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1
Beatty, David Thomas. "Prolonged and continuous heat stress in cattle: physiology, welfare, and electrolyte and nutritional interventions." Thesis, Beatty, David Thomas (2005) Prolonged and continuous heat stress in cattle: physiology, welfare, and electrolyte and nutritional interventions. PhD thesis, Murdoch University, 2005. https://researchrepository.murdoch.edu.au/id/eprint/258/.
Testo completoAbstract (sommario):
The live export of cattle is an important industry for Australia. Concerns have arisen about animal welfare and in particular heat stress which may cause production losses and death. Cattle shipped live to the Middle East from a southern Australian winter can face continuous and prolonged periods of high heat and humidity as they cross the equator and arrive into a northern hemisphere summer, leading to heat stress and excessive heat load. Some live animal exporters treat heat stressed cattle with electrolyte supplements, but no scientific data exists as to whether this is beneficial to cattle in these unique environmental conditions.
In response to industry's concerns, the experiments described here monitored the physiological responses of Bos taurus and Bos indicus to conditions similar to those experienced by cattle being shipped from southern Australian to the Middle East. Initial experiments were conducted in climate controlled rooms at Murdoch University where intensive monitoring was possible. In the Bos taurus, increases in core body temperature, reductions in feed intake, and increased water intake were measured. There were also changes in blood gas variables consistent with the observed panting causing a compensated respiratory alkalosis. Following the heating period, there were decreases in blood and urinary pH. Bos indicus showed similar responses to the heat, but the changes were less pronounced at the temperatures tested. A pair feeding experiment was conducted to separate the effects of heat from the reductions in feed intake, and this indicated that the major measured effects were due to the responses to heat. On the basis of the measured responses, an electrolyte supplement was formulated and tested on Bos taurus, in the climate controlled rooms, and then on a commercial live export vessel. Results from these experiments indicated improved buffering capacity and a weight advantage for supplemented cattle, even in the absence of extreme heat stress.
A final experiment investigated the effects of amount and quality of roughage in a pelleted feed on core and rumen temperature and feed intakes in Bos taurus subjected to hot environmental conditions in climate controlled rooms at Murdoch University. Both pelleted feeds had approximately the same metabolisable energy and crude protein but differed in content and type of roughage. There were no differences in feed intake, core temperature or rumen temperature between diets.
This work has led to a greater understanding of the physiological responses of cattle to prolonged and continuous high heat and humidity, the requirements and effects of supplemental electrolytes in these conditions, and the effect of manipulating export diets. The demonstration of advantages in weight and buffering capacity with the electrolyte supplement highlights future areas of research to investigate electrolyte doses, route and types of supplementation, and dietary manipulation.
2
Beatty, David Thomas. "Prolonged and continuous heat stress in cattle : physiology, welfare, and electrolyte and nutritional interventions /." Beatty, David Thomas (2005) Prolonged and continuous heat stress in cattle: physiology, welfare, and electrolyte and nutritional interventions. PhD thesis, Murdoch University, 2005. http://researchrepository.murdoch.edu.au/258/.
Testo completoAbstract (sommario):
The live export of cattle is an important industry for Australia. Concerns have arisen about animal welfare and in particular heat stress which may cause production losses and death. Cattle shipped live to the Middle East from a southern Australian winter can face continuous and prolonged periods of high heat and humidity as they cross the equator and arrive into a northern hemisphere summer, leading to heat stress and excessive heat load. Some live animal exporters treat heat stressed cattle with electrolyte supplements, but no scientific data exists as to whether this is beneficial to cattle in these unique environmental conditions.
In response to industry's concerns, the experiments described here monitored the physiological responses of Bos taurus and Bos indicus to conditions similar to those experienced by cattle being shipped from southern Australian to the Middle East. Initial experiments were conducted in climate controlled rooms at Murdoch University where intensive monitoring was possible. In the Bos taurus, increases in core body temperature, reductions in feed intake, and increased water intake were measured. There were also changes in blood gas variables consistent with the observed panting causing a compensated respiratory alkalosis. Following the heating period, there were decreases in blood and urinary pH. Bos indicus showed similar responses to the heat, but the changes were less pronounced at the temperatures tested. A pair feeding experiment was conducted to separate the effects of heat from the reductions in feed intake, and this indicated that the major measured effects were due to the responses to heat. On the basis of the measured responses, an electrolyte supplement was formulated and tested on Bos taurus, in the climate controlled rooms, and then on a commercial live export vessel. Results from these experiments indicated improved buffering capacity and a weight advantage for supplemented cattle, even in the absence of extreme heat stress.
A final experiment investigated the effects of amount and quality of roughage in a pelleted feed on core and rumen temperature and feed intakes in Bos taurus subjected to hot environmental conditions in climate controlled rooms at Murdoch University. Both pelleted feeds had approximately the same metabolisable energy and crude protein but differed in content and type of roughage. There were no differences in feed intake, core temperature or rumen temperature between diets.
This work has led to a greater understanding of the physiological responses of cattle to prolonged and continuous high heat and humidity, the requirements and effects of supplemental electrolytes in these conditions, and the effect of manipulating export diets. The demonstration of advantages in weight and buffering capacity with the electrolyte supplement highlights future areas of research to investigate electrolyte doses, route and types of supplementation, and dietary manipulation.
3
Hayes, Marianne Kay. "Bovine testicular cells in vitro: establishment of primary cultures and investigations of secretory functions : a thesis presented for the degree of Doctor of Philosophy in the University of Adelaide." Title page, contents and summary only, 1986. http://web4.library.adelaide.edu.au/theses/09PH/09phh4178.pdf.
Testo completoAbstract (sommario):
Includes bibliographical references (leaves 98-128). Investigates protein secretion by bovine Sertoli cells in culture. Cultures were obtained from bulls at all stages of post natal development and from sexually mature animals.
4
Theurer, Miles E. "Objective monitoring of cattle." Diss., Kansas State University, 2015. http://hdl.handle.net/2097/32794.
Testo completoAbstract (sommario):
Doctor of Philosophy<br>Department of Diagnostic Medicine/Pathobiology<br>Robert L. Larson<br>Bradley J. White<br>There are multiple modalities available to evaluate health or stress status of animals. The objective of my research was to evaluate different modalities including behavior, rectal and nasal temperature, and blood samples to determine the relationship with these outcomes of interest in bovine respiratory disease (BRD) events, environmental conditions, transportation, and Mannheimia haemolytica challenge model. The objective for the final project was to determine whether diagnostic sensitivity or specificity resulted in greater economic value for the industry using simulation models for identification of BRD.
There was a positive association with rectal temperature and probability of not finishing the production cycle normally, but this relationship was not linear. Rectal temperature of feedlot calves at first treatment for BRD had limited value as a prognostic indicator of whether those calves would finish the production cycle normally. A positive association between rectal temperature and ambient temperature and temperature-humidity index was determined. Environmental conditions must be considered when rectal temperature is used as a diagnostic tool.
At 48 hours after initiation of transportation there were no differences in body weight, rectal temperature, and time spent at various locations in the pen detected between transported and non-transported control heifers. Transportation of heifers during periods of high ambient temperatures caused transient changes in physiologic and behavioral indices of heifers. Calves challenged with Mannheimia haemolytica had more changes in behavior, body weight, and blood biomarkers during high ambient temperatures compared to control calves. Results of this study may guide research in development of objective assessment tools for identification and management of cattle affected with BRD during extreme summer conditions.
For both low and high apparent prevalence cohorts, increasing diagnostic specificity resulted in more rapid, positive change in net returns compared to change in increasing sensitivity. Improvement of diagnostic specificity, perhaps through a confirmatory test or pen-level diagnostics, can increase diagnostic value. Mortality risk was the primary driver for net returns. Results from this study are important for determining future research priorities to analyze diagnostic techniques for BRD and provide a novel way for modeling diagnostic tests.
5
Collinder, Eje. "Intestinal functions in animals : an experimental study on horses, pigs, cows and fish /." Stockholm : Karolinska Univ. Press, 2001. http://diss.kib.ki.se/2001/91-7349-066-0/.
Testo completo
6
Kruk, Zbigniew Antoni. "Genetic and non-genetic factors affecting carotenoid concentration in cattle tissues : a thesis for the degree of Doctor of Philosophy at the University of Adelaide in the Department of Animal Science." Title page, table of contents and abstract only, 2001. http://web4.library.adelaide.edu.au/theses/09PH/09phk94.pdf.
Testo completoAbstract (sommario):
Includes bibliographical references (leaves 178-194). Genetic and non-genetic factors affecting fat colour in cattle were examined in biopsy and carcass samples of Jersey and Limousin cattle in their F1 and backcross progeny.
7
Mena, Humberto 1959. "Factors affecting uptake of gossypol in cattle." Diss., The University of Arizona, 1997. http://hdl.handle.net/10150/288761.
Testo completoAbstract (sommario):
Experiments were conducted to determine effects of feeding whole cottonseed (WCS), expander solvent cottonseed meal (CSM), or a combination of these, as well as other factors on blood gossypol concentrations in cattle. In an 84 d trial, lactating cows were fed zero, 900 or 1800 ppm total gossypol (TG) in diets from WCS and/or CSM. Plasma gossypol (PG) in cows receiving 1800 ppm TG plateaued at 3.28 μg/ml after 28 d. However, by 28 d, erythrocyte fragility increased for cows receiving WCS diets. Plasma chemistry, vitamin A, body temperatures, and respiration rates were within normal ranges. Serum vitamin E levels increased with cottonseed in diets. Milk yield and FCM higher (P < 0.05) for cows fed 13.5% WCS and 7% CSM diet than controls. Feed efficiency and milk fat and protein percentages were not influenced by diets. In another study, young Holstein steers were fed diets during five consecutive treatment periods of 28 d each. The following was shown: (1) A basal diet with 15% Upland WCS resulted in average TG intakes of 9.08 g/d. (2) When varying concentrations of dietary iron (5 treatments) were fed with 15% WCS, PG and plasma total gossypol response (PG/TG intake) decreased as iron in diets increased. (3) Five diets with 15% cottonseed in the whole, cracked, roasted, roasted and cracked, or extruded forms showed that roasting or excluding WCS reduced FG in seed up to 86%. The PG concentration was higher (P < 0.05) for the whole and cracked diets, but plasma total gossypol response (PTGR) increased over controls for the cracked and roasted treatments. (4) When varying amounts of WCS and CSM (6 treatments) were fed up to 14 and 9% of the diet, respectively, PG concentration was higher (P for diets with 14% than 7% WCS. The PTGR was not affected by CSM supplementation for the 7% WCS treatments. (5) When feeding of four diets with 15% cottonseed as whole Upland, cracked Upland, whole Pima, or cracked Pima seed, PG and PTGR were higher for the Pima than Upland diets. Performance for the 28 d periods was not altered by treatments.
