maximization vs. optimization (or, why I am not a sheep farmer)

Ross and I just returned from the Dairy Sheep Association of North America's annual symposium in Albany, NY. We were really excited about this conference, about the schedule planned, the networking opportunities, the things we would learn. Most of the farming conferences I have been to are charged with excitement: people are learning and exchanging ideas, loudly criticizing or praising speakers, and making new friends. Albeit, this was largely the case here, but to be blunt, I felt like an outsider. I had expected a degree of this feeling, considering the fact that Ross and I are dairy novices, but with that, I also expected that the veterans out there would be excited about bright, new, young farmers working their way into the fold. Unfortunately, this was not the case. There were several reasons for this, first, numbers: there are only some 150 sheep dairies in the United States. Not all of these folks attend conferences, and those who do have known each other for years. Because of the smallness of the group, it felt very hard to make inroads and get to know folks, which I understand, but was disappointed by. The second reason was something of an eye-opener. In the past, I've attended farming conferences that were ideologically driven; folks come because they believe in organic/sustainable/local/insertothermichealpollanesquebuzzwordhere agricultural practices. At the DSANA Symposium, the primary focus is sheep and cheese, not an ideology. As such, the presentations tended to centre around the concepts of maximizing production at lower cost and time inputs. Lectures included discussions of feeding dairy sheep spent brewery grains (including the purchase of a large, expensive, mechanical press to squeeze out moisture and excluding discussion of clostridium and listeria issues linked to these types of feed), the benefits of using a new hormone insert made by Pfizer that sychronizes estrus in ewes (with minimal discussion of how this can be done by simply staggering the introduction of a ram across a fence, which takes more time, but does not require that you purchase a drug), and a lecture on the effects of prepubertal lamb nutrition where lambs were fed huge amounts of grain and TMR in the study. The lecturer, Dr. Dave Thomas, who conducted the research, showed a photo of lambs eating all they wanted of a TMR, so much that they were lying down, eating, and who's distended bellies were, to use the lecturer's words, "tighter than a tick." The audience laughed. I cringed. It was all I could do to not explode with anger and frustration. Here's why.

On the other side of the world from these lectures was one given by Dr. Darrell Emmick, which was sponsored by the good folks at ATTRA. His presentation was terrific. Dr. Emmick is currently conducting research on natural bahvior-based livestock management and the benefits of allowing ruminant animals to have free choice of forages on pasture. In his talk, he outlined how cows and sheep tend to choose the foods in a pasture that optimize their overall health and productivity. The crux of his argument is that the typical animal management systems operate under the assumption that an animal is a machine: it is a known entity that has known and measurable needs in order to maximize performance. TMZ is therefore a perfect food that meets all the health and nutrition requirements for an animal. Emmick then constructs an argument that clearly articulates how this is a flawed assumption. Animals are in fact much more dynamic in their nutritional needs. His argument is that animals are individuals, each one has its own specific genetic make-up and its own specific behaviors, some instinctual, most learned. As with humans, no two sheep, cows, goats, llamas, horses, buffalo, whatever, have the exact same food preferences. Some of these preferences are learned, others are driven by genetic responses, such as allergies. Furthermore, as with people, animals do not typically enjoy eating the same foods day after day. Given the choice, people will stop eating the leftover Turkey from Thanksgiving before it's all gone. The body grows tired of eating the same food; the nutritional requirements that food can serve has been fulfilled, and now the body craves something else. Animals are no different. Dr. Emmick is not simply anthropomorphizing. He spends days at a time sitting with animals, watching them eat pasture, counting chomps, recording what they choose. His research demonstrates that grazing animals do not eat any one kind of food. Instead, animals forage for the foods that balance their needs for energy, protein, and other nutrients. So, for example, if you feed a high-energy grain or other supplement in the barn during milking, the animal will be dis-inclined to consume more energy-rich pasture plants and so will have decreased total dry matter intake, risking malnutrition and increasing the need for further supplementation. On the other hand, if one were to feed a protein-rich feed in the barn, the animal would still intake pasture because it is more energy rich during the milking season (spring and summer), but still contains protein. As a result, the gut of the animal converts excess nitrogen from protein into ammonia that then uses the animal's energy and water consumption to flush-out the ammonia instead of making milk. To further explain this phenomenon of adept animal food choices, I quote directly from materials on Dr. Emmick's website. Farmers know that clover is one of the best foods to have in a pasture: cows love it, sheep love it. The problem arises when ruminants eat too much of it and they get bloat, a sudden and fatal condition when the fermentation processes in the rumen becomes over-active. Turns out, these critters know what to do about it if they have diverse pasture species to choose from:

Looking Over Clover

Sheep in the United Kingdom prefer to eat clover in the morning and grass in the afternoon, even though clover is more digestible and higher in protein than grass. Why? Animals prefer highly digestible foods because the delay between beginning to eat and nutrient reinforcement is short and the amount of reinforcement is high. However, if animals eat too much of a highly digestible food, and rates of fermentation are too high, they become ill and begin eating less
digestible foods. When the immediate positive postingestive effects of nutrients are then followed by mild illness, the pattern of intake becomes cyclic: gradual increases followed by sharp declines. The more familiar an animal is with a food, and the greater the positive feedback from nutrients, the less likely the animal is to acquire a lasting aversion. This response is characteristic of nutritious foods like larkspur, which contains toxic alkaloids, or rapidly fermentable foods like grain (high in carbohydrates) and some pasture forages (high in protein).

