Parasite prevention helps cows eat, drink and rest more comfortably
“It’s often assumed a herd is parasite-free simply because there are no outward signs of parasitism,” explained Linda Tikofsky, DVM, senior associate director of dairy professional veterinary services, Boehringer Ingelheim. “However, parasites commonly remain unseen as subclinical cases. Lice and mange are a constant challenge for confined dairy operations. That’s why it is important for dairy producers to have a strategic external parasite control program in place, with the guidance of their herd veterinarian.”
Dr. Tikofsky offered these best practices for effective deworming on dairy operations:
- Know the enemy
- Chorioptic mange is the most common mange mite affecting dairy cattle. Clinical signs include hair loss, crusting and wrinkled skin on the tailhead, on areas immediately adjacent to the tailhead and just above the rear udder and medial thigh.
- Sarcoptic mange is much less common, but it is a reportable disease. Clinical signs include skin lesions on the tail, neck, shoulders, brisket, rump and inner thighs.
Lice are another common parasite, and breaking their life cycle can be a challenge. There are two types of lice: biting and sucking. One feeds on skin debris, the other sucks blood. By the time producers see symptoms of hair loss, the population and number of eggs present on a cow’s hair coat have skyrocketed.
- Follow the label
Ensure the pour-on you choose is approved for lactating dairy cows and read and follow all label directions. Off-label use of an unapproved pour-on dewormer may be tempting because of cost savings, but any amount of an unapproved product detected in milk is illegal, and can lead to fines and lost milk sales.
- Get the timing right
A whole-herd annual pour-on application in the late fall or early winter is ideal. Mange is usually a problem in the winter months because cooler temperatures and longer hair coats favor parasite survival. Consider pouring all adult animals in the lactating herd at one time to establish baseline control.
Following the annual application, deworm all new herd additions (dry cows, first-calf heifers, bulls and purchased animals) 14 days prior to entry into the adult herd. This helps prevent re-infestation of lice and mange if incoming animals are harboring these parasites.
If your adult herd has access to pasture, apply an additional round of dewormer around four weeks following spring turnout to help control internal parasites.
- Maximize efficacy and fight resistance
When using a pour-on dewormer, carefully apply along the topline in a narrow strip from withers to tailhead. This will reduce product runoff and maximize efficacy.
A common practice is to treat for the average weight of the cows within a herd. Although convenient, dosing to average weight will under- or overdose many cows. Under-dosing will diminish the effectiveness of a dewormer and contribute to parasite resistance, while overdosing wastes product and money. A scale, weight tape or cull-weight slips can be used to determine cow weight, and will increase dosing accuracy.
Your herd veterinarian is your best cattle parasite resource, and will help develop a control program tailored to your operation’s specific needs. Look for a product that can control internal and external parasites, is approved for lactating cows, and has a 100% product satisfaction guarantee.