8
Lomas, Caroline Anne. "The effect of supplementary light on the behaviour, physiology and productivity of cattle." Thesis, Bangor University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239841.
Testo completo
9
Nguyen, Quant. "The myofibrillar and connective tissue content of selected bovine muscles and porcine cardiac and skin tissues /." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66137.
Testo completo
10
Harstine, Bo R. "Novel Approaches to Positively Impact the Early Life Physiology, Endocrinology, and Productivity of Bulls." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1480521360099455.
Testo completo
11
Li, Shihhui. "Angiopoietin-like protein 4 in bovine physiology." Thesis, Kansas State University, 2011. http://hdl.handle.net/2097/13107.
Testo completoAbstract (sommario):
Master of Science<br>Department of Animal Sciences and Industry<br>Barry Bradford<br>Angiopoietin-like protein 4 (ANGPTL4) is a 55-kDa secreted glycoprotein which is an important factor for regulation of energy and lipid metabolism. Plasma ANGPTL4 has the ability to inhibit lipoprotein lipase (LPL) function by preventing it from catalyzing hydrolysis of lipoprotein triglyceride, which contributes to ANGPTL4’s ability to decrease fat storage. Furthermore, research in mice suggests that gut microbes suppress gastrointestinal ANGPTL4 production, and that decreased plasma ANGPTL4 concentrations promote fat storage. In our previous work, we found that bovine ruminal epithelial cells expressed ANGPTL4 to a greater extent than liver hepatocytes, which are usually considered the predominant source of circulating ANGPTL4. Therefore, 3 studies were conducted to evaluate the hypothesis that ruminal expression and plasma concentrations of ANGPTL4 could be influenced by alterations in ruminal fermentation. The first and second studies utilized dietary treatments intended to alter ruminal fermentability. Diets with relatively low or high forage content were fed to 12 non-lactating dairy cows (study 1) and 8 beef cattle (study 2) prior to collection of ruminal fluid and ruminal tissue samples. The results suggested that increasing the dietary concentrate decreased ruminal expression of ANGPTL4 but did not significantly alter plasma ANGPTL4 concentrations. The third study was designed to assess whether effects of diet fermentability on ruminal ANGPTL4 synthesis are mediated by changes in volatile fatty acid concentrations. In this study, 6 lactating cows were infused with acetate, propionate, or butyrate in a Latin square design. Results showed that ANGPTL4 expression was not significantly altered by volatile fatty acid infusions, but that expression was correlated with ruminal pH and total volatile fatty acid concentration. The mechanism by which ANGPTL4 regulates intracellular lipid metabolism also remains unclear. Although ANGPTL4 is known to associate with β1 and β5 integrins, it is unknown if these extracellular matrix proteins mediate the effects of ANGPTL4 in adipose tissue or muscle. The objective of the last experiment was to detect the ANGPTL4 receptor or mediator in muscle satellite cells and adipose tissue. We successfully expressed recombinant bovine ANGPTL4 with a cell free glycoprotein synthesis system. However, we did not detect the ANGPTL4–receptor complex following exposure to bovine adipose tissue explants or cultured bovine muscle satellite cells. Overall, these research projects determined that the ruminal ANGPTL4 production is influenced by fermentation, but it remains unclear whether fermentation products or direct host/microbe interactions are responsible. Finally, it will be important to identify the ANGPTL4 receptor or mediator to better understand the downstream regulatory mechanisms involved in mediating the metabolic effects of ANGPTL4.
12
au, dbeatty@murdoch edu, and David Beatty. "Prolonged and continuous heat stress in cattle: Physiology, welfare, and electrolyte and nutritional interventions." Murdoch University, 2005. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20060831.144000.
Testo completoAbstract (sommario):
The live export of cattle is an important industry for Australia. Concerns have arisen about animal welfare and in particular heat stress which may cause production losses and death. Cattle shipped live to the Middle East from a southern Australian winter can face continuous and prolonged periods of high heat and humidity as they cross the equator and arrive into a northern hemisphere summer, leading to heat stress and excessive heat load. Some live animal exporters treat heat stressed cattle with electrolyte supplements, but no scientific data exists as to whether this is beneficial to cattle in these unique environmental conditions.
In response to industrys concerns, the experiments described here monitored the physiological responses of Bos taurus and Bos indicus to conditions similar to those experienced by cattle being shipped from southern Australian to the Middle East. Initial experiments were conducted in climate controlled rooms at Murdoch University where intensive monitoring was possible. In the Bos taurus, increases in core body temperature, reductions in feed intake, and increased water intake were measured. There were also changes in blood gas variables consistent with the observed panting causing a compensated respiratory alkalosis. Following the heating period, there were decreases in blood and urinary pH. Bos indicus showed similar responses to the heat, but the changes were less pronounced at the temperatures tested. A pair feeding experiment was conducted to separate the effects of heat from the reductions in feed intake, and this indicated that the major measured effects were due to the responses to heat. On the basis of the measured responses, an electrolyte supplement was formulated and tested on Bos taurus, in the climate controlled rooms, and then on a commercial live export vessel. Results from these experiments indicated improved buffering capacity and a weight advantage for supplemented cattle, even in the absence of extreme heat stress.
A final experiment investigated the effects of amount and quality of roughage in a pelleted feed on core and rumen temperature and feed intakes in Bos taurus subjected to hot environmental conditions in climate controlled rooms at Murdoch University. Both pelleted feeds had approximately the same metabolisable energy and crude protein but differed in content and type of roughage. There were no differences in feed intake, core temperature or rumen temperature between diets.
This work has led to a greater understanding of the physiological responses of cattle to prolonged and continuous high heat and humidity, the requirements and effects of supplemental electrolytes in these conditions, and the effect of manipulating export diets. The demonstration of advantages in weight and buffering capacity with the electrolyte supplement highlights future areas of research to investigate electrolyte doses, route and types of supplementation, and dietary manipulation.
13
Riekert, Sydney Peter. "The influence of slaughter on blood composition in cattle." Thesis, University of the Witwatersrand, 1986. http://hdl.handle.net/10539/20118.
Testo completoAbstract (sommario):
In this study the effects of blood sampling, transportation and slaughter
on certain blood variables (sodium, potasium, chloride, glucose,
lactates, lipids, proteins, colloidal osmotic pressure, cortisol, ACTH,
T3, TSH, osmolality etc.) of cattle were investigated.
The experimental animals, crossbreed (Brahman, Afrikander and Hereford)
heifers and oxen obtained from Kanhym Estates, Middelburg,
were unaccustomed to handling. One group of animals was subjected
to the stress of sampling with restraint, a second group was sampled
with restraint after transportation and a third group had blood taken
after slaughter at the Kanhym abattoir at Balfour. Control blood
samples were obtained from Friesland dairy cows accustomed to
handling and blood sampling and from crossbreed oxen unaware of
the sampling procedure. Both control and experiment groups were
studied in the same season. (April and May, 1984).
Results were analysed and compared statistically. The blood cortisol,
ACTH, lactates and glucose were significantly higher in the experimental
groups than in the control group. Cortisol and ACTH values were
significantly higher, and the lactate and glucose values significantly
lower in the group subjected to the stress of sampling with restraint
than in the other two experimental groups.
Therefore, if the variables measured are an assessment of stress and
change because of stress, then the animals investigated experienced
stress. In addition, cattle unaccustomed to handling perceive the
slaughtering process as less stressful than blood sampling in a crush
(based on cortisol and ACTH results).
14
Warner, Sharon Elaine. "Foot design, locomotor impact dynamics and pathology in large mammals." Thesis, Royal Veterinary College (University of London), 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.618328.
Testo completo
15
Nguyen-Bresinsky, Dong Thi. "Immunopurification of Bovine Placental Lactogen." Fogler Library, University of Maine, 2005. http://www.library.umaine.edu/theses/pdf/Nguyen-Bresinsky2005.pdf.
Testo completo
16
Burke, Christopher R. "Regulation of Ovarian Follicular Development with Estradiol in Cattle." The Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=osu1054666226.
Testo completo
17
Lee, Tiffany. "The effects of intake on steers administered anabolic implants." Thesis, Kansas State University, 2012. http://hdl.handle.net/2097/13890.
Testo completoAbstract (sommario):
Master of Science<br>Department of Clinical Sciences<br>Daniel Thomson<br>The objectives of this study were to examine the effect of anabolic implants on nutrient balance, metabolic status, and growth factors in animals consuming nutrients either adequate or inadequate to support growth. Sixteen crossbred steers (BW 293 ± 19.3 kg) were trained to individual Calan gates, and randomly assigned to one of four treatments in a 2x2 factorial arrangement: (1) administration of an anabolic growth implant, and fed a moderate energy starting cattle diet at 2.0 × maintenance; (2) implant administration, and fed the same starting diet at 1.0 × maintenance; (3) no implant, and 2.0 × maintenance; (4) no implant and 1.0 × maintenance diet. Cattle were implanted with RevalorXS, containing 200 mg TBA and 40 mg estradiol. Animals were weighed on d 0, 14, and 28, with total gain, ADG, and feed efficiency determined at each time point. Blood samples were taken from each animal at d 0, 14, and 28 and used in determining serum concentrations of IGF-1 and plasma urea nitrogen (PUN). Serum collected on d 14, and 28 was applied to satellite cells (previously isolated from non-study steers and frozen). Protein abundance of myosin heavy chain (MYH; d 0, 14, and 28), phosphorylated extracellular signal related kinase (pERK; d 0 and 28), and phosphorylated mammalian target of rapamycin (pmTOR; d 0 and 28) was analyzed in differentiated satellite cells to determine effects of implant, intake, and their interaction (applied via the serum). There was a significant effect of diet on weight (P < 0.0001). There was a tendancy for an interaction between diet and implant on PUN (P = 0.09). Only diet had an effect on IGF-1 levels (P < 0.001). Implant increased MYH abundance (P < 0.01), and the abundance of pERK (P < 0.01). At high intake, implant increased abundance of pmTOR (P = 0.02) but had no effect on pmTOR at restricted intake (P = 0.21; interaction P < 0.01). These preliminary results show that implantation, which has previously been shown to improve gain, ADG, and feed efficiency, may not be as beneficial in cattle fed a restricted diet.
