Black woolled and white socked, Zwartbles were considered a bit of a joke when they first arrived in the UK nearly 15 years ago.
They were initially sidelined by mainstream sheep producers, who saw it as a breed for hobbyists. But the breed is now in big demand, and livestock producers such as Frank Mattinson are among its newest supporters.
In its native Holland it is thought to have developed as a milk-sheep; its docile nature certainly proves it enjoyed close contact with Dutch shepherds, who recognised the breed's qualities.
A small band of UK enthusiasts generated interest in the Zwartbles in the early 1990s and highlighted its good carcass shape and milkiness.
Gradually, the prejudices were eroded and this year Zwartbles sheep have been the talk of the autumn trade, with more commercial buyers starting to look at the sheep.
Cumbria dairy farmer Mr Mattinson milks 115 Ayrshires at Brampton, Carlisle, and admits he had always had an inkling to keep some Zwartbles. He had run a flock of Rouge de l'Ouest for many years, but when he restocked after foot-and-mouth, he decided to buy two Zwartbles ewes.
He was so impressed with these two foundations ewes, he decided to establish a bigger flock, but finding enough ewes in the UK was difficult. Determined to be under way for the 2005 lambing season, he imported breeding stock from Holland, although even then he was only able to find sheep in small numbers and had to buy from several breeders. "They are not about in big numbers in Holland and a lot of breeders are reluctant to sell. We thought we would have a big choice, but they are just as hard to come by there as they are here," says Mr Mattinson.
He hand-picked 20 ewes and 15 ewe lambs on his buying trip to Holland and bought the highest priced tup lamb for 900gns at the breed society's sale at Carlisle this autumn. All the ewes have been AI'd to this lamb.
He is convinced the breed's qualities have a strong commercial value. "The Zwartbles is quiet; you don't need a dog, just a bucket. The breed doesn't suffer from foot problems and has hard, black feet.
"Our ewes are good mothers with bags of milk. Lambing percentage is about 200% and ewes will suckle triplets. I am convinced you could put any tup on to Zwartbles ewes and they would produce tremendous lambs, or you could do it the other way round."
Zwartbles are firmly established in the farming enterprise of Carol Calder at Billiemains, Chirnside, Berwickshire. Alongside the family's beef and arable business, she runs one of the UK's largest pedigree Zwartbles flocks, numbering 90 ewes and is now busy expanding her commercial flock based on Zwartbles crosses.
She finds no colour prejudice against black-woolled prime lambs at her local market at St Boswells. "Buyers buy on finish and weight up here, not colour. Once they have had these lambs they are back for more. They are a real winner with buyers sourcing lambs for the catering trade."
"Our January-born Texel-sired lambs are usually ready by 10 weeks old and will weigh 40kg. Even purebred male Zwartbles lambs sold for slaughter will reach 40-50kg at 12-14 weeks.
"But you have to market them at the right time or they start to grow frame instead of putting on flesh. We had some April-born lambs which we have left on grass all summer. They have grown into big lambs and will easily reach 50kg with perhaps just a bit of feed for a couple of weeks before we sell them," she adds.
Minimal feet problems