Nutritional Wisdom of the Body: Behavior-Based Management for Animal Well-Being
Presented by Fred Provenza, Acres Conference 2008
Written by Lisa McCrory
Added March 31, 2009. The areas covered in this article include: 1) Looking at behavior and realizing how relevant it is, 2) Identifying the processes and how they work and, 3) How we can take this information and use it to manage landscapes. Behavioral solutions cost little to implement on the farm. They are not fossil fuel intensive, and are easily transferable from one site to another. Creatures are adapting to their environment every day and it is up to humans to decide whether or not they want to participate in this process.
So, why do we do the things we do?
Behavior is based upon consequences; whether it is a positive or a negative reinforcement, we are all conditioned to respond to things in a certain way. But it is more complicated than that; each individual responds differently to a given stimuli. How does that happen? Genes are an important part of the make-up of creatures and how they behave, but an animal is also constantly interacting with social influences, and the biophysical environment. These interactions, which cause genes to be expressed, influence what the individual will do or how they will react.
First we will look at the chemistry of plants and how it influences the behavior of animals, the culture, and social influences on food and habitat selection. Then we will look at biodiversity and variety and why that is so important. Chemistry and biodiversity are interacting with each other all the time, and their interplay is critical.
So why do you like a particular food? Because it tastes good, right? But is it all about taste? Let’s look at a herd of goats that are offered a diet of nutritious new growth from blackbrush. The new growth is higher in energy, protein, and phosphorous than the old growth, but by itself, the goats are not interested in eating it. Why does the addition of polyethylene glycol to the diet increase the goats’ preference for new growth of blackbrush? Blackbrush is high in tannins, which is a secondary compound that binds to protein and causes food aversions in ruminants. Polyethylene Glycol binds to tannins and renders them inactive, allowing the goats to increase their intake of the blackbrush.
Another study has a group of goats in a pasture that is predominantly blackbrush and instead of eating these plants they are eating woodrat houses that are in their pasture. These fibrous houses are of lower palatability and nutritional value than the plants available in their pasture. So why do the goats in this study choose to eat wood rat houses? It turns out the goats were deficient in protein and inside the wood rat houses is a lot of vegetation that is densely packed and soaked in urine - which is high in protein. One goat discovered this protein source and taught the others in his group. Before long, they were all eating the woodrat houses. This is an example where information and culture passes on the behavior. Over a period of 3 winters with 18 different groups of goats, only one group figured out the protein source of the woodrat houses. If a goat from that one group, however, was introduced to one of the other 17 groups, then he would have taught the goats in this second group.
Palatability is more than a matter of taste. It involves feedback mechanisms traveling from cells back to the pallet telling us what we do and do not want to eat and is organic in its response to primary and secondary compounds (taste feedback loop). The way that researchers have studied this is to make animals mildly deficient in a nutrient to see if the animals can detect it in a ration - enhancing the feedback loop.
In some of Dr Provenza’s research, they have looked at post-ingestive feedback based upon primary compounds (protein, energy, minerals) as well as secondary compounds thought to be toxins like alkaloids (endopyyte infected fescue), terpenes (sagebrush), and tannins (woody species and forbs like Birdsfoot Trefoil and Sainfoin). What they are finding is that all compounds are interactive and palatability is related to the balances of the primary and secondary items. The more balanced or adequate it is, relative to the needs of the animals, the greater the palatability. None of these responses are conscious; they are happening automatically below the level of conscious awareness. All of this has implications for how people can work with animals on landscapes.
In one of their research trials, two groups of lambs were made mildly deficient in energy. On odd days, animals in group 1 got apple flavored straw for one hour and animals in group 2 were given maple flavored straw for 1 hour. After the meal, they were drenched with a quart of water, using a stomach tube. Groups 1 and 2 were then given the alternate flavored straw for one hour and following that meal, they were given a source of energy in a drench using a stomach tube.
Following these treatments, the groups were then given a choice between apple- or maple-flavored straw. The groups strongly preferred the flavored straw that was paired with the energy starch, even at only 1% of their energy requirements, and their preference became absolute at 10% of their energy needs. The flavor paired with the starch conditioned the animals to prefer a particular flavor; all they had done was change the feedback to mediate what the animals would do.