18
MacKintosh, Sian Bethan Patricia. "Development of 3D cultural models of epithelial and stromal cells to study the pathophysiology of the bovine endometrium." Thesis, Royal Veterinary College (University of London), 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.572141.
Testo completo
19
Seymour, William Matthew. "Effect of body condition and ration protein source on performance of high producing cows during early lactation." Thesis, Virginia Tech, 1985. http://hdl.handle.net/10919/41560.
Testo completoAbstract (sommario):
<p>Forty-two high producing Holstein cows were paired by
body condition and mature equivalent milk production and fed
either a high or low energy complete ration ad libitum during
the last 16-20 weeks of lactation. Cows fed the high energy ration ate more feed, produced more milk and gained
more body condition than cows fed the low energy ration. Cows were fed to maintain condition during the dry period.
During weeks 3-15 of the next lactation, half the cows in
each condition group (fat or thin) were fed a mixed ration
with soybean meal (SBM) as the major protein source. The
remaining cows were fed a ration with dried brewers grains
(DBG) as the main protein source.</p><br>Master of Science
20
Chester-Jones, Hugh. "Physiological effects of feeding high magnesium levels to steers." Diss., Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/54264.
Testo completoAbstract (sommario):
A 130-d study was conducted with 24 363kg steers allotted to four diets containing .3 (basal), 1.4, 2.5 and 3.7% Mg, dry basis. An attempt was made to feed cattle on all treatments equal amounts of the basal diet, but steers fed the two high levels refused some feed. Grab fecal samples were collected during nine 10-d periods. Chromic oxide was used as a digesta marker. Jugular blood samples were taken on d 1, 5, 10, 20 and every 10 d thereafter. Steers were sacrificed at the end of the study for gross pathological and histological observations and tissue samples were taken for mineral analysis. Severe diarrhea was observed in steers fed the two higher Mg levels. Tubular strands of mucosal tissue were consistently voided in the feces of cattle fed these levels of Mg. Steers fed the two higher Mg levels became more lethargic as the study progressed. Fecal dry matter content and apparent dry matter digestibility decreased linearly (P<.01) with increasing dietary Mg. Weight losses for steers fed 1.4, 2.5, or 4.7% Mg were 5, 27 and 29 kg, respectively, during the study, compared to a weight gain of 9 kg for cattle fed .3% Mg (quadratic effect, P<.01). Apparent absorption of Mg generally increased with dietary Mg (P<.01), except between d 20 and 70 when it decreased (P<.01). Apparent absorption of Ca and P generally decreased with dietary Mg but effects on P absorption were not always significant. Increasing dietary Mg resulted in a linear elevation of serum and erythrocyte Mg (P<.01) and inorganic P (P<.05) and a linear decrease in serum Ca (P<.01). Plasma osmolality tended to be lowest in steers fed the highest dietary Mg. Serum parathyroid hormone was suppressed at the higher Mg intakes at 3 h but not at 9 h after feeding. Ruminal fluid pH increased as dietary Mg increased from .3 to 2.5%, then decreased (quadratic effect, P<.05). A linear increase in pH (P<.05) was recorded with increasing dietary Mg in digesta samples taken at slaughter from the lower ileum and large intestine. The Mg concentration in the liver, kidney, skeletal muscle and rib-bone and the P concentration in the skeletal muscle increased linearly (P<.05) with dietary Mg. Histologically, amorphous crystals were seen in the kidney tubules of all animals. Increasing dietary Mg in the steers caused a progressive degeneration of the rumen papillae epithelium.<br>Ph. D.
21
Rodriguez, Maria A. (Maria Angeles) 1958. "Physiological responses to 60 Hz electric and magnetic fields in dairy cows under short photoperiod conditions." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=84426.
Testo completoAbstract (sommario):
This study consisted of a series of experiments designed to test the hypothesis that exposure to extremely low frequency (ELF) electric and magnetic fields (EMF), similar to those generated by power transmission lines, can modify the response to photoperiod in dairy cows. Thirty two Holstein cows, 16 pregnant and lactating and 16 non-pregnant and non-lactating, maintained under short photoperiod (8 h light, 16 h dark), were exposed to an electric field of 10 kV/m and a magnetic field of 30 muTesla for 16 h/d, using cross-over experimental designs with three-period sequences. These exposure conditions resembled those prevalent under a 735 kV line carrying an extreme current load. Feed consumption, milk yield and composition, body weight, circulating concentrations of melatonin, prolactin, IGF-1 and growth hormone were assessed, as well as estrous cycle traits. A positive association was found between EMF exposure and feed consumption, uncorrected milk yield at the end of the exposure period and blood concentration of IGF-1. EMF exposure was also associated with an increase in blood prolactin concentration and decreased melatonin levels during the photophase in lactating pregnant cows. Non-lactating cows exposed to EMF showed longer estrous cycles. It was concluded that exposure to ELF EMF similar to those found under power transmission lines under extreme conditions of load elicits a biological response in dairy cows. Some aspects of this response are consistent with the hypothesis of a modification of the response to photoperiod.
22
Brake, Derek William. "Effects of duodenal amino acid infusion on small intestinal starch digestion in cattle." Diss., Kansas State University, 2012. http://hdl.handle.net/2097/15071.
Testo completoAbstract (sommario):
Doctor of Philosophy<br>Department of Animal Sciences and Industry<br>Evan C. Titgemeyer<br>Previous data suggest that greater amounts of postruminal protein increase small
intestinal starch digestion in cattle. Duodenally and ileally cannulated steers were used in 5 studies to measure responses in small intestinal starch digestion to amino acids (AA) or casein. Flows of starch to the ileum from the diet were small. Small intestinal starch digestibility was 34.0% when raw cornstarch was continuously infused into the duodenum. Infusion of casein linearly increased (P ≤ 0.05) small intestinal starch digestibility, and small intestinal starch digestion adapted to infusion of casein in 6 d. Ethanol-soluble starch and unpolymerized glucose flowing to the ileum increased linearly (P ≤ 0.05) with increasing infusion of casein. Plasma cholecystokinin was not affected by casein infusion, but circulating levels of glucose increased linearly (P ≤ 0.05). In another study, 5 steers were fed a low-starch diet and provided continuous
duodenal infusion of raw cornstarch in combination with AA or casein in order to measure response of small intestinal starch digestion. Duodenal infusion of casein increased (P ≤ 0.05) small intestinal starch digestion. When a mixture of AA with a profile similar to casein (CASAA) was infused, small intestinal starch digestion was similar (P = 0.30) to casein infusion. Infusion of only non-essential AA tended to increase (P = 0.14) small intestinal starch digestion relative to control; however, infusion of essential AA alone did not affect (P = 0.84) small intestinal starch digestion. Additionally, infusion of casein or essential AA increased ileal flows of ethanol-soluble starch, but non-essential AA alone were not different than the negative control. Duodenal infusion of Glu increased (P ≤ 0.05) small intestinal starch digestion, whereas a mixture of Phe, Trp, and Met (PTM) did not. Neither Glu nor PTM increased ileal flow of ethanol-soluble starch, but Glu and PTM provided together tended (P = 0.07) to increase ileal flows of ethanol-soluble starch. Our data suggest that Glu alone can increase small intestinal starch digestion in cattle similar to casein, but increases in small intestinal starch digestion in response to Glu are not associated with an increase in ileal flows of ethanol-soluble starch.
23
Carter, Jessica Meagan. "PERFORMANCE AND PHYSIOLOGY OF YEARLING STEERS GRAZING TOXIC TALL FESCUE AS INFLUENCED BY CONCENTRATE FEEDING AND STEROIDAL IMPLANTS." UKnowledge, 2008. http://uknowledge.uky.edu/gradschool_theses/569.
Testo completoAbstract (sommario):
Fescue toxicosis can produce negative effects on animal weight gain and physiology. Sixty-four steers were grazed on endophyte-infected (E+) KY-31 tall fescue for 77 days in 2007 and sixty steers grazed for 86 days in 2008 to evaluate interactions with implantation of steroidal implants and concentrate feeding on performance and physiology of yearling steers. Steers were stratified by body weight for assignment to six, 3.0-ha toxic tall fescue pastures. The main plot treatment of with or without pelleted soybean hulls (SBH) were randomly assigned to pastures. Pelleted SBH were group-fed to provide daily consumptions of 2.3 kg/steer/d (as fed). Sub-plot treatments of with or without ear implantation with steroid hormone (200 mg progesterone--20 mg estradiol were assigned to groups of five or six steers within each pasture. Average daily gain in the experiment showed an additive effect of feeding SBH and implanting (P
24
Batchelder, Cynthia A. "Cloning in cattle : effect of the nuclear-donor cell on cloning efficiency, perinatal physiology, and long-term health of cloned calves /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2005. http://uclibs.org/PID/11984.
Testo completo
25
Kazmer, Gary Wayne. "Aspects of lactation endocrinology: I. lactogenic receptors in bovine mammary tissue at different stages of lactation: II. growth hormone concentrations in Holstein cattle of differing genetic merit." Diss., Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/52298.
