"Weeds" would be the least of my concern about manure from a dairy herd. What kind and how much antibiotics are regularly fed to these cows?

kimmq is kimmsr

Very good point. I will need to investigate... or more likely just find another source.

First, there is absolutely no risk to you or your lawn from antibiotics if you use the compost. The antibiotics used degrade reasonably quickly, and do not, in any case, impact the value of the compost to improving your soil. The antibiotics are not going to impact your lawn in the slightest. The idea that these antibiotics are a risk to compost in such a situation is one of the great internet myths propagated through the years. Note that if you are using the compost for growing food crops you should follow recommended wait intervals, and be conscious of issues associated with antibiotic resistant bacteria. See http://www.foodsafetynews.com/2015/11/managing-black-gold-animal-manure-and-antibiotic-resistance/#.VyNsoo-cHIU for more info on this issue.

As the referenced article mentions, manure spreading is a prime source for the release of antibiotics into the terrestrial environment. For many dairies, the only solution they have to address their waste issues is to spread huge quantities onto agricultural fields. Issues of ground water contamination and nutrient dispersal then become much more significant. One of the things we can do as individuals that helps the environment we all live in is to help provide another, more environmentally conscious method of dealing with this waste product. If you use this material on your lawn, you will not only be helping the lawn and the dairy, but also impacting the environment in a positive manner.

Second, dairy cows don't usually get feed with a lot of weed seeds in it, so even fresh manure is usually not a significant weed source. If the dairy composts it, as many now do, the risk is even smaller.

I've used dairy manure, mostly composted for years, and seen good results. The dairies in our area will give it to you for free because it eliminates a significant waste stream issue for them. When we moved a number of years ago, I found a trucker who was driving from our area to a dairy with loads of silage, and then returning empty. He passed close to our place in either direction. For only $25 a load, he would bring back 30 tons of manure to us on each of his return trips. The dairy loaded the manure for free. It was a fun sight, drawing neighborhood children, to see the tipping semi truck with its load of manure. As the truck bed tipped back, the manure would stay put because it had packed a bit during the trip. The trucker would take a long stick and carefully prod it. Out would come the manure in a great swish.

Renais

Antibiotics from animal manure, soaps, and many other sources that are out and about where disease pathogens are exposed to them allow those disease pathogens to develop immunities to those antibiotics which then renders them useless in controlling the disease those pathogens cause.

There is a risk to everyone when antibiotics are used indiscriminately.

kimmq is kimmsr