Dairy Cattle Genetics: Are we breeding cows for the correct environment?

Thursday, August 30th, 2018

What does a bull’s daughter profile reveal? A description of how the daughters are expected to perform in an intensive barn-housed environment. That works for temperate climates where there is winter, machinery for harvesting forages and cheap fossil fuels. However, what about areas, where only grasses can be grown? Are today’s dairy genetics suited for heat, new bugs and grazing?

The World is Changing

Our dairy cows, developed in north central Europe, operate best in temperatures -20C to +22C ( -5F to 72F). In the 21^st century, there are many new factors at play as we breed cows for a variety of environments. Some of these factors include:

Climate Change: Predictions are that North America will be 5F warmer by 2050. Dairy cows, like humans, will need to be able to operate optimally at higher temperatures. It will be a significant added cost to keep cows cool for more than half the year. Heat resistance in cattle will be an important characteristic in the future.
Land Use: Around the world land for cities is gobbling up vegetable, grains and fruit lands. In turn those crops will push forages for livestock on to land only suitable for grasses or pasture.
Regions of Population Increase: The next 2B people, bringing the world to 9B, will be in Asia. Dairy cows there will need to be able to pasture the hillsides and floodplains.
Diseases / Insects Resistance: Hot climate and non-temperate climate diseases and insects will add stress to a cow’s life.
Fossil Fuel Usage, Machinery and Technology: All of these will become costlier. This will have a significant effect on farms without high cow/heifer numbers. The current trend to replace the cost of labor with technology will continue. Many producers will have cows harvest the forage instead of machinery doing it.
Consumer Opinion / Support: The world is no longer about farmers producing food and consumers accepting what is in the store. Consumers are making their needs and requirements known and, in the future, will put many more stipulations on the food they buy. Sure, the milk will be wholesome, but animal welfare, use of drugs on animals, feeds fed to cows, natural environments and many more items will be dictated by consumer understanding. The customer is always right, and they will only buy products that meet their specifications.

As with all things, it comes down to economics. The need to include and the relative importance of these and other factors in genetic indexing and breeding schemes will take time to become a reality. Cows will need to take care of their needs by themselves as much as possible. That also includes nutrition, health, welfare, … and intelligent robots everywhere.

Breeding Must be Ready

Our one-size-fits-all dairy cows are not ready for coping with and prospering under some of the above and other factors. It will take planning and implementation for dairy cattle breeders to be ready with adapted breeds or blood lines. It is hard to look long term when the current cost of production (COP) is not being exceeded by farm gate price in many dairy countries, but the future COP on dairy farms must be addressed by both progressive breeders and breeding organization. First come the ideas, then the research, then the development and finally the application.

A Breeding Goal – A Cow that Manages to Her Own Needs.

We already are breeding for the cow that, on her own, visits the milking machine. Now can we breed the cow that harvests her forage, resists diseases and infections and does it at optimal levels when the thermometer reads 90+F (32+C). Oh yes and she needs to do all that and get back in calf within 80-100 days after her previous calving.

Currently we do not have farm data to use in developing genomic ratings for sires and cows for their ability to forage and exist in tomorrow’s hotter world. So, it will be some time before we can rate and select animals genetically for the traits associated with grazing and a warmer planet.

Some genetic matters that are being worked on include: Slick hair gene, where animals with that gene cope better in hot climates; Tick resistance has yet to be successfully introduced into dairy cattle; Fertility (cow and heifer) is presently receiving much research study; Calf livability and scour resistance is being worked on but with only very limited farm data it is almost impossible to genetically rank sires for these matters. Without devices that attach to cows it is not possible to measure intake for pastured animals. Information on feed conversion efficiency genetic indexing for animals consuming harvested forages was covered by the Bullvine (reference) but that is for machine harvested forage not for grazing animals.

Information Currently Available to Breeders

Health and wellness genetic ratings have become available for milk cows in the past 3-4 years and for calves and heifer in the past year. More health and disease will be added in the future.

That still leaves research into which sires are genetically the best in terms of heat resistance and forage intake from pasture.

Regarding the ability to cope with tropical temperatures relatively little new information has been found to help breeders. Some breeders rely on their understanding of added body capacity for lungs, solid red color, crossbreeding (i.e. using the Gyr breed from India) and raising heifers at higher altitudes to develop larger lungs. There are no sire indexes for breeders to use. Research needs to be done and field data captured so that more is known on the genetics of dairy cattle coping with tropical conditions.

On the matter of which sires produce daughters more suited to grazing, there are currently three indexes provided by organizations. These indexes are:

GM$ (Grazing Merit is published by CDCB) – it includes the same traits as NM$ (Net Merit) but puts 253% as much emphasis on fertility, 85% as much emphasis on production traits and 59% as much emphasis on PL and LIV as NM$ does. The AIPL-USDA research shows that grazed cows need to calve annually, do not need to produce as much fat and protein volume and have fewer longevity and livability problems as compared to housed cows. As in NM$, higher milk volume, higher SCS and higher body weight all receive a negative weighting in GM$. The trait emphasis for GM$(2018) follows:

GM$ = 38% Yield* + 24.5% Fertility* + 16% Type* + 13.5% PL/LIV/Health* + 3.5% SCS + 4.5% CA*

(* indicates that a number of traits are combined to create the category. Calving Ability is 4 traits related to calving.)

Table 1: Top Ranking US Holstein Sires for GM$ (Grazing Merit)

Daughter Proven Sires			Genomic Sires
GM$	NAAB Code	Name	GM$	NAAB Code	Name
893	203HO1468	Delta	1016	551HO3529	Charl
880	29HO17553	Josuper	990	11HO12174	AltaExplosion
874	7HO12600	Modesty	975	11HO12157	AltaLawson
827	151HO0681	Rubicon	972	29HO18611	Skywalker
827	151HO1602	Director	947	29HO18682	Colorado
815	1HO10396	Cabriolet	939	29HO18693	Crimson
797	7HO12266	Yoder	935	1HO13404	Samsung
787	7HO12021	Ponder	932	29HO18708	Kenobi
785	1HO11327	Gatekeeper	932	29HO18296	Achiever
783	7HO13250	Jedi	916	29HO18633	Roxbury

GrazingPRO™ (Published by Select Sires Inc.) – SSI designates their sires as GrazingPRO™ based in their GM$ rating and requiring that the DPR is >+3.0, Stature is <+0.5, Fat% is positive and Protein% is positive.
GrazingPro™ (Published by Semex) – Semex designates their sires as GrazingPro™ and thereby Pasture Perfect for sires that will maximize component yield and put a focus on health and reproductive traits to ensure highly profitable, long-lasting animals with limited problems. These sires will also produce easier calvings and darker colored calves.
Outside of North America both Ireland and New Zealand prove their sires on grass-based feeding systems so their EBI (Ireland) and BW (New Zealand) indexes rank sires with consideration of grazing.

The Bullvine Bottom Line

Dairy cattle being fed on grazing systems and living in warmer and warmer climates will be part of our industry’s future. To date there is only limited genetic information, based on assumed trait emphasis, available for breeders to use if they choose to graze their cattle or farm in regions having heat and humidity. Research and genetic evaluation centers need to address these topics.