Testo completoAbstract (sommario):
Mammary tissue from nine Holstein cows was collected within one week of parturition, at 60 and 180 days postpartum. Blood samples were collected at 6-hr intervals from two days prior to . until two days after surgery. A membrane-enriched fraction of tissue homogenates was prepared by differential centrifugation. Displacement curve data was analyzed by a microcomputer program. Mean prolactin (Prl) during the periparturient period was greater than either postpartum period, but not prior to biopsy. Dissociation constants (Kd) estimated with NIH-bPRL-6 as competitor were not different among stages of lactation, and averaged 8.97 x 10⁻⁸M. Receptor concentrations were less during _the periparturient period than later lactation. The Kd was 100-fold greater when estimated with human growth hormone as competitor. It is concluded that lactogenic hormone receptor concentrations in bovine mammary tissue increase with the onset of lactation, following a pattern similar to that observed in non-ruminants.
Three experiments were conducted to investigate endocrine metabolic hormone profiles in Holstein cattle of differing genetic merit at several ages. Control animals were randomly bred to non-AI sires originating in the Virginia Tech Dairy herd. Selected animals were offspring of commercially available AI sires. In one experiment, mean plasma Prl was greater in control animals after feeding and insulin injection, while growth hormone (GH) was greater in selected animals at all ages. Free fatty acids were greater in selected animals at 6 and 24 months of age, while glucose (Glc) and urea were unaffected by genetic merit. In a second experiment, Holstein bull calves were administered Glc and thyrotropin releasing hormone (TRH) on different days. Plasma GH was greater in selected animals. Plasma Prl was greater in control animals after TRH. In the third experiment, Holstein cows received TRH at 30, 90 and 200 days postpartum (DPP). Net energy balance was negative at 30, while positive at 90 and 200 DPP. Plasma GH before and after TRH was greater in selected animals, and greater during early than later lactation. Thus, the results of the three experiments indicate that increased plasma GH may be associated with selection for increased milk yield.<br>Ph. D.
26
McFadden, Thomas Bernard. "Influence of hormones on synthesis and secretion of milk proteins by mammary tissue from male and female cattle of beef and dairy breeds." Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/101238.
Testo completoAbstract (sommario):
The ability of mammary tissue from prepubertal bulls and heifers of beef and dairy breeds to respond to hormonal stimuli through synthesis and secretion of milk proteins was studied. Experimental animals were six to eight month old Angus and Holstein cattle. All subjects were injected with estradiol and progesterone for seven days and slaughtered on day 15. Mammary tissue was explanted and cultured for 96 h in basal medium (B) which contained hormones necessary for maintenance, or stimulatory medium (P), further supplemented with prolactin. Selected cultures were incubated for 24 h in B or P medium containing 3H-amino acids. Concentrations of non-labeled alpha-lactalbumin (Alac), 3H-Alac, and 3H-total protein (TP) were determined in media and in explant homogenates.
Among cultures of bull mammary tissue, Angus explants secreted greater overall quantities of 3 H-TP and 3H-Alac than Holstein explants (p<.05). Secretion of Alac was also greater in Angus cultures at two of eight treatment periods (p<.01). Concentrations of all three protein fractions were likewise enhanced in homogenates of Angus explants for at least three of four treatment periods (p≤.05). Presence of prolactin in medium stimulated secretion of Alac (p<.005), and accumulation of all three fractions in explants (p<.10).
Holstein heifer explants secreted more Alac at three of eight treatment periods than Angus explants (p<.0005). Overall secretion of ³H-TP and ³H-Alac also was elevated in Holstein over Angus females (p<.10), as were concentrations of all three fractions in homogenates (p≤.01). Presence of prolactin had no direct effect on any protein parameters in female tissue.
I conclude that mammary tissue of immature bulls and heifers can be hormonally induced to express it's genetic merit for milk production (based on breed differences), through synthesis and secretion of milk proteins. Prolactin stimulated protein production in bulls but not in heifers. These findings indicate that similar methods of stimulating mammary tissue to produce milk proteins may be adaptable for commercial evaluation of genetic potential for milk production, especially in young bulls.<br>M.S.
27
Burchard, Javier F. "Effects of 60 Hz electric and magnetic fields on productivity, reproductive hormones, plasma minerals and minerals and neurotransmitter metabolites in cerebrospinal fluid in dairy cattle." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=41992.
Testo completoAbstract (sommario):
This study was designed to determine the potential biological effects of electric and magnetic fields (EMF), generated by 735 kV alternating current (AC) high tension lines upon the hormonal profile, some health-related parameters, stress response and productivity in dairy cattle. An EMF exposure chamber to house eight animals at one time was constructed. Forty-nine cows were divided according to their production stage; 8 pregnant non-lactating cows, 16 pregnant lactating cows, 16 non-pregnant lactating cows and 9 non-lactating non-pregnant heifers. They were exposed to an EMF of 10 kilovolts per meter (kV/m) and 30 micro-Tesla $( mu T)$ in two different fashions: (a) for three consecutive periods of 28 days in two sequences either with the EMF on/off/on or off/on/off, in a switch back design; (b) for three consecutive periods with the sequence OFF (5 days), ON (30 days) and OFF (5-12 days). The intensity of the EMF chosen for the experiments resembled a situation in which the cattle are standing continuously under a 735 kV AC high tension line when the line has a maximum load of current. In reality, these conditions are found only for a few days during the winter in the Province of Quebec.<br>Milk production and composition, feed consumption, blood hormonal profiles and cerebrospinal fluid (CSF) components were assessed during the different periods of exposure. Most of the variables assessed were not affected by EMF. However, there was a positive association between EMF and feed consumption, milk fat content, blood plasma progesterone during pregnancy and estrous cycle length. Also, there were changes in the mineral and neurotransmitter metabolite concentrations in the CSF that showed a relationship to the EMF.<br>In conclusion, it could be stated that EMF caused a biological response in dairy cattle. It is speculated that these changes do not represent a health hazard for exposed cattle, although they warrant further research.
28
McCann, P. J. J. "Aspects of the ecology and physiology of the Eurasian badger (Meles meles L.), cattle management and the epidemiology of bovine tuberculosis (Mycobacterium bovis)." Thesis, Queen's University Belfast, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268440.
Testo completo
29
Wilson, Jonathan Wesley. "Lysine and methionine transport by bovine jejunal and ileal brush border membrane vesicles." Diss., Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/54464.
Testo completoAbstract (sommario):
Purified brush border and basolateral membranes were isolated from homogenized intestinal enterocytes of Holstein steers by divalent cation precipitation followed by differential and sucrose density gradient centrifugation. Membrane marker enzymes were used to determine the effectiveness of the fractionation procedure. Alkaline phosphatase and sodium-potassium adenosine triphosphatase served as the marker enzymes for the brush border and basolateral membranes, respectively. The brush border fraction was enriched 5.1-fold over the cellular homogenate. Purification of 10.1-fold over cellular homogenate was obtained for the basolateral membrane fraction. Electronmicrographs and osmotic response data were used to confirm the vesicular nature of the membrane preparations. Brush border membrane vesicles from bovine jejunal and ileal tissue were used to evaluate lysine (LYS) and methionine (MET) transport. Total transport of LYS and MET was divided into mediated and diffusion components. Mediated uptake was further divided into sodium-dependent (Na⁺) and sodium independent (Na⁻) systems. Total LYS and MET uptake by ileal tissue tended to be higher than jejunal tissue at all concentrations evaluated but differences were significant (P<.O5) at 2.5 and 7.5 mM for LYS and 5, 12.5 and 15 mM for MET. The greater capacity of ileal tissue appeared to be due to the Na⁺ component of LYS uptake and the diffusion component of MET uptake. Methionine transporters had lower affinities and higher capacities than the corresponding LYS transporters in both ileal and jejunal tissue. Methionine transport was greater (P<.O5) than LYS transport in both ileal and jejunal tissue when initial amino acid concentration was 7.5 mM. When initial amino acid concentration was 1.25 mM, MET uptake was greater (P<.13) than LYS uptake in jejunal but not ileal tissue. The relative contribution of mediated and diffusion uptake systems to total MET and LYS uptake was found to be dependent of substrate concentration.<br>Ph. D.
30
Abreu, Fernanda Martins de. "The Effect of Progesterone Concentrations during Follicular Development in Cattle on Luteinizing Hormone Secretion, Follicular Development, Oocyte Competence and Fertility." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1420620191.
Testo completo
31
Crites, Benjamin R. "COMPARISON OF CONCEPTION RATES IN BEEF CATTLE INSEMINATED WITH EITHER SEXEDULTRA™ SEX-SORTED SEMEN OR CONVENTIONAL SEMEN IN FIXED-TIME ARTIFICIAL INSEMINATION (FTAI) PROTOCOLS." UKnowledge, 2017. https://uknowledge.uky.edu/animalsci_etds/80.
Testo completoAbstract (sommario):
Estrous synchronization and artificial insemination (ESAI) are reproductive technologies that cattlemen can use to improve the reproductive performance of their herds. Controlling the gender ratio of the calf-crop can also improve the opportunity for increased revenue and profit. Producers are able to shift and/or control the gender ratio of their calf crop by incorporating sex-sorted semen into their AI programs. However, decreased conception rates to AI have been previously observed when sex-sorted semen was used in comparison to conventional semen of the same sires. The objective of the first study was to determine if conception rates will differ in females inseminated with conventional semen or SexedULTRA™ sex-sorted semen when estrus is synchronized using an industry-standard, 7-d CO-Synch + Controlled Internal Drug Release (CIDR) protocol for fixed-time artificial insemination (FTAI). The objective of the second study was to determine if conception rate to FTAI differs between SexedULTRA™ sex-sorted and conventional semen when yearling beef heifers are synchronized using a 14-d controlled internal drug release (CIDR) - PGF2α (PGF) protocol modified to optimize the control of ovulation and timing of insemination.
32
Sedano, Rodolfo Canseco. "Effect of immunoglobulins on early bovine embryo development in vitro." Thesis, Virginia Tech, 1985. http://hdl.handle.net/10919/41575.
