Parasites prove costly
Farmers could be paid less for their sheep at the works if a spike in parasites in the animals is not managed carefully over autumn, experts say.
A wetter summer has created optimal conditions for parasites to thrive. Data from technology and testing company Techion shows a 25 per cent increase compared to this time last year.
A heavy parasite load can lead to health problems, preventing sheep from gaining weight, and sometimes even lead to death, vets say.
Hawke’s Bay farmer Jim Galloway said parasites affected the growth rates of sheep because they competed for food.
‘‘They live in the gut and decrease nutrition available for the animal to grow,’’ Galloway said.
The options were to keep them on the farm longer, or sell them at a lighter weight, which would reduce their value and the farmer’s income, he said.
It could lead to a lower lambing percentage next year.
Managing parasites was more challenging in moist conditions, and testing was important because it could pick up any drench resistance in a flock, Galloway said. ‘‘[Drench] product rotation can help with that and vets need to be involved to work out a strategy.’’
Techion chief executive Greg Mirams said year-on-year analysis of faecal egg counts from 15,000 samples between January and February showed stock across the country were facing a significant increase in parasites.
Breeders were surveyed, including during the alert level 4 lockdown last year, indicating the increase was due to purely seasonal issues.
‘‘We had more rain across the country in the summer and we haven’t had a summer drought this year. We’re getting it now, an autumn drought,’’ Mirams said.
Last year’s drought would have slowed down the parasites’ cycle, he said.
Another contributing factor was farmers holding lambs for longer to grow them to heavier weights.
‘‘Summer has produced an abundance of quality feed, so stock have generally been protected from the impact of parasites,’’ he said.
‘‘However, the parasites have been laid down on pasture and are waiting for the autumn pinch conditions to occur.
‘‘The weather factors and high lamb numbers will combine to create a significantly higher parasite challenge to all stock through late autumn early winter period.’’
Farmers should look out for weight loss, poor condition, lethargy and an increase in dags and scouring.
Central Hawke’s Bay vet Karen Phillips said parasite counts were likely to be a bit higher going into autumn but it was not anything that farmers would not be expecting.
Farmers should not assume parasites were always the cause and should check with a vet, Phillips said.
Parasites could cause fluid loss or secondary infections.
‘‘The sheep are normally a bit thin and there’s a chance they might not even make the weight to get to the works,’’ she said.