Signs of lice

  • Cattle rubbing from irritation, the presence of matted hair coat, hair loss, dandruff-like appearance from skin flakes and raw spots are indicators of lice. Lice usually occur in areas where cattle have difficulty grooming.
  • Closer inspection will reveal lice moving on the skin or amongst the hair as well as eggs and faeces on the hair fibres.
  • Biting lice move away from light more rapidly than sucking lice which are often clumped together giving the appearance of dark patches on the skin.

The first signs of lice are often the observation of cattle rubbing or loss of hair from the effects of lice as the level of infestation increases. The hair-coat in infested areas tends to take on a ‘scurfy’ or dandruff-like appearance from the accumulation of skin flakes, louse faeces and exoskeletons from moulted lice and eggs. The hair often becomes matted from the effects of cattle licking and rubbing (Figure 1). Sometimes there can be raw spots from scratching or rubbing in areas of high louse numbers.

Figure 1. Loss of hair on thigh caused by rubbing irritation caused by cattle lice. Image credit Jess Morgan
Figure 1. Loss of hair on thigh caused by rubbing irritation caused by cattle lice. Image credit Jess Morgan

On close inspection, when the hair is parted, lice can be seen moving on the skin surface or in the hair and often eggs can be seen ‘glued’ to the hair fibres. Biting lice tend to roam through the hair and rapidly move away from the light (Figure 2). Individual biting lice are often seen, whereas sucking lice don’t move as much when disturbed during inspection and are often densely packed together and may appear as black or blue patches on the skin until closely inspected (Figure 3). See ‘Types of Lice” for information and pictures of the different louse species.

Figure 2. Pulling aside tail hairs reveals cattle biting lice. Image credit Jess Morgan
Figure 2. Pulling aside tail hairs reveals cattle biting lice. Image credit Jess Morgan
Figure 3. Tail-switch louse Haematopinus quadripertusus nymphs on the vulva of an adult cow. Image credit the National Centre for Veterinary Parasitology, ncvetp.org
Figure 3. Tail-switch louse Haematopinus quadripertusus nymphs on the vulva of an adult cow. Image credit the National Centre for Veterinary Parasitology, ncvetp.org

Lice are susceptible to the grooming activities of cattle and tend to reach higher levels in areas that the cattle can’t reach to lick. Areas where lice are commonly seen include the head, neck, withers and dewlap, in the longer hair along the topline of the back, on the rump and near the base of the tail, depending on the louse species present.