How important is genetic selection to a grazier?

Dairymen who have transitioned from free stall confinement to rotation grazing, will tell you “grazing”  adds a year to the average cow’s productive life.    Likewise, the “hybrid vigor” for health and fertility traits from a first generation of crossbreeding will on average add a year to the cow’s productive life.

An extra year of production (which produces an extra calf from each cow, with successful breeding) generally means the grazier no longer worries about keeping his milking cow barn full.   So there is the mistaken belief, shared among many in grazing circles, that you can skip AI and just buy bulls anywhere and stay profitably in the dairy business.

But the physical vigor, structural mobility, and ruminant/abomasal capacity, combined with easy body conditioning, that optimizes a dairy cow’s productivity under grass-based dairying cannot be preserved from random mating or indiscriminate crossbreeding.    The productivity benefit in cross-breeding has a history of peaking with the third-breed cross,-- likewise the fertility benefit from crossbreeding has a history of plateauing quickly when in a two-breed rotation.    And in any generation, the “wrong” bull can give you undesirable traits in udder balance or texture, teat placement or shape, feet or leg structure, or pelvic calving capacity—that cost you extra labor, breeding, or veterinary expenses, or just put a “glass ceiling” on cow milk production.     So you will still be producing cull cows in every heifer crop.