Parasites (internal and external) are very dependent on their environment and therefore, unfortunately, we cannot lay out the same strict plan for every farm - you need to monitor what’s going on year to year and put a plan in place that works for your system. There is always help available through Wynnstay’s SQP team, and your vet, if you need assistance.
All grazing cattle are exposed to worms and are at risk of production losses. Youngstock in their first grazing season have not had chance to build up immunity and are most at risk of disease until they acquire immunity. Larval worms accumulate on pasture over the grazing season and infective stages typically peak from mid-summer (July) onwards when the risk of disease is highest.
Production losses include, decreased appetite and, therefore, lower feed intakes leading to slower growth and development. It can leave animals vulnerable to secondary disease because it puts the immune system under pressure.
Anthelmintics are used to both protect the animal itself by killing worm burdens but also to prevent worm populations increasing on pasture over the grazing season.
Flies are an external parasite that also causes production losses: youngstock at grass are less likely to stand to eat/drink/rest because they feel irritated. They will spend more time swishing tails, shaking heads and generally putting more energy into moving around than growing and building an immune system.
Flies can be a serious vector for disease spread. The non-biting flies that feed on bodily secretion can be responsible for transmitting costly diseases such as summer mastitis and New Forest eye.
85% of the fly population is in developing stages in the environment. If we do not attempt to implement control measures until we see visible problems, high numbers of adult flies, then the number of eggs, larvae and pupae in the environment will be so large, no matter how we attempt to control them at this point – we are fighting a losing battle for the rest of the season.
It is self-explanatory that the more adult flies there are, the more eggs can be laid in the environment each day. Based on this simple fact, if we start killing adult flies as soon as we notice odd ones, there will be lower egg numbers in the environment.
Pour on products are available to kill adult flies, they have varying lengths of effectiveness. Electron ear tags act as a season long repellent which is ideal for cattle that aren’t handled often.