Lice infestations pose a significant threat to cattle health and productivity. These tiny external parasites can cause a range of problems, from discomfort and irritation to decreases in milk production and weight gain. Early detection and effective treatment are crucial for minimising the impact on your herd.
According to Dr Stefan Steyn, a technical and regulatory veterinarian at Afrivet, two main types of lice plague cattle: chewing lice and sucking lice.
Steyn explains the difference in their habits: “Chewing lice tend to prefer the neck and shoulder region, as well as the top line of the bovine and also then around the root of the tail.”
These reddish-coloured lice have broad heads and feed on skin debris. Sucking lice, also known as blue lice due to their distinctive colour, have a different feeding strategy.
“They have a very long, sharp head, and the mouth parts are actually adapted to go through the skin into small vessels and then actually suck blood,” explains Steyn.
Sucking lice typically target areas like the shoulder, dewlap, and front legs.
Spotting the signs
Early detection of a lice infestation is crucial for minimising harm to your cattle. Observing your herd’s behaviour can provide valuable clues.
Steyn says, “You will see those signs typically this time of year [late autumn] and a little bit later. Then that starts giving you clues as to what to watch out for and what to be worried about. If you get a severe infestation, you will see a marked drop in the production parameters that you use to see if they’re healthy.”
Here are some key signs to watch out for:
- Irritability and scratching: Discomfort caused by lice feeding will lead to excessive scratching against objects or other cattle.
- Hair loss: Patches of hair loss, particularly in areas favoured by specific lice types, are a tell-tale sign.
- Decreased production: In severe cases, milk production in dairy cows and weight gain in beef cattle can be significantly impacted.
- Skin lesions: Constant scratching and irritation can lead to secondary bacterial or fungal infections, manifesting as skin lesions.
Diagnosing lice infestation
While a veterinarian can definitively diagnose lice infestations through microscopic examination, there are steps you can take to get a head start. Here’s what you can do:
Visual inspection: Carefully examine areas of hair loss for small insects (around 1-2 millimetres) using a magnifying glass if necessary.
Location: The location of hair loss can offer clues about the type of lice present. Chewing lice favour the neck, shoulder, and topliner, while sucking lice prefer the shoulder, dewlap, and front legs.
Colour: Chewing lice are typically reddish, while sucking lice appear blue due to the presence of digested blood in their bodies.
“Overall, cattle herdsmen may tend to spend time with the herd. They will pick up if there’s a little bit of fidgetiness in the herd, with them scratching more, moving towards scratching poles more often, or scratching against some of the cribs,” says Steyn.
Treatment options
There are two main approaches to treating lice infestation: prophylactic treatment and therapeutic treatment. Prophylactic treatment aims to prevent infestation before it occurs. Ideally, cattle should be treated prophylactically in late autumn, when lice populations typically rise.
“Treatment options include pour-on medications, sprays, or sponge dips containing ingredients effective against lice,” he explains.
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Therapeutic treatment approaches tackle existing lice infestations. For sucking lice, injectable medications are often used. Alternatively, topical treatments effective against both chewing and sucking lice can be applied.
It is crucial to repeat the treatment after 7-10 days to target newly hatched lice that weren’t affected by the initial treatment. When choosing a lice treatment, Steyn stresses the importance of using registered products.
“It’s always important when looking at treatments that once you’ve got an idea what type of organism it is you’re trying to kill, just check your label. Go and make sure that the product that you use is actually registered for cattle, and it will cover biting lice and chewing lice.”
Using unregistered products can be ineffective and even pose health risks to your cattle, potentially leaving residues in their meat or milk.
Proactive management
The best approach for lice infestation is to prevent it from happening in the first place. Here are some key strategies to implement:
Maintain good animal health: Stressful conditions can worsen lice infestations. Ensure your cattle receive proper nutrition, have access to clean water, and are not overcrowded.
Biosecurity measures: Implement biosecurity measures to minimise the spread of lice between animals. Isolate sick animals from healthy ones and maintain proper hygiene in housing areas.
Regular treatment plan: Develop a regular treatment plan, especially during the cooler months.
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