Animal welfare is a major concern among livestock producers in the U.S. Heat stress, particularly, compromises animal welfare and productivity, causing >$2B annual economic loss to producers. The presence of toxic alkaloids within tall fescue (Schedonorus phoenix syn Lolium arundinaceum, syn Festuca arundinacea) plants induces a complex of disorders collectively known as fescue toxicosis. Summer slump, a reduction in animal performance due to heat stress, is common and evident of the symptoms. Various techniques for assessing animal physiological and behavioral responses to heat stress were explored in this dissertation, with particular emphasis on fescue toxicosis and its mitigation strategies. In the first study, the physiological and behavioral responses of heifers was evaluated when grazing either toxic tall fescue with wildtype endophyte (WE) or tall fescue with a novel endophyte (NE). Heifers (n = 24) were assigned to either WE or NE pastures for a 56-d grazing study during the summers of 2020 and 2021. Heifer average daily gain (ADG), intravaginal temperature, and degree of hair shedding were recorded during the grazing period. Blood samples were collected through coccygeal venipuncture and hair was collected from the left rump for cortisol analysis. Ear, tail, and hoof temperatures were collected for each heifer using an infrared thermal imaging camera. In 2020, heifers that grazed NE tall fescue had greater (P = 0.0160) ADG over the season (0.22 vs. 0.12 kg day-1). Hair retention score was greater (P = 0.0029) for heifers that grazed WE tall fescue compared to heifers that grazed NE tall fescue across both years. Heifers that grazed WE tall fescue had decreased ear skin temperature (P = 0.0001), tail skin temperature (P = 0.0058), and hoof surface temperature (P = 0.0075) compared to heifers that grazed NE. Heifers that grazed WE had 0.3-0.9 ºC hotter intravaginal temperatures than heifers that grazed NE, especially during daytime. Hair cortisol levels of heifers that grazed WE tall fescue were greater (P < 0.0001) compared to hair cortisol levels of heifers that grazed NE tall fescue. From 1200h-1700h each day, heifers that grazed WE tall fescue spent 1.5 more (P = 0.0003) hours standing and 0.9 fewer (P = 0.0402) hours lying down compared to heifers that grazed NE tall fescue. These results suggest that heat stress and other physiological changes in heifers grazing WE tall fescue could be mitigated by renovating pastures with NE tall fescue that does not impose any negative effects on grazing animals. The second study explored the potential benefits of consuming condensed tannins as a means of negating the effects of toxic alkaloids in tall fescue. Twelve fall-born steers were assigned to one of the two diet supplement treatments - sericea lespedeza pellets (LES) or sericea lespedeza pellets mixed with polyethylene glycol (LES+PEG) for 12 weeks during the summers of 2020 and 2021. The LES+PEG treatment served as a positive control since polyethylene glycol binds tannins, rendering them inactive in the gastrointestinal system. Animal body weight (BW), hair retention score (HRS), rectal temperature, and thermographic images were collected every 4 weeks. Hair and blood samples were also collected for cortisol analysis. Fecal and urine samples were collected and analyzed for total ergot alkaloid (TEA) concentration. Steers on LES had greater (P = 0.0033) ADG compared to steers on LES+PEG in 2021, but not in 2020 (P = 0.8707). In 2021, HRS was greater (P < 0.05) for steers fed LES+PEG compared to steers fed LES. In 2020, ear skin temperature (P < 0.0001) and hoof surface temperature (P = 0.0382) was greater in steers on LES compared to steers on LES+PEG. Rectal temperatures were lower (P = 0.02905) for steers fed LES compared to steers fed LES+PEG in 2021. Plasma cortisol levels did not differ (P ≥ 0.1566) between LES and LES+PEG treatments for both years. In 2020, hair cortisol levels did not differ (P = 0.8295) between treatments while in 2021, the hair cortisol level of steers on LES+PEG was greater (P = 0.0221) compared to hair cortisol levels of steers on LES. This study indicated some changes in animal physiology in response to dietary supplements containing condensed tannins, but results were inconsistent and further studies are needed to better understand the potential benefits of tannins in reducing the effects of toxic alkaloids consumption. In the third study, behavioral and physiological responses of ewes that grazed either mid-stage hardwood silvopastures or open pasture (OP) were compared. The study site consists of 0.27-ha of black walnut (Juglans nigra; BSP) and honeylocust (Gleditsia triacanthos; HSP) silvopastures and open pasture treatments, each replicated three times. During the summers of 2020 