We are currently seeing and hearing about young cattle that are losing body condition and scouring. Some animals are being found dead or close to it. Examination of these animals is revealing that internal parasitism is a major factor. Some animals have only been drenched one month ago with an oral drench. There are a number of factors leading to this situation. A major lack of feed is causing animals to graze the sward to a very low level and are therefore ingesting large numbers of larvae. High levels of rainfall has lead to parasitic larvae being mobilized from the dung pats and migrating onto pasture very efficiently. Warmer than usual temperatures have led to a high number of eggs hatching and surviving to become infective larvae. Combine this with the fact that young stock do not have fully developed immune systems to deal with the incoming parasitic larvae and we have the perfect situation for severe infection.

At this time of year it is usually Ostertagia worms that are causing infections. These worms infect the true stomach of cattle. They cause losses due to inflammation of the stomach lining causing fluid losses, depressed appetite and reduced feed conversion efficiency. We usually see a very liquid scour and sudden weight loss. We can see sudden death in a certain type of Ostertagia infection where inhibited larvae emerge from the stomach lining all at once.

There are a number of ways to try and prevent this from occurring. Ensuring good feeding levels is essential. Where this cannot be achieved supplements should be provided. A preventative drenching program should be in place to help young stock in the fight against these parasites. From here forward to mating the yearling dairy heifers should be receiving a combination pour-on now in mid- late August, and then a follow up just prior to joining with the bull in October.

Also trace mineral status of young stock should not be overlooked, especially if they are not doing well. Blood tests or liver biopsies can help us diagnose any deficiencies.

The main message is to be vigilant with young dairy stock at this time of the year to ensure they have adequate feeding and parasite control in place. We are ideally placed to discuss and help prevent these situations occurring or investigate current cases of ill-thrift.