Quadruplet calves born on a South Taranaki dairy farm last month are thriving says their owner.
Michael Kavanagh got the surprise of his life when the twin heifers he was helping deliver on their 100ha farm near Maxwell turned out to be triplets, then quadruplets.
Local vets told him it was an extremely rare occurrence and none of them had had first-hand knowledge of quadruplets before.
Despite calving three of the four heifers himself, Kavanagh DNA sampled all four and sent this away to LIC's GeneMark laboratory to confirm parentage.
Results came back this week confirming the quads' parentage.
Kavanagh said he was relieved to have the results in black and white.
"Just to have that confirmation is good and no one can doubt our story now. We were pretty sure, but, with something as rare as this, there's always that little bit of doubt ... but now it's 100 per cent."
Lorna McNaughton, an LIC (Livestock Improvement Corporation) research scientist specialising in cow reproduction, told The Country quadruplets were generally a rare occurrence in dairy cattle.
"Having all four calves be heifers and in good health is particularly lucky. They would be a good boost to the farm's heifer/calf ratio.
She said the incidence of quadruplets was reported as 1:650,000 in beef cattle.
"DNA results have confirmed the heifers are non-identical quadruplets, so the cow would have produced four separate eggs all fertilised by one LIC insemination," she said.
Kavanagh said the quads' mother Becky was doing well after a touch of ketosis early on and was back in the milking herd, he said.
The calves, which Michael's mother Eileen Kavanagh named Blossom, Bluebell, Bonnie and Belinda, due to their dam and sire, Becky and Byreburn PF Eternal, both beginning with a B, were also thriving. "They're still a tiny bit on the smaller side, but are putting on weight well and look no worse for having shared a uterus."
Kavanagh said the vets were amazed Becky managed to carry all four embryos to term.
"Because the four heifers are not identical, that means they originated from four embryos.
Normally the cow drops any other potential embryos and only holds on to the strongest, but obviously, in this situation, she held on to all four."
Kavanagh said it was nice to have some good news after the prolonged wet weather this season.
"Even though there's been water in places we haven't seen puddles in more than 20 years on the property, we're still quite dry compared to others.
"The grass is finally starting to take off with a bit of recent sunshine and there's only one cow left to go, so things are looking up now."