Feed conversion efficiency is much greater while a cow is lactating so you get more bang for your buck feeding them well while cows are still in milk. It takes 50MJME to put on 1kg of body condition during lactation but this increases to 72MJME/kg of live-weight gain in a dry state.

Many farmers make the observation that their cows become loose and lose weight over the March, April and May months. It is no coincidence that this coincides with when we see the highest pasture larval challenge in the season.

The graph below shows a pasture larval contamination study taken from the same two paddocks on a spray irrigated dairy farm on the Waitaki Plains. Pasture samples (taken above 5cm height) were collected before grazing over the course of summer through to the following spring.

The farm above had a nil drenching policy and a whopping level of autumn contamination, but we see similar increasing trends during the autumn on farms which used drenched in the spring. 

Previous trials have shown that cows consuming just 50 larvae/kg of dry matter grazed for 50 minutes less in a 24hour period. Imagine the effect the degree of contamination was having in this farm!

Timing of Drenching

Cows drenched 3-6 weeks before drying off, can gain additional body condition and will have better milk production. Use quality, nil milk withhold pour – ons such as Eprinex, Genesis and Cydectin.

For more information get in touch with your local Veterinary Centre:

Oamaru Phone: (03) 434 5666  Send Email
Waimate Phone: (03) 689 7213  Send Email
Glenavy Phone: (03) 465 1291  Send Email
Omarama Phone: (03) 438 9868  Send Email
Kurow Phone: (03) 436 0567  Send Email
Ranfurly Phone: (03) 444 1020  Send Email