The mammary gland cell growth and differentiation are under the control of both systemic hormones and locally produced growth factors. Among all these important hormones and growth factors, estrogen plays a central role in mammary gland development. The biological function of estrogen is mediated by estrogen receptor α (ERα) and estrogen receptor β (ERβ). Both ERα and ERβ are expressed in the mammary gland, but with distinct expression patterns. In the mammary gland, ERα has been proved to be the estrogen receptor that mediates the mitogenic function of estrogen. However the function of ERβ in mammary cell proliferation is less understood and there remains some controversy. Accumulating evidence indicates that ERβ, unlike ERα, is a negative regulator of mammary epithelial cell proliferation. In this dissertation, ERα and ERβ were evaluated for their expression patterns in the mammary gland. In the proestrus phase, ERα was detected in about 20% of mammary epithelial cells; in the diestrus phase, no ERα staining was detected in the mammary gland. ERβ was expressed in more than 50% of mammary epithelial cells and ERβ staining was detected in some stromal cells in the proestrus phase. In the diestrus phase, ERβ staining cells were very limited and the staining intensity was very weak. These data suggest that the expression levels of both ERα and ERβ undergo dynamic changes during the estrous cycle. In the ovariectomised (OVX) rats, both ERα and ERβ were detected in more than 50% of mammary epithelial cells. Compared with the ovary-intact rats, the mammary gland of the OVX rats showed more cells with ERα expression, but the staining intensity was weaker. Taken together, the expression of ERα and ERβ is regulated by estrogen in normal mammary gland, while without estrogen stimulation in the OVX rats, more mammary cells showed ERα expression, but at a lower level in these cells. The effects of ERα and ERβ on mammary cell proliferation were studied by two different approaches, activation of endogenous ERα and ERβ via selective agonists, and overexpression of ERα and ERβ via lentiviral infection. In the first approach, we used ERα and ERβ selective agonists, propylpyrazole-triol (PPT) and diarylpropionitrile (DPN) respectively, to activate endogenous ERα and ERβ in the OVX rats. We found that ERβ selective agonist DPN counteracts the proliferative effect of ERα selective agonist PPT in the mammary gland. In the second approach, ERα and ERβ were ectopically overexpressed in the mammary gland of mature virgin rats by lentivirus infection. We found that ERβ overexpression significantly decreased mammary cell proliferation rate in both the proestrus and diestrus phases, indicating that ERβ, unlike ERα, is a negative regulator for mammary cell proliferation. Collectively, these data supports that in contrast to ERα, ERβ activation or overexpression is able to inhibit mammary cell proliferation.

The goal of the work presented herein was to further our understanding of the rumen microbiota and microbiome of wild moose, and to use that understanding to improve other processes. The moose has adapted to eating a diet of woody browse, which is very high in fiber, but low in digestibility due to the complexity of the plant polysaccharides, and the presence of tannins, lignin, and other plant-secondary compounds. Therefore, it was hypothesized that the moose would host novel microorganisms that would be capable of a wide variety of enzymatic functions, such as improved fiber breakdown, metabolism of digestibility-reducing or toxic plant compounds, or production of functional metabolites, such as volatile fatty acids, biogenic amines, etc. The first aim, naturally, was to identify the microorganisms present in the rumen of moose, in this case, the bacteria, archaea, and protozoa. This was done using a variety of high-throughput techniques focusing on the SSU rRNA gene (see CHAPTERS 2-5). The second aim was to culture bacteria from the rumen of the moose in order to study their biochemical capabilities (see CHAPTERS 6-7). The final aim was to apply those cultured bacterial isolates to improve other systems. Specifically, bacteria from the rumen of the moose was introduced to young lambs in order to colonize the digestive tract, speed the pace of rumen development, and improve dietary efficiency (see CHAPTER 8).

