Genetic Evaluation is only thinking “pounds per cow”
If you are milking cows inside a barn all year long, feeding stored fermented feed all year long, and your barn has a limited number of stalls – you likely are thinking in terms of “pounds per cow”.
In other words, your dairy design cannot add more cows to generate more income without added facility investment, but if the cows milked more your income would likely be more, and you can always buy extra feed. Grain is of course the easiest feed to buy for dairy cows, so you feed more of it.
Conventional dairying as above generates more milk because the technology has evolved for decades to support that design—but financial data shows the average of conventional dairies operate on higher costs per cow.
However, if you are grazing …
Seasonal calving to follow the growth of grass species (spring first and fall second, in our climate) can utilize a variable number of cows to harvest the fresh grass, with housing only an issue for winter months.
In grazing, the focus is “how many acres can I get to grow how much grass (nutrient energy)?” The key to more income in grazing is in “how much milk per acre will this pasture produce?” The better grasses produce more milk per acre than traditional row crops, while cows will need less grain.
Sire selection in a grazing environment
Do we really need a “different” cow for grazing than we do in confinement? Maybe. Not necessarily. The only certainty is “higher natural fertility”.
Geneticists are getting challenged on this, so the latest fad is “grazing index” which puts more emphasis on fertility and SCS than all other indexes.
What would ultimately be better, however, is a way to identify genetics with flat lactation curves. Grass may not support high “peak” yields of ranking genetics, but it will support the full season of productivity you can get from a healthy, naturally fertile, heat resistant, “flat curve” persistent dairy cow.
Breeds originally developed by geographical segregation and fit their region of the world. All dairy cattle in the USA originated elsewhere in the world, mostly in Northern Europe, and were genetically selected in phases to match the development of our milk markets (fluid volume and butter first, protein products after) AND our feed growing abilities. Breeds developed on grass alone have different lactation curves from those developed with added feeds. Over time, one size fits all genetic evaluation approaches have diluted breed differences as geneticists focused on the higher input dairy model.
Persistency data from Canada ranks the breeds as follows: Jersey, Holstein, Guernsey, Brown Swiss, Ayrshire, Shorthorn, Dutch Belted. Within that data are buried individual sire differences that would help graziers. If we only select on fertility measures and health traits, we can lose persistency.
Today there is more difference within (most) breeds in individuals than there is between breeds in overall selection characteristics.
This can be “proven” “scientifically” by realizing that 90% of all bos taurus breeds of cattle have nearly 90% of their genotypes in common.
The simple point is, good breeding is where you find it when you need it. The country of origin for the sires you use is not the only determinant of grazing fitness, to the exclusion of everything else we know about genetic selection. Each new generation may have different mating needs.
If you transitioned conventional AI bred high genetic Holsteins to a grazing environment, it should have been clear that “index rank” under USA genetic evaluations did not fit what you needed. Instead we just blamed the breed. Real genetic differences are identified by comparing individuals—and not all USA bred cows were failures at grazing (witness Jersey breed growth). In “aAa” terms, the “round” cattle in each breed did fine, while the “sharp” cattle in any breed have failed when asked to convert from TMR feeding to grazing. As your soils develop to produce more grass, and we use higher feed value grasses in more adept rotation, cows more able to milk can also stay healthy and breed back.
The “balanced” physique (between “sharp” milk characteristics and “round” health characteristics) is going to always be the most productive, no matter whether it is grazing season or winter barn season, no matter what breed(s).
The industry’s fixation on “genetic ranking” obscures this basic truth.