Covering risk from abortion losses
Losing healthy sets of twins through abortion when you’ve worked so hard to get them safely to this point is
“heart-breaking”, says Southland farmer Shane Roy.
Shane and his brother Justin farm Ben Callum Station in the Hokonui Hills, where they run sheep, beef and deer on 1400
hectares. About 800 hectares of this is hill country, with the balance cultivated rolling to flat. They have about 7,000
Composite ewes, 160 Angus beef cows and 450 red hinds. All lambs and deer are finished on the property but the cows are
put to a Charolais terminal sire, with all the highly sought-after progeny sold.
Shane, Justin and their parents bought the station 15 years ago and have also recently rcquired a small dairy unit
nearby.
Their lambing productivity is generally pretty reasonable, lambing about 140–145 percent to the ram over the past three
or four years. But Shane knows it could be better.
In 2014, between 40–50 twin-bearing two-tooths slipped their lambs when they were on a break and Shane suspects more
could have been lost once they were set stocked on the hills.
Last year there was a similar scenario and again it was the two-tooths, this time losing about 50 sets that he knew of.
“It looked like a battle zone,” he says.
“It always seems to be the two-tooths that get hit. We don’t cull the ones that lose their lambs – it’s hardly their
fault.”
Shane and Justin work to improve the lambing performance by regularly vaccinating their sheep against toxoplasmosis
caused by the parasite Toxoplasma gondii and against Campylobacter. They are confident the abortion risk from these
diseases is being covered, but to be sure they have included a booster shot for the two-tooths with CampyVax4® for the
past two years. (The Roys mate their hoggets, so the animals are initially vaccinated against Campylobacter with a
sensitiser and pre-tup booster as hoggets. Their maiden ewes also receive their Toxovax® shot – only needed once for
lifetime protection – as hoggets.)
The more likely culprit for most of the recent spate of abortions is Salmonella Brandenburg, which has been in the
district to a greater or lesser extent since it first flared up in the 1990s.
Earlier lab tests had shown up Brandenburg as an important cause of the abortions on the farm and their veterinarian
suggested it was again to blame for last year’s cases on field inspection of aborted lambs. That’s something they’ll
talk some more about with their vet.
Shane is aware a lot of factors can influence productivity, some controllable, some less so.
For example they’ve been hit hard by clover root weevil in recent years and are hoping the introduction of a parasitic
wasp to control it will start to help them win back some of the ground they’ve lost to the pest. On the other side of
the equation, he says it’s a “fine line”
bringing through pregnant ewes in the right condition to successfully raise two lambs. “If we overfeed them we have to
look out for bearings.”
In the meantime they are concentrating on the things they can control, and vaccinating to improve sheep performance
through better lambing percentages is an important component of their animal health plan.
--- ends ---