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Gut worms in beef youngstock – which worms are a problem and how to diagnose them
Gut worms in beef youngstock – which worms are a problem and how to diagnose them
- What gut worms can be a problemfor beef youngstock?
- Are gut worms a concern in older cows?
- What are the signs of gut wormsin beef youngstock?
- How to diagnose gut worms in beefyoungstock
Gut worms in cattle (parasiticgastro-enteritis or PGE) are a significant welfare, economic and animal health concern affecting the UK beef industry. PGE can cause clinical signs such as scour and weightloss, however, the main unseen impact of PGE in beef cattle is reduced growth rates – leading to a delay in reaching slaughter weight and increased rearing costs. The animals with the highest PGE risk are youngstock in their first grazing season.
What gut worms can be a problem for beef youngstock?
There are several ways in which gut roundwormsc an affect beef youngstock:
1) Parasitic gastro-enteritis(PGE) – this can be due to Ostertagia ostertagi (stomach worm) or Cooperiaoncophora (intestinal worm). These worm species can act individually or together to reduce appetite and feed intake, damaging the gut to prevent cattlefrom extracting nutrients efficiently from their feed.
Cattle ingest worm larvae which develop into adult worms over approximately 3 weeks (timing dependent on weather). Adult worms then shed eggs into the faeces, which further contaminates the pasture. In permanently grazed pasture, the worm burden will gradually increase over the grazing season. This can be worsened if there is sudden wet weather after a hot dry spell, as this causes many eggs tohatch at once leading to severe gut damage and diarrhoea (so-called Type I Ostertagia).
2) Type II Ostertagia – Ostertagialarvae ingested by youngstock in late autumn and winter undergo hypobiosis– a hibernation of larvae within the lining of the fourth stomach. In spring,large numbers of larvae hatch out at once, causing severe damage to the stomachlining and sudden onset of severe diarrhoea which can be fatal. This can beseen in housed youngstock if they were not treated appropriately after housing.
Are gut worms a concern in older cows?
Cattle do develop immunity to gut worms over time, but this can take up to two grazing seasons. Generally, adult beef cattle build up a good immunity to gut worms and may not need treating if theyare otherwise healthy. An exception to this would be adult cows which have nothad exposure to gut worms previously (i.e. purchased cattle). The immunity levels are not permanent, even in adults, but can be boosted each year whenexposed to gut worms while grazing. Older immune animals often carry a lownumber of adult worms but do not show any signs of disease or production losses.
Some cattle can be considered ‘naïve’meaning they have not developed any immunity to gut worms. This can occur in young cattle who have not been out to pasture as calves. It can also occur in animals during their first grazing season if they are treated excessively with wormers.
What are the signs of gut worms in beef youngstock?
A high worm burden in beef youngstock canhave a huge effect on production. It’s estimated that 60-70% of production losses in beef youngstock can be attributed to gut worms, as even sub-clinical (animals showing no sign of disease) levels can reduce growth rates by up to30%.1 A 2020 study estimated that parasites cost the UK beef industry around £78 million annually, with the biggest factor (over two-thirdsthe cost) being due to loss of production.2
Type I Disease
Youngstock or adult cattle with lowimmunity to worms, who have ingested high numbers of larvae from the pasturecan suffer from a loss of appetite, loss of condition and often scour;producing large amounts of green diarrhoea. This is most often seen in latesummer (timing depends on pasture worm burden) and usually affects the majorityof the group.
Type II Disease
Cattle that ingested large numbers of worm larvae in the previous grazing season, which then became dormant, can show signs ofdisease in late winter and early spring. These animals can suffer with huge amounts of watery scour, leading to weight loss and dehydration. In some cases,animals can die suddenly before they have time to show scour. Usually, only asmall number of animals are affected, rather than the whole group.
How to diagnose gut worms in beef youngstock
Regular weighing of youngstock and monitoring of Daily Liveweight Gains
To finish beef youngstock under two years of age, they must grow by at least 0.7KG/day. If the animals have the right nutrition, and there are no other diseases present, reduced growth rates in grazing cattle are a reliable indicator of a high worm burden and can be used to detect the problem before diarrhoea occurs. Some animals in a group will always carry a higher number of worms than others, so targeting treatment to these animals with reduced growth rates can reduce the amount of wormer needing to be used overall.
