Is it worth drenching dairy cows at dry off?

There is a long history of research that has addressed this question, starting in the 1970’s looking at compounds like copper sulphate and the “white” drenches,  progressing to investigating the “clear” drenches in the 1980’s and finally  the “mectin” drenches when they arrived in the 1990’s. The focus of research over this time has been on milk production responses with very few studies looking at other health effects, repro effects or pasture contamination.

The body of research up to 2004 was subjected to a meta-analysis (Sanchez et al., 2004) where all the data from the eligible trials was pooled and re-analysed to statistically summarise the research.  This meta-analysis found that although the milk production response to a drench at dry off has declined over the years, it is still significant at 0.46 kg milk/day (~145 litres / lactation) across all studies and drenches. When the older drenches were excluded and only the “mectin” drenches were included in the meta-analysis, the production response was 0.67 kg milk/day (~210 litres / lactation).

The number of products that are suitable for use at dry off is a bit limited due to withhold periods. Cydectin Platinum is the ideal choice as it’s a dual active drench (moxidectin and levamisole - which is important when dealing with the problem of drench resistance) and has a zero milk withhold period, 7 day meat withhold for the cow and 20 days for calves from cows drenched during pregnancy.  Of the single active pour-on drenches, Neovomox (moxidectin) has a zero meat and milk withhold  as does Neoverin (eprinomectin), making them safe choices as well.  It is important when using a pour-on drench that all cattle in a mob are drenched at once and they are not mixed with un-drenched cattle for a week or so.

Check out our Autumn specials with up to 16 % off dry-off drenches until the end of May.