A careful farmer, a beautifully maintained farm, good breeding sheep, but mysteriously few lambs.
Sheep are a vanishing species in the Far North, for a variety of reasons. Some farmers are sick of dealing with manky hooves as the animals struggle with problems due to the humid conditions. Others are tired of attacks by neglected hunting dogs.
But there are a few traditional souls who prefer the work of the woolshed and drenching a 50kg fluffy animal to the stink of dairy or beef cow shit and having to argue with something that weighs 600kg whenever treatment is required.
Angus Macintyre was one. He had taken over the family farm and 1500 ewes about 10 years ago. He had done his time at Lincoln University, plus a bit of work on large stations, and was gradually bringing his own touch to the farm.
The most obvious change was in the breeding lines of the sheep. He was trending away from previous generations of ‘fat lambs’ with Southdown lines and opting instead for an open-faced, easycare animal.
He was right into tagging, recording, and keeping things scientific. A bit of an academic, but the Vet reckoned he looked after the stock pretty well too.
One spring he rang the Vet for a bit of advice.
“Well, I dunno what is going on. I scanned the first lambers about six weeks after tupping and reckoned the lambing rate would be pretty high among them. I didn’t bother doing the mixed aged ewes but I palpated udders a month or so back and don’t think there were many empties there either.
“But lambing is well along now, and I’m just not getting the numbers on the ground, especially in the young ones. They should have finished by now, but there’s only half as many lambs as ewes, and some of those lambs just don’t seem to have any go in them.”
“Ok,” said the Vet. “I’ll come and have a look and take some samples. Have you noticed any aborted foetuses?”
“Well, there were a couple of slips I found a fortnight or so ago but that seemed to be all so I didn’t worry. Maybe I should have. It was after the cyclone passed through and I just figured the weather had brought them on a bit early.”
The Vet and I went out for the drive. We passed rolling paddocks with the grass as short and tidy as a golf course. Plantings of trees provided shelter for stock from the westerlies, and the troughs were on nice little hillocks of shingle. Angus met us by the woolshed. “I found this freshly-dead lamb just after talking to you. Would it give you any clues?”
The Vet got out his post mortem knife and with a few quick slices from he had all four legs splayed wide, and then took off a slither of skin from brisket to groin. All the organs were then clearly displayed. He was particularly interested in the liver.
“See these pale yellowy spots on the liver? Well I reckon you might have campylobacter. I will send some samples away to get a definite diagnosis. But with what you have told me... I would think it highly likely.”
“Oh great. That is the one that causes abortion storms isn’t it?”
“Yep, it can drop your live lambing rate up to 40%.”
“Just what we need. Will the ewes be ok?”
I dunno what is going on. There’s only half as many lambs as ewes.
“That’s the good news. They might abort, but usually come through with no lasting effects. They will go on shedding though. There are a couple of likely species: Campylobacter jejuni and Campylobacter fetus, what we used to call vibrio. It can be bad news for people too.”
“It was campylobacter that caused all those problems in some town water supply wasn’t it?”
“Amongst others, yes. You need to watch yourself and your family. Be careful with your hygiene, especially handling affected sheep or aborted lambs.” Angus rubbed his chin. “Come to think of it, I had a good dose of the shits a while back. I just thought it was the cockles the old man brought back from the coast. I came right in a few days. Funny thing is, he was ok, never got sick at all, the old rogue, and he ate more cockles than me, so it might not have been the cockles at all eh? Can I do anything now to stop the abortions?”
“It might be a bit late this season,” said the Vet. “The time from infection to abortion can be anything from a couple of weeks to over three months so it could be a while before the worst is over. But if you think the main flock is ok, then your job is to keep them that way. Make sure you don’t transmit the bacteria between the mobs. Do your lambing checks on the clean mobs first. Don’t mix them up. And give your hands and boots a wash before going into the clean mob. Keep the quad out of the clean mob until lambing is over anyway. Aborted ewes can be infective for a long time.”
“Won’t they develop their own immunity?”
“Yes, the ones that have had it will. But you risk losing a heap more lambs with an abortion storm in the nonimmune stock if we don’t get it right. There is a vaccine available now, give them that, then you know for sure everything is immune. Or you could try managing it. Run the two mobs together about a month over tupping. That should expose most of them to it and they can get a natural immunity.
“It is usually transmitted via the feed or water. At this time of year it can survive on the paddock for about 20 days. But your waterways are fenced off and your troughs are well placed so it must have come in from outside. Have you brought in any new stock lately?”
“No, but we did have a huge flock of black-backed gulls camping down on the flats for a week or so. They all came inland ahead of that cyclone and that’s where I had set-stocked the young ewes.”
“That could be it then... storm clouds really were gathering.” Angus shook his head. “Yeah... for an abortion storm. Well bugger it, is all I can say.” n
TRISHA FISK is a farmer, author of Practical Smallfarming in New Zealand, and long-time assistant to her husband in his vet work. They now live on 4ha near Whangarei and Trisha concentrates on her art: www.braveart.biz