Delta: The Making of a #1 Sire

Dan Carroll and Patrice Simard, ST Genetics

MR MOGUL DELTA photo by Frank Robinson

Mr Mogul Delta is one of 80 sons from the celebrated Miss Ocd Robst Delicious-ET VG-87 GMD DOM and he is no doubt the most successful. Now almost five years old, Delta is the #1 GTPI (+2849) proven Holstein sire in the world.  Dairy producers appreciate his ability to sire medium sized cows with elite production, calving ease and outstanding health traits, and do so with consistent fertility to get heifers and cows pregnant.

Delta delivers correct stature, balance of strength and dairyness.  His daughters have very athletic feet and legs, making for mobile heifers and cows that are improvements over previous generations. Their udders are snug with excellent attachments making for daughters that are generally the highest milking 2-year-olds on farms in the U.S. and internationally. Delta’s genetics improve fat percent and hold protein percent, allowing him to have outstanding rankings in many counties. It is clear that Delta puts together production and type traits matched by few in the past.

The Delicious family has a reputation for producing sons and daughters with breed-leading genetics, which is not surprising when you consider that this DOM was the #1 GTPI female in the world in 2014. In addition to her 80 sons, Delicious boasts more than 50 high quality daughters. Delicious is still working today to make new matings with next generation outstanding sires. She has been an exceptional animal since her first genomic test and she is currently more than +2800 GTPI at 80 months of age. No other female her age is in this category.


Mating Mogul and Delicious was an easy decision and one repeated often. At the time, Mogul was an outlier and unique sire as his genetic makeup was not as prevalent in the breed. Multiple outstanding sons and daughters of Delicious were made to this mating. Delta was the result of a partnership between Mark Butz, Tim Rauen, Frank and Carol Borba, Farnear Holsteins and Sexing Technologies® .

In the coming sire summaries, Delta’s brothers will have an opportunity to impact the Top 100 TPI Proven Sire list.  Mogul Denver, McCut Dante, Mogul Dion, Day Dearing, Mogul Drama, Daytime, Draco, Delco and Dozer all have daughters freshening and being classified to confirm their values as elite proven bulls. Delicious has more young sons being used as sire fathers, including Dynamo and Dynasty, both Rubicon sons. Waiting in the wings is a Superhero son that has a higher ranking than Delta. He will most likely be ready in 2018.

Delta’s genetic composition makes him a bit of an anomaly even with his exceptional pedigree, so it is only fitting that his semen was marketed in an innovated and purposely unconventional way.

Delta was the #2 NM$ (+1005) and #5 GTPI (+2567) genomic sire in the breed when his semen was released following the April 2015 proof. At the time, STgenetics® was making its first major push onto the U.S. and international markets and had recently launched its revolutionary SexedULTRA™ sex sorted semen. SexedULTRA™ marked a significant evolution in sex sorted semen and boasted conception rates rivaling conventional semen.

Given Delta’s elite genetics, the standard dairy reproductive plan of action would have been to use his first semen to sire sons as part of contract or partnership matings, and then release him in both sexed and conventional semen to the general public. But senior STgenetics® management opted to offer Delta exclusively in female sex sorted semen straight to the public market. Dairymen jumped at the opportunity to use the 15-month-old elite sire on their herds, enabling them to increase the genetic progress of their herds.


Just a year later, Delta’s first daughters were occupying top spots on the index charts through genomic evaluation. His genetic profile has remained stable over time. His young daughters are very popular at high profile sales and auctions and favorably regarded to be donors and dams of multiple offspring.

“I saw thirty fresh Delta two-year-olds today. I have never seen a more uniform group of heifers by one sire,” said Jerry Jorgensen, of Ri-Val-Re Holsteins, in March 2017 after touring dairy herds in the Midwest. “They are well balanced, clean boned, square rumped with welded on udders. Big things are coming from this bull. He is the complete package.”

With this past August’s genetic summary, Delta added to his proof data from 400 milking daughters and 150 classified daughters.  His +2849 GTPI makes him the #1 proven sire in the breed and the only one above +2800 GTPI.  Delta is also #1 for NM$ (+951), MACE LPI (+3410) and MACE PRO$ (+2926).

Delta continues to be a major influence in the dairy industry. Many A.I. companies now offer their most dominant genomic sires exclusively in sexed female semen. What was once a vanguard marketing strategy, developed especially for Delta’s semen, is now a common industry practice.