Bulk Milk Testing

Over 78% of milking herds are exposed to moderate or high levels of worm burdens1 resulting in sub-clinical effects to health and productivity. 

Gutworms are economically damaging parasites and can contribute to several production losses. They can be particularly detrimental in mature dairy cows at calving and during lactation; this can result in serious economic losses for the dairy farm.

We are offering complimentary Bulk Milk Tank Tests which detect the presence of antibodies against ostertagia (one of the major gutworms which affect cattle); this result will display the level of infestation, providing a scientific basis for the decision on whether to treat your dairy herd.

What is a Bulk Milk Tank Test?

  • Also known as ODR (Optical Density Ratio) test or ELISA test
  • Detects the presence of antibodies to O.ostertagi
  • Determines the sub-clinical level of gutworm burden in the milking herd
  • Tests to establish if treatment is required – NOT to test efficacy of treatment
  • Single test tube sample of milk from the bulk milk tank processed by independent lab, Bio-best
  • Results shown on an easy to interpret scale

Benefits of Testing

  • Offers scientific justification for the need to invest in worming the dairy herd – allowing the farmer to make an informed choice about worming
  • Detects subclincal gutworm
  • Accessible – Fully funded by Norbrook – processed by Bio-best – quick 7 working day turn around time
  • Promotes responsible worming practices
  • Easy to use & non invasive
  • Results assist with future herd health planning

Best time to conduct a test?

  • Test mid-grazing for subclinical gutworm to ensure the herd achieves the most from the remaining grazing weeks
  • Ideally minimum of 8 weeks post turn out


  • Test at housing to identify antibody levels (no later than 6 weeks post housing).
  • There is no benefit to testing if treatment has already been used this season. The antibody level will remain high for some time after a treatment (cannot be used as a test of efficacy)
  • If a low result is received early in the season why not test again later?

Get in touch with your Carrs Billington rep to arrange a test.