Thursday, November 30, 2023

Scanning numbers down, metabolic problems up

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With scanning percentages down and animal health problems increasing, the hangover of an extended drought in the lower central North Island has left many farmers with a headache they could do without.
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Vet Services Hawke’s Bay managing director Richard Hilson says parts of Central Hawke’s Bay are dealing with higher rates of metabolic diseases and nitrate toxicity, along with lower than usual scanning percentages, but farmers in areas towards the east and south of the district have fared better than others.

Hilson says in general there’s plenty of fresh green grass but the flipside of that is some farmers are having trouble with milk fever in ewes.

There is a concern that it’s been mistaken for sleeping sickness, as the two diseases can be hard to tell apart, and the treatments are different.

To deal with winter feed shortages in recent years, an increasing amount of land in the area has been planted in oats and annual grasses but that needs careful stock feed management or farmers run the risk of stock dying from nitrate poisoning – a problem that has also increased in the past month or two following rapid grass growth after the drought.

Hilson says he has not heard of many cases of bearings, which is not surprising as multiples are well down and there have been very few triplets.

Scanning percentages in his practice’s area are 15% lower than last year for mixed age ewes and two-tooths because of fewer multiples. Empty rates are slightly better than last year.

The numbers are similar to 2013 and 2011 but not as bad as in 2008.

Taking into account the lower percentages and expected mortality rate, he says the Hawke’s Bay lamb flock could be down 150,000 this year.

VetsOne Hastings director Jason Clark says from what he has seen, stock has been hanging in, although there have been metabolic problems, including sleeping sickness in ewes.

The drought, followed by relatively warm weather, has made it feel like autumn pushed into winter and as a result, internal parasites have become a problem, with parasite burdens particularly prevalent among weaner cattle.

Clark has also seen farmers having problems with nitrate toxicity.

VetsOne does not get involved in ewe scanning but Clark says most clients he has spoken to are pretty happy with the results they are getting.

The situation in Manawatu is similar to Hawke’s Bay.

Totally Vets director Trevor Cook, who is based out of Feilding, says scanning percentages are down 10 to 20%, with two-tooths suffering the most. He says the gap between two-tooths and mixed age ewes is always there but this year the difference is bigger than usual.

The fall in percentages is being driven by a drop in multiples rather than dry ewes, which he says is consistent with ewes not having enough feed.

Like their Hawke’s Bay counterparts Manawatu farmers are experiencing an increase in metabolic diseases and nitrate poisoning, while there has also been an increase in worms at a time and severity not normally expected.

Nitrate poisoning has carried on longer than usual, caused by nitrates accumulating in the soil during the drought followed by a warm June, which led to abnormally high grass growth rates.

That’s been followed by plenty of overcast days, stopping sunlight detoxifying grass leaves.

It’s not much different up the road further north, with scanning percentages down 10 to 15% in Rangitikei.

Hunterville Vet Club practice manager and vet Martin Walshe says two-tooths have been more severely affected, although the number of dries is similar to previous years.

He puts the fall down to a lack of, or falling, body weight of ewes at tupping, with that lack of weight more critical among two-tooths.

There has been a small number of farmers with dry problems, with those farmers having to leave gates open for stock to get water, resulting in a lack of ram power.

Stock condition has bounced back significantly since May.

“We got a bit of a get out of jail free card,” Walshe said.

Rain and soil moisture levels didn’t drop in June and hardly fell away for much of July, so pasture growth in some hill country areas was twice as much as what might have been expected.

Unfortunately, that resulting grass growth, which has been more spring-like than winter, has meant a lot more cases of milk fever than normal.

Liver fluke is also up significantly.

Walshe says that increase has built on a rise during the past two or three seasons but this year it’s jumped again, with stock getting into wet areas that are perfect environments for them to be infected by the parasite.

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