Saturday, August 13, 2011

How stuff works: spraying cattle


It's the peak of summer and the cattle are out on range down behind the barn. The pasture is several hundred acres so we don't see the herd every day but they make the trek back to the barn every four or five days. When they came in the other day they were absolutely covered with flies. They didn't look too bad the week before so the flies must have had a big hatch after the rains.

In general we don't spray the cattle very much to control flies. Many stockmen will run the herd through several times a year and treat with a systemic insecticide (similar to the flea and tick medicine given to dogs and cats) or set out an oiler or dustbag in the paddock that the cattle must rub against to get to water, feed or mineral. Flies and other parasites do influence the gain and overall thriftiness of cattle but we try to treat the herd as naturally as possible. In the same way that bacteria and viruses can develop resistance to antibiotics in people, parasites can also develop a resistance to insecticides with indiscriminate use. We don't much want superbugs around here but mostly we prefer to not have to use chemical insecticides period.

Here at the ranch we practice farm-wide Integrated Pest Management, essentially a management technique aimed at establishing acceptable levels of pests through prevention, monitoring and application of targeted management practices. In plain English - instead of spraying preemptively each year at the same time just because the stock are already in the corral, we aim to prevent infestations, monitor any changes and if an infestation does occur in numbers that impact the quality of life of the animal or negatively influence the market value of the stock then we develop a plan to treat the source of the problem using the most environmentally sensitive treatment.


The treatment today was a heavy spray of neem oil, an organic oil pressed from the seeds of a plant native to the Indian subcontinent. It doesn't kill the flies right away but does act as a strong repellant. One spraying of neem isn't going to solve all fly problems but it will knock back the population significantly. We'll turn the herd back out and spray them again in a few days when they come up to the barn next time. After they get a good spray down, we will direct the herd to a new pasture area, moving them away from the accumulated manure on the old pasture where flies breed. This is one of the reasons why an IPM strategy works so well - removing the original source of the infestation (in this case, manure), coupled with a targeted treatment means that we are able to knock back the pests to appropriate levels without automatically reaching for a commercial insecticide.

As an added bonus the neem reminds me of peanut sauce - hints of peanutty, garlicky goodness - at least until we make it to the corral where those smells mingle with dirt, dust, poo and cow's breath. Even so, at least it doesn't smell like chemicals and give one a headache with the first big whiff or burn your skin on contact. That seems like a good thing.

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