Testo completoAbstract (sommario):
Bovine morulae (day 6: n=257) were obtained to evaluate
the [effect of immunoglobulins (Ig) on early bovine embryo
development in vitro. Fifty-four cows superovulations were
conducted in 36 cows with follicle stimulating hormone.
Embryos were collected by non-surgical procedures and
morphologically evaluated and randomly assigned to culture.
Embryos were cultured in Ham's F-10 containing 10%
(6.4 mg/ml) steer serum (SS), 1% (.64 mg/ml) bovine gamma .
globulins (GG), 1% (.64 mg/ml) bovine IgG, 1% (.64 mg/ml)
bovine 1gM, 10% SS plus 1% GG, 10% SS plus 1% 1gG, or 10% SS
plus 1% 1gM. Embryos were cultured to the hatched blastocyst stage or degeneration and evaluated at 12 h intervals.<br>Master of Science
33
Nelson, John Stephen. "Fixed-time insemination of porcine luteinizing hormone-treated superovulated beef cows and the resynchronization of beef cows for fixed-time embryo transfer." [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-3239.
Testo completo
34
Bourguet, Cécile. "Stress pendant la période d'abattage chez les bovins : rôles de la réactivité émotionnelle et des facteurs environnementaux." Thesis, Clermont-Ferrand 2, 2010. http://www.theses.fr/2010CLF22079/document.
Testo completoAbstract (sommario):
La période d’abattage est complexe car elle se compose d’une succession de situations associées à une multitude de facteurs de stress. L’animal est généralement privé d’alimentation et est ensuite confronté à un environnement changeant et contraignant qui demande en permanence des adaptations comportementales et physiologiques affectant son état émotionnel. Les objectifs de cette thèse sont (i) de mieux comprendre l’origine des réactions des bovins au cours de la période d’abattage, et (ii) d’évaluer leur stress d’un point de vue comportemental et physiologique à l’aide d’études menées à la fois en abattoir industriel et dans des conditions expérimentales.Nos travaux sur le terrain mettent en évidence la nécessité de tenir compte de toutes les procédures d’abattage, y compris les plus courtes, ainsi que des contraintes organisationnelles des abattoirs car elles influencent l’état de stress des bovins. Pendant la période d’élevage, la caractérisation des bovins selon leur réactivité émotionnelle,qui dépend en partie de leur expérience antérieure et de leur race, permet d’identifier les animaux susceptibles de réagir plus fortement aux procédures d’abattage. Elle permet également de déterminer les facteurs de stress prépondérants associés à ces procédures. Ainsi, la nouveauté et la séparation sociale expliquent en partie les réactions de stress à l’abattage chez les vaches. Chez les taurillons, les réactions de stress à l’abattage sont liées à leur réactivité cardiaque à la soudaineté et à l’Homme. De plus, les bovins réagissent plus fortement à différents facteurs de stress lorsqu’ils sont privés de nourriture. L’état physiologique des bovins influence donc leurs réactions de stress à l’abattage, probablement en modulant leur perception de la situation. Afin de réduire le niveau de stress des bovins pendant la période d’abattage, nos travaux montrent qu’il est possible d’agir sur l’environnement en limitant les sources de stress directes et indirectes. Il est également possible d’agir au niveau de l’animal par le biais de son expérience antérieure et de sa génétique<br>The slaughter period is complex as it consists of a series of situations during which the animal is confronted with various stress-inducing factors. The animal is often food deprived and subjected to a changing and demanding environment that it needs constantly to adapt to in behavioural and physiological terms and which may affect the emotional status of the animal. The present thesis aimed to (i) better understand causes underlying the reactions of cattle during the slaughter period and (ii) evaluate their stress status using behavioural and physiological measurements, in studies conducted in industrial and experimental conditions.Results show that all slaughter procedures, even short-lasting, as well as organisational constraints of the abattoir, should be taken into account as they may all influence cattle stress status. During rearing, characterising the cattle according to their emotional reactivity, which depends partly on prior experience and genetic background, allows identifying animals that are likely to react relatively strongly to the slaughter procedures. It allows also identifying the main factors associated with slaughter procedures that may cause stress. Thus, novelty and social separation explain part of the slaughter stress reactions in cows. In young bulls, stress reactions at slaughter are related to their cardiac reactivity to suddenness and to human. Additionally, cattle reacted more strongly to different stressful situations when they are food-deprived. This suggests that in cattle, physiological status may influence stress reactions slaughter, possibly by modulating their perception of the situation. In order to reduce stress levels during the slaughter period in cattle, it is possible to improve aspects of the environment by avoiding direct and indirect stress-inducing factors. It is also possible to take action at the animal level by modifying its prior experience or genetic background
35
DeDonder, Keith David. "Lung auscultation as a predictor of lung lesions and bovine respiratory disease outcome in feed yard cattle." Thesis, Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/789.
Testo completo
36
Litton, Leanne Kay. "Effects of flaxseed supplementation and exogenous hormones on finishing performance, carcass characteristics, and plasma and longissimus muscle fatty acid profiles in finishing cattle." Thesis, Kansas State University, 2011. http://hdl.handle.net/2097/8757.
Testo completoAbstract (sommario):
Master of Science<br>Department of Animal Sciences and Industry<br>James S. Drouillard<br>Christopher D. Reinhardt<br>The effects of supplementing forms of flaxseed on plasma and longissimus muscle (LM) fatty acid (FA) composition, finishing performance, and carcass characteristics were evaluated in five studies. In study 1, steers were fed diets with soy oil (SO), ground flaxseed (Flaxseed), or urea formaldehyde condensation polymer treated flaxseed (UFCP). In study 2, steers were fed diets with SO, linseed oil (LO), or a combination of flaxseed and field peas that was extruded (LinPro). Feeding flaxseed products increased (P < 0.01) α-linolenic acid (ALA), omega-3 FA, and decreased (P < 0.01) n-6:n-3 in LM compared to cattle fed SO. Feeding LinPro increased (P < 0.01) ALA, omega-3 FA, and decreased (P < 0.01) n-6:n-3 in LM compared to steers fed SO or LO. In studies 3 and 4, steers were fed diets with and without Flaxseed and implanted or not. Implanting improved (P ≤ 0.05) DMI, ADG, feed efficiency, HCW, and LM area compared to cattle not implanted. In study 4, cattle fed Flaxseed had increased (P < 0.01) ALA and omega-3 FA, and decreased (P < 0.01) n-6:n-3 in LM compared to cattle fed SO. In study 5, heifers were fed diets with 0% or 5% linseed meal, and administered with or without exogenous hormones (NHTC). Administering exogenous hormones improved (P ≤ 0.02) DMI, ADG, G:F, and HCW compared to NHTC cattle. Omega-3 FA increased in LM when cattle were supplemented with flaxseed products. Cattle fed LinPro achieved the highest levels of ALA and omega-3 FA. Flaxseed products did not interact with implants as a natural growth promoter in finishing cattle.
37
Morey, Scott D. "Novel approaches to diagnosis and prevention of bovine fatty liver." Thesis, Kansas State University, 2010. http://hdl.handle.net/2097/4640.
Testo completoAbstract (sommario):
Master of Science<br>Department of Animal Sciences and Industry<br>Barry J. Bradford<br>The prevalence of fatty liver in transition dairy cattle has been reported to be as high as 50%. There are a few reliable on-farm diagnostic tools and even fewer methods to effectively prevent fatty liver. Non-alcoholic steatohepatitis, an advanced form of non-alcoholic fatty liver in humans, is accurately diagnosed with a commercial blood test that detects plasma cytokeratin-18 (CK18) fragments released during hepatocyte apoptosis. A study was performed using 89 Holstein cows in early lactation to determine if CK18 could serve as a novel indicator of liver triglyceride (TG) content. Although no previous work has been done with CK18 in bovine plasma, our results indicated that CK18 fragments were present in plasma. However, CK18 concentrations did not correlate with liver TG content or other measures of liver function, suggesting it is not a reliable diagnostic tool. Nevertheless, based on liver TG, plasma non-esterified fatty acid (NEFA), and plasma β-hydroxybutyric acid (BHBA) concentrations, this sample population as a whole was not suffering from severe metabolic problems or fatty liver, making it possible that plasma CK18 fragments are elevated only in the most extreme cases. Currently, there is no widely-adopted preventative strategy for fatty liver. A second study was performed to evaluate if encapsulated niacin (EN) could prevent liver TG accumulation during the transition period. Twenty-four primiparous (n=9) and multiparous (n=13) cows were randomly assigned to receive 0 or 24 g of dietary EN, beginning 3 weeks prior to expected calving until 21 days postpartum. Feeding EN did not influence liver TG content, but decreased plasma NEFA concentrations, suggesting inhibition of lipolysis. Multiparous EN cows also experienced depressed dry matter intake (DMI) in the 4 days prior to calving. However, even when EN reduced DMI, plasma NEFA was still suppressed. A novel finding was the prolonged clearance of caffeine in plasma on day 7 postpartum in EN-treated animals. In contrast to other studies, this dose and delivery method of EN did not result in an increase in plasma NEFA after EN treatment ended. These research projects determined that plasma CK18 is likely not a useful diagnostic tool for mild to moderate bovine fatty liver and that feeding EN can inhibit lipolysis but may influence DMI as well. This is one of the first studies into the metabolic effects of feeding EN, and further research is needed in this field.
38
Gibson, Troy John. "Electroencephalographic responses of calves to the noxious sensory input of slaughter by ventral neck incision and its modulation with non-penetrative captive bolt stunning : a thesis presented in partial fulfilment of the requirements of the degree of Doctor of Philosophy in Physiology, Massey University, Palmerston North, New Zealand." Massey University, 2009. http://hdl.handle.net/10179/1010.
