Utilizing Standard Jerseys for Your Breeding Program
How Breeding Down Stature Works
- PROVEN PURITY –
If you want a Mini Jersey that will provide all the wonderful Jersey traits you’ve read about, you’re in the right place! Purebred Mini Jersey Society is here to help you learn to use DNA science to produce REAL miniaturized Jerseys, not a mystery composite with unknown reproductive and dairy traits. By applying the science of Breed Based Representation (BBR), Purebred Mini Jerseys can be produced. We want to help you improve upon your Mini Jerseys so the offspring are more consistent in type and traits.
DNA testing is the future of Mini Jerseys.
Cattle breeders, including standard Jersey breeders, the world over are using genomics in their herds to reach their goals. Mini Jerseys must move forward to gain respect and recognition as a dairy breed and not a “hobby farm fad”. By improving conformation, producing consistent high quality udder and dairy traits, our Mini Jerseys will stand out from the crowd. We must begin testing for purity and genomics to make educated breeding choices and stop guessing or solely focusing on stature.
The key to improvement is testing our cattle. Determining a baseline for the breed and identifying the Mini Jersey bulls that carry the highest percent of Jersey DNA but are near the 42″ cutoff for Mini. These bulls can be collected to improve Mini Jerseys and create an additional source of revenue. Purebred Mini Jersey Artificial Insemination straws are in high demand!
With the massive demand for Purebred Mini Jerseys, it’s nearly impossible to find one or honestly, to afford them. But, with a lower upfront investment in a small standard Jersey, you can breed and create your own Purebred Mini Jersey.
Meet Ruby. She’s an AJCA registered, standard Jersey. She doesn’t have any Mini Jersey bloodlines. She’s 47.5″ and BBR100*.
She was bred as a heifer to a Mini Jersey bull of unknown genomics and purity. He was 41″ at 3 years old.
Ruby had a heifer calf, Fern, from that breeding. Fern was 21.5″ at birth and genomic testing shows her as BBR100.
So, Fern’s sire did not noticeably reduce her purity but did reduce her genetic stature.
Fern was 39″ at two years old and 40.5″ at 3 years old.
Fern was bred to TDH Dino Smurf. He previously sired a heifer, Willow, with Ruby. Willow is BBR100 with the GT45K test. Because of this, we knew Dino would not noticeably reduce the BBR of Fern’s calf. Their calf, Lilac, 20″ at birth, is BBR100 and 38.5″ at 2 years old.
It’s SIMPLE.
You can use a standard Jersey cow and a Mini Jersey bull to reduce stature 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 BBR scores, in time, will produce a Purebred Mini Jersey.
Purebred is defined as;
Bred from members of a recognized breed, strain, or kind without admixture
of other blood over generations. – Merriam-Webster Dictionary
Example A: Vanguard
Generation 1 is a 48″, purebred standard Jersey cow, Creme Caramel/small standard Jersey bull, Toro
Generation 1 produced = 47.5″, BBR100 cow, Ruby (3 yr permanent height measurement)
Stature reduced .5″.
Generation 2 is a 47.5″, BBR100 cow, Ruby/41″, BBR100 Mini Jersey bull, Dino
Generation 2 produced = 22″, BBR100 heifer, Willow (measured 22″ at birth, 44″ at 26 months, 45″ at 3 years)
Stature reduced another 2.5″ in generation 2, for a 3″ total reduction.
Generation 3 is a 45″, BBR100 cow, Willow/40″, purity unknown Mini Jersey bull, Loyal
Generation 3 produced = 20.25″, BBR100 bull calf, Vanguard (measured 20.25″ at birth, 30″ at 5 months,
38.75″ at 15 months, 39.25″ at 2 years, with an expected mature height of under 41″)
Stature reduced another 4″ in generation 3 for a 7″ total reduction in 3 generations.
Miniature height was expected at maturity and Jersey purity (BBR100) was maintained.
This is one example. As you can see, stature is reduced by half an inch to four inches in each generation. In this case, it took 3 generations to reach Mini stature from a standard Jersey cow. What you may not have noticed was Generation 1 were horned cattle. By generation 3 homozygous Polled was achieved. When breeding with Mini Jerseys of unknown BBR the results will not be the same. We’re finding through testing that most Mini Jerseys are already in the BBR 80-100 range. Purity can be maintained over several generations with careful bull selection starting with a standard Jersey cow that is known to be purebred.
Sweet Cream was a standard Jersey. She was Ruby’s great grand dam, Vanguard’s great great great grand dam. 
Buttermilk was a standard Jersey. Sired by a standard Jersey, out of Sweet Cream and is Vanguard’s great great grand dam. 
Creme Caramel was a standard Jersey. Sired by a standard Jersey, out of Buttermilk and is Ruby’s dam, Vanguard’s great grand dam. 
Frey’s Dairy Toro at 20 months. His sire was Forest Glenn Avery Action. Toro is Willow’s grand sire and Vanguard’s great grand sire. NW Ruby was sired by Toro. She’s certified 47.5″ at 3 yrs old and BBR100. She is Vanguard’s grand dam. 
TDH Dino Smurf was 41″ at 2.5 yrs and BBR100. He is Vanguard’s grand sire and Willow’s sire. 
NW Willow is 45″ at 3 years old and BBR100. She’s sired by TDH Dino Smurf and is Vanguard’s dam. 
