Managing mites and lice on cattle
- Which external parasites can affect housed cattle?
- Management options for lice and mites
- Treatment options for lice and mites
- Which external parasites are a problem for cattle in the summer?
External parasites, or ectoparasites, of cattle include lice, mange mites, ticks and biting/nuisance flies. All of these can cause both irritation and discomfort to cattle, while impacting their milk production and growth. In addition, ticks can carry pathogens which can cause severe, even fatal diseases in cattle and sheep, and flies can carry bacteria which can spread diseases such as mastitis and eye infections.
Nuisance flies (and ticks in high-risk tick areas) are generally a problem during summer, while lice and mites more commonly cause disease in the winter when animals are housed. Ectoparasites are almost ubiquitous in cattle farming across the UK except for ticks which have regional variations.
Which external parasites can affect housed cattle?
Lice
live on cattle for their entire life cycle and are commonly found in small numbers without causing obvious signs of discomfort. Chewing lice feed on skin and hair fragments, while sucking lice are blood-sucking. In most cases, lice numbers will be controlled by cattle grooming – however, if cattle are debilitated due to disease or poor nutrition then they will groom less frequently and less effectively. This can allow louse populations to increase, causing itching, rubbing, licking, and bald scaly patches will develop.
Lice problems are more commonly seen in housed animals in winter due to several factors:
- The winter coat is much thicker and provides an optimum habitat for lice growth
- Lice are not exposed to high levels of UV light as they are in summer (which limits lice reproduction)
- Housed cattle may be more prone to infectious disease as they are stocked closely together, so disease can spread quicker through a group. Any disease which leads to reduced grooming will lead to an increase in lice numbers.
Mange mites
There are several different species of mite which live on the skin of cattle (and some species on sheep). Allergic reactions to them can cause significant itching and result in raw and scabby patches of skin. Some cattle have a greater reaction to mites than others – thus some cattle will remain symptom-free (but remain a source of mites to other cattle) while others will show severe clinical signs. In severe cases mange will reduce milk production and cause weight loss, as well as affecting hide quality. Like lice, mange mites are more commonly seen in housed animals in winter for similar reasons.
Management options for lice and mites
Housing is an ideal time to consider management options for lice and mange. Elimination of lice and mites is almost impossible but good management can be used to help keep them under low numbers:
- Ensure cattle are not overstocked - optimal space allowances for cattle of different ages can be found via AHDB4
- Ensure shed ventilation and drainage is optimal to minimise the risk of disease such as pneumonia
- Good hygiene and bedding management
- Ensure optimal nutrition including trace element supplementation where required.
- Prevention of common infectious diseases during housing e.g. through pneumonia vaccination.
- Rapid treatment of sick animals during housing period
- Investigation of outbreaks of lice/mange mites to identify any underlying issues
Treatment options for lice and mites
If groups of cattle are known to be at risk over winter the farm vet will recommend treatment at housing along with any other treatments required. Alternatively, sometimes ectoparasites will cause skin problems and group treatment will be required. There are a range of topical products that can treat lice and/or mites:
Lice:
Topical ‘spot-on’ products (synthetic pyrethroids e.g. deltamethrin, permethrin) will kill both biting and sucking lice. These products do not kill louse eggs so severe infestations will need a repeat treatment after 4 weeks once the eggs have hatched. Some resistance to these products has been reported so it is important to monitor cattle to be sure treatment was successful.
The ‘clear’ class of wormers (macrocytic lactones (ML) including ivermectin, moxidectin, doramectin and eprinomectin) have activity against lice. Injectable forms are less effective against chewing lice so pour-on products are generally recommended. Products with residual activity such as Doramax Pour -on may be useful in cases of severe infestation to avoid the need for repeat treatment. It is important to be aware that these will also affect gut worms and repeated dosing of MLs when not necessary for worm control can increase the risk of resistance developing within the worm population.
Mites:
Topical ‘spot-on’ (synthetic pyrethroids e.g. deltamethrin, permethrin) products are not usually effective against mange mites, and macrocytic lactone (ML) products are generally preferred. Pour-on ML products are more effective than ML injections – some options are given in the table below. As always when using pour-on products, ensure that animals are not treated when wet and that they are kept indoors after treatment if rain is likely. All animals in a group should be treated including any in-contact animals, and treated animals should be moved to a clean environment as mange mites can survive for several weeks off the host in bedding etc.
