future growth.

It has been suggested that glyphosate, Round Up, is being used by farmers as a desiccant or drying agent to help prevent hay from spoiling and allowing farmers to put their hay up earlier and more quickly. This is a misconception. If we go back to the way in which glyphosate acts as an herbicide it is easy to understand why this would not benefit farmers. Farmers do not reseed their hay fields every year. Forage crops, the majority of grass grown for hay, is perennial, meaning it comes back year after year after year. When hay is harvested the farmer cuts the grass or the legume several inches above the ground. It is important to leave some plant material above ground when cutting for two reasons; we hope it will prevent dirt and rocks from being mixed into the resulting bales of hay, but more importantly this leaves some plant material exposed to sunlight to allow for photosynthesis to occur.

As we all learned in grade school, photosynthesis is the process by which plants use sunlight for energy. In the same way we, and our horses, as mammals, need to consume food for energy for growth, plants absorb sunlight during a process called oxygenic photosynthesis. Light energy transfers electrons from water molecules to carbon dioxide molecules, producing carbohydrates (sugar) and oxygen. These carbohydrates are energy for plant grown and cellular regeneration. If a hay field is cut too short and not left with enough leaf for adequate photosynthesis to occur we will see plant loss and poor-quality future growth.

This future growth is the key to successful hay production. Newly seeded fields are often weedy with poor quality growth. Most forage crops need time to establish a good stand. We see improved forage from fields which are 2-5 years old and most fields will be in production for 6-8 years before they need to be reseeded. Of course, the better managed a hay field is the longer it will produce quality forage. If a farmer applied round up to a hay field  in production the plants would be killed, this is the action of glyphosate, this is what its used for, to kill plants. Farmers do not want to kill their hay fields.

There are a few exceptions. The United States approved Round Up Ready alfalfa in 2011. Round Up Ready plants are quite common in North America, both in the United States and in Canada. These crops include canola, sugar beet and soy beans. Canada has not approved Round Up Ready alfalfa however. There are currently no other genetically modified, Round Up Ready forage crops available on the market. What this means for the potential for glyphosate contamination in hay is that unless you buy straight alfalfa from the US your hay is not going to have been sprayed with Round Up. Even in the US, if a farmer grows an alfalfa with any other grass, think orchard alfalfa mix, timothy alfalfa mix, even if the alfalfa is GM Round Up Ready the grass portion of the crop is not and if the farmer sprays these fields with Round Up, the grass will be killed.

The science shows us clearly that glyphosate as a desiccant in forage production makes no sense. I suspect the idea of this use stems from the common practice of using glyphosate in grain production. Grain crops, unlike hay crops, are annuals. Grains such as wheat, oats and barley need to be replanted every year. When a field of grain is getting close to ripe some farmers will apply an herbicide, Round Up being a popular and effective choice, to trick the plant into ripening its seed faster. When a plant thinks its dying it speeds up seed production as much as it is able. The biological imperative of plants, and most living things, is to reproduce. Plants that do this by way of seed need to have their seed ripen before the plant dies in order to pass on its genes, in order to ensure the continuation of the species. If we kill a plant that is close to ripe it will often speed up the ripening of the seed. This happens in grain if the timing is correct.

Imagine you are a farmer in Alberta who grows oats. Your crop is close to ripe but the long-range forecast shows sub-zero temperatures in the near future. Do you let mother nature ruin your crop or do you try to get that crop harvested early? With the use of an herbicide a farmer can save the crop and harvest before the weather turns. One can’t help but sympathize with the often poor options open to farmers. Farming is a thankless job and weather can destroy a famers entire annual income in a few short days.

While we can understand the benefits to the farmer there is the question of safety in consumption of this herbicide sprayed grain. That is something well beyond the scope of this blog post but many people would say no and there is mounting evidence that glyphosate in particular is harmful to human and animal health. I suspect this concern and the misunderstanding of the use of herbicides in farm practice has led to a concern about glyphosate contamination in hay.

These test results were very reassuring to me. It’s easy to be misled. We all want what is best for our equine partners. We can be assured that Canadian grown hay and most US grown hay, is not contaminated with harmful chemicals.


~Tamara Wrayton


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