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Item Impact of weight classifications on weight loss behavior: a regression discontinuity design(Montana State University - Bozeman, College of Agriculture, 2020) Worley, Ronald Wayne, III (Trey); Co-Chairs, Graduate Committee: Andrew Hill and Mariana CarreraAround 70% of US adults are overweight or obese, conditions strongly associated with medical issues and lower worker productivity. Efforts to address this issue have largely failed to instill long-term healthy living habits in individuals, and a better understanding of how individuals respond to these weight classifications may aid in creating effective interventions. Using the National Longitudinal Survey of Youth 1979, I exploit the quasi-random assignment of weight classifications through the body mass index in a regression discontinuity design (RD) to analyze the impacts of overweight and obese assignments on weight change behavior and attempts to lose weight. My results suggest that individuals do not respond to these classifications by altering their weight change behavior or their efforts to lose weight. Limitations to my study make it uncertain whether this is the true relationship between weight classifications and weight-related behaviors. However, these findings align with previous research utilizing similar natural experiments. Future studies could exploit additional sources of variation in weight information, utilize different techniques, and explore alternative samples to contribute to the small, yet growing, literature on this topic.Item Sources of variation in maternal allocation to offspring during lactation in the Weddell seal(Montana State University - Bozeman, College of Letters & Science, 2018) Macdonald, Kaitlin Rose; Chairperson, Graduate Committee: Jay J. RotellaVariation in the allocation of energy to reproduction by mothers can have fitness consequences for mothers and offspring. Diverse features of a mother, and annual environmental fluctuations may affect the amount of energy a mother allocates to offspring and may obscure age-specific patterns that are of interest when evaluating predictions made from existing life history theory. To properly evaluate possible sources of variation, especially age-specific variation in maternal allocation, analyses of data for known-age mothers with a wide range of ages, diverse reproductive histories, and multiple measures of allocation to reproduction are needed. We used data from a long-term study of Weddell seals that were individually marked as pups and monitored annually and a Bayesian hierarchical modeling framework to characterize age-specific variation in maternal allocation and test predictions about age-specific variation while considering additional maternal features that might influence maternal allocation. Based on masses for 311 mothers and associated pups from 2002 to 2016, we found that maternal allocation was moderately associated with maternal age and strongly associated with maternal body mass at birth of her pup. We found that heavier mothers lost a greater proportion of mass during the entire lactation period but that the efficiency with which mothers transferred this mass to their pups was lower than that of lighter individuals. The proportion of mass lost by a mother during the entire lactation period was greater for mothers that had reproduced the previous year and for those who started reproducing young, which suggests that individual quality and perhaps experience are determinants of maternal allocation in this species. Our study did not find support for our predictions that older mothers would allocate more body reserves, be more efficient at transferring mass during early lactation, or alter their behavior in ways that would improve mass transfer efficiency during late lactation, relative to prime-age mothers. The large variation we found in energy allocation to pups translates to large variation in pup weaning mass. Our results highlight that maternal multiple features should be considered when evaluating patterns of age-specific variation in maternal allocation.Item Grazing, feed intake, and milk production differences in beef cows of varying efficiency classification and size(Montana State University - Bozeman, College of Agriculture, 2018) Williams, Alyson Rose; Chairperson, Graduate Committee: Timothy DelCurto; C.T. Parsons, J.G.P. Bowman, D.L. Boss and T. DelCurto were co-authors of the article, 'The influence of weaning weight ratio and cow size on feed intake behavior, milk yield, and milk constituents' submitted to the journal 'Journal of animal science' which is contained within this thesis.; S.A. Wyffels, C.T. Parsons, J.G.P. Bowman, D.L. Boss and T. DelCurto were co-authors of the article, 'The influence of weaning weight ratio and cow size on winter grazing and supplement intake behavior' submitted to the journal 'Journal of animal science' which is contained within this thesis.Metrics that identify beef cow efficiency in extensive rangeland environments has long been desired in both beef cattle research and production settings. However, research is limited relative to matching cattle metrics to western production systems. Previous research has suggested the ratio of calf weight weaned to cow weight, or weaning weight ratio, is an accurate estimate of cow efficiency. Furthermore, milk production has been attributed to influence calf pre-weaning average daily gain. Few studies have evaluated how cow type or cow characteristics influence grazing distribution and supplement consumption on native landscapes. The objectives of this study were to assess cow feed intake, grazing behavior, supplement intake, and milk production differences between cows of differing weaning weight ratio and body weight classification. Individual cow average daily feed consumption, average daily feeding bout duration, number of visits per day, and total time spent eating per day were collected during a feed intake period and a supplement intake period. Total distance traveled and time spent grazing were collected on individual cows with global positioning system collars. Milk samples were analyzed for fat, solids not fat, total solids, protein, and lactose content, and milk yield was calculated as the change in calf weight following