There are different species of mange mite and one in particular (Psoroptes) can be very difficult to treat effectively. If there is a poor response to treatment, then veterinary intervention is recommended to assess which type of mite is the problem and formulate a control plan.
Which external parasites are a problem for cattle in the summer?
Flies
Flies are usually a problem during the summer months. They can cause cattle to spend more time swishing and avoiding flies, and less time resting, grazing and carrying out other normal behaviour. This can result in reduced milk production in dairy cows (estimated at 139kg of milk/cow/year) and reduced growth rates in youngstock of around 0.5kg/head/day.1 Control includes chemical methods (pour-ons or impregnated eartags), good farm hygiene and biological methods (releasing fly parasites which eat the maggots of nuisance flies and so reduce their population).2
Ticks
Ticks are uncommon in the UK as a whole but can be found in high-risk areas such as South-West England, Wales and Scotland.3 They attach to cattle, sheep and other mammals for a short period of time to blood feed. During this time they can transmit pathogens which can cause diseases in livestock such as louping ill, babesiosis and tick-borne fever. Costs of tick-borne diseases vary hugely depending on the region and have not been fully researched in the UK – but as climate change increases average temperatures they are likely to become more significant. There are no products currently licensed to prevent ticks in cattle, and a discussion with your vet is recommended to make a control plan if your farm is a high-risk area.
References:
1. David B. Taylor, Roger D. Moon, Darrell R. Mark. Economic Impact of Stable Flies (Diptera: Muscidae) on Dairy and Beef Cattle Production. Journal of Medical Entomology. 2012 Jan;49(1):198-209.
2. Kaufman PE, Strong C, Waldron JK, Rutz DA. Individual and combined releases of Muscidifurax raptor and M. raptorellus (Hymenoptera: Pteromalidae) as a biological control tactic targeting house flies in dairy calf facilities. J Med Entomol. 2012 Sep;49(5):1059-66.
3. http://apha.defra.gov.uk/documents/surveillance/tick-borne-disease-presentation.pdf
4. https://projectblue.blob.core.windows.net/media/Default/Imported%20Publication%20Docs/BRP-plus-Better-cattle-housing-design.pdf
Managing mites and lice on cattle
- Which external parasites can affect housed cattle?
- Management options for lice and mites
- Treatment options for lice and mites
- Which external parasites are a problem for cattle in the summer?
External parasites, or ectoparasites, of cattle include lice, mange mites, ticks and biting/nuisance flies. All of these can cause both irritation and discomfort to cattle, while impacting their milk production and growth. In addition, ticks can carry pathogens which can cause severe, even fatal diseases in cattle and sheep, and flies can carry bacteria which can spread diseases such as mastitis and eye infections.
Nuisance flies (and ticks in high-risk tick areas) are generally a problem during summer, while lice and mites more commonly cause disease in the winter when animals are housed. Ectoparasites are almost ubiquitous in cattle farming across the UK except for ticks which have regional variations.
Which external parasites can affect housed cattle?
Lice
live on cattle for their entire life cycle and are commonly found in small numbers without causing obvious signs of discomfort. Chewing lice feed on skin and hair fragments, while sucking lice are blood-sucking. In most cases, lice numbers will be controlled by cattle grooming – however, if cattle are debilitated due to disease or poor nutrition then they will groom less frequently and less effectively. This can allow louse populations to increase, causing itching, rubbing, licking, and bald scaly patches will develop.
Lice problems are more commonly seen in housed animals in winter due to several factors:
- The winter coat is much thicker and provides an optimum habitat for lice growth
- Lice are not exposed to high levels of UV light as they are in summer (which limits lice reproduction)
- Housed cattle may be more prone to infectious disease as they are stocked closely together, so disease can spread quicker through a group. Any disease which leads to reduced grooming will lead to an increase in lice numbers.
Mange mites
There are several different species of mite which live on the skin of cattle (and some species on sheep). Allergic reactions to them can cause significant itching and result in raw and scabby patches of skin. Some cattle have a greater reaction to mites than others – thus some cattle will remain symptom-free (but remain a source of mites to other cattle) while others will show severe clinical signs. In severe cases mange will reduce milk production and cause weight loss, as well as affecting hide quality. Like lice, mange mites are more commonly seen in housed animals in winter for similar reasons.
