Hi Jennifer,

Thanks for your question. I'm sorry to hear about your pets' health issues. I cannot comment on herbicide related toxicology for your animals; however, anytime you can minimize exposure to chemicals the better. I've consulted my weed specialist and pesticide applicator colleagues and summarized their responses below.

It's important to consider behavioral changes that would reduce the exposure of animals to chemicals (leaving or forcing them inside during an application, quarantine treated areas for the entire residual time and beyond, and be proactive in finding out what, when, and where things will be applied, etc.).

The EPA has information about all labels (registered and expired). They also provide links to safety data sheets for chemicals. The link below takes you to the website that houses that information. Enter a chemical name (common name is fine) or brand name or EPA registration # (fastest way to specific product). A search will come back with all currently labeled products. Click on the product and it will take you to a page that houses a PDF label and a Chemical tab to find more info about the chemical.

In short, the EPA tests each chemical for safety and insists that the instructions for use adequately reduce the risk of off target exposures such that the risk of the long-term effects of pesticide exposure are reduced to a negligible level. When using any pesticide/herbicide, it is critical to follow the label instructions and to wear appropriate personal protective equipment.

Horses can attribute to weed infestations. Having horses graze areas exposes the soil and can create a space easily colonized by weeds. One option is to rotationally graze pastures to keep vegetation competitive with weeds.

Mowing is another option. You can increase mowing height so vegetation shades out weeds but so the mower will still cut the top growth of the weeds. Handweeding in smaller isolated patches will pay dividends because dense areas have high capacity to reproduce.

Using herbicides on heavily infested areas will probably help reduce the load of mowing and hand weeding. 2,4 D and glyphosate are commonly used, but again, follow all label instructions carefully and be aware of residual effect times to minimize animal exposure. I've also added a link to the SDSU Private Applicator Training,

Sincerely,

Robin

https://extension.sdstate.edu/private-applicator-training-pesticides?gad_source=1

https://ordspub.epa.gov/ords/pesticides/f?p=PPLS:1