Understanding how palatability and plant biochemistry works:
Horses and cattle can be trained to avoid eating toxic plants, to eat weeds, or to avoid plants that they otherwise would prefer. Kathy Voth, who studied under Fred Provenza, has videos and other training packets, which can be found on her website: (www.livestockforlandscape.com). One video titled ‘We’d Eat It!’ shows you how to teach your cows to eat a number of unwanted pasture weeds such as thistles, leafy spurge, black mustard, and knapweed. One of the first things to do, of course, is to make sure that the plants you want your livestock to eat are not poisonous.
An example of how some sheep were trained can be seen at organic vineyards in California and Colorado. The owners were interested in using sheep to eat the under story and grass beneath the grapes, and they needed to find a way to make the grapes unpalatable The way they trained the sheep was to allow the sheep to eat some grapes, followed by feeding them something that causes nausea. The feedback loop was implemented, and the sheep left the grapes alone.
Livestock can also be used to rejuvenate landscapes. Sheep and cattle have been trained to increase their intake of sagebrush. Sagebrush provides critical habitat for soil, plants, and wildlife, but the shrubs have over populated in some areas, which in turn has decreased the volume of herbaceous plants, and reduced the biodiversity and habitat it once provided. Chemical and mechanical controls are costly and less desirable, and there are risks with burning. Researchers have found that one can train sheep and cattle to graze the sagebrush in the fall and winter using a high stocking rate complemented with a protein and energy supplement. The protein and energy supplement helps the sheep and cattle detoxify the toxins (terpenes) found in the sagebrush, which allows them to eat more of the plant. With this management, the sagebrush population is reduced. This in turn increased grasses and forbs, which increases the biodiversity and improves wildlife habitat for sage grouse and other birds.
There is one more angle to consider when trying toinfluence what an animal does and does not eat, and that is culture. A culture develops when habits contribute to the group’s success in solving problems, and cultures can change as individuals in groups discover new ways of behaving – such as finding new foods or habitats or better ways to select a nutritionally balanced diet.’(1) (Social Organization in Bison and Habitat Selection, www.behave.net/projects/range-bison.html)
A colleague of Dr. Provenza’s, Dr. Randy Wiedmeier, is a nutritionist who years ago was interested in feeding ammoniated straw to a group of 5 year old beef cows as a way to reduce the cost of feed over the winter (December – May). About 1 month into the study, half of the cows were performing very well, and half were not. The cows were all the same breed, so why was this happening?
The researcher had a technician who remembered that a bunch of the cows that were in this study were exposed to ammoniated straw earlier in life for a one month period of time. Body weight and condition was significantly higher for those cows that had that one-month exposure early in life. It took 3 years for the cows in this research group to show no difference in their eating behavior. When we change management, it takes time for behaviors to change. For soils it takes 3-5 years and things oftentimes tend to get worse before they get better.
Culture is a part of landscape
What does it mean for animals to be locally adapted to the landscape that they inhabit? It means possessing anatomical and physiological adaptations that they need as well as behavioral knowledge that enables survival in particular environments. Which foods to eat and where to forage are experiences early in life that have an effect on habitat preferences.
In domestic animals and wild animals, mom is the critical trans-generational link who adds stability, showing her offspring what to eat, what not to eat and where to go. Young animals (offspring) add creativity by exploring the unknown. They bring new behaviors to the group by trying other things once they have learned from mom what to do. This dynamic brings a balance between stability and creativity.
Experiences early in life increase intake of poorly nutritious foods and foods high in secondary compounds. Many research studies with cattle and sheep (cross-fostering studies) have shown that even animals reared by a foster mother will learn what to eat and where to go based on how and where they were reared.
The impacts of experiences in utero and early in life have been termed Predictive Adaptive Responses. These responses, which are induced by the environment where the animal is born and raised, cause changes neurologically, morphologically and physiologically that lead to ongoing adaptation to the local environment. An example of this type of adaptive response is shown in a study in Western Australia where the landscape is dominated by saltbrush. This plant is very high in salt and can cause toxicities. In utero exposure enabled lambs to be able to handle salt brush in larger volumes than lambs from mothers raised on pasture. They were able to excrete salt more rapidly, drink less water and maintain higher intake when eating saltbrush.
