ANIMAL BEHAVIOR: IMPACTS ON GRAZING

Mark Kennedy State Grazingland Specialist Missouri USDA-NRCS

I am not an expert on this subject and give Systems Research Center in Linneus, all credit for my limited understanding of this Missouri shows that as travel distance to subject to Dr. Fred Provenza, Utah State water increased above 800 feet, then the University; Katy Voth, Livestock for animals traveled as a herd to water and Landscapes, LLC; Jim Gerrish and others. I utilization of the pasture beyond 800 feet have tried to put into practice, both was greatly reduced. When travel distance personally and with other producers, many to water is kept below 800 feet then the of these principles to aid in improved animals normally drink individually or in grazing management. This presentation will small groups and resume grazing across address only 2 aspects of animal behavior; the pasture. Subsequent research shows 1) How animal behavior impacts grazing the effect that water location, shade and distribution and forage utilization over the paddock size have on grazing distribution landscape, and 2) How animal behavior and manure distribution. Pasture utilization affects diet selection. is affected by the length of the grazing period and stock density. Grazing period is the length of time grazing animals are in any Impacts on grazing distribution/forage one pasture. The longer grazing animals utilization over the landscape are in a pasture the lower the utilization rate will be. This is due to the animal’s ability to Most, if not all, of the grazing animals that selectively graze choice plants and new we work with evolved as herd animals. The regrowth while letting others go to maturity herd mentality developed as a means of and desiccation. Losses due to trampling, protection, safety in numbers. Herd animals soiling, manure and urine are greater with like to stay in close proximity of their herd longer grazing periods. When pastures are mates for protection. This instinct can have sub-divided into smaller units, stock density an effect on the grazing distribution and increases and grazing period length utilization of the overall pasture. When decreases. As stock density increases this some of the animal’s basic needs such as decreases the animal’s ability to selectively shade, water, salt and/or minerals are graze due to competition from herd mates. located some distance away from where the As grazing period length and selectivity are animals are grazing, they will travel as a decreased, pasture utilization is increased. herd to these areas. This reduces the herd’s ability to uniformly graze throughout the entire pasture. Conversely, if all of Effects on diet selection these basic needs are in close proximity to each other, it can cause the herd to camp Grazing animals have the ability to select a out in this area for an extended period higher quality diet than the average for the causing overgrazing, reduced plant vigor, pasture. This is due to the animal’s ability increased soil erosion, increased weed to select particular plant species, individual invasion, soil compaction, increased plants and plant parts to eat. Selection is pollution potential from runoff and degraded driven by: 1) Availability; 2) Palatability; 3) wildlife habitat. Research at the Forage Differential access due to plant growth form;

32 and 4) Habit and experience. Each of these Toxin Plant Species four factors will be discussed in more detail. Cyanide compounds White clover, Sudan grass, Johnson grass, Chokecherry, Availability Serviceberry Alkaloids Reed canarygrass, Bindweed, Jimsonweed Dry matter intake on pasture is based 75% Fungal endophytes Tall fescue, Perennial on availability and 25% on forage quality. (ergot alkaloids, Ryegrass The reason availability is so important is ergovaline) due to the mechanics of grazing. Intake is Nitrate Oats, Wheat, Rye, driven by: time spent grazing; biting rate; Pigweed, Sweet clover, and bite size. Grazing animals spend 6 – Alfalfa, Sudangrass 10 hours per day grazing. During this time Tannins and Birdsfoot trefoil, Serricea they can only take so many bites per phenolic compounds lespedeza, Crown Vetch, minute. Cattle generally take 30,000 to Walnut, Oak 50,000 bites per day. This seems like a lot Terpenes Juniper, Pine, Bitterweed but it is still a limited number. There is quite a difference in intake between 50,000 mouthfuls and 50,000 small bites. The only Palatability operates along a continuum to thing that we as managers can regulate is influence preferences. When nutrients are bite size. To maximize intake each bite eaten in proper amounts the post-ingestive needs to be a mouthful. Research shows feedback is positive and the animals that for animals to reach potential intake, develop a liking for the flavor. However, 1800 – 2400 pounds of forage dry matter when animals overingest either nutrients or per acre should be on offer. In our cool toxins a negative post-ingestive feedback season grass/legume mixed pastures this occurs and they develop a dislike or equates to approximately 6 – 8 inch tall aversion to the flavor. Aversions can be pasture sward. This would give a good bite strong or mild, long lasting or short-lived size of high quality forage. Conversely, depending on the severity of the post- animals forced to graze on 2 inch tall ingestive feedback and other factors we will pasture will be limited on intake due to bite discuss later. Nutrient and toxin size. concentrations limit the amount of feed an animal can ingest. Excesses or deficits of nutrients decrease palatability. Animals Palatability show little preference for foods low in nutrients and eat limited amounts of foods Palatability also drives diet selection. too high in nutrients. Excess protein Palatability is often defined as pleasant reduces palatability and intake because of tasting, but research by Dr. Fred Provenza an increased production of ammonia. shows that palatability is more than a matter Excess energy can cause acidosis which of taste. Palatability is determined by post- reduces palatability and intake. ingestive feedback interrelationships between nutrients, toxins and flavor. Animals like variety in their diets. Variety in Animals associate a particular flavor to the diet helps reduce the chance of either a positive or negative post-ingestive overingesting toxins. Diversity or variety feedback. All plants contain differing levels also helps meet the nutritional needs. of nutrients and toxins. Some common Different types of plants supply differing plant species that contain toxins include: levels of protein, energy, minerals and vitamins. Animals can develop aversions to foods when they become satiated on that particular food flavor. Providing animals

