Animal Benefits of a 100% Forage Diet
The statement that cattle were made to eat grass is substantiated by too many obvious reasons to ignore. Let’s have a short discussion on the physiology of the cow and its digestive tract.
The cow is an animal with four compartments to its stomach, the largest of the four is the rumen, thus these animals are called ruminants. Sheep, goats, bison and deer are other examples of ruminants and this information pertains to them also. The rumen acts somewhat like a large fermentation vat. Inside this vat are bacteria and protozoa that are cellulolytic, meaning they are able to digest cellulose, the major component of plant cell walls. The host animal, in this case the cow, provides the environment for these microbes and they in turn aid in digestion of plant components that the host could not otherwise utilize. These microbes also continue down the digestive tract of the animal where they are digested as part of the protein in the animals diet. Monogastrics, or single stomached animals like humans and pigs don’t have this symbiotic relationship going on to this extent and cannot make good use of the type of plants that cattle typically eat.
So in cattle, particles of food are bitten off, masticated to some extent and swallowed. Once a ruminant has eaten, it will go and peacefully stand or lie down while it “chews its cud”. I say peacefully because if one is doing it’s “cud chewing” it is at ease. The “cud” is actually a portion of regurgitated food that needs shredded into smaller particle for effective digestion in the rumen and beyond. The importance of this is often not noted. The long fiber in a ruminant’s diet causes the need for cud chewing. During this process large amount of saliva are produced and swallowed. Saliva in cattle has a pH of 8.4 to 8.7, very basic or non acidic; however, you want to look at it. This is very important to a healthy environment in the rumen for proper digestion, for both the microbes and for the animal’s health. In a feedlot situation where starches from byproducts or grain feeding make up a large portion of the diet, digestive upsets from acidosis are a major problem.
When corn and soy products make up the majority of the finishing diet in cattle, very little forage or fiber is fed so cud chewing is minimal and only small amounts of saliva are produced to buffer the rumen. When rumen pH drops below 6.0, fiber digestion is hampered by the loss of cellulolytic bacteria that cannot survive at these unnaturally acidic rumen conditions. Low rumen pH can cause diarrhea and stomach aches and over time can induce lameness and liver abscesses. Low levels of antibiotics are constantly kept in the diets of many feedlot finishing cattle to keep the animals from going “off feed” and also reducing various other health maladies. Therefore, cows eating grass are eating their natural and healthy diet. Those with the proper genetic makeup can also add marbling to their muscle for great tasting, wholesome beef without the need to feed any grains.