Ruminants evolved in diverse landscapes of which they utilized, by choice, a diverse arrangement of plants (grasses, forbs, and trees) for food. These plants provide them with both primary (carbohydrates, protein, etc.) and secondary (phenolics, terpenes, etc.) compounds (PPC and PSC, respectively). As no one plant could possibly constitute a “balanced-diet,” ruminants mix diets so that they can exploit arrangements of PPC to meet their individual requirements. Diet mixing also allows for ruminants to ingest PSC at levels, acquiring their benefits such as antioxidants and reduced gastrointestinal parasites, without overstepping thresholds of toxicity. Meeting dietary requirements is assumed to provide satisfaction through achieving positive internal status and comfort, thereby a sense of hedonic (happiness through pleasure) well-being. Furthermore, choice including dietary choice is a factor influencing well-being of ruminants in a manner akin to that in humans. Choice may facilitate eudaimonic (happiness through pursuit of purpose) well-being in livestock. Nutritional status plays an integral role in oxidative stress, which is linked with illness. Several diseases in livestock have been directly linked to oxidative stress. Mastitis, metritis, hypocalcaemia, and retained placenta occur in animals transitioning from dry to lactating and have been linked to oxidative stress and such a stress has likewise been linked to diseases that occur in growing livestock as well, such as bovine respiratory disease. The link between physiological stress and oxidative stress is not well-defined in livestock but is evident in humans. As dietary diversity allows animals to select more adequately balanced diets (improved nutrition), take advantage of PSC (natural antioxidants), and allows for choice (improved animal well-being) there is a strong possibility for ruminants to improve their oxidative status and thus health, well-being, and therefor production. The purposes of this review are to first, provide an introduction to oxidative and physiological stress, and nutritional status as effected by dietary diversity, with special attention to providing support and on answering the “how.” Second, to provide evidence of how these stresses are connected and influence each other, and finally discuss how dietary diversity provides a beneficial link to all three and enhances both eudaimonic and hedonic well-being.

Ruminants are a source of enteric CH₄, which has been identified as an anthropogenic greenhouse gas that contributes to climate change. With interest in developing technologies to decrease enteric CH₄ emissions, systems are currently being developed to measure CH₄ emissions by cattle. An issue with grazing cattle is the ability to measure CH₄ emissions in open-air environments. A scientific instrument for this task is an automated, open-circuit gas quantification system (GQS; C-Lock, Inc.; Rapid City, SD). The GQS is a head-chamber that grazing cattle occasionally visit (3 to 8 min/visit; 3 to 6 visits/d) and, while the animal consumes a small portion of bait (0.5 to 1.0 kg/visit), the GQS captures the animal’s breath cloud by exhausting air through the GQS. The breath cloud is then analyzed for CH₄, CO₂, and O₂ concentrations. Data are hourly uploaded to a server where it is processed using algorithms to determine total daily fluxes. Several factors affect emission estimates generated by the GQS including the animal’s visitation rate, length of sampling period, and airflow through the system. The location of the GQS is an important factor in determining the cattle’s willingness to visit. Further, cattle need to be trained to use the GQS, which normally requires 4 to 8 wk. Several researchers have shown that 30 or more visits are required to obtained high-quality estimates of gas fluxes. Once cattle are trained to use the GQS, the bait delivery rate has little effect on the animal’s willingness to use the system. Airflow through the GQS is an important factor, but as long as airflow is maintained above 26 L/s the breath-cloud capture seems nearly complete. There is great concern regarding circadian variation in the instantaneous production rates of CH₄ because the GQS normally only spot-samples 2 to 4 times/d. Preliminary analysis has shown variation in the instantaneous production rates of CH₄ do not vary as greatly with grazing cattle compared to meal-fed cattle. It seems that increasing the visitation length decreases variation in estimated emissions, but there is a diminishing return to increasing visitation length. The GQS is a useful tool for researching the nutrition and emissions of grazing cattle, but great care must be taken to obtain the best quality data possible for use in this high-impact research.

The aim of the present research was to compare milk fatty acid composition of cows grazing perennial ryegrass–white clover pasture (RGWC), with that of cows grazing alternative forages of chicory or plantain. Fifty-four cows, balanced for milk solids, days in milk and bodyweight, were divided evenly into replicated groups of six cows/group. Cows grazing chicory or plantain had similar estimated dry-matter intake (17.7 kg DM/cow.day) and milk-solid (MS) yield (1.93 kg MS/cow.day), which were greater (P < 0.05) than for cows grazing RGWC (15.6 kg DM/cow.day and 1.65 kg MS/cow.day). Milk produced from cows grazing chicory or plantain contained greater proportions of omega-3 fatty acids (FA) than that from cows on RGWC (P < 0.01), despite lower omega-3 FA in herbage. RGWC increased the percentage of conjugated linoleic and vaccenic acids in milk compared with those of milk produced from herbs (P < 0.01). This reflects the greater percentage of α-linolenic acid in RGWC (P ≤ 0.02) than in forage herbs. The changes in FA profile from the herbage to the milk suggests less biohydrogenation in cows grazing the herbs. Forage herbs demonstrated the potential benefit to alter milk FA composition, while increasing milk production.

Pastoral livestock production systems are facing considerable societal pressure to reduce environmental impact, enhance animal welfare, and promote product integrity, while maintaining or increasing system profitability. Design theory is the conscious tailoring of a system for a specific or set of purposes. Then, animals—as biological systems nested in grazing environments—can be designed in order to achieve multi-faceted goals. We argue that phytochemical rich diets through dietary taxonomical diversity can be used as a design tool for both current animal product integrity and to develop future multipurpose animals. Through conscious choice, animals offered a diverse array of plants tailor a diet, which better meets their individual requirements for nutrients, pharmaceuticals, and prophylactics. Phytochemical rich diets with diverse arrangements of plant secondary compounds also reduce environmental impacts of grazing animals by manipulating the use of C and N, thereby reducing methane production and excretion of N. Subsequently functional dietary diversity (FDD), as opposed to dietary monotony, offers better nourishment, health benefits and hedonic value (positive reward increasing “liking” of feed), as well as the opportunity for individualism; and thereby eudaimonic well-being. Moreover, phytochemical rich diets with diverse arrangements of plant secondary compounds may translate in animal products with similar richness, enhancing consumer human health and well-being. Functional dietary diversity also allows us to design future animals. Dietary exposure begins in utero, continues through mothers' milk, and carries on in early-life experiences, influencing dietary preferences later in life. More specifically, in utero exposure to specific flavors cause epigenetic changes that alter morphological and physiological mechanisms that influence future “wanting,” “liking” and learning of particular foods and foodscapes. In this context, we argue that in utero and early life exposure to designed flavors of future multifunctional foodscapes allow us to graze future ruminants with enhanced multiple ecosystem services. Collectively, the strategic use of FDD allows us to “create” animals and their products for immediate and future food, health, and wealth. Finally, implementing design theory provides a link between our thoughtscape (i.e., the use of FDD as design) to future landscapes, which provides a beneficial foodscape to the animals, an subsequently to us.