This helps explain why sheep in the United Kingdom eat clover in the morning and switch to grass in the afternoon. Hungry sheep initially prefer clover because it is highly digestible compared with grass. As they continue to eat clover, however, sheep satiate—acquire a mild aversion—from the effects of soluble carbohydrates and proteins and from the effects of toxic cyanogenic compounds. The mild aversion causes them to seek the less nutritious grass, which is lower in nutrients and toxins, in the afternoon. During the afternoon and evening, the sheep recuperate from eating clover, and the aversion subsides. By morning, they’re ready for more clover.

Indeed, this is how animals self-regulate against bloat, caused by a diet of foods that are too rich. If Dr. Emmick's observations are correct, and I think they are, then the only reason and animal should bloat from eating too much clover is when there is not enough other stuff too eat. In addition, animals on pasture also know about medicinal plants. Dr. Emmick mentioned in his talk that dandelion has a chemical in it that calms the development of gas in the rumen. He said that he has never heard of a case of bloat in animals where pasture had both clover and dandelions.

Another somewhat alarming example came when Dr. Emmick showed us a photograph of a cow actually consuming a small rabbit which was documented by Dr. Michiel Wallisdevries and first appeared in the Journal of Applied Ecology.

What the heck is going on here?! Cows aren't supposed to eat meat!!! But here it is. Once again, biology shows us that in the natural world there is no such thing as "always" and "never." These cows were deficient in phosphorous due to poor pasture. Mammal bones contain huge amounts of phosphorous. Do you see where this is going yet? The rabbits would die of natural causes, leaving behind their bones. The cows would curiously eat some of the bone while grazing on the homogenous pasture. Post-ingestive feedback inside the cow lead it to gain interest in the rabbits themselves in their attempts to access their bones and the phosphorous within.

Dr. Emmick got me thinking about the prospect that all animals are omnivores to a certain extent. All animals fall on a spectrum of preference that is much more dynamic than the reductionist "these animals eat plants," "these eat meat," and "these eat both." The truth is, we all eat whatever it takes to get what we need. Sure, some animals prefer meat, others plants, but the reality is that life finds a way to get what it needs to perpetuate itself, regardless of human-made, superimposed distinctions. Even within the domain of "plants" there is so much variety and diversity of what any one speicies will eat that reducing herbivores to mere "plant-eaters" seems ludicrous. They are timothy grass, big bluestem, gamma grass, birdsfoot trefoil, white clover, fescue, dandelion, pigweed and about 100 other plant-eaters. What all animals, humans included, have a stake in is diversity. Nature abhors a monoculture. Polyculture, the many, not the one, is the source and sustenance of life.

These examples are only the tip of the iceberg when one stops to consider how many variables there are to consider in working with an animal to optimize its nutrition. The moment feed is introduced to the animal, pasture intake is affected. One woman asked, "how is this information useful unless we are constantly taking protein and energy samples from our pasture? How are we to know what to feed them in the barn or if the pasture itself is giving them enough?" It's a good question, but one that is ultimately confined to the realm of working to control for the sake of maximization. To her, the animal was still a machine, just an infinitely more complex one, too complex to continue managing like a machine. There is something else in order here. The beauty of grass-based systems is that as the animals eat and move on, never destroying the whole plant and always leaving behind rich fertilizer, they prune for stronger regrowth of existing plants and prime the soil for new plants to take root. Therefore, the plants your animals like best (the only ones they are given time to eat) get pruned and become more robust, pushing out less desirable foods, while new foods are finding their way to the well-fertilized soil. Biodiversity, more forage choices, yield healthy, strong animals that need few, if any, inputs. The farmer, need only manage, not micro-manage, what nature already does.

The biggest issue here is the distinction between two schools of thought: maximization and optimization. Many of the folks at the DSANA conference come from the maximization perspective. It's what they were taught, what they know best, what they trust. More in equals more out. While that's true, it is only true to a point. Scale becomes a confounding factor. If you are an industrial-scale farmer, with thousands, sometimes tens of thousands of animals, you're always going to get a lot of meat, milk, or whatever you're producing. As a result, you can afford the equipment, medication, and infrastructure it takes to be successful. Indeed, you need them to function at all. However, if you are a small-scale farmer, with maybe a few hundred animals at most, industrial systems of management and care, though they may maximize production, cost more, and ignore resources that are already plentiful and free. Perhaps the animals will not maximize their capacities for meat or milk, but odds are, they will optimize them, minimizing cost and work for the small farmer. A simple chart illustrates the point:

In this chart, we see that the animals that had free choice ate less, cost considerably less to feed, and gained the same weight in the same number of days as the TMR fed animals. Why would a small farm, highly concerned with cost inputs and completely capable of managing pasture because of its small-scale, ever want to feed out TMR?

It was hard for me to believe, but as I spoke with Dr. Emmick, he told me that there were people at the conference there who hated him; thought he was batty, and who couldn't understand what he was on about. His thinking is the minority viewpoint. I was stunned. My eyes were totally opened. It made me sad to a certain extent. Most of these dairy farmers do what they do because they love these animals. They really, emotionally care about them, give them names, pet them, and take amusement in their quirky, individual behaviors. Yet, these sheep lovers ask their animals to behave in ways that aren't in their nature, that are more likely to make them unhealthy, and that harm the economic viability of the farm, making maintaining it more of a struggle than it should be. It's a delicate issue. Folks on either side don't take kindly to criticism. But ultimately, it is a fundamental issue of perspective. On the one hand and one we have a point of view that revolves around an adherence to a philosophy of which the animals are a part, and on the other, a straightforward love and enjoyment of the animals for themselves. The question that puts you on one side or the other is, are you farming because you love sheep with their wool, meat, and milk; or do you love nature, natural processes, and see the sheep as a way of caring for nature and the land? In the end, this is why I have had a lot more fun at other conferences: I am an ideological farmer, a grass farmer, not a sheep farmer.