Zinc oxide rumen boluses for prevention of facial eczema

By Stephanie Bullen

Dairy Australia has recently secured an emergency use permit (PER 90370) for importation of controlled release, intra-ruminal zinc oxide boluses to aid in the prevention of facial eczema in dairy cattle.

Facial eczema is a liver disease (often accompanied by photosensitisation) caused by spores of a pasture fungus that multiply rapidly in warm and humid conditions. It can have devastating impacts on herd productivity and animal welfare.

Feeding the correct amount of zinc oxide in grain/concentrates at milking can be highly effective for facial eczema prevention in the milking herd. However, dry stock (such as heifers, bulls, and dry cows) is also at risk of facial eczema.

An online Q&A session with Dr Andrew Dowling (PGG Wrightson), Tim Harcombe and Nikky Dally (NZ AgriTrade) and Nadine Krippner (Fortis Vets Ltd) from New Zealand was held on 17 December 2021 to introduce the boluses.

If you were unable to attend, a recording is available under 'Zinc oxide boluses for dry stock' on the facial eczema page on the Dairy Australia website.

The key messages from the online session were as follows:

• Zinc oxide boluses provide highly effective prevention against facial eczema in cattle for four weeks
• The boluses have no meat or milk withholding period
• Boluses will be available to purchase from several veterinary clinics in the Gippsland and Bega Valley regions under an APVMA (Australian Pesticides and Veterinary Medicines Authority) emergency use permit
• Boluses will cost between $7-16 per bolus depending on freight and weight of the animals being treated
• Animals must be weighed (or weight tape used) prior to administration to avoid the risk of zinc toxicity particularly in smaller animals
• Three different sized applicators are available according to the size of the bolus, these can be purchased or loaned from veterinary clinics stocking product
• Never administer more than one bolus, or alongside other rumen boluses, to avoid damage to the wax capsule
• If spore counts remain high, re-administration after four weeks is required
• Do not administer any other zinc supplements to treated stock
• Do not use boluses that are broken or damaged
• Administer boluses when pasture spore counts exceed 20,000 spores/gram or if poor performing animals have an elevated blood GGT (Gamma Glutamyl Transferase) levels
• To purchase zinc oxide boluses, please speak to your veterinarian or contact Nadine Krippner (Business Development Manager; Fortis) at nadine.krippner@fortisnz.co.nz or + 64 21 494 016.

Pasture spore monitoring

Farmers and stockfeed manufacturers are urged to monitor spore counts throughout the high danger period. Given the unseasonably wet and humid conditions, the Spore Monitoring Program will be supported by Dairy Australia again this year. Results will be reported by region and e-mailed fortnightly to the facial eczema e-mail subscriber list. To join the e-mail subscriber list, please contact Kristen Davis (kristen.davis@gippsdairy.com.au or 0476 159 591).

Farmers in other regions, or who are not participating in the sentinel farm program are strongly encouraged to monitor their own spore counts. Instructions for sampling pasture for facial eczema spore counting can be found on the Dairy Australia facial eczema page here. Samples should be refrigerated if not being processed immediately. Spore counting costs between $20-50 per sample and can be submitted to any of the following veterinary practices, either in person or by express post.

More information

More information for farmers about the disease, spore counting and facial eczema prevention can be obtained by speaking to their nutrition advisor or vet or by accessing the facial eczema information on the Dairy Australia website or by contacting Kristen Davis, GippsDairy Regional Extension Officer, at kristen.davis@gippsdairy.com.au or on 0476 159 591.