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Best cows have traits that help them efficiently convert grass into nutrient-dense foods for people.

January 24, 2013

4 Min Read

By Walt Davis

In general, the most profitable animals for grazing operations will be the ones with the physical traits that allow them to be effective ruminants.

Ruminants such as cattle, sheep, goats and water buffalo have long been valuable to humans because they have the ability to convert material with low nutritional density – grass – into food with high nutritional density, primarily meat, fat and milk.


Theoretically, people could live on a diet of grass. Everything needed by humans is present in grass: proteins, carbohydrates, fats, vitamins and minerals. The problem comes in the concentration of these materials. The human body is not capable of consuming and digesting enough grass to meet its nutritional requirements.

Ruminants, however, have developed some physical adaptations that permit them to form a symbiotic relationship with other organisms – bacteria and other microbes – which allow both the ruminants and the microbes to thrive.

A functioning rumen provides a habitat that perfectly meets the requirements of its microbe partners. It has large amounts of masticated plant material, warmth, moisture and agitation – perfect!

The microorganisms get to live out their full life spans busily concentrating the nutrients from the grass into their bodies. However they live only a few hours. When they die they become feedstock the ruminants can digest to meet their nutritional needs.

Therefore, successful ruminants are those whose form follows function within a given environment; those with the abilities to gather and process large amounts of material that varies widely over time in density and in nutritional value.

Physical traits such as wide mouths, large bellies and small to moderate size are strong advantages to animals that must travel long distances gathering the large amounts of material needed, one bite at a time. The ability to take up to 30,000 bites a day when forage is sparse also permits the animals to consume more forage than is required when forage conditions are good.

This capacity to consume more feed than is needed on a daily basis combined with another trait – the capability to store nutrients as fat – gives ruminants the where-with-all to survive and even thrive in areas where forage growth is limited to small portions of the year.

It also gives a cow the ability to survive periods of drought and it gives her the readily available energy needed to give birth, start lactation, repair the ravages of birth and rebreed, all in a very short period of time.

The amount of supplemental winter feed she needs is a function of the quantity and quality of forage available but it is also a function of how much fat the animal carries at the start of the dormant season. Aside from fertility, the ability to get fat and stay fat on grass alone is the most valuable trait a beef cow can possess.

Enter man: For many years, we have actively selected for large animals and against the ability of animals to put on fat because the packers want a large carcass with very little fat cover.

We have been assured constantly by the "experts" that we must produce this kind of animal because "the trade demands it."

As producers, we have locked arms and marched to the beat of the packers' drum, shooting ourselves in the foot on every second step. Only in a world of gobblespeak would the easy fleshing, fertile and moderate sized animal be called "wastey."

I am not blaming the packers. They are only looking out for their interests. I do, however, blame the "experts" who are still advising cattle producers to breed ever-larger cattle that give more milk and have less fat. If these people are going to give advice to producers it should be advice that benefits the producers.

No one wins long-term by turning cattle into oversized grain eaters. The packers gain some short-term advantage but does anyone think the cheap grain that is needed to support this kind of beef production is going to be available in the future?

I think I am going to start looking for some of those "wastey" cattle that can both make it on grass and make a profit.

Walt Davis is a semi-retired rancher who does teaching, consulting and writing. He can be reached at [email protected] or

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