However, it appears that an average of 10 or more per square inch are necessary to have a significant effect. Lice are most abundant on animals during the period of greatest winter stress. Many veterinarians and producers believe that losses occur and some cattlemen will treat animals for lice just for the improved appearance that results. The potential for severe, direct losses caused by sucking or biting lice is low. Moderate to heavy infestations add to the impact of cold weather, shipping stress, inadequate nutrition, or harm from internal parasites or disease.
Manifestations can be anemia, slow recovery from diseases, poor gains, or general unthriftiness.
Crowding or bunching of the animals at this time of year provides many chances for lice to move from animal to animal. Reduced light intensity appears to play a significant role in louse numbers on animals but nutrition, general health, immune system response, and weather are important factors. Monitoring lice numbers Heavily infested animals can be diagnosed easily. The most obvious signs are rubbing and clumps of hair falling out. There can be raw spots from constant attempts to groom or scratch areas where lice are abundant.