Testo completoAbstract (sommario):
Slaughter by ventral neck incision (VNI) is performed on some animals without prior stunning in New Zealand and other countries. A single incision with a razor sharp blade is made in the ventral aspect of the neck, sectioning both carotid arteries and jugular veins, though, not the vertebral arteries. There are a number of potential welfare concerns surrounding slaughter by VNI including pain due to the incision, which may lead to distress during the time before loss of consciousness. The aims of this thesis were to identify cortical responses indicative of noxious stimulation due to slaughter by VNI using analysis of the electroencephalogram (EEG) power spectrum and to investigate the effects of non-penetrative captive bolt (NPCB) stunning on these cortical responses. The studies utilised adaptations of a minimal anaesthesia model, which has been validated in a range of mammalian species. Surgical dehorning was used as a validation technique for this methodology in cattle and demonstrated a ‘typical’ EEG response to noxious stimulation. Cattle slaughtered by VNI without prior stunning produced specific responses in the EEG that strongly indicated responses to noxious stimulation. Causation was investigated in cattle where blood flow through the brain remained intact during neck tissue incision (NTI) or the major blood vessels of the neck were isolated and transected independently of other neck tissues (BVT). The response to neck incision in intact animals was principally due to the noxious sensory input due to incision of neck tissues and not mainly as a result of loss of blood flow through the brain. NPCB stunning produced states of cortical activity that were incompatible with the maintenance of sensibility and pain perception. Experimental examination of the time to onset of undoubted insensibility was attempted in cattle subsequent to a pilot study in sheep. The generation of somatosensory-evoked potentials was problematic in cattle. The conclusions of this thesis are that incision of neck tissues during slaughter without prior stunning constitutes a substantial noxious stimulus. Were an animal conscious, this stimulus would be perceived as painful until the onset of hypoxiainduced insensibility. This would represent a significant compromise to animal welfare.
39
Lupinacci, Adriano Vecchiatti. "Reservas orgânicas, índice de área foliar e produção de forragem em Brachiaria brizantha cv. Marandu submetida a intensidades de pastejo por bovinos de corte." Universidade de São Paulo, 2002. http://www.teses.usp.br/teses/disponiveis/11/11139/tde-27082002-135702/.
Testo completoAbstract (sommario):
As áreas de pastagens no Brasil ocupam cerca de 180 milhões de hectares, que são responsáveis por cerca de 90% da carne bovina produzida no país. No entanto, em torno de 80% das pastagens cultivadas apresentam algum grau de degradação, sendo este apontado como o maior problema relacionado com a sustentabilidade da produção animal em pastagens. Uma das principais razões para esse fato está relacionada a erros grosseiros no manejo das pastagens, conseqüência do desconhecimento dos limites ecofisiológicos e de resistência ao pastejo das plantas forrageiras. Dentro desse contexto, o objetivo deste experimento foi determinar quantitativamente o índice de área foliar, os teores e estoques de carboidratos não estruturais e frações nitrogenadas (N total, N solúvel, N aminoácidos, N amônio, N nitrato) de reserva, a taxa de acúmulo e a produção de forragem em pastos de Brachiaria brizantha cv. Marandu pastejados por bovinos em regime de lotação contínua e taxa de lotação variável. O experimento foi realizado em área do Departamento de Produção Animal da USP/ESALQ, em Piracicaba, SP, entre 27 de agosto de 2001 e 28 de fevereiro de 2002. Os tratamentos corresponderam a quatro alturas de pasto (10, 20, 30 e 40 cm), mantidas em steady state, e foram alocados às unidades experimentais conforme um delineamento de blocos completos casualizados, com quatro repetições. Os valores de IAF (1,7; 3,5; 4,0 e 3,8) foram crescentes para as alturas de pasto estudadas (10, 20, 30 e 40 cm, respectivamente) e semelhantes para as alturas de 20, 30 e 40 cm. Comportamento semelhante foi identificado para as taxas de acúmulo (102,0; 118,5; 121,6 e 113,9 kg ha -1 dia -1 MS) e acúmulo total de forragem (10.300; 13.340; 12.620 e 13.880 kg ha -1 ). Os teores (88,5; 111,7; 109,8 e 118,4 g kg -1 ) e estoques (0,152; 0,167; 0,180 e 0,157 kg m -2 ) de carboidratos não estruturais foram crescentes com as alturas de pasto (10, 20, 30 e 40 cm, respectivamente), ao passo que o inverso foi detectado para os teores e estoques de todas as frações nitrogenadas (10,65; 8,93; 8,64; 8,04 g kg -1 N total e 0,018; 0,017; 0,014; 0,012 kg m -2 N total, respectivamente). Com relação ao meses, houve uma redução acentuada ao longo do período experimental nos teores (118,8 para 87,2 g kg -1 de setembro a fevereiro) e estoques (0,225 para 0,111 kg m -2 de setembro a fevereiro) de carboidratos não estruturais e, também nos teores e estoques correspondentes às frações nitrogenadas (12,76 para 3,98 g kg -1 N total e 0,031 para 0,005 kg m -2 N total de setembro a fevereiro), motivadas inicialmente pelo início do verão (estação de crescimento) e posteriormente pelo início do desenvolvimento reprodutivo das plantas. Os estoques de carboidratos e de frações nitrogenadas foram consistentemente maiores para a base do colmo relativamente às raízes, tendo sido utilizados como fonte preferencial de matéria prima para o crescimento das plantas, razão pela qual sofreram as maiores reduções ao longo do tempo. As inflorescências se mostraram drenos metabólicos muito fortes durante a fase reprodutiva, assim como os meristemas apicais durante a fase vegetativa. O teor de N total nas folhas dos perfilhos diminuiu com o tempo (17,4 para 13,1 g kg -1 de dezembro a fevereiro), sendo os valores crescentes para folhas senescentes, maduras e em expansão (11,4, 14,0 e 16,7 g kg -1 , respectivamente). A altura de pasto de 10 cm correspondeu a uma condição de desfolha drástica, de modo que o manejo do pastejo deveria ser efetuado entre as condições de pasto de 20 e 40 cm. A escolha da condição de pasto mais indicada deve ser feita mediante o objetivo da atividade e a natureza da exploração animal proposta.<br>Grassland areas in Brazil occupy around 180 million hectares and support about 90% of the countrys beef production. However, approximately 80% of the cultivated pasture areas present some degree of degradation, that being the main problem related to the sustainability of pasture-based animal production systems. One of the main reasons for this is the mismanagement of pastures, consequence of the lack of knowledge and understanding about the ecophysiological limits and tolerance to grazing of forage plants. Against this background, the objective of this experiment was to determine the leaf area index (LAI), concentrations and pools of non structural carbohydrates (NSC) and nitrogenous reserve compounds (total N, soluble N, amino acid N, ammonium N, nitrate N), herbage dry matter accumulation rates and forage yield from Brachiaria brizantha cv. Marandu pastures continuously stocked by cattle, with variable stocking rate. The experiment was carried out at Departamento de Produção Animal, USP/ESALQ, Piracicaba, SP, from 27 August 2001 until 28 February 2002. Treatments corresponded to four steady state conditions characterized by sward surface heights (SSH) of 10, 20, 30 and 40 cm, assigned to experimental units according to a complete randomized block design, with four replications. LAI values (1.7, 3.5, 4.0 and 3.8) increased with increasing SSH (10, 20, 30 and 40 cm, respectively) and were not different among the 20, 30 and 40 cm treatments. Similar trend was recorded for herbage accumulation rates (102.0, 118.5, 121.6 and 113.9 kg ha -1 ) and forage yield (10,300, 13,340, 12,620 and 13,880 kg ha -1 ). The concentration (88.5, 111.7, 109.8 and 118.4 g kg -1 ) and pool (0.152, 0.167, 0.180 and 0.157 kg m -2 ) of NSC increased with increasing SSH (10, 20, 30 and 40 cm, respectively), whereas the inverse occurred with the concentration and pool of all nitrogenous compounds (10.65, 8.93, 8.64 and 8.04 g kg -1 total N and 0.018, 0.017, 0.014 and 0.012 kg m -2 total N, respectively). In relation to time of the year, there was a sharp decrease in the concentration and pool of NSC throughout the experimental period (118.8 to 87.2 g kg -1 and 0.225 to 0.111 kg m -2 , respectively, from September to February) as well as in the concentration and pool of all nitrogenous compounds (12.76 to 3.98 g kg -1 total N and 0.031 to 0.005 kg m -2 total N, respectively, from September to February), initially motivated by the commencement of summer (growing season) and followed by the beginning of reproductive development of plants. Pools of NSC and all nitrogenous compounds stored in stem base were consistently higher than those stored in roots and comprised the prime source of substances for plant growth, that being the reason for presenting the greatest reductions throughout the experimental period. Reproductive stems proved to be very strong metabolic drains during the reproductive phase of plant development as well as tiller growing points during the vegetative phase. The total N concentration in tiller leaves decreased with time (17.4 to 13.1 g kg -1 from December to February), with values increasing for senescent, mature and elongating leaves (11.4, 14.0 and 16.7 g kg -1 , respectively). The 10 cm SSH corresponded to a drastic defoliation condition, indicating that grazing management should be conducted within the 20 to 40 cm SSH range. The choice of the most appropriate SSH condition must take into account the main objective and nature of the animal production system proposed.
40
Lesage, Audrey. "Rôles de FOXL2 dans la physiologie endométriale chez les bovins." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS422/document.