In experiment I), dry matter disappearance (DMD) and nitrogen disappearance (ND) of raw soybeans (RAW), solvent extracted soybean meal (SBM), heat treated whole soybeans (HT), mechanically extracted soybean meal (MEX), dry extruded soybeans (DEX), and wet extruded soybeans (TEX), were studied in situ for times of 3, 6, 12 and 24 h of rumen exposure. Five gram, air dry, samples were suspended in the rumen of a lactating Holstein cow fed a total mixed ration twice daily. The percent DMD for 24 h was as follows: RAW-85.9; SBM-56.6; HT-39.0; MEX-40.2; DEX-28.0; TEX-43.3. The greatest DMD was observed with RAW and was greater than all others (P<.01), followed by SBM which was significantly greater than all but Raw (P<.01). DEX presented the lowest DMD when compared to all other (P<.01). Percent ND values for 24 h for the soy products were: RAW-90.8; SBM-47.0; HT-32.7; MEX-23.7; DEX-16.5; TEX-23.0. The ND for RAW was significantly greater (P<.01) than all others, while the ND for SBM was similar P>.01) to HT but greater (P<.01) than MEX, DEX and TEX. ND for HT, MEX, DEX and TEX were similar (P>.01). Significant differences were observed in DMD and ND of various soybean products. As expected a high degree of degradation and ND was observed with raw soybeans. The application of heat decreased DMD and ND in SBM and application of greater heat (HT, MEX and DEX) and application of heat with moisture (TEX) resulted in products with lower DMD and lower ND. In experiment II) wheat straw acid detergent fiber (ADF) was subjected to in situ DMD and ND studies. Effects of time (612-24 h) and sample weight (1-2-3 grams) were evaluated. A lactating Holstein cow being fed a mixed ration was used. ADF dry matter (DM) weights (after incubation) expressed as a % of the original sample, were as follows: one gram: 101, 110 and 136; two grams: 99, 106 and 110; and three grams: 97, 110 and 114 for 6, 12 and 24 h respectively. The ADF DM weights of the one and two gram samples were significantly higher (P<.05) for 12 and 24 h than 6 h. When sample sizes were combined for each time, comparisons found 24 h to be significantly higher (P<.01) than 6 h. The DM changes were also reflected and magnified in the % N changes in the ADF residues. The amount of N of the one gram ADF samples increased 32% after 6 h, 122% after 12 h and 287% after 24 h (24>12>6-P<.01), and for two grams 29%-6 h, 97%-12 h and 117%-24 h (24>12>6-P<.05), and for three grams 34%-6 h, 140%-12 h and 142%-24 h (24 and 12>6-P<.01). Potential problems with DM and N contamination of ADF residue with in situ studies were demonstrated with small increases in DM weights and larger increases in N content.

Master of Science / Department of Animal Sciences and Industry / Joe D. Hancock / Nine experiments were completed to evaluate the effects of feed manufacturing practices on milling characteristics of diets and growth performance and stomach morphology in pigs. In Exp. 1 and 2, reducing the particle size of sorghum from 800 to 400 μm improved (P < 0.04) efficiency of gain in finishing pigs by 5% but had negative effects on cost of milling and stomach morphology. In Exp. 3 and 4, finishing pigs fed diets with 10 mg/kg of ractopamine HCl, had improved (P < 0.05) ADG, G:F, HCW, dressing percentage, and percentage carcass lean. However, increasing mix time of the diet from 0 to 360 s did not affect (P > 0.06) the response of finishing pigs to ractopamine HCl. In Exp. 5 and 6, adding ground and cracked corn to a pelleted supplement for nursery pigs decreased (P < 0.01) growth performance compared to feeding a complete pellet. In Exp. 7, increasing the percentage of cracked corn in a diet for finishing pigs decreased development of stomach lesions but also had a generally negative effect on efficiency of gain. In Exp. 8, adding cracked corn to a pelleted supplement (as done for the nursery pigs) decreased milling costs and improved health of stomach tissue. But, G:F was decreased by 6% (P < 0.05) which will make this technology unattractive to swine producers. In our final experiment (Exp. 9), pigs fed pellets tended to have the greatest growth performance, pigs fed mash the worst, and pigs fed pellets for only part of the grow-finish phase fell in between. In conclusion, grinding sorghum-based diets for finishing pigs improved efficiency of growth but extensive mixing to maximize diet uniformity had no effect on growth performance or carcass measurements. Use of cracked corn in diets does decrease diet costs and improve stomach health in finishing pigs but feeding of complete pellets for the entire finishing period supports maximum rate and (or) efficiency of gain.

Master of Science / Department of Animal Sciences and Industry / Teresa L. Slough / Teresa L. Slough / There is increasing interest in the use of point-of-care glucometers to monitor glucose concentrations in horses with metabolic disorders. The first study reported herein compared equine glucose concentrations obtained by a handheld glucometer using whole blood or plasma, a YSI 2300 bench top glucose analyzer using whole blood or plasma, and a SEVEN continuous glucose monitoring (CGM) device that measured glucose in interstitial fluid to readings obtained by a standard laboratory glucose analyzer utilizing plasma. In addition, glucose concentrations obtained by the CGM were compared to those obtained by the handheld glucometer using whole blood or plasma. Post-prandial increases and decreases in glucose concentrations were detected utilizing all glucometers tested. When glucose measurements obtained with the CGM in interstitial fluid were compared to glucose measured using the handheld glucometer in plasma or whole blood, glucose measurements from plasma had better reproducibility. Although the CGM could be a useful instrument for collecting nearly continuous data for the researcher and clinician, there are technical difficulties related to the CGM that must first be overcome. The second study was designed to compare the effects of consuming a twice-daily meal of sweet feed (SF) to ad libitum access to a molasses-based block (BL) supplement on patterns of interstitial glucose concentrations in horses. A novelty effect of the BL was observed, in which horses consumed increased quantities in the first 12 h. Treatments had no effect on intake of forage in this study. The range and means of glucose values were similar between treatments, and significant glucose responses to treatments had lag times that were indirectly similar, even though molasses intake was greater for horses on BL. Variability between horses was noted in quantity of BL consumed as well as timing and magnitude of glucose responses. Based on the results of this experiment, there does not appear to be a clear advantage to either treatment, SF or BL, in attenuating post-prandial glucose increases or in minimizing glucose fluctuations in the horse.

