Parasites, Worms

(Producer Questions prior to 2009)

What can I use to control internal parasites?

Depending on the region of the United States that your operation is located will dictate the internal parasites that will be of concern. There are many products that are available to treat for parasites. There are pour-ons and there are pastes or gels that are administered orally. Contact you veterinarian for advice.

Is Fall in Nebraska the best and safest time to use a pour-on type of wormer and lice control product for cattle, including bred cows? Should a second treatment be given later to extend the protection against only lice, mites, etc., because sometimes our cows begin showing signs of lice in late winter. Over all, what is a good schedule for control of grubs, worms, lice, and mites?

Fall applications of the systemic pour-on, spot-on, spray, injectable or dip insecticides for grub and lice control are generally very effective. In Nebraska, treatment in late August or at fall weaning provides excellent control. The newer, broad-spectrum products control both internal and external parasites and are extensively and very effectively used for grub control.

Systemic insecticides do reduce numbers of the blood-feeding lice considerably, but may not prevent a buildup of blood-feeding lice later in the winter. Non-systemic pour-ons and spot-ons are more effective at controlling chewing lice and should be applied along the back line of the cattle. Chewing lice are killed by insecticide contact, and treatment down the back line exposes more lice to the treatment.

In Nebraska, systemic insecticides used between November 1 and February 1 might bring about a host-parasite reaction as a result of killing grubs while they are in the esophagus or spinal canal of the animal and therefore, caution should be used in treating animals during this time. However, cattle can be treated effectively with non-systemic insecticides if they need treatment during the cutoff period for grub control. Sometimes, fall treatments may be insufficient to prevent a build-up of lice during severe winters. If cattle are scratching because of lice, treatment is recommended. Besides improving hide quality, this will decrease the likelihood of damage to fencing and other fixtures that cattle tend to use as rubbing posts. Most treatments can be used again after the grub treatment cut-off date (Nov. 1 to Feb.1), and are quite effective.

Generally speaking, products on the market today for internal and external parasite control are safe for use in pregnant cattle. However, as with any product, some restrictions may apply and therefore careful reading, understanding and following label directions are critical.