Management options for lice and mites
Housing is an ideal time to consider management options for lice and mange. Elimination of lice and mites is almost impossible but good management can be used to help keep them under low numbers:
- Ensure cattle are not overstocked - optimal space allowances for cattle of different ages can be found via AHDB4
- Ensure shed ventilation and drainage is optimal to minimise the risk of disease such as pneumonia
- Good hygiene and bedding management
- Ensure optimal nutrition including trace element supplementation where required.
- Prevention of common infectious diseases during housing e.g. through pneumonia vaccination.
- Rapid treatment of sick animals during housing period
- Investigation of outbreaks of lice/mange mites to identify any underlying issues
Treatment options for lice and mites
If groups of cattle are known to be at risk over winter the farm vet will recommend treatment at housing along with any other treatments required. Alternatively, sometimes ectoparasites will cause skin problems and group treatment will be required. There are a range of topical products that can treat lice and/or mites:
Lice:
Topical ‘spot-on’ products (synthetic pyrethroids e.g. deltamethrin, permethrin) will kill both biting and sucking lice. These products do not kill louse eggs so severe infestations will need a repeat treatment after 4 weeks once the eggs have hatched. Some resistance to these products has been reported so it is important to monitor cattle to be sure treatment was successful.
The ‘clear’ class of wormers (macrocytic lactones (ML) including ivermectin, moxidectin, doramectin and eprinomectin) have activity against lice. Injectable forms are less effective against chewing lice so pour-on products are generally recommended. Products with residual activity such as Doramax Pour -on may be useful in cases of severe infestation to avoid the need for repeat treatment. It is important to be aware that these will also affect gut worms and repeated dosing of MLs when not necessary for worm control can increase the risk of resistance developing within the worm population.
Mites:
Topical ‘spot-on’ (synthetic pyrethroids e.g. deltamethrin, permethrin) products are not usually effective against mange mites, and macrocytic lactone (ML) products are generally preferred. Pour-on ML products are more effective than ML injections – some options are given in the table below. As always when using pour-on products, ensure that animals are not treated when wet and that they are kept indoors after treatment if rain is likely. All animals in a group should be treated including any in-contact animals, and treated animals should be moved to a clean environment as mange mites can survive for several weeks off the host in bedding etc.
There are different species of mange mite and one in particular (Psoroptes) can be very difficult to treat effectively. If there is a poor response to treatment, then veterinary intervention is recommended to assess which type of mite is the problem and formulate a control plan.
Which external parasites are a problem for cattle in the summer?
Flies
Flies are usually a problem during the summer months. They can cause cattle to spend more time swishing and avoiding flies, and less time resting, grazing and carrying out other normal behaviour. This can result in reduced milk production in dairy cows (estimated at 139kg of milk/cow/year) and reduced growth rates in youngstock of around 0.5kg/head/day.1 Control includes chemical methods (pour-ons or impregnated eartags), good farm hygiene and biological methods (releasing fly parasites which eat the maggots of nuisance flies and so reduce their population).2
Ticks
Ticks are uncommon in the UK as a whole but can be found in high-risk areas such as South-West England, Wales and Scotland.3 They attach to cattle, sheep and other mammals for a short period of time to blood feed. During this time they can transmit pathogens which can cause diseases in livestock such as louping ill, babesiosis and tick-borne fever. Costs of tick-borne diseases vary hugely depending on the region and have not been fully researched in the UK – but as climate change increases average temperatures they are likely to become more significant. There are no products currently licensed to prevent ticks in cattle, and a discussion with your vet is recommended to make a control plan if your farm is a high-risk area.
References:
1. David B. Taylor, Roger D. Moon, Darrell R. Mark. Economic Impact of Stable Flies (Diptera: Muscidae) on Dairy and Beef Cattle Production. Journal of Medical Entomology. 2012 Jan;49(1):198-209.
2. Kaufman PE, Strong C, Waldron JK, Rutz DA. Individual and combined releases of Muscidifurax raptor and M. raptorellus (Hymenoptera: Pteromalidae) as a biological control tactic targeting house flies in dairy calf facilities. J Med Entomol. 2012 Sep;49(5):1059-66.
3. http://apha.defra.gov.uk/documents/surveillance/tick-borne-disease-presentation.pdf
4. https://projectblue.blob.core.windows.net/media/Default/Imported%20Publication%20Docs/BRP-plus-Better-cattle-housing-design.pdf