Doctor of Philosophy / Department of Psychology / Jerome Frieman / The present experiment investigated whether dwarf hamsters (Phodopus campbelli) demonstrate temporal discounting. This was investigated by comparing the behavior of dwarf hamsters and Sprague-Dawley rats (Rattus norvegicus) in an adjusting delay procedure and applying the theory of behavioral economics to explain the resulting behavior. Dwarf hamsters demonstrated temporal discounting and tolerated longer delays than did the more impulsive rats. There was not a statistically significant difference between these species concerning indifference points. There was a statistically significant difference in the slopes of their discounting functions and the delay at which the end criterion was met. Neither species exhibited sex differences with respect to these measures nor with storage of food. There were a number of differences between the species. Rats started responding quickly, whereas dwarf hamsters waited significantly longer. When faced with increasing delays, rats increased the number of pellets earned while dwarf hamsters earned the same amount. Finally, rats lost weight throughout the experiment while dwarf hamsters gained weight. There were also a number of similarities. When faced with an increasing delay, both rats and dwarf hamsters increased the number of responses made, and increased the number of times they timed out on Larger Later trials. Some of these findings disagree with previous research and predictions of the behavioral economic theory of demand, creating a need for further research.

Master of Science / Department of Clinical Sciences / Luciana Bergamasco / As public concern for food animal welfare increases, the need for objective pain assessment and methods to alleviate pain associated with production practices such as castration gains attention. The aims of this study were (i) to evaluate the physiological response to pain induced by castration in calves and (ii) to elucidate age-related differences in pain response of calves subjected to different castration methods. Seventy six Holstein bull calves were blocked by age (≤ 6 weeks and ≥ 6 months) and randomly assigned to one of four treatment groups: control (n = 20), castration by banding (n = 18), cut and clamp surgical castration (n = 20), and cut and pull surgical castration (n = 18). Measurements included electroencephalogram, heart rate variability, infrared thermography, electrodermal activity, and concentrations of serum cortisol, and plasma substance P prior to, during, and following castration. Electroencephalogram recordings showed desynchronization for all treatments, consistent with increased arousal; yet the magnitude of desynchronization was greatest for 6-month-old calves castrated by cut and clamp. Additionally, older calves in the cut and pull group showed greater desynchronization than younger calves in the same group. Based on the heart rate variability analysis, 6-month-old calves in the control or cut and pull castration groups showed greater sympathetic tone than younger calves in the same treatment groups. Overall, younger calves showed lower electrodermal activity than older calves. Regardless of treatment, concentrations of cortisol and plasma substance P were greater in 6-month-old calves relative to their younger counterparts. In summary, neurohormonal and electroencephalographic stress responses of calves to castration were age-specific. Castration by cut and clamp showed the most pronounced stress response in 6-month-old calves.