Testo completoAbstract (sommario):
L'implantation est une étape cruciale de la gestation et du développement post-natal chez les mammifères. L'implantation est définie comme l'établissement d'interactions cellulaires et permanentes entre un endomètre réceptif et un embryon compétent et synchronisé. L'endomètre est un capteur (sensor) biologique de qualité embryonnaire qui conduit la trajectoire de développement du conceptus jusqu'à terme. Les données préalables de notre équipe et d'autres ont suggéré que FOXL2 - un facteur de transcription clé pour l'établissement et le maintien de la fonction ovarienne – pourrait avoir des rôles biologiques majeurs dans le développement et les fonctions de l'endomètre chez les mammifères. L'objectif de mon travail était de comprendre dans quelle mesure FOXL2 contribue à la régulation de la fonction endométriale chez les bovins laitiers. Nous avons d'abord évalué les conséquences des variations du métabolisme maternel sur l'expression endométriale de FOXL2 et une sélection de gènes candidats. Notre étude a mis en évidence que, chez les femelles Holstein primipares taries immédiatement après le vêlage, l'expression de FOXL2 est augmentée alors que l'expression des enzymes antioxydantes est diminuée dans l'endomètre lors de l'implantation. Grâce à un modèle in vitro de cultures primaires de cellules endométriales bovines (fibroblastes et cellules épithéliales glandulaires) surexprimant transitoirement FOXL2, nous avons pu montrer que l'expression des gènes codant pour les enzymes antioxydantes n’est pas dépendante de FOXL2. Sur la base de notre modèle expérimental in vitro, les profils d'expression des gènes ont ensuite été déterminés à l'aide d'un oligoarray bovin non commercial. L’analyse des données a révélé une variation de l’identité des gènes cible de FOXL2 en fonction du type cellulaire considéré. Comme dans l'ovaire, FOXL2 régule des gènes liés à "la réponse immunitaire", "l’apoptose" et "la détermination du sexe". Nos résultats ont également mis en évidence la régulation par FOXL2 de fonctions spécifiques de l'endomètre, telles que «la réponse à l'interféron de type I» et «la modification de matrice extracellulaire». En somme, nos données mettent en lumière le rôle de FOXL2 dans la régulation de la physiologie endométriale bovine. Ses fonctions biologiques mériteraient d'être analysées et comparées chez d'autres espèces de mammifères<br>Implantation is a critical milestone ensuring a successful pregnancy and normal post-natal development in mammals. Implantation is defined as the establishment of cellular and permanent interactions between a receptive endometrium and a competent and synchronised embryo. Endometrium has been proposed to be a biological sensor of embryo quality that drives the developmental trajectory of the conceptus until term. Previous data from our team and others have suggested major biological roles for FOXL2 – a key transcription factor for the establishment and maintenance of ovarian function- in the development and functions of the mammalian endometrium. The aim of my work was to provide new insights on the contribution of FOXL2 to the regulation of the endometrial function in dairy cattle. We first evaluated the consequences of variations in maternal metabolism on the endometrial expression of FOXL2 and a selection of candidate genes. Our data demonstrated that, in Holstein primiparous females dried immediately after parturition, FOXL2 expression was increased whereas antioxidant enzymes expression was decreased in the endometrium at implantation. Using an in vitro model of primary cultures of bovine endometrial cells (fibroblasts and glandular epithelial cells) transiently overexpressing FOXL2, expression of genes encoding antioxidant enzymes did not appear to be FOXL2 dependant. Based on our in vitro experimental model, gene expression profiles were then determined using a bovine custom oligoarray. Data analyses unveil differences in FOXL2-regulated genes according to endometrial cell origin. As in the ovary, FOXL2 regulated sets of genes related to "immune response", "apoptosis" and "sex determination". Our results also highlighted regulation of endometrium-specific genes by FOXL2 including “response to type I interferon” and “extracellular matrix modification”. Altogether our data support the involvement of FOXL2 in the regulation of bovine endometrial physiology that deserves to be analyzed in other mammalian species
41
Diaza, Angela Maria Gonella. "Effect of Peri-Ovulatory Endocrine Milieu in the Oviductal Physiology of Beef Cows: Regulation of the Transcriptome, Tissue Morphology, Cell Proliferation, Extracellular Matrix Remodeling, microRNAs Abundance Profile, and Oviductal Fluid Composition." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/10/10131/tde-02082017-152246/.
Testo completoAbstract (sommario):
In cattle, the oviduct plays an important role in the reproductive process. Oviductal secretions characterize the environment where storage and sperm capacitation, fertilization, and early embryo development take place. Because molecular control of bovine oviduct receptivity is poorly understood, this Thesis proposed a model of receptivity based on the manipulation of pre-ovulatory follicle growth (POF) used to study the effects of periovulatory endocrine profile on oviductal physiology. Growth of POF in Nelore cows (Bos indicus) was manipulated to produce two groups: cows with large POF and large corpus luteum (LF-LCL; higher fertility) and cows with small POF and small CL (SF-SCL; Lower fertility). Ampulla and isthmus samples were collected on day 4 after induction of ovulation with GnRH. In the first study, the transcriptome of the ipsilateral to CL ampulla and isthmus was determined by RNAseq, the regional expression of genes was studied by qPCR, and the distribution of the PGR and ER proteins was assessed by immunohistochemistry. Greater abundance of PGR and ER was found in the oviduct of the LF-LCL animals indicating that there is a greater availability of receptors and, possibly, of signaling-mechanisms stimulated by steroids in both oviductal regions. The transcripts profile showed enriched oviductal functional characteristics that could affect its embryo receptivity. These characteristics include changes in morphology i.e. branching morphogenesis, and changes in cell functioning i.e. cell secretion, that were enriched in the LF-LCL group. In the second study, after morphological analyses, it was concluded that the ampulla of the LF-LCL animals presented more primary folds, a larger perimeter of the luminal epithelium, and a higher proportion of secretory and proliferating cells, when compared to SF-SCL group. There was no difference in isthmus morphology between groups. In the third study, the extracellular matrix remodeling was reserched. It was concluded that in the isthmus region of the LF-LCL animals, there is less type 1 collagen fibers and greater abundance of proteins involved in extracellular matrix remodeling. In the fourth study, it was determined that the periovulatory endocrine milieu affects the expression of components of the microRNAs biosynthesis pathway and the microRNAs profile, both different between groups. Finally, in the fifth study, 205 metabolites were quantified in the oviductal fluid and 37 were found to be in different concentrations when both groups were compared. It was concluded that oviduct of cows of higher fertility presents a profile of transcripts, proteins, and metabolites that is associated with morphological and functional characteristics favorable to the survival and development of the embryo.<br>Em fêmeas bovinas, o oviduto apresenta um importante papel no processo reprodutivo. As secreções ovidutais representam o ambiente onde ocorrem o armazenamento e a capacitação espermática, a fecundação e o desenvolvimento embrionário inicial. O controle molecular da receptividade do oviduto em bovinos é pouco conhecido. Na presente tese, empregou-se um modelo de receptividade baseado na manipulação do crescimento do folículo pré-ovulatório (FPO) para o estudo dos efeitos do perfil endócrino periovulatório na fisiologia do oviduto. O crescimento do FPO de vacas Nelore (Bos indicus) foi manipulado com o objetivo de produzir dois grupos: vacas com FPO e corpo lúteo (CL) grandes (FG-CLG; maior fertilidade) e vacas com FPO e CL pequenos (FP-CLP; menor fertilidade). Amostras da ampola e istmo foram coletadas no dia 4 após da indução da ovulação com GnRH. No primeiro estudo, o transcriptoma da ampola e istmo do lado ipsolateral ao CL foi determinado por RNAseq, à expressão gênica regional e a distribuição das proteínas PGR e ER foram analisadas por qPCR e imunohistoquímica, respectivamente. Houve maior abundância de PGR e ER no oviduto dos animais do grupo FG-CLG, o que indica uma maior disponibilidade de receptores e possivelmente, de mecanismos intracelulares de sinalização estimulados pelos esteroides em ambas as regiões. O perfil global de transcritos mostrou enriquecimento de características funcionais do oviduto que poderiam afetar sua receptividade ao embrião. Tais características incluem mudanças morfológicas, como a ramificação morfogênica, e celulares, como a secreção, que foram aumentadas no grupo FG-CLG. No segundo estudo, após analisarem-se características morfológicas dos tecidos, concluiu-se que a ampola dos animais FG-CLG apresentou maior número de pregas primárias, maior perímetro do epitélio luminal, e maior proporção de células secretoras e de células em proliferação quando comparado aos animais do grupo FP-CLP. Não houve diferença na morfologia do istmo entre os grupos. No terceiro estudo, foi analisado o processo de remodelamento de matriz extracelular. Concluiu-se que no istmo dos animais do grupo FG-CLG existe menor quantidade de fibras de colágeno tipo 1 e maior abundância de proteínas envolvidas no remodelamento de matriz. No quarto estudo, determinou-se que o perfil endócrino periovulatório afeta a expressão de componentes da via de biossíntese e o perfil de microRNAs, que são diferentes entre os grupos. Finalmente, no quinto estudo, foram quantificados 205 metabólitos no fluido ovidutal dos animais. Destes, 37 encontram-se em concentrações diferentes entre os grupos. Concluiu-se que o oviduto de vacas de maior fertilidade apresenta um perfil de transcritos, proteínas e metabólitos que está associado a características morfológicas e funcionais favoráveis à sobrevivência e desenvolvimento do embrião.
42
Baldridge, Sarah. "Pharmacokinetics and physiologic effects of xylazine-ketamine-butorphanol administered intramuscularly or in combination with orally administered sodium salicylate on biomarkers of pain in Holstein calves following concurrent castration and dehorning." Thesis, Kansas State University, 2010. http://hdl.handle.net/2097/7035.
Testo completoAbstract (sommario):
Master of Science<br>Department of Clinical Sciences<br>Johann F. Coetzee<br>Objective—To determine the pharmacokinetic parameters of xylazine, ketamine, and butorphanol administered IM and sodium salicylate administered PO and to compare their effect on biomarkers of pain and distress following sham (Period 1) and actual (Period 2) castration and dehorning.
Animals—40 Holstein bull calves
Procedures—Calves weighing 108 to 235 kg received the following treatments prior to sham castration and dehorning (Period 1) and castration and dehorning (Period 2) (n=10 calves/group): (i) 0.9% saline solution IM (PLACEBO) (ii) sodium salicylate (SAL) supplied free-choice in water to provide concentrations from 2.5 to 5 mg/mL beginning 24 hours prior to Period 1 to 48 hours after Period 2; (iii) 0.025 mg/kg butorphanol, 0.05 mg/kg xylazine, 0.1 mg/kg ketamine co-administered IM immediately prior to both periods (XKB); and (iv) a combination of treatments (ii) and (iii) (SAL + XKB). Plasma drug concentrations, average daily gain (ADG), chute exit speed, serum cortisol concentrations and electrodermal activity (EDA) were evaluated.
