Be a (parasite) control freak |

Be a (parasite) control freak

We have been lucky here in southeastern South Dakota. We had some snow and now we have been catching some timely rains. We are a long way from saying the drought is over, but the grass is at least growing with the warmer temperatures. Now is the time to plan our parasite control for the summer season.

The winter and spring were tough on the cows in our area and the pastures are short and over grazed. They are coming back slowly but will be the source of internal parasites. Some of the cows are thin and may be more susceptible to heavy infestation of parasites. As the summer progresses the parasites multiply on the pasture grasses. They cycle monthly and populations grow exponentially. This puts your calves at extreme risk late in grazing season.

It is important to deworm your cows at turnout. Many of you use pour-ons when moving to pasture. Some of the newer products are better dewormers, but decreasing shedding is important. These products have very little effect on flying parasites.

Injectable products can be used on both cows and calves and give a longer duration of treatment. A new product on the market claims 150 days of protection. If you use these products at turnout we recommend their use again at pre-weaning vaccination. The timely use of these products usually means thirty extra pounds at weaning. On a $1.50 market that’s $45.00 per head.

Oral wormers can be drenched or fed in mineral and blocks. A drench at turnout can be followed by timely addition of blocks or mineral. If you are feeding creep, dewormer can be added near the end of pasture season. A few dollars of treatment can keep you pastures clean and free of parasites as well as increase your profits.

Fly products are needed throughout the summer. This spring we have not seen many flies yet, but I am sure they will be here soon. Horn flies are a major problem in pasture animals because they suck blood from their host. It may only be a drop per day, but if the cow is host to 3,000-4,000 flies it will decrease a cow’s efficiency. Decreased milk production and constant irritation will decrease the weights of your weaning calves. Fly tags are effective in horn flies because they prefer the cow’s shoulders and back. We recommend you rotate yearly between pyrethrin and organophosphate tags. This avoids resistance buildup to chemical in the tag.

Face flies don’t suck blood. They live on the face and consume exudates from the eyes. These flies are not affected by fly tags. The major problem with them is the transmission of diseases such as pinkeye.

These two flies replicate in cow pies. Feeding products such as IGR eliminate the reproductive cycle in the manure. They work well, but if your neighbors aren’t using it, flies can travel several miles to infest your herd.

In our area we are seeing the stable fly affecting some pasture animals. It prefers the lower legs so it is not affected by eartags or sprays unless you can cover the lower legs. This is also a biting fly, but unlike the cow-pie replicators, it prefers to replicate in decomposing grass. If your animals are showing irritation to their legs and you have decomposing grasses nearby, consider the stable fly.

During the summer as fly populations increase, you may need to apply more insecticide. If you are working your cows and calves, pour-ons with several weeks duration can be applied. Sprays and foggers are also very effective.

Careful control of internal and external parasites result in great creature comfort as well as increased efficiency. Consult with your veterinarian or extension specialist to formulate programs specifically designed for your herd. Good animal health and decreased stress will increase your profits.


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