Weather takes its toll on ewes and lambs

Sheep farmers doing their spring flock counts in many parts of the North Island are getting nasty shocks that will reverberate through the meat industry.

They are finding more lambs than usual have died and, much more serious, are finding many of the lambs' mothers have died too.

Earlier this year, pregnancy scans of flocks had shown record numbers of lambs being carried by ewes, leading to forecasts of more than a million extra lambs for the intensely competitive lower North Island meat industry.

But the long, cold, wet winter appears to have taken its toll.

Manawatu veterinarian Trevor Cook, who advises farmers across the central and lower North Island, says many farmers who are bringing their flocks together for the first time since scanning are discovering their lamb numbers are a lot less than they were expecting.

Most worrying is the high number of ewes that have died, he says.

The results will be a bitter disappointment to farmers who were hard hit by the floods and slips that devastated Wanganui, Rangitikei, Manawatu, Horowhenua and Tararua in February and Wairarapa and Tararua again in August. Many were hoping for a much-needed economic boost from the extra lambs the scans showed were coming.

Meat companies will also be affected, with the arrival of a new-built freezing works at Marton later in the season adding to an already intensely competitive region.

Mr Cook said the reasons for the increase in deaths were varied, but the winter appeared to have been so stressful on ewes that when it came time to lamb they had no energy left.

"They just sat down and died," he said.

"In Manawatu, we never went more than four days without rain after the floods in February. Sheep don't like rain - there's a lot of evidence that they display stress responses to being wet. Those stresses accumulate, particularly in a ewe getting more and more pregnant."

The ewe losses were "huge" - 6 to 7 per cent over lambing and some even higher at 8 to 9 per cent. Lamb losses from scanning to docking were more than 20 per cent in many flocks and he expected the North Island's total lamb numbers to be about the same as last year.

Another reason for the losses was a rise in bearings - prolapsed vaginas - in ewes that were carrying more than one lamb. As the ewe died so did her lambs.

"Bearings are a mystery to us, we don't know why they vary from farm to farm and from year to year but whatever it is that sets those up, they're set them up this year over quite a big area," Mr Cook said. "That's intriguing. I'm seeing increased numbers of bearings in Manawatu, Gisborne, East Coast, Waikato and Wairarapa. It's been quite a feature."

The record scannings meant many more ewes were carrying two or three lambs, increasing the risk of something going wrong. Most farmers did not identify triplet-carrying ewes from twins in scanning but the death rate in triplet ewes could be huge if they were not fed properly in late pregnancy.

Cast ewes - those that could not get back on their feet if they fell down - were also more frequent and lamb birthweights appeared to be higher than normal, another cause of ewe deaths.

Mr Cook said that in the prolonged bad weather farmers could not have done much more to save their ewes and lambs. "I know many farmers are revisiting their attitude to doing a lambing beat - thinking if they could have spent more time with the ewes they could have intervened to save a few. Other farmers argue that by being there you just disrupt them and cause more damage."

The loss of the producers of several generations of lambs would be an economic blow to farmers that would be felt for years, he said.

"I've always said the good farmers are the ones who can respond to all sorts of variations, but this winter's caught even out the good farmers."

- NZPA