Accuracy vital in eczema control

Veterinarian William Cuttance spore counting for a client.

Spore counts should be trending down and consistently below 10,000 to ensure herds get sufficient protection.

It's time to do more to reduce the number of animals affected by facial eczema, says veterinarian Emma Cuttance.

A survey and sampling conducted on 106 farms throughout the North Island in this year's facial eczema season showed that one-third of farms had cows affected by sub-clinical facial eczema damage.

Most of these farms had not seen any clinical cases of facial eczema.

The DairyNZ and Sustainable Farming Fund research showed things farmers can do to start preparing for the facial eczema season.

That season will vary depending on location and climate, so it's important to base actions on spore counts rather than certain months.

PLAN THE CONTROL METHOD

Put a plan in place and start control early.

Every management system for facial eczema has gaps or weaknesses, whether it is zinc sulphate water treatment or fungicide spraying. If those gaps are not identified and addressed, cows will not be fully protected.

It is important to review the situation regularly to check your control method is working.

Visit dairynz.co.nz/facial-eczema to work through the recommended management system and to read the facial eczema Farmfact on treatment and prevention (Farmfact 3-6).

SPORE COUNTING INVALUABLE

Pasture spore counting is an excellent tool to identify trends. However, research from 2012 to 2014 found the variability between farms to be very large.

This is because every farm, paddock and even sections of paddocks, contain a slightly different micro-climate for the spore-producing fungus.

It is possible to have spore counts varying by as much as a 500,000 spores/g pasture or more between farms and even between paddocks.

Although rainfall, minimum temperatures, humidity, topography and regional spore counts give some indication of trends, when regional spore counts start trending upwards to reach 20,000 spores/g of pasture it is important to gather a more accurate picture of your farm.

Identify four paddocks representative of the farm and monitor them regularly for trends in rising spore counts.

Use this as a base for management decisions because it is a preferable method to spore counting a few of the paddocks the cows might graze in the next 24 to 48 hours.

It is not uncommon for spore counts to decrease unusually early or unusually late so do not stop the programme until the spore counts are trending down and are consistently below 10,000 spores/g of pasture for three weeks.

FACIAL ECZEMA

Facial eczema is a disease affecting the liver of cows. While many associate facial eczema with skin peeling and red, sensitive teats, the real damage comes from the 95 percent of cows that will not show any clinical signs of the liver damage facial eczema causes. This unseen damage affects milk production and survival in the herd. dairynz.co.nz/facial-eczema