33 with a variety of foods (diversity) may feedback, then a more definite aversion to provide animals with a more balanced diet, that food is formed. increase intake, decrease stress and increase efficiency. As young animals grow older they interact increasingly with their peers. Peers become a major influence on each others behavior. Plant Growth Form/Physical Attributes of Young animals encourage one another to Plants try new things. Each young animal may have different past learning experiences. Grazing animals must deal with plant Socializing enhances the learning efficiency physical characteristics such as standing of the group. Each individual animal no dead material in some grasses, thorns in longer has to discover everything by itself. some forbs and woody plants, leaf size, and plant canopy shape and structure. These Animal behavior is a function of physical features can facilitate or inhibit consequences. Consequences come in two foraging and increase or decrease intake. forms – reinforcement and punishment. Some animals such as goats and sheep Behavior results from various combinations with their small mouths and prehensile lips of these consequences. Consequences have the ability to select the most desirable that increase the probability of a behavior parts of plants. Cattle on the other hand, are called reinforcement and they can be with their large rumen capacity can handle either positive or negative. By nature, more volume and thus can digest lower animals seek positive reinforcement and quality material. Any combination of plant avoid negative reinforcement. physical and nutritional characteristics that Consequences that decrease the probability optimizes intake will be a preferred food. of a behavior are called punishment. Positive punishment is based on the presence of positive aversive stimuli, such Habit and Experience as an electric fence shock. Negative punishment is based on the removal of a Research indicates that animals learn which positive re-inforcement, such as when an plants to eat and which to avoid through animal eats a plant that was once nutritious three avenues: watching mothers, but is no longer nutritious. They no longer interacting with peers, and reinforced receive positive post- ingestive feedback through personal experience. Young and decrease the occurrence of this animals learn about every facet of their behavior. There is a growing movement environment from socializing with their away from the use of negative mothers. As young animals begin to forage, reinforcement and punishment and towards they quickly learn to eat the foods mother the use of positive reinforcement. eats and they remember those foods for Punishment often times arouses anger and years. Research also shows that a mother fear. Whereas the removal of positive can help reduce her offspring’s risk of eating stimuli of leads to disappointment or toxins. If a mother avoids harmful foods the depression. This happens when animals offspring will also avoid ingesting those are removed from familiar environments and foods in any large quantity. Young animals placed in unfamiliar environments. acquire preferences for foods its mother Performance is poor and stress is high eats and aversions for foods she does not because all familiar positive reinforcements eat. This training from mom is further have been removed. Behavior is better reinforced by personal experiences. If the developed by positive reinforcement than by young animal eats a plant that mom avoids negative reinforcement or punishment. A and later has a negative post-ingestive combination of positive reinforcement and punishment or negative reinforcement may

34 be the most effective means to change a 5. Make the unfamiliar seem familiar particular behavior. Through punishment a. Add the novel plant to the (electric fence, removal of nutrients or familiar feed and feeder addition of toxins), animals can be trained to avoid palatable plants. However, the 6. Field test your animals aversion may not be long lasting unless the a. Pasture size is critical animals are given access to nutritious i. Too large and animals can alternatives (positive reinforcement). For be selective training to be most effective, it’s not enough ii. Too small and they may to simply discourage unwanted behavior. not be able to adequately Animals also need to be encouraged to mix toxins and nutrients change behavior. 7. Observe and adapt By using the information of how animals a. Monitor and make adjustments choose foods, they can be trained (taught) in pasture size, timing and to eat unfamiliar and/or less preferred foods duration of grazing by creating a positive reinforcement. Animals can also be trained to avoid preferred foods by creating an aversion References through negative reinforcers, positive punishment or negative punishment. Kathy Provenza, Frederick d., Foraging Behavior: Voth, Livestock for Landscapes, LLC, has Managing to Survive in a World of developed a 7 step process for training Change, 2003 animals to eat unfamiliar foods. This process has been used to train animals to Voth, Kathy; Teach Your Cows to Eat eat foods such as weeds that they normally Weeds, Proceedings 2005 MFGC wouldn’t eat. Below is a summary of the 7 Annual Conference step process: Gerrish, etal. Missouri Grazing Manual, 1. Know your plants. 1999 a. Know what toxins they contain b. Know their nutritive value BEHAVE – Behavioral Education for Human, Animal, Vegetation & 2. Choose your animals to train Ecosystem Management, a. Younger animals are more likely www.behave.net to try new things b. Females will tend to teach Livestock for Landscapes, Kathy Voth, offspring www.livestockforlandscapes.com

3. Maintain a healthy herd a. Healthy animals can handle toxins better

4. Reduce the fear of new things a. Feed a series of unfamiliar, nutritious foods to produce positive post-ingestive feedback. b. Use familiar feed tubs or troughs

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