Grass-fed vs. grain-fed is a never-ending debate in the cattle industry and I have heard many different arguments on both sides. I will try to stay neutral in this article because I think that the natural biology of the rumen has a lot to say about the topic. As you know, I try to follow nature’s model as much as I can.
It is natural for ruminants to get a little bit of starch in their diet. Some plants go to seed and the animals like the seed heads. Therefore, our management of ruminant animals might be to limit the amount of starch fed, but not necessarily eliminate it. Maybe that little bit of grain is important for the animals just before heading into the dormant season. Let me explain why I am stuck in the middle.
I would like to introduce a rumen metabolic process to you. It’s not new but very few people know about it. The term “metabolic welfare” describes a process that occurs in the rumen. I first heard the term from Dick Divon many years ago. His knowledge on livestock nutrition was incredible. Dick passed away a number of years ago and it was a huge loss to our industry.
I also ran across this term in the Ranching for Profit school but both sources were very brief on the subject. You can’t Google it. Nothing comes up. I am here to tell you that there is not a lot of information out there on metabolic welfare and today, I have more questions for you than answers.
I am not a scientist, and there has been very little research done on this topic, so take this with a grain of salt. I hope that this article will be a conversation starter that might lead us all to a source of information about it. I might not have all the details lined up perfectly, as most of this is going off my memory and from my notes scribbled in the margin of my old course materials. Please feel free to contact me if you have any information about this topic. Positive or negative, I would be interested. Maybe this column will stimulate a research project on metabolic welfare by someone, somewhere.
In my mind, the debate with grass-fed vs. grain-fed is about the change in the rumen that the higher-starch diet (grain) causes. It’s simply a chemical change inside the rumen. According to my notes from Dick Divon’s school, by feeding more than 0.4 per cent of the animal’s body weight in grain, the pH of the rumen changes because of the breakdown of starch. This alters the microbial populations within the rumen, causing the microbes that digest starch to increase and the microbes that digest forage to die off. This is the point when the animal goes into metabolic welfare because the additional nutrients provided by the grain results in a loss of nutrients from the forage out the back end.
In real life terms, for a 1,200-pound cow, this 0.4 per cent would be at about 4.8 pounds of grain per day in her diet. At this point, for every pound of grain increase to the diet, you lose more of the nutritional value of the forage. In other words, every pound of grain you pay for, more nutrients from your hay gets wasted out the back end. According to Dick Divon, this welfare state continues until about 0.8 per cent in body weight (9.8 pounds for our 1,200-pound cow), where it levels off and then the additional grain means additional gain.
In other words, the first five pounds of grain gives you added gains, but if you bump up your grain in the ration from five lbs./day to six lbs./day, there is no additional gains and you wasted your money. It carries on with pounds seven, eight, nine and 10. For every pound of grain added, more nutrients from the hay are deposited on the ground.
After 10 pounds, they go off welfare again and for every dollar of grain you add to the ration, your livestock will gain more and your money is better spent. There is just no net gain with pounds five through 10. My take-home from this was that feeding my cows less than 0.4 per cent grain was perfectly fine. I just don’t want to go higher.
Now this leaves me with more questions. Is this 0.4 per cent of grain also the point when the reduction in essential amino acids occurs in the “grass-fed” argument? Are those bacteria that die off needed to convert the nutrients? If you are not familiar with this concept, there has been research done by scientists like Dr. Richard Bazinet from the University of Toronto which shows a nutritional difference in pasture-raised meats. I would love to have Dr. Bazinet out to a conference again sometime soon so I can grill him. I missed him when he was here in Alberta a couple of years ago.
So, here is one version of the grass-fed side: Pasture-fed meat can be higher in beta carotene, calcium, selenium, magnesium and potassium, and vitamins E and B, and conjugated linolenic acid (CLA) — a powerful anti-carcinogen. The big one, however, is the higher levels of the long-chain omega-3 fatty acid DHA, which is vital for human brain development.
I know that CLA and omega 3s are essential amino acids that our bodies cannot manufacture, so they need to be consumed. Omega 3s are produced by the chloroplasts of the plants and are then converted by the livestock into a usable form for us to consume. Omega 3s are a big deal in the health food world. You know it is a big deal when you start seeing the “omega 3 enriched” claims in the grocery store.
What causes this change? Why is the grass-fed meat higher in these nutrients? Is it because of the metabolic welfare? I am just trying to put two and two together. Like I said, I have more questions than answers.
Does it matter what type of grain we’re feeding? Dick Divon stated that feeding peas is better as the starch does not break down as fast. I have also supplemented malt sprout pellets before because those supposedly do not change the rumen nearly as much as they are technically not the grain. I fed a 50:50 pea/malt sprout pellet supplement a few years ago, but I still stayed at five lbs./cow/day to prevent the change in the rumen. Where is the research on this? What about barley vs. oats? Does it matter if and how the grain is processed? If it is rolled vs. hammered? Does it really matter what they are fed as a calf or is the finishing diet the important part? I was also told that finishing on growing plants was essential to the nutritional benefits of grass-fed as hay will not give you all of the same benefits as a living, growing pasture will. This is why I always try to butcher in August or September off high-quality pasture. Does it matter? If you butcher your grass-fed animal fed high-quality hay in February, is it lower in nutrition?
More questions lead to answers that lead to more questions. I wish Dick was still around as I am sure he could answer most of these questions for me. Google totally failed me on this one.