Heifers and Worms
Lots of dairies have transition heifers on pasture and/or dry lots during temperate months. At some time in the fall they come off of these facilities into winter housing.
If you dairy in western New York heifers usually come in when it gets both wet and cold; that is, sometime in September. It may sound somewhat insane to be thinking about this at the end of July. However, a little bit of planning may make parasite control six or seven weeks from now go smoother (especially if in September we are up to our ears chopping corn and trying to get in one last cutting of haylage).
Recall that the need for parasite control is related to risk of exposure. Calves and heifers in total confinement housing usually have low risk. In contrast, we have heifers that go out on the same "heifer pasture" year after year. The stocking rate may be high enough to support high levels of contamination. Thus, the risk may be high.
The economics of parasite control have been well demonstrated. Feed efficiency is lower and general health is suppressed among parasitic animals. At our vet clinic we sell pour-on wormer that will treat 550 pound heifers for less than $3.00 each. So, we are not talking about a huge expense.
Now is a good time to start talking with the herd veterinarian about the choice of wormer, method of delivery and timing. If the supplies are on hand (September is only 4 weeks away) the rainy-day job can be taking care of parasites in the heifers.