Sunshine Acres Loyal was 40″ at 3 yrs. BBR is unknown. He’s Vanguard’s sire. 
NW Willow is 45″ at 3 yrs old. NW Vanguard was 20.25″ at birth and expected to be under 41″ at 3 yrs. 
NW Vanguard is 20.25″ at birth and BBR100. He is by small square hay bales and a barn cat. 
NW Vanguard 30″ at about 5 months old by a 1 month standard Jersey bull calf, a T-post and a 50″ cattle panel. 
NW Vanguard 39″ at 18 months old by a 50″ gate.
Example B: Lilac
Generation 1 is a 48″ purebred standard Jersey cow, Creme Caramel/small standard Jersey bull, Toro
Generation 1 produced = 47.5″, BBR100 cow, Ruby (3 yr permanent height measurement)
Stature reduced by 0.5″.
Generation 2 is a 47.5″ cow, Ruby/42″ at 33 months, Mini Jersey bull, Firecracker Generation 2 produced = 40.5″, BBR100 cow, Fern (3 yr. permanent height measurement) Stature reduced another 7″ for 7.5″ total reduction and Miniature height achieved. Jersey purity (BBR100) was maintained.
Generation 3 is a 40.5″, BBR100 cow, Fern/41″, BBR100 Mini Jersey bull, Dino
Generation 3 produced = 20″, BBR100 heifer, Lilac (measured 20″ at birth, 37″ at 18 months, 40″ at 3 years)
Stature reduced another 0.5″ for an 8″ total reduction and Mini height at maturity.
Jersey purity (BBR100) was maintained.
Creme Caramel was a standard Jersey. Sired by a standard Jersey, out of Buttermilk and is Ruby’s dam, Vanguard’s great grand dam. 
Frey’s Dairy Toro at 20 months. His sire was Forest Glenn Avery Action. Toro is Fern’s grand sire and Lilac’s great grand sire. 
NW Fern is 40.5″ at 3 yrs old. NW Lilac was 20″ at birth and 40″ at 3 yrs. They are by a 5 gallon pail. 
NW Lilac is 20″ at birth and BBR100. She is by a 50″ Behlen gate. 
NW Lilac was 36″ at about 17 months old. 
NW Lilac was 40″ at about 3 years old by a 50″ gate.
Example C: Thistle
It’s important to notice Lilac and Thistle are full sisters, sharing the same parents.
Generation 1 is a 48″ purebred standard Jersey cow, Creme Caramel/small standard Jersey bull, Toro
Generation 1 produced = 47.5″, BBR100 cow, Ruby (3 yr permanent height measurement)
Stature reduced 0.5″.
Generation 2 is a 47.5″ cow, Ruby/42″ at 33 months, Mini Jersey bull, Firecracker
Generation 2 produced = 40.5″, BBR100 cow, Fern (3 yr. permanent height measurement)
Stature reduced another 7″ for a 7.5″ total reduction and Miniature height was achieved.
Jersey purity (BBR100) was maintained.
Generation 3 is a 40.5″, BBR100 cow, Fern/41″, BBR100 Mini Jersey bull, Dino
Generation 3 produced = 22.5″, BBR100 heifer, Thistle (measured 22.5″ at birth, 43.5″ at 2 years, expected to finish at 44″) Stature INCREASED 2.5″ and Midsize height at maturity.
Jersey purity (BBR100) was maintained.
How did this happen? Well, remember Thistle is only a couple of generations removed from standard Jerseys.
Those genes were passed down but Lilac didn’t inherit them and Thistle did. Thistle’s still 3.5″ smaller
than her grand dam, Ruby, and 4″ shorter than her great grand dam, Creme Caramel.
Thistle is a beautiful heifer and a few inches in height, 4″ to be exact, which doesn’t diminish her value to a breeding program
or her ability to produce milk. So, while Mini height is the goal, it’s not the only piece of the puzzle. She has her own genetic strengths, as seen here in the Genomic Evaluation Reports of Thistle and Lilac, side-by-side.
Example D: Autumn
Generation 1 is a 48″, BBR100 purebred standard Jersey cow, Brook/42″ Mini Jersey bull of unknown purity, Kristoff
Generation 1 produced = 40″, BBR90 heifer, Autumn (22.5″ at birth, 40″ at 23 months, 42″ at maturity)
Stature reduced 6″ and Miniature height at maturity.
While Polled genetics were added, Jersey purity was reduced to BBR90.
Betsy is a 48″ purebred standard Jersey. She is Autumn’s grand dam. 
Faria Bros Prop Joe is a standard Jersey. He is Autumn’s grand sire 
Brook is a 48″ purebred standard Jersey. She is Autumn’s dam 
Rush Fars Kristoff was 42″ at 33 months. He is Autumn’s sire 
Autumn was 22.5″ at birth 
Autumn next to a 50″ gate at 11 months old 
Autumn was 36″ at 1 year old next to her dam, Brook, 47.5″ at 2 years old 
Autumn 41.5″ at 2.5 years old next to a 50″ gate
As a PMJS Member you can be mentored by experienced breeders, if you wish, and get advice for breeding.
As Purebred Mini Jersey Society grows, and more Mini Jerseys are proven to carry pure Jersey genetics, you’ll have access to the expanding online database, accessible 24/7. You can also register your Purebred Mini Jerseys and
breeding stock certified, increasing their value to others looking for true miniaturized Jerseys.
Pooling our genomic data will save us all time and money.
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.