and 2021, thirty-six Katahdin ewes were assigned to one of the treatments for a 6-week summer grazing trial. Ewe weights were recorded for two consecutive days at the beginning and end of the study and intravaginal temperatures were recorded for two consecutive days at every 3-week intervals. Trail cameras captured animal behavior. Blood was collected via jugular venipuncture. Hair grown during the trial was collected from the loin region. Blood and hair cortisol concentrations were determined by ELISA. Ewe ADG was greater in HSP compared to OP (P = 0.0456) but did not differ with BSP (P = 0.4686) across both years. Ewes on OP had hotter (P ≤ 0.0343) intravaginal temperatures than ewes on both silvopasture treatments between 1100h-1700h. Plasma cortisol level was lower in ewes on BSP compared to ewes on OP (P = 0.0400) but did not differ with ewes on HSP (P = 0.6954) across both years. Ewes that grazed OP had greater hair cortisol levels compared to ewes on silvopasture treatments both in 2020 and 2021 (P < 0.0001). In 2020, ewes on BSP spent about 20% more time grazing than ewes on OP (P = 0.0054) while in 2021 ewes on BSP spent about 36% more time grazing than ewes on HSP (P = 0.0014). Ewes on OP spent 400% more time standing than ewes on BSP (P < 0.0001) and 750% more time standing than ewes on HSP (P < 0.0001). Ewe on OP spent 20% less time lying down compared to ewes on BSP (P < 0.0001) and 33% less time lying down compared to ewes on HSP (P < 0.0001). Hair cortisol measures and intravaginal temperature sensors can be utilized as reliable and relatively non-invasive techniques for measuring heat stress response in livestock managed in extensive grazing systems. / Doctor of Philosophy / Heat stress compromises animal welfare and productivity, causing > $2B annual economic loss to producers in the U.S. In the southeastern U.S, heat stress in livestock is largely due both to an environmental condition and to the effect of fescue toxicosis caused by toxic alkaloids. Various management strategies to mitigate the effect of heat stress in livestock due to environmental conditions or due to the effect of tall fescue toxicosis are explored in this dissertation. In the first study, behavioral and physiological responses of heifers that grazed either toxic (WE) or novel (NE) endophyte-infected tall fescue was compared. Heifers that grazed WE tall fescue had lower gains, rough hair coat, higher hair cortisol level (stress measure), cooler extremity temperature, and hotter intravaginal temperature compared to heifers that grazed NE tall fescue. These results suggest that heat stress and other physiological changes in heifers grazing WE tall fescue could be mitigated by renovating pastures with NE tall fescue, a forage cultivar that does not impose any negative physiological effects on grazing animals. In the second study, we tested the effect of condensed tannins in reducing the severity of fescue toxicosis in steers. We fed sericea lespedeza pellets to steers in a study to test this effect. All steers were fed sericea pellets, but pellets for half (6) of the steers were treated with polyethylene glycol, which inactivates the condensed tannins in the sericea lespedeza. In our study, we found that the steers fed the sericea lespedeza had higher temperatures at their extremities (ears and tail), but lower rectal temperatures than the control steers. Interestingly, the steers fed the sericea lespedeza pellets also had slicker hair coats and lower levels of hair cortisol (indicating reduced stress) in the second year compared to the control steers. This study showed some potential of condensed tannins in reducing the effects of fescue toxicosis, but needs further study to better understand the potential benefits of tannins in reducing the post-ingestive effects of fescue toxicosis. In the third study, we compared behavioral and physiological (temperature, hair, and blood cortisol) responses of ewes that grazed either mid-stage hardwood silvopastures or open pastures (OP). Ewes on OP showed signs of heat stress with higher hair cortisol levels and hotter intravaginal temperatures during the daytime compared to ewes on silvopasture treatments. Ewes on OP spent 400% more time standing compared to ewes on BSP and 750% more time standing than ewes on HSP. Ewe on OP spent 20% less time lying down compared to ewes on BSP and 33% less time lying down compared to ewes on HSP. Ewes on silvopasture treatments spent 70% less time drinking water compared to ewes on OP. Trees within the silvopasture systems can alter the micro climatic condition thus creating a suitable environment for livestock. This can ultimately reduce stress and improve overall behavioral and physiological responses of livestock in silvopastures compared to open pastures.