Master of Science / Department of Animal Sciences and Industry / Joel DeRouchey / Thirteen experiments using a total of 7,589 nursery and finishing pigs were conducted to evaluate the effects of deoxynivalenol (DON), feed additives and processing conditions on nursery pig growth performance. In addition, feed withdrawal and diet blending were evaluated in finishing pigs. Experiment 1 tested 3 feed additives in DON-contaminated diets with only Defusion Plus improving performance. Experiment 2 evaluated Biofix in both low- and high-DON diets and showed no effects on growth. Experiments 3 and 4 further evaluated levels of Defusion and the effects of pelleting and supplemental nutrients in DON-contaminated diets. Defusion improved growth in low-DON diets, but had variable effects in high DON diets. Pelleting DON-contaminated diets resulted in comparable growth to pigs fed positive control diets in meal form. In Exp. 5 and 6, pilot studies evaluated DON-detoxification using sodium metabisulfite (SMB) with hydrothermal treatment in both an autoclave and a pellet mill. These conditions reduced analyzed DON by as much as 89 and 75% for the autoclave and pellet mill, respectively. In Exp. 7 and 8, pelleting DON-contaminated diets with SMB improved growth. Experiments 9 and 10 evaluated feed-withdrawal time on carcass composition and economic returns. These experiments showed that pre-slaughter fasting for up to 36 h prior can be used to avoid weight discounts in heavyweight pigs without negatively impacting carcass composition and maintaining overall revenue. However, these advantages come with a potential reduction in carcass weight and increased incidence of leaking ingesta, which can result in condemned heads. Experiments 11, 12, and 13 compared phase-feeding to blending diets using an automated feed delivery system. These studies showed that corn-supplement blending is not economical and feeding diets blended to a Lys curve results in lower feed costs compared to phase-feeding, but due to reductions in growth and carcass weight, these savings do not translate into higher income over feed cost. Finally, Exp. 13 showed that over- and under-budgeting situations do not significantly influence overall returns, but pigs fed under-budgeted diets performed more closely to those fed correctly estimated feed budgets.

Doctor of Philosophy / Department of Animal Sciences / Barry Bradford / The transition into lactation is a period of primary concern to dairy producers because of the tremendous incidence of health disorders observed during this time. Two common disorders that lead to decreases in production and retention within the herd include fatty liver disorder (FL) and ketosis. These two disorders have been commonly associated with negative energy balance, yet recently it has been hypothesized that inflammation is a contributor to the etiology of these disorders. Three individual projects were completed for this dissertation, all involving inflammation. The role of endogenous inflammation was determined by administration of sodium salicylate (SS) to cows for 7 d after parturition, and metabolites and production responses were evaluated. Overall it appears that SS induced hypoglycemic conditions and increased triglyceride accumulation in the liver (while administered), increased lipid mobilization and ketones (2 weeks after administration ended), and increased whole lactation milk production in older cows. A sensitive, specific sandwich ELISA for bovine tumor necrosis factor-[alpha] was developed, which provided the ability to measure “normal” circulating levels of this cytokine. The final study involved inducing inflammation by daily injections of the TNF[alpha] to the early lactation dairy cow. In this model, cows receiving TNF[alpha] had a reduction in dry matter intake, water intake, and decreases in milk production and milk components. Overall, it appears that inflammation is involved in the normal biology of the transition dairy cow and disrupting this can lead to interesting negative effects and some improvements of production; however, when inflammation is much greater it can lead to negative production effects.

Master of Science / Department of Animal Sciences and Industry / Timothy G. Rozell / Malnourished piglets that suffer from periweaning failure to thrive syndrome (PFTS) may show no signs of respiratory or enteric diseases but may have decreased feed intake and become debilitated after weaning. Euthanasia is a necessary component of swine production as it is sometimes the only option to alleviate suffering of piglets that are born with congenital defects or suffer from PFTS. Fifty-eight nursery-aged piglets were utilized in two experiments to evaluate blood parameter differences between healthy and unthrifty piglets and to compare euthanasia methods. Piglets were categorized into two health groups: healthy or unthrifty. During selection, blood was collected for analysis of blood parameters. Piglets were euthanized 24-32 hours after initial blood sampling and a second sample was collected for comparison. After euthanasia, piglets were necropsied for evaluation of euthanasia on pulmonary lesions. No significant difference in number of pulmonary lesions was found between health groups (P = 0.88). Healthy piglets had higher concentrations of glucose, ionized calcium and sodium, and greater pCO₂ than unthrifty piglets (P ≤ 0.05). Unthrifty piglets showed higher concentrations of hemoglobin and hematocrit (P = 0.0002) than healthy piglets. Piglets were assigned to one of two euthanasia methods to compare electrophysiological and behavioral parameters of hypobaric hypoxia and carbon dioxide gas. Two piglets at a time were euthanized for each method. One animal in the pair was fitted with electrocardiogram and electroencephalogram monitoring devices during euthanasia. Behavioral parameters were also recorded. The average treatment times were 27.4 ± 6.7 minutes for HH and 13.8 ± 5.1 minutes for CO2. Piglets euthanized via CO2 reached an isoelectric state faster than piglets euthanized via HH (P = 0.009). Behavioral observations revealed gasping in 100% of CO2 euthanized piglets during the first five minutes of treatment and only 28.6% of HH euthanized piglets during the same period. During HH, 57.1% of piglets became ataxic in the first five minutes while 76.9% of CO2¬ piglets became ataxic during the same period. Results of this trial indicate that HH may be a lower stress alternative to CO₂ as it causes fewer incidences of aversive behaviors in early stages of treatment.