Hybrid dairy cattle and systems for maximizing hybrid advantage

A method of maintaining an F1 hybrid crossbreed herd of dairy cattle comprising steps of:

• implanting an F1 hybrid crossbreed embryo into each of a plurality of F1 female dairy cattle, wherein each of the F1 female dairy cattle resulted from a first F1-selected crossbreed cross, wherein an F1-selected cross is one that involves fertilization of an F0 female gamete with an F0 male gamete, wherein the F0 male and female gametes are from different breeds;
• and
• one or both of the F0 male and female gametes is from an F0 individual or line selected based on one or more improved performance characteristics of prior F1 progeny generated in crosses of the same individual or line;
• wherein each implanted F1 hybrid crossbreed embryo results from a second F1-selected crossbreed cross.