Fossil fuels have enabled people to select for animals that lack the ability to thrive on the foods and habitats in the landscape. Cultural knowledge of people and environments; knowing which plants are poisonous, etc. are pieces of wisdom that we as humans have lost. The same thing has happened with animals. It just makes sense ecologically and economically to match what an animal needs based upon what is on hand; retaining animals that can survive on the landscapes that you have: matching production cycle to forage resources; matching cow size and type to the forage resource.
Primary and Secondary Compound Satiety
Animals satiate on forages – they get sick and tired of eating the same old foods day after day, just as people do. Satiety is influenced by interactions among flavor, nutrients and secondary compounds. Nutrient-Specific Satiety research looks at the ratios of protein to energy in the diet and how they influence what an animal chooses to eat. An example of nutrient satiety research is the work that Darrell Emmick did in New York where groups of cows were supplemented with diets high in protein or energy in the barn and then took note of what the cows grazed when they went out to pasture. Cows fed a high-protein diet in the barn do not want to eat clover as it is high in protein and their protein needs have been met. Instead, they preferred the grass. Conversely, when the amount of protein fed in the barn is reduced, the cows eat much more of the clover.
Secondary compound satiety: All plants have secondary compounds that limit how much of any one food an animal can eat. As a result they are considered plant defenses against herbivory. In animal science literature, we have considered these compounds to be toxins and have selected against them so that the animal can consume more food. What researchers have learned is that there are a huge number of roles that the secondary compounds play that are critical for the health of plants and for our bodies and we need to step back and think of biodiversity versus monocultures and where that has brought us. Tannins, for example, are valuable in nutrition and health. They can decrease internal parasite loads and bind the compounds that create bloat. Birdsfoot trefoil is a good complement to a ration with alfalfa, because the tannins reduce the chances of bloat. Tannins can also bind protein and release it in a way that is better for the animal to absorb.
Complementary Species and Sequence
A diverse diet encourages animals to encounter certain plants that, when mixed with others can stimulate appetite and increase intake. French herders have come to recognize complementary species of plants that offer this reaction provided they are eaten in a particular sequence. This knowledge was gained while ‘out on the job’, watching their animals while they graze and has been passed down from generation to generation.
An example of complementary species and sequence comes from the US Sheep Experiment Station in Dubois, Idaho. They found that sheep that eat a lot of sagebrush also eat a huge amount of bitterbrush. Bitterbrush has tannins in it and the sagebrush has terpenes, and the tannins evidently are binding with the terpenes alleviating their aversive effects. Sheep have learned to mix these plants by eating the bitterbrush first.
These same sorts of things are happening with the managed grazing of pasture plants. For example, if you were to start grazing your cattle or sheep on a stand of tall fescue followed by a meal of birdsfoot trefoil (high in tannins) and alfalfa (high in saponins), over a couple week period, they will stop eating the tall fescue all together. But if you reverse the sequence and offer them birdsfoot trefoil and alfalfa first, then they will continue to eat large quantities of the tall fescue. What’s probably happening is the saponins and tannins are binding with the alkaloids in the tall fescue and having those plant compounds in the gut allows the animal to graze greater quantities.
Currently, Dr Provenza is looking at the linking of secondary compounds from soil through plant through herbivore, and through people. How does the health of the soil influence the compounds in diverse stands versus monoculture? Do plants growing in healthy soil produce the same amount of secondary compounds? How does diversity of plants impact nutrition and the health of livestock? And then, how does that link to our health? A group in Italy is the first to start looking at how secondary compounds in forages influences the quality of meat, milk, and cheese for human consumption. Their research is hoping to determine the influence of secondary compounds on flavor and nutritional characteristics of cheese and other dairy products and this is proving to be very interesting research.
Fred Provenza studies dietary behavior of range animals and has learned much about nature’s program for full nutrition. It is clear there is an inherent “nutritional wisdom” within these animals, wisdom that can be taught as well. In order to farm and ranch more sustainably, we must learn to appreciate diversity, live in an evolutionary spirit and develop agricultural management strategies that enable us to adapt quickly to change. www.Behave.net