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MAY 2019
www.irishfarmersmonthly.com
Dairy
44
MAY
Beef Focus
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A roundworm burden in beef cattle can lead to losses in productivity through reduced growth
rates and reduced average daily live weight-gain (ADLWG). Controlling and treating roundworms
therefore plays an important role in improving profitability for cattle farmers.
Reductions in feed intake associated with parasitism
can vary considerably over a range of -4 per cent
to -77 per cent
1
. Indeed, research carried out in the
U.S. has revealed major improvements to animal
health and welfare as well as enhanced performance
and productivity through the use of parasite control
treatments
2
. Individual trials with beef cattle show the
e ect of anthelmintics on pregnancy rate range from an
increase of 2.4 per cent
3
to an increase of 120 per cent
4
,
the di erence likely reflecting the specific nutritional,
environmental and genetic conditions of the animals
in the study. The de-wormer's e ect on the weaning
weight ranged from an increase of nearly 0.3 per cent
5
to
over 13 per cent
6
. Prevention of parasites can therefore
have a major impact the productivity of beef cattle.
Worms may impact significantly on performance without
producing signs of clinical disease. Even subclinical
parasitism, where only a few roundworms are present,
can impact on productivity. Cattle may not only eat less
but their feed e ciency can also be negatively impacted
due to disruption of the digestive process. Nutritional
resource gets allocated towards staging an immune
response against the parasite challenge instead of growth
and weight gain. Grazing management practices will
heavily influence exposure to roundworm larvae, while
on-going preventative practices will minimise losses
caused by clinical and sub-clinical parasite infections.
During the grazing season parasite control programmes
should take into consideration the farm type, topography
and facilities, so that the approach can be matched
to the farm's objectives and attitudes. Seasonality will
inevitably impact on climate, plant growth, parasite
epidemiology, cattle husbandry, farm management and
housing, and thus parasite control. Parasite populations
typically increase from mid-July onwards for parasitic
gastroenteritis and lungworm infections are more
common from July onwards. Map the farm at the start
of the grazing season to determine the use of pastures,
particularly in terms of parasite risk, when hay and silage
aftermaths will become available, and which classes of
stock will graze each pasture.
Each spring decide whether the parasite control
plan will be strategic; adopting a planned approach
to anthelmintic use, with whole-group treatments
administered at specific risk periods, or whether a
targeted approach to treatment, utilising a regular
assessment of parasite risk to determine whether
treatments are required is more appropriate.
For control of roundworm challenge in groups of
youngstock to be e ective, strategic anthelmintic
treatments need to begin early in the grazing season.
Thereafter, aim to minimise pasture contamination up to
mid-July, by which time the over-wintered population
should have declined to insignificant levels. If the
approach is targeted, ensure that e ective, regular
monitoring such as weighing of cattle to assess growth
performance is in place, to allow poorer performing
individuals not meeting growth targets to be treated.
Close monitoring of pasture quality throughout the
grass-growing season will allow farmers to cope with the
unpredictability associated with grazing.
Set growth targets for young stock at grass, manage and
feed accordingly and use anthelmintics alongside grazing
management to ensure that parasite challenge does not
prevent targets from being met. Growing cattle should
be weighed regularly, as it is the only way to accurately
monitor performance.
An e ective, planned parasite control strategy can
overcome the threat posed by all the major parasites
of cattle. The appropriate use of anthelmintics can
alleviate the e ects of existing burdens and reduce the
risk of subsequent disease. Best practice is key; use
parasite control products as recommended, using the
correct applicator. Accurate dosing can only be achieved
if animals are weighed before applying treatments,
estimating liveweight by eye is inaccurate and can lead to
over or under-dosing.
In order to get the best from parasite control products,
farmers should: maintain all equipment and cattle
handling facilities; use the most appropriate product for
the parasites present; administer products at the right
dose; store and handle products safely and correctly;
consult the label and/or datasheet before using a
product.
Controlling roundworms helps protect profits
References:
1.
Forbes, A., 2008. Grazing behaviour, inappetence and production losses in cattle with sub-clinical parasitic
gastroenterisits. Thesis. University Gent, Merelbeke.
2.
Larson, R. L., et al (1992). E ect of deworming with Ivomec on reproductive performance of yearling beef heifers. Kansas
Agricultural Expermiment Station Research Reports, 0 (1), 53-55.
3.
Lawrence, J. D., and Ibarburu, M. A., (2007). Economic analysis of pharmaceutical technologies in modern beef
production. Paper presented at the NCCC-134 Conference on Applied Commodity Price Analysis, Forecasting and Market
Risk Management, Chicago, IL.
4.
Purvis, H. T., et al (1994). Weight gain and reproductive performance of spring-born beef heifer calves intraruminally
administered oxfendazole. Journal of Animal Sciencce, 72 (4), 817-823.
5.
Stroh, T. L., et al (1999). E icacy of spring time worming among beef cow calf pairs. Dakota: North Dakota State University.
6.
Stromberg, B. E., et al (1997). Production responses following strategic parasite control in a beef cow/calf herd. Veterinary
Parasitology, 68, 315-322.
An educational service from Boehringer Ingelheim Animal Health UK Ltd ("BI"). Further information available from BI, RG12 8YS, UK.
2019. All rights reserved. Date of preparation: Apr 2019. AHD 12002. Use Medicines Responsibly.
About Boehringer Ingelheim Animal Health UK Ltd Business Unit
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