AUTUMN Pasture & Fertiliser Now is the time to keep an eye on FE spore counts

Last week saw a dramatic leap in facial eczema (FE) spore counts in the Wairarapa, according to the Gribbles Veterinary Facial Eczema Report (labportal. gribbles.co.nz). The ÿ rst week of February saw spore counts jump to nearly 70,000 spores/g in the Wairarapa, from around 9000 the week before, while in the Tararua district spore counts have gone from around 90,000 to 120,000.

The past three years have seen spore counts steadily go up during February across New Zealand.

Gribbles advises that “when local pasture spore counts are trending upwards of 30,000 spores/g and weather conditions look favourable for sporulation, monitor your own farm’s pasture spore counts week to week and implement facial eczema control and prevention strategies.”

Facial eczema a° ects most ruminants but especially cattle and sheep throughout most North Island regions plus the northern end of the South Island, the website says.

“During summer and autumn months warm, humid conditions together with dead litter in pasture support the growth of a fungus (Pithomyces chartarum) in pasture.

“Animals graze toxic pasture and once in the rumen the spores release a mycotoxin sporidesmin, which then enters the blood stream eventually ÿ nding its way into the liver.

“The toxin speciÿ cally attacks the cells of the bile duct resulting in the liver being unable to process and excrete waste products and phylloerythrin, a chlorophyll breakdown product.

“Infected animals display signs of photosensitisation and look distressed.

The ÿ rst signs are often reddening and swelling of skin exposed to the sun (i.e. around the eyes, ears, lips and nose) as well as restlessness, shaking and rubbing of the head and ears, and seeking shade.”

Warm summer temperatures and high humidity are presently creating the perfect conditions for facial eczema, says Beef + Lamb New Zealand which is urging farmers to be vigilant.

The organisation has started publishing weekly spore counts in its weekly e-diaries and will be launching a regional text service in the near future to alert farmers of high spore counts.

Will Halliday, B+LNZ’s Senior Advisor for Biosecurity and Animal Welfare recommends that farmers in high-risk regions undertake weekly monitoring of their own property and when spore counts start to rise, put management strategies in place to prevent stock being a° ected by this productionlimiting disease.

These strategies could include avoiding hard grazing, feeding “clean” forage crops such as chicory or plantain, dosing sheep and cattle with zinc oxide boluses or drenches, or adding zinc oxide to cattle water troughs. When monitoring indicates rising spore counts, he urges farmers to keep a close eye on stock, looking out for signs of discomfort, photosensitivity and skin lesions.

“For every animal with clinical signs of FE – which are obvious skin lesions – there will be many more with subclinical disease, which is the invisible ongoing liver damage that can cause major productivity losses including reduced liveweight gain especially at mating resulting in lower lambing and calving percentages.”

B+LNZ has a number of resources to help farmers understand and manage FE in both the short and long-term. In sheep, genetics (buying FE-tolerant rams) o° ers a long-term solution to limiting the impacts of this disease.

Pasture spore counting is an excellent tool to visualise pasture spore count trends, says Dairy NZ on its website www.dairynz.co.nz.

“However variability between farms is very large because every farm, paddock and even sections of paddocks contains a slightly di° erent micro-climate for the fungus. It is possible to have spore counts varying by as much as a 500,000 spores/g of pasture or more between farms and between paddocks.