a weigh-suckle-weigh procedure. High weaning weight ratio cows consumed more feed when expressed on a g/kg bodyweight basis (P < 0.001) but did not differ in supplement consumption (P > 0.10). High weaning weight ratio cows produced more milk both in total kg (P < 0.03) and when expressed as /kg bodyweight (P < 0.001). Heavy bodyweight cows tended to consume more feed than light bodyweight cows (P < 0.09) but neither bodyweight group ate more supplement than the other (P > 0.10). High weaning weight ratio cows spent an hour longer grazing per day than low weaning weight ratio cows (P < 0.02). Total distanced traveled per day did not differ (P > 0.10). Results suggest weaning weight ratio and cow size are not accurate metrics of cow efficiency and the use of weaning weight ratio may unintentionally favor cows with higher milk production and higher feed requirements.Item Exposure to terrorism and birthweight outcomes in Nigeria(Montana State University - Bozeman, College of Agriculture, 2018) Matonte, James Philip; Chairperson, Graduate Committee: Brock SmithUsing readily available vitality and GPS data from the Nigerian Demographic and Health Survey, in conjunction with terrorism data from the open sourced Global Terrorism Database, I estimate the effect of in-utero exposure to terrorism within three kilometers of individuals in Nigeria on the likelihood of an infant to be born low-birthweight. Previous economic studies have explored the similar impacts to birthweight from arguably exogenous violent shocks to fetuses in-utero, however, no previous study has yet performed such an analysis of in-utero violence exposure within such a defined geographic area. I claim that previous studies' inability to perform their analysis on a smaller geographic scale has likely underestimated the effects of in-utero violence exposure. Additionally, I exploit detailed information on each terrorism event to address varying degrees of violence severity. I find that exposure to a Boko Haram civilian targeted terrorism related fatality, anywhere within Nigeria and within three kilometers of an individual, as well as within the first trimester of pregnancy, is associated with an approximate 3.2 percentage point increase in the likelihood that a child is born less than or equal to 2500 grams. There is also evidence to suggest that exposure to terrorist events greater than three kilometers away and outside of the first trimester increase the likelihood of an infant being born low birthweight as well.Item The relationship between weight gain in high-risk infants and mothers' levels of social support(Montana State University - Bozeman, College of Nursing, 1989) Jaeger, Kathleen RaeItem The effect of aureomycin upon lamb mortality and body weights and the effect of delayed feeding upon weaning weights(Montana State University - Bozeman, College of Agriculture, 1957) Bassett, James WilburItem The effects of calving date, weaning date, and duration of fall grazing on the sustainability of beef cow-calf operations in central and southeastern Montana(Montana State University - Bozeman, College of Agriculture, 1997) Julien, Debra JeanItem Production of two-year-old ewes(Montana State University - Bozeman, College of Agriculture, 1957) Colman, Kenneth L.; Chairperson, Graduate Committee: J. L. Van HornThe purpose of the investigation of these data was to explore the possibilities of relationships existing between the body weights of the ewes during their early life and their subsequent lamb and wool production as two-year-olds. The effects of environmental influences, such as type of birth and age at weaning, on the growth of ewe lambs and their production as two-year-olds were studied. The growth of two-hundred and fifty-nine ewes was measured by body weights taken at irregular intervals from birth to twenty-three months of age. Records of the individual lamb and wool production of these ewes were tabulated with the body weights. Results showed that the effect of type of birth and age at weaning, on body weights of ewe lambs was reduced as the lambs progressed toward maturity from weanling age. It was also found that the birth weights, weaning weights, and fall yearling weights of the ewes were significantly related. The fall yearling weight of the ewes was most indicative of two-year-old lamb and wool production. A significant relationship was found between the birth weights of the Rambouillet ewes and the pounds of lamb born per ewe as two-year-olds. The relationship between the birth weights of the Targhee ewes and the pounds of lamb born per ewe was not significant nor was this relationship significant for the birth weights of the Columbia ewes and the pounds of lamb born per ewe. The early single-born lambs were consistently lighter at birth than the late single-born lambs; however, at weaning time, the early single-born lambs were consistently heavier than the late single-born lambs. The average daily gain of the early single-born lambs and the late single-born lambs was about the same. The weaning weights of the ewes and their yearling fleece weights were significantly and positively related. The difference between the yearling fleece weights of the ewes and their two-year-old fleece weights was significant, the yearling fleece weights being the heaviest. It is evident from this study that valuable genetic breeding stock may be lost if suitable precautions are not taken to adjust for environmental conditions affecting the size of ewe lambs at weaning time when most replacements are selected. According to these data and that published previously by other workers, a sounder method of selecting higher producing replacements is to retain a larger number of ewe lambs at weaning and to make final selections at fall yearling age. Since production factors are closely related to body weight at fall yearling age, the heavier ewes of similar breeding will be better producers than the lighter ewes if selections are made at this age.Item Evaluation of pelleted or wafered rations for wintering or fattening beef cattle(Montana State University - Bozeman, College of Agriculture, 1965) Matz, John J.Item Measurements and effects of size in white leghorns and white leghorn bantams(Montana State University - Bozeman, College of Agriculture, 1970) Mecha, Inyang