Submitted by Jordan (jordanbiblio@gmail.com) on 2018-02-21T15:55:33Z No. of bitstreams: 1 DISS_2015_Henrique Guimarães de Favare.pdf: 2850990 bytes, checksum: 2a69e994ca9fc76939fe4b76c9eb3f5a (MD5) / Approved for entry into archive by Jordan (jordanbiblio@gmail.com) on 2018-02-21T15:56:23Z (GMT) No. of bitstreams: 1 DISS_2015_Henrique Guimarães de Favare.pdf: 2850990 bytes, checksum: 2a69e994ca9fc76939fe4b76c9eb3f5a (MD5) / Made available in DSpace on 2018-02-21T15:56:23Z (GMT). No. of bitstreams: 1 DISS_2015_Henrique Guimarães de Favare.pdf: 2850990 bytes, checksum: 2a69e994ca9fc76939fe4b76c9eb3f5a (MD5) Previous issue date: 2015-02-12 / CAPES / O sinergismo dos componentes de um sistema esta ligado na escolha das espécies a se associarem, o que requer conhecimentos sobre as suas características, de tal forma que os componentes envolvidos beneficiem-se dessa integração. Conhecer as características silviculturais e a forma de distribuição espacial da espécie nativa pode auxiliar no manejo e implantação do sistema silvipastoril. Este estudo avaliou o padrão de distribuição espacial de indivíduos adultos de pequi (Caryocar brasiliense), em área de pastagem mista de gramíneas e leguminosas no pantanal mato-grossense. Efetuou-se um censo dos indivíduos adultos de pequi em uma área remanescente do bioma cerrado, cujas coordenadas geográficas foram 15º58’25.49”S e 57º34’36.11”O. O mapeamento dos indivíduos e da área foram efetuados usando o sistema de coordenadas retangulares (UTM) através de georreferenciamento utilizando GPS de precisão e posteriormente exportado para o TrackMaker 3.5. Os indivíduos foram analisados quanto à população e em função da seleção de classes da área de copa. A seleção foi feita a partir do desvio padrão (S), onde foram estabelecidas cinco classes amostrais, onde uma classe representa à média e as outras quatro a média mais e menos um e dois S. A densidade de distribuição da população de pequi foi analisada pelo estimador de Kernel e a distribuição espacial foi calculada a partir da Função K de Ripley, usando o programa estatístico R, com o pacote spatstat. O número de vizinhos próximos a uma árvore aleatória de pequi está acima do previsto para a Completa Aleatoriedade. Deste modo, a população de pequi apresentou um padrão de distribuição espacial agregado e quando analisado em função da área de copa observou-se a distribuição de árvores com tendência a aleatoriedade. A formação de adensamentos de indivíduos com áreas de transição possibilita a passagem dos raios solares para o desenvolvimento das gramíneas apresentando as características necessárias para condução do sistema silvipastoril. / The synergism of the components of a system is linked in selecting of the species to associate, which requires knowledge of their characteristics, such that it participating components to benefit from this integration. Getting to know the silvicultural characteristics and the form of the spatial distribution of native species can help in the management and implementation of silvopastoral system. This study evaluated the spatial distribution pattern of adult individuals of pequi (Caryocar brasiliense Camb.) in mixed pasture grasses and legumes in the Mato Grosso Pantanal. It was conducted a census of adult individuals of pequi in a remaining area of the biome cerrado, with geographical coordinates were 15º58'25.49 "S and 57º34'36.11" W. The mapping of individuals and the area were carried out by using the rectangular coordinate system (UTM) through georeferencing utilizing precision GPS and is subsequently exported to the TrackMaker 3.5. The individuals were analyzed regarding population and according to selection of crown area classes. The selection was made from the standard deviation (SD), where five classes of samples were established with one class represents the average, and the other four samples, the average most and least one and two SD. The distribution density of pequi population was analyzed by the Kernel estimator and the spatial distribution was calculated from the function K of Ripley, using the statistical software R, with the spatstat package. The number of neighbors near a random tree pequi is higher than expected for the Complete Randomness. Therefore, the population of Pequi showed a pattern of spatial distribution and aggregate when assessed by reference of the crown area was observed the distribution trees prone to randomness. The formation of aggregation trees and transition areas allows the passage of solar rays to the development of grasses having the necessary characteristics for driving the silvipastoral system.

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On the frontier of biodiversity-rich tropical forests, how land is used has an important role in buffering the primary ecosystem. Unsustainable small-scale cattle farming endangers soil quality and degrades the landscape. Silvopasture is a type of agroforestry that provides both ecological and livelihood benefits. A number of projects have been implemented across the tropics to encourage silvopasture adoption, with varying success. This dissertation questions the reasons for variable outcomes among participants within these projects: what motivates smallholders to adopt innovative land-use practices, and what form of incentives may help to overcome obstacles and catalyse adoption. This dissertation contributes to the ongoing debate on payments for ecosystem services, specifically about their suitability and effectiveness. To understand what influences decisions to adopt sustainable land-use practices, I review systematically and quantitatively the literature on adoption predictors, and I empirically analyse participation and short-term adoption in a pilot project for planting fodder trees in the border of a protected forest in Chiapas, Mexico, using primary and secondary data. I focus on subjective perspectives and livelihood strategies of actual and potential participants as explanatory variables, which have received unduly scarce attention in past studies. This lack of attention is partially caused by the difficulties of operationalising internal variables. I address this challenge by developing an analytical approach that increases the precision of the resulting perspectives in Q methodology. I cluster livelihood strategies and model adoption. This in-depth case-study suggests the type of incentives that are adequate to encourage adoption of sustainable land-use practices. Results indicate that payments may not be the best incentive for pioneer adopters, and that the adoption process is composed of separate individual steps, which are influenced distinctly by identifiable predictors, such as livelihood diversity. Uncovering this heterogeneity of motivations towards adoption provides useful knowledge for designing more effective external policy interventions.