It is vital cattle producers have a plan to minimise, manage and treat parasitic infections before they reduce productivity and business profitability, according to Boehringer Ingelheim.
Production-limiting internal parasites are responsible for reducing the profitability of beef and dairy businesses.
Where cattle are grazed, it is nearly impossible to prevent infection by major parasitic species.
Seasonal and climatic differences, pasture management and cattle husbandry will affect the number and type of parasites on pasture and subsequent burden in cattle.
Well-designed parasite control programmes will take these factors into account and aim to prevent outbreaks of clinical disease and slow the potential development of resistance to wormers.
Cattle frequently carry a number of parasite species simultaneously.
The make-up of these infections including the species present, combined with the age and immunity status of the animal, and its previous worming history, will dictate the impact on the animal’s health, welfare and production.
Understanding the attributes of key parasite species and their particular impact on cattle can help you identify risks for potential infection and create processes for prevention and control.
It is also important to be able to identify the signs of parasitic infection and disease, so you take the most appropriate action.
The liver fluke Fasciola hepatica is a parasitic flatworm which is a problem for cattle producers.
The liver fluke requires an intermediate host, the mud snail, to complete its lifecycle.
This snail is commonly found in slow-moving fresh water and stagnant water often associated with wet pastures and around gateways and water troughs.
Liver fluke infection is a significant cause of production loss by slowing the growth of youngstock(4).
It can also reduce milk yield and impair the reproductive rates of breeding cattle.
As well as slowing growth, mature liver fluke also damages liver tissue by burrowing through it.
This can lead to condemnation of livers at the abattoir, and fluke has also been shown to reduce the quality score of entire carcases(4), thereby reducing potential income from each animal.
Resistance to a commonly used flukicide, triclabendazole, is increasing.
This is a concern to all livestock farmers and means cattle producers must take care to use all available husbandry methods to prevent and treat infection, including quarantine of bought-in animals.
Alternative treatments are available and their use should be discussed with your vet or animal health adviser.
Abattoir reports are a useful form of infection diagnosis.
Feacal egg counts can be useful to monitor trends, but farm history, treatment records and measuring ADLWG against targets should all form part of the diagnosis toolkit for liver fluke.
Preventing contamination of pasture with eggs from mature liver fluke at turnout is an effective way to reduce potential infectivity later in the year.
This, combined with strategic treatments at grass, can help reduce liver fluke burden in animals and associated losses in productivity.
Ostertagi Aostertagi and species of the Cooperia genus are significant roundworm parasites which are found in the digestive tracts of cattle and can cause parasitic disease.
Ostertagia ostertagi and Cooperia spp. are commonly associated with parasitic gastroenteritis, but Ostertagia is the more pathogenic of the two.
Cooperia spp. are more likely to infect young cattle and co-infection with Ostertagia can cause a larger reduction in average daily liveweight gain (ADLWG), than either species does alone.
With exposure to gutworms, cattle can develop immunity to these particular species.
This can prevent the likelihood of clinical disease developing.
However, even immune cattle will carry a gutworm burden.
It is the presence of these parasites within the gut which can impair an animal’s productivity.
Gutworm species have been shown to slow growth in young cattle.
This reduces their productive potential by increasing the time to slaughter for beef cattle and potentially delaying puberty and increasing age at first calving in breeding heifers.
Adult cows carrying gutworm will produce less milk.
Fertility can also suffer, with dairy heifers taking longer to conceive and potentially requiring more inseminations if they are facing a gutworm challenge (1).
Even an adult cow’s fertility can be affected, since the presence of gutworm at calving can exacerbate the energy gap and increase the time from calving to conception (2,3).
All of these factors can chip away at an animal’s lifetime production value and its profitability.
Signs that a gutworm infection may be having a negative impact on your cattle include: scouring youngstock, weight loss in cattle or those not meeting ADLWG when on adequate ration, a positive feacal egg count test, or a high result for Ostertagia antibodies in a bulk milk test.
These signs warrant further discussion with your animal health adviser.
Dictyocalus viviparus, the cattle lungworm, can cause significant respiratory disease in susceptible animals, leading to production loss and potentially death in serious cases.
Lungworm infection and respiratory disease is most common in dairy calves and heifers, but adult cows can be affected where parasite burdens are high or immunity has waned.
Lungworm can also be found in grazing beef youngstock, so all cattle producers should be vigilant for this parasite.
Respiratory disease caused by lungworm can impair the productivity potential of young cattle.
Even after successful treatment, their lungs are likely to be permanently damaged and, as a result, will not reach their full potential.
Prevention and intervention is key to reducing losses from lungworm.
Control options include vaccination before turnout, and/or strategic use of anthelmintics at and following turnout.
The period for lungworm infectivity usually starts around July and, depending on climatic conditions, can last well into late autumn.
Vaccine-induced/natural immunity can wane over the season and in the face of high challenge, so vigilance is vital during the high risk period.
Outbreaks of coughing in cattle should be investigated by a vet.
Lungworm is highly contagious once infective stages of the parasite are active within the pasture and herd.
If one animal is infected, the whole group or herd will need treatment.
All will have varying levels of lungworm burden, even if they are not exhibiting signs of disease.
Treatments should be used following best practice to ensure they are effective and sustainable in the long-term.
The advice from COWS(5) is:
An educational service from Boehringer Ingelheim Animal Health UK Ltd (“BI”). Further information available from BI, RG12 8YS, UK. ©2020. All rights reserved. Date of preparation: February 2020. UI-BOV-0042-2020. Use Medicines Responsibly.
1. Mejia et al. (2009) Effect of anthelmintics on reproductive performance and first lactation culling rate in Holstein heifers. Veterinary Record 165: 143–146.
2. Forbes et al. (2004) Impact of eprinomectin on grazing behaviour and performance in dairy cattle with sub-clinical gastrointestinal nematode infections under continuous stocking management. Veterinary Parasitology 125, 353-364.
3. McPherson et al. (1999) Proceedings of the American Association of Veterinary Parasitologists. 44th Annual Meeting, New Orleans, Louisiana, USA, Abstr. 28.
4. Sanchez-Vazquez, M.J., and Lewis, F.I. (2013) Investigating the impact fasciolosis on cattle carcase performance. Veterinary Parasitology. 193 (1-3): 307-11.
5. COWS (2018) The COWS Guide to the effective use of cattle wormers [online] Available at cattleparasites.org.uk/app/uploads/2018/04/Worming-have-you-got-it-right-english.pdf [Accessed Feb 2020].
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