The domino effect. Who can't start it? Who can't visualize it? Place a set dominos in a line, nudge the first one and watch a power from within cause the entire line to tumble toward an end. Or, in cattle breeding, a change in sire breeds can create a cascade that changes everything from cow to carcass. The change has to occur-for better or for worse.

To illustrate how the domino effect works in cattle breeding, I have set up a computer herd-a hypothetical model. The charts that make up the accompanying table show you a number of things revealed by this model. In a horizontal sense, you can see how a change in sire breeds dominos through your cowherds over time as you replace cows with herd-produced replacement heifers (top chart). And, you can see how these changes domino horizontally through your calf crops, changing their breed makeup over time and making them look more and more like their sires.

But the really important thing here is not the horizontal domino effects in the cowherd and the calf crops-it is the vertical domino effect that ends up affecting the carcass makeup of your calves. This is the central point of the series of columns I have been doing on crossbreeding for the grid era.

The point I have been making in these columns is that changes in bull breeds shouldn't be made just to make calves heavier, leaner or trimmer. Above everything, sire-breed changes should be about carcass-about creating that combination of quality grade, yield grade and retail yield that is optimally rewarding when carcasses are priced on the grids. These are being called 70-70-64 carcasses-carcasses that are 70 percent or better Choice and Prime, 70 percent or better yield grade 1 and 2, and 64 percent or better for retail yield.

The bottom chart in the accompanying table shows that the parent animals in this breeding plan fell short on the quality line in producing 70-70-64 carcasses. This is because the breed mix of the parent animals, sires and dams, was not weighted heavily enough on the quality factor. So what could be done to correct this deficiency? I think you would be as intrigued as I was about how this result can be changed by changing things in the spreadsheet-breeds, breed percentages, breed strains. I was easily able to hit the quality grade target without changing breeds. I just changed the values for just two of the four breeds involved. This would be the equivalent of changing to higher quality strains within these breeds.

I realize I haven't fully explained all of the methods I used in this analysis. But I am encouraged by how my computer model works. It gives me a tool to go beyond my gut feelings in seeing the domino effects of breed changes in any situation-with any battery of bulls and any set of cows. It goes without saying that I would be glad to answer any questions you have.

I hope that I have at least contributed positively to your insight into the domino effects of breeding decisions. The important thing to remember is that your decisions will produce a domino effect, either for the better or the worse.

To contact Fred Knop, write Drovers or send e-mail to fredlyn@aol.com