Dairy cows are also exposed to parasites
Worm infection in cows can significantly impact productivity and welfare.
HERD HEALTH SERIES: Maura Langan, Commercial and Technical Manager (Large Animal) at Norbrook.
Although most adult cattle have some immunity, dairy cows at grass will likely have some level of worm burden and studies show that could be negatively impacting milk yield by up to 2 litres per cow per day.
Ostertagia infection is responsible for changes to the abomasum that result in appetite suppression, disrupted protein digestion and an imbalance of gut bacteria in infected cattle. Studies in dairy cows that have been wormed show an increase in their dry matter intake by up to 1kg per day and that has a positive impact not only on the volume of milk produced, but also milk fat and protein levels. Milk yield naturally reduces throughout lactation, so a post peak dose can deliver improved results.
Studies have also shown that treating for gutworms also has a positive impact on fertility, including shorter calving to conception intervals and higher conception rates at first service.
As an industry, we really don’t want to worm unnecessarily, but it’s easy to take bulk milk tank samples and get them tested for antibody levels to Ostertagia, so speak to your vet and see what they advise.
Although we are trying to balance the number of worming treatments with welfare and production benefits, the one time you can’t afford to hold back is with lungworm.
At this time of year, lungworm is a real risk. Many herds will have some experience of reinfection syndrome in adult cows, more commonly referred to as coughing cows.
Stock that is exposed to lungworm develop immunity relatively quickly, however there are two strands to this immunity. The first is to the larval stage and this lasts around 6 months. It wanes over the housing period when cattle are no longer exposed. The second strand is targeted at the developing larvae and this immunity stops the larvae maturing into adults.
If initial immunity has waned or was poorly developed, cattle of any age that are exposed to a heavy larval challenge can experience severe respiratory signs. A hypersensitivity response by the cow’s immune system leads to excess fluid and inflammatory cells pouring into the lungs causing severe coughing. These cows are also more vulnerable to secondary pneumonia.
It’s worth noting also that faecal sample are of little use in diagnosing lungworm in adult cattle. The cows are likely to have the immunity that stops the larvae maturing to egg-producing adults, so no larvae are detectable in faecal samples!!
Lungworm infection in dairy cows causes a sudden milk drop, often before coughing even begins. It is possible to pick up on potential infection in the parlour or using predictive technology such as collars or boluses. If even one cow has lungworm, it’s recommended to treat them all.
Eprizero is an easy to use, rainfast pour-on that contains eprinomectin, a broad-spectrum wormer with a zero-day milk withhold. As well as gutworms, it is also an effective treatment for lungworm and external parasites including lice and mange.
Eprinomectin also has up to 28 days persistency against lungworm, meaning that cows are protected from further infection for a month after treatment.
Visit www.norbrook.com for more information.