Faecal Worm Egg Counts (FWECs)
FWECs give a good indication of the worm burden on the pasture and can be helpful in predicting the need forfuture anthelmintic treatments. FWECs do not tell us the number of worms present in an individual animal and cannot tell us if the animal is carrying dormant larvae in its stomach lining. It’s a good idea to carry out regular FWECs throughout the summer, for youngstock in their first or second grazing season.The exact timing will depend on the pasture risk assessment; for example, if a FWEC comes back positive for worms, but with a worm egg count <200 epg (which isthe threshold for treatment) and the group showed no clinical signs it would generally be advised to repeat the FWEC in 2-3 weeks’ time.
Blood tests
Plasma pepsinogen relates to the amount of damage to the stomach lining caused by gut worms and can be measured in an animal’s blood. It can be useful to test at the end of the first grazing season to assess levels of exposure; too low and the animals are likely to have poor levels of immunity. Too high and it’s likely the animals have suffered production losses due to high levels of exposure. This blood test can also beused to diagnose both type I and type II acute disease in live animals.
Worming beef youngstock
Historically, gut worms in cattle have been controlled with regular, routine worming treatments, without always thinking about whether wormer treatments were necessary. This can lead to unnecessary treatments and accelerate the development of wormer resistance. Using a more targeted treatment system, combining the diagnostic measures above, to work out when treatment is required can help reduce the amount of wormer used on your farm. You can read more about this in the next blog on worming beef young stock - ‘Gut worms in beef youngstock – treatment and tips to reduce thedevelopment of resistance’.
References:
1. roundworm-140120.pdf(cattleparasites.org.uk)
2. J. Charlier, L. Et al. Initialassessment of the economic burden of major parasitic helminth infections to theruminant livestock industry in Europe, Preventive Veterinary Medicine, Volume182, 2020, 105103, ISSN 0167-5877, https://doi.org/10.1016/j.prevetmed.2020.105103.
Other sourceused for this blog:
roundworm-140120.pdf(cattleparasites.org.uk)
Gut and LungWorms - COWS - Promoting Sustainable Control of Cattle Parasites
NADIS - PGE in Cattle| NADIS Forecasts
AHDB - Parasitecontrol guide | AHDB
Administering-wormers-anthelmintics-effectively.pdf(cattleparasites.org.uk)
Gut worms in beef youngstock – which worms are a problem and how to diagnose them
- What gut worms can be a problemfor beef youngstock?
- Are gut worms a concern in older cows?
- What are the signs of gut wormsin beef youngstock?
- How to diagnose gut worms in beefyoungstock
Gut worms in cattle (parasiticgastro-enteritis or PGE) are a significant welfare, economic and animal health concern affecting the UK beef industry. PGE can cause clinical signs such as scour and weightloss, however, the main unseen impact of PGE in beef cattle is reduced growth rates – leading to a delay in reaching slaughter weight and increased rearing costs. The animals with the highest PGE risk are youngstock in their first grazing season.
What gut worms can be a problem for beef youngstock?
There are several ways in which gut roundwormsc an affect beef youngstock:
1) Parasitic gastro-enteritis(PGE) – this can be due to Ostertagia ostertagi (stomach worm) or Cooperiaoncophora (intestinal worm). These worm species can act individually or together to reduce appetite and feed intake, damaging the gut to prevent cattlefrom extracting nutrients efficiently from their feed.
Cattle ingest worm larvae which develop into adult worms over approximately 3 weeks (timing dependent on weather). Adult worms then shed eggs into the faeces, which further contaminates the pasture. In permanently grazed pasture, the worm burden will gradually increase over the grazing season. This can be worsened if there is sudden wet weather after a hot dry spell, as this causes many eggs tohatch at once leading to severe gut damage and diarrhoea (so-called Type I Ostertagia).
2) Type II Ostertagia – Ostertagialarvae ingested by youngstock in late autumn and winter undergo hypobiosis– a hibernation of larvae within the lining of the fourth stomach. In spring,large numbers of larvae hatch out at once, causing severe damage to the stomachlining and sudden onset of severe diarrhoea which can be fatal. This can beseen in housed youngstock if they were not treated appropriately after housing.
Are gut worms a concern in older cows?
Cattle do develop immunity to gut worms over time, but this can take up to two grazing seasons. Generally, adult beef cattle build up a good immunity to gut worms and may not need treating if theyare otherwise healthy. An exception to this would be adult cows which have nothad exposure to gut worms previously (i.e. purchased cattle). The immunity levels are not permanent, even in adults, but can be boosted each year whenexposed to gut worms while grazing. Older immune animals often carry a lownumber of adult worms but do not show any signs of disease or production losses.
