Weight loss and reduced performance due toliver fluke disease in housed and out-wintered beef cattle is likely to bereaching peak levels in the New Year, according to the January NADIS ParasiteForecast, sponsored by Merial Animal Health.
Information on liver fluke damage should berequested from slaughterhouses to give an indication of the level of disease inthe herd. This will help to inform control measures on individual farms anddetermine the ideal treatment policy. If cattle were not treated at the time ofhousing, a dose of nitroxynil (Trodax) or closantel should be given now toremove liver flukes picked up from pasture before animals were brought in.Says Fiona MacGillivray, Veterinary Health Advisor for Merial Animal Health
Dairy cows can also suffer reduced milkyield, lower quality milk and poorer fertility, despite adequate feeding, buttreatment of liver fluke in dairy cows is more difficult. Albendazole andoxyclozanide are the only flukicides available for treatment of fluke inlactating dairy cows, with 60 or 72 hours milk withdrawal, respectively.
An increased risk of type 2 ostertagiosis islikely this winter with large numbers of larvae inhibited in the abomasal walldue to a late challenge from autumn pastures. If cattle were not treated withan anthelmintic at housing, now is the time to dose with a larvicidal wormer(or a combined wormer and flukicide, such as Ivomec Super) which will alsoremove lungworm infection if present, says Fiona.
Cattle housed over the winter are at risk oflouse infestation. Heavy infestations can cause production losses due toreduced feeding time and damaged hides. In order to achieve the best results,all cattle in direct contact must be treated on the same day, using anappropriate product. Topical treatments are effective at controlling both liceand mange infestations during the housing period.
Farmers should remain vigilant for ParasiticGastroenteritis disease and poor growth in sheep over the winter. Above averagetemperatures in November allowed continued larval development in some areasmeaning many pastures remain infective.
Cases of acute fluke may still occur inJanuary or even later on high risk farms. Treatment with triclabendazole inJanuary is recommended on farms which face a high risk of infection frompastures and any apparent treatment failures should be investigated toestablish if triclabendazole resistance is present on that farm. Where possiblesheep should be moved to fluke-free ground after treatment to reducere-infection over the remainder of winter.