After working for an electrical company, Lyle Smith decided to buy a farm and started milking 70 cows in Winona County, Minnesota in 1973. He slowly started building up the herd, and when his son Dean joined him on the farm in 1995 after graduating from college they were milking 150 cows.

They gradually expanded the herd to 300 in 2002, and in 2007 they bought in with a neighbor that was milking 150 cows at the time, building a brand new state-of-the-art cross ventilated barn and expanding the herd to 1,000 cows. Just a few short years later they bought out their neighbour, and today the partnership consists of Dean, his brothers Greg and Randy, who also grain farm and supply the feed for the dairy. D&D Dairy LLP is a Holstein herd being milked on two locations, with the two-year-olds on the original home farm and second lactation and older cows in the new cross ventilation barn.

Smith’s philosophy of breeding for profitable cows and selecting for health in genetics is what led him to conversations with his Semex team about Immunity+™ in December of 2012.

“I know there are cows in my barn that I never see and I don’t know who they are because they never have a problem and they are paying their way,” said Smith. Before using Immunity+ sires he was selecting for Productive Life, Daughter Pregnancy Rate, Somatic Cell Count, Protein, Fat and Net Merit. Looking at each figure individually, while trying to find bulls to meet his criteria overall.

“Immunity+ bulls show a great balance of everything I was selecting for before, but now I have the science behind it to prove the health traits more accurately,” Dean says. “I am also more comfortable with the 25% heritability of Immunity+ than just Productive Life and other health traits alone. This will speed up the rate at which disease resistance is built up in my herd. Proven science is more attractive to me than a calculation.”

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