Some cattle can be considered ‘naïve’meaning they have not developed any immunity to gut worms. This can occur in young cattle who have not been out to pasture as calves. It can also occur in animals during their first grazing season if they are treated excessively with wormers.
What are the signs of gut worms in beef youngstock?
A high worm burden in beef youngstock canhave a huge effect on production. It’s estimated that 60-70% of production losses in beef youngstock can be attributed to gut worms, as even sub-clinical (animals showing no sign of disease) levels can reduce growth rates by up to30%.1 A 2020 study estimated that parasites cost the UK beef industry around £78 million annually, with the biggest factor (over two-thirdsthe cost) being due to loss of production.2
Type I Disease
Youngstock or adult cattle with lowimmunity to worms, who have ingested high numbers of larvae from the pasturecan suffer from a loss of appetite, loss of condition and often scour;producing large amounts of green diarrhoea. This is most often seen in latesummer (timing depends on pasture worm burden) and usually affects the majorityof the group.
Type II Disease
Cattle that ingested large numbers of worm larvae in the previous grazing season, which then became dormant, can show signs ofdisease in late winter and early spring. These animals can suffer with huge amounts of watery scour, leading to weight loss and dehydration. In some cases,animals can die suddenly before they have time to show scour. Usually, only asmall number of animals are affected, rather than the whole group.
How to diagnose gut worms in beef youngstock
Regular weighing of youngstock and monitoring of Daily Liveweight Gains
To finish beef youngstock under two years of age, they must grow by at least 0.7KG/day. If the animals have the right nutrition, and there are no other diseases present, reduced growth rates in grazing cattle are a reliable indicator of a high worm burden and can be used to detect the problem before diarrhoea occurs. Some animals in a group will always carry a higher number of worms than others, so targeting treatment to these animals with reduced growth rates can reduce the amount of wormer needing to be used overall.
Faecal Worm Egg Counts (FWECs)
FWECs give a good indication of the worm burden on the pasture and can be helpful in predicting the need forfuture anthelmintic treatments. FWECs do not tell us the number of worms present in an individual animal and cannot tell us if the animal is carrying dormant larvae in its stomach lining. It’s a good idea to carry out regular FWECs throughout the summer, for youngstock in their first or second grazing season.The exact timing will depend on the pasture risk assessment; for example, if a FWEC comes back positive for worms, but with a worm egg count <200 epg (which isthe threshold for treatment) and the group showed no clinical signs it would generally be advised to repeat the FWEC in 2-3 weeks’ time.
Blood tests
Plasma pepsinogen relates to the amount of damage to the stomach lining caused by gut worms and can be measured in an animal’s blood. It can be useful to test at the end of the first grazing season to assess levels of exposure; too low and the animals are likely to have poor levels of immunity. Too high and it’s likely the animals have suffered production losses due to high levels of exposure. This blood test can also beused to diagnose both type I and type II acute disease in live animals.
Worming beef youngstock
Historically, gut worms in cattle have been controlled with regular, routine worming treatments, without always thinking about whether wormer treatments were necessary. This can lead to unnecessary treatments and accelerate the development of wormer resistance. Using a more targeted treatment system, combining the diagnostic measures above, to work out when treatment is required can help reduce the amount of wormer used on your farm. You can read more about this in the next blog on worming beef young stock - ‘Gut worms in beef youngstock – treatment and tips to reduce thedevelopment of resistance’.
References:
1. roundworm-140120.pdf(cattleparasites.org.uk)
2. J. Charlier, L. Et al. Initialassessment of the economic burden of major parasitic helminth infections to theruminant livestock industry in Europe, Preventive Veterinary Medicine, Volume182, 2020, 105103, ISSN 0167-5877, https://doi.org/10.1016/j.prevetmed.2020.105103.
Other sourceused for this blog:
roundworm-140120.pdf(cattleparasites.org.uk)
Gut and LungWorms - COWS - Promoting Sustainable Control of Cattle Parasites
NADIS - PGE in Cattle| NADIS Forecasts
AHDB - Parasitecontrol guide | AHDB
Administering-wormers-anthelmintics-effectively.pdf(cattleparasites.org.uk)