Changing approaches to cattle worming
Many farmers will be handling cattle around this time of year, so the use of a persistent wormer at this time can be appropriate.
HERD HEALTH SERIES: Maura Langan, Commercial and Technical Manager (Large Animal) at Norbrook.
One of the key principles of the responsible use of anthelmintics is to treat cattle only when necessary and to reduce numbers of treatments throughout the grazing period, if appropriate. By monitoring the potential worm burden, we hope to achieve a balance between welfare and performance and the need to preserve anthelmintic efficacy, as well as development of immunity.
However, as the grazing season progresses it is important to acknowledge that the parasite burden increases throughout the summer. This year we’ve had cool but wet conditions through the early part of the season, followed by some late summer sunshine. Many first and second season cattle may not have needed earlier treatments but could now be carrying a significant worm burden.
At this time of year farmers would expect to see the benefits of late summer grass with good growth rates ahead of the housing period. Infection with Ostertagia will affect weight gain and production losses can be significant. Your vet is able to advise whether specific management groups should be treated and may run diagnostic tests such as a Faecal Egg Count (FEC).
Many farmers will be handling cattle around this time of year, so it’s relatively straightforward to slot in a worm dose to those that need it.
The use of a persistent wormer at this time can be appropriate on many farms. These products continue to protect cattle from infection after treatment and the period of protection depends on the product and the parasites being treated.
Taurador® Pour-on contains 5mg/ml doramectin and has persistent action against Osterstagia (35 days), lungworm (42 days), as well as a range of other internal and external parasites. If used up to 5 weeks prior to housing it not only treats gutworms and protects against lungworm, but could remove the need for an additional worming dose when cattle are brought in.
However, they may still need to be treated for fluke post-housing, depending on the seasonal risk and in line with a parasite control (herd health) plan. A fluke-only treatment is likely to be the most appropriate treatment for these cattle, and also for adult cattle that have good immunity to gut worms and may not have received a wormer.
The Animal Health Ireland BeefCheck programme has observed an increase in live fluke found in cattle at slaughter in the period up to May. While this may indicate that some fluke survived treatment due to an inappropriate drug selection or timing, the age of the cattle affected suggests early infection from overwintered larvae on pasture. This combined with the wet spring and summer suggests that the fluke risk in some areas may be high.
There are a range of different flukicides on the market and they are generally classified according to the stages of fluke they are effective against. For this reason, it is important that the most appropriate product is used at the correct time in the fluke season.
Solantel Pour-on contains 200mg/ml closantel and is licensed for the treatment of late immature (>7 weeks) and adult Fasciola hepatica (liver fluke) infestations in cattle. Treating cattle with Solantel Pour-On at least 7 weeks after they are housed will mean any fluke ingested just before housing will then be susceptible to treatment and therefore lead to a more complete fluke kill.
Of course, it is always hard to predict exactly when cattle are housed, with the weather and availability of feed important factors in keeping herds at grass into the autumn.
In the event of favourable weather and grazing conditions in the autumn, cattle will be kept out as late as possible, increasing their exposure to fluke and worms. Often times a good autumn allows the grazing of wetter, more marginal, land further increasing the risk.
In this instance, treatment protocols may need to be revised, and an additional worm dose added. Your vet may recommend another non-persistent worm treatment, like Levacide Low-Volume in the later grazing season, or a combined fluke and worm dose such as Levafas Diamond or Closamectin Pour-On once housed.
Visit www.norbrook.com for more information.
