![Yield Response to Dosing in Dairy Cows](https://cdn.prod.website-files.com/5d4988118d7625356b2ecf4e/5d6e258ac9361a620cf34b35_Picture1.webp)
We are often told by dairy farmers that they routinely worm cows during the year, regardless of whether symptoms of parasite infection are present or not, and immediately see lifts in yield. Why is this?
Mature dairy cows develop immunity to worms (stomach, gut and lungworm), but this immunity has an energy cost.
Think of our cow as a bank account. We make deposits (feed energy) and we then withdraw energy in the form of milk yield, maintenance, condition gain and the reproductive system. The immune system also requires an energy withdrawal. The harder it has to work, the more energy it withdraws. This leaves less energy in the account for the other processes.
In practical terms, from around eight weeks post turnout in a moist, warm season, we would expect a big burden of worm larvae on dairy pastures and so our animals’ immune systems would be working hard.
The only wormer we can use in lactating dairy cows is an eprinomectin, such as Epromec. This belongs to the clear wormer, or Macrocyclic Lactone, family. In cattle, these products have persistent activity. Meaning they keep killing worms for weeks after they’re applied.
The likes of Epromec takes the pressure off the cow’s immune system for weeks (depending on the worm) following treatment and in this way leaves more energy in the account for the cow to produce yield, hence the post-treatment lift.
We are often told by dairy farmers that they routinely worm cows during the year, regardless of whether symptoms of parasite infection are present or not, and immediately see lifts in yield. Why is this?
Mature dairy cows develop immunity to worms (stomach, gut and lungworm), but this immunity has an energy cost.
Think of our cow as a bank account. We make deposits (feed energy) and we then withdraw energy in the form of milk yield, maintenance, condition gain and the reproductive system. The immune system also requires an energy withdrawal. The harder it has to work, the more energy it withdraws. This leaves less energy in the account for the other processes.
In practical terms, from around eight weeks post turnout in a moist, warm season, we would expect a big burden of worm larvae on dairy pastures and so our animals’ immune systems would be working hard.
The only wormer we can use in lactating dairy cows is an eprinomectin, such as Epromec. This belongs to the clear wormer, or Macrocyclic Lactone, family. In cattle, these products have persistent activity. Meaning they keep killing worms for weeks after they’re applied.
The likes of Epromec takes the pressure off the cow’s immune system for weeks (depending on the worm) following treatment and in this way leaves more energy in the account for the cow to produce yield, hence the post-treatment lift.