Taken from “Reducing Stature” at PurebredMiniJerseys.com
Demand Exceeds Supply
In shopping for a Mini Jersey you’ll soon learn there are very few true miniaturized Jerseys available. You’ll also learn that the high demand and low supply has driven up the market; pricing many out of their dream of a Mini Jersey. I’d like to offer you an alternate route to your little family cow.
“DNA Testing Is The Future Of Mini Jerseys.”
– Lorinda Barnes, PMJS President
Cattle breeders, including standard Jersey breeders the world over, are using genomics in their herds to reach their goals. To make educated breeding choices we must begin testing for purity and genomic traits and stop guessing or solely focusing on stature.
You can get a standard Jersey cow for a lower up front investment and breed her to a Mini Jersey bull to reduce stature of the offspring over several generations. With each breeding you can also improve other traits, like fat, teat length, and fore udder. Breeding each generation to Mini Jersey bulls with known high Breed Based Representation (BBR), in time, will produce a Purebred Mini Jersey.
Reducing Stature
This is Ruby. She’s an AJCA registered, standard Jersey. She doesn’t have any Mini Jersey bloodlines. She’s 47.5″, dehorned, A1/A1, and BBR100. She was bred as a heifer to a Mini Jersey bull of unknown genomics and purity. He was 41″ at 3 yrs old. Ruby had a heifer calf, Fern (below), from that breeding. Fern was 21.5″ at birth and genomic testing shows her as BBR100.
Fern’s sire didn’t noticeably reduce her purity but did reduce her genetic stature and physical height. Fern was 39″ at two years old and 40.5″ at 3 years old. That’s a full 7″ shorter than her dam, Ruby. Genomics also showed several improvements. Fern is Polled, A1/A2, and has higher health and conformation traits.
Fern was bred to TDH Dino Smurf. He has been tested as BBR100. Their calf, Lilac, was 20″ at birth, is BBR100, and 38.5″ at 2 years old.
One Method: Breed A Purebred Jersey Cow To A High BBR Mini Jersey Bull To Produce Purebred Mini Jerseys.
Producing Purebred Mini Jerseys
As you can see in the photos, Fern and Lilac are miniature. What genomic testing can “see” is that their stature was genetically reduced with each generation. Ruby’s genomic stature is -0.8. Her daughter, Fern’s genomic stature is -0.9, and Lilac’s genomic stature is -1.2.
With each of these breedings BBR was kept at 100. When breeding with Mini Jerseys of unknown BBR the results may not be the same. We’re finding through genomic testing that most Mini Jerseys are already in the BBR 80-100 range. Purity can be maintained over several generations with careful bull selection and starting with a standard Jersey cow that is known to be purebred.
Purebred Mini Jersey Society is a community of Mini Jersey owners seeking to produce Mini Jerseys with DNA tested, pure Jersey genetics, leading to consistent appearance, dairy traits, temperament, and performance. The Purebred Herd Book lists bulls with BBR testing that are available for Artificial Insemination (AI) breeding. If you need help selecting a bull for your cow you can email Admin@PurebredMiniJerseys.com.
– Lorinda Barnes, PMJS President
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