Results—ADG (0-13d) was significantly greater in the SAL and SAL + XKB groups. Calves receiving XKB had significantly slower chute exit speed in both periods. Serum cortisol concentrations were significantly increased in all groups during Period 2 compared to Period 1. However, XKB attenuated serum cortisol response for the first hour after castration and dehorning while oral salicylate significantly reduced cortisol from 1-6 hours. XKB administration significantly decreased EDA scores in both periods.
Conclusions and Clinical Relevance—Free-choice sodium salicylate decreases cortisol concentrations and reduced weight loss associated with castration and dehorning in calves.
43
Agnolin, Carlos Alberto. "Avaliação de óleos essenciais de capim limão, citronela e eucalipto no controle do carrapato." Universidade Federal de Santa Maria, 2012. http://repositorio.ufsm.br/handle/1/4332.
Testo completoAbstract (sommario):
This research was aimed at evaluating in vitro and in vivo effects of lemongrass
(Cymbopogon flexuosus Stapf.) oil, citronella (Cymbopogon winterianus Jowitt) oil and
eucalyptus (Corymbia citriodora) oil on cattle ticks (Rhipicephalus (Boophilus)
microplus), each of which corresponds to an essential oil experiment. Negative control
group end eight concentrations of lemongrass oil, citronella oil and eucalyptus oil (0.5;
1; 2; 5; 10; 20; 50; 100%), were used on in vitro trials with engorged female ticks. The
efficacy control ticks was 0; 20; 39; 99.5; 100; 100; 100; 100 and 100%, for
lemongrass oil, of 0; 34.5; 43; 48; 82; 99; 99; 100 and 100%, for citronella oil and 0;
30.5; 75.5; 91; 100; 100; 100; 100 and 100%, of oil, respectively. On in vivo trial
eighteen Holstein cows were allocated to three groups for each treatment (negative
control, essential oil - level estimated by regression analysis, accounting for 95%
efficacy of control ticks on in vitro trial and amitraz at 0.025%). Engorged female ticks
were counted before (mean of days -3, -2, -1) and after treatment (1, 2, 3, 5, 7, 10, 14,
21 days). Twenty one days after application of the products, the efficacy on control
ticks was 0; 54 (lemongrass oil at 2%) and 74.5%; of 0; 91.3 (citronella oil at 8.6%)
and 60%; and 0; 96.4 (eucalyptus oil at 3.5%) and 69%, respectively for in vivo
treatments. On the 1st and 2nd milked after treatments, physiologic variables were
evaluate and milk samples were collected to evaluate organoleptic properties in milk
and yoghurt (negative control x phytotherapic treatment). Similar results were found
with sensorial acceptance test of milk and physiologic variables, in the three in vivo
experiments.<br>Esta pesquisa foi conduzida com o objetivo de avaliar o efeito in vitro e in vivo
do óleo de capim limão (Cymbopogon flexuosus Stapf.), citronela (Cymbopogon
winterianus Jowitt) e eucalipto (Corymbia citriodora) sobre o carrapato bovino
(Rhipicephalus (Boophilus) microplus), sendo que cada óleo essencial corresponde a
um experimento. Nas experimentações in vitro foi utilizado o grupo controle negativo
e oito concentrações de óleo de capim limão, de citronela e de eucalipto (0,5; 1,0; 2,0;
5,0; 10,0; 20,0; 50,0; 100,0%), em fêmeas ingurgitadas de carrapatos. A eficácia de
controle foi de 0; 20; 39; 99,5; 100; 100; 100; 100 e 100% para o óleo de capim limão;
de 0; 34,5; 43; 48; 82; 99; 99; 100 e 100% para o óleo de citronela e de 0; 30,5; 75,5;
91; 100; 100; 100; 100 e 100% para o óleo de eucalipto, respectivamente. Para a
experimentação in vivo foram constituídos três grupos para cada experimento
(controle negativo, óleo essencial - nível estimado mediante análise de regressão,
correspondendo a 95% de eficácia de controle do carrapato da pesquisa in vitro e
amitraz a 0,025%), com dezoito vacas da raça Holandesa. Antes (média dos dias -3, -
2, -1) e após a aplicação do produto (1, 2, 3, 5, 7, 10, 14, 21 dias), foram contadas
fêmeas ingurgitadas de carrapato. A eficácia de controle 21 dias após a aplicação dos
produtos foi de 0; 54 (capim limão a 2%) e 74,5%; de 0; 91,3 (citronela a 8,6%) e 60%
e de 0; 96,4 (eucalipto a 3,5%), e 69%, para os respectivos tratamentos in vivo. Na 1ª
e na 2ª ordenha após a aplicação dos tratamentos, foram avaliadas variáveis
fisiológicas e coletadas amostras de leite para avaliar as propriedades organolépticas
no leite e do iogurte (controle negativo x tratamento fitoterápico). O teste de aceitação
sensorial do leite e as variáveis fisiológicas avaliadas foram similares entre os
tratamentos nos três experimentos in vivo.
44
Silva, del Rio Noelia. "Epidemiology, physiology and nutritional management of twinning in Holstein cattle." 2007. http://www.library.wisc.edu/databases/connect/dissertations.html.
Testo completo
45
Collins, Jonna Erin. "Expression of the Ets family of transcription factors in early bovine and ovine embryo development." Thesis, 2002. http://hdl.handle.net/1957/32048.
Testo completoAbstract (sommario):
Maternally-derived transcripts and proteins support early bovine and ovine
embryo development until the 8- to 16-cell stage, at which time embryonic
transcripts become essential for continued development. One purported
mechanism for the switch from maternal to zygotic control of development
(maternal to zygotic genome activation; MZGA) is the appearance of transcription
factors that activate specific genes in the embryonic genome. Members of the E26
transformation specific (Ets) family are unique transcription factors involved in
development, differentiation, and protease regulation. This study was undertaken
to evaluate expression and function of the Ets transcription factors, Ets-1, Ets-2,
and Elf-1, in early bovine and ovine embryos from the one-cell stage to Day 15 of
pregnancy (Day 0 onset of estrus).
In the first experiment, bovine embryos from the one- to 16-cell stages were
derived by in vitro maturation, fertilization, and culture. Days 6, 8, 10, 12, and 14
embryos were collected nonsurgically from estrous synchronized and
superovulated cows. RNA was extracted at the appropriate time interval and
reverse transcribed. The resultant cDNA was amplified by PCR using primers
designed for Ets-1, Elf-1, and Ets-2. Ets-1 transcripts were present in both primary
and matured oocytes, cleavage stage embryos, and Days 10, 12, and 14 embryos, as
well as in the positive control, bovine ovary. Elf-1 transcripts were detected in the
matured oocyte, cleavage stage embryos, and Days 6, 10, and 14 embryos. Ets-2
transcripts were not observed in the embryonic stages investigated or the bovine
ovary.
Ovine embryos were surgically collected from synchronized and
superovulated ewes and similarly analyzed for Ets-1 and Elf-1 expression using the
same RNA extraction and RT-PCR technique. Embryos expressed both transcripts
at Days 13 and 15, but did not show expression at any of the earlier stages
evaluated.
The second experiment was designed to determine if inhibition of ETS-1
translation would interfere with development and plasminogen activator (PA)
production in bovine embryos. Plasminogen activator production was evaluated in
Days 5 and 6 embryos nonsurgically collected from superovulated cows and
cultured in 1, 2.5, 5, or 10 ��M concentrations of sense or antisense Ets-1
oligonucleotides. In preliminary experiments, 1 ��M antisense was ineffective in
suppressing PA production, and 10 ��M oligonucleotides were detrimental to
development. Day 5 embryos treated with 2.5 ��M oligonucleotides inhibited
developmental effect and total PA production was (P<0.05) lower in antisense treatments when compared to either control or sense treatments. No difference
(P>0.10) in PA production was observed between Day 6 embryos treated with 2.5
or 5 ��M sense and antisense oligonucleotides. A significant time effect on PA
production was observed in both Day 5 and Day 6 embryos cultured in either 2.5 or
5 ��M concentrations of oligonucleotides.
Based on these results, it is unlikely that Elf-1 and Ets-2 are involved in
MZGA because the former is constituitively expressed throughout development,
and the latter was not observed. There is some uncertainty regarding the
expression of Ets-1 during MZGA. This factor may be expressed after MZGA for
controlling PA production and other proteases involved in extracellular matrix
turnover and early germ layer formation.<br>Graduation date: 2003
46
Gümen, Ahmet. "Studies on the underlying physiology and treatment of anovulatory condition in dairy cattle." 2003. http://www.library.wisc.edu/databases/connect/dissertations.html.
Testo completo
47
Schreiner, Daniel A. "Effects of tail docking on behavior, physiology and milk quality of dairy cattle." 2001. http://catalog.hathitrust.org/api/volumes/oclc/50082298.html.
Testo completoAbstract (sommario):
Thesis (M.S.)--University of Wisconsin--Madison, 2001.<br>Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 58-59).
48
Hayes, Marianne Kay. "Bovine testicular cells in vitro: establishment of primary cultures and investigations of secretory functions / by Marianne Kay Hayes." Thesis, 1986. http://hdl.handle.net/2440/20634.
Testo completoAbstract (sommario):
Includes bibliographical references (leaves 98-128).<br>iv, 128 leaves, [22] leaves of plates : ill. ; 30 cm.<br>Investigates protein secretion by bovine Sertoli cells in culture. Cultures were obtained from bulls at all stages of post natal development and from sexually mature animals.<br>Thesis (Ph.D.) -- University of Adelaide, Dept. of Animal Sciences, 1987
49
Duncan, Jennifer S. "The role of phosphoenolpyruvate carboxykinase in the periparturient and ketotic dairy cow." Thesis, 1998. http://hdl.handle.net/1957/33674.
Testo completoAbstract (sommario):
Although the occurrence of ketosis is a postpartum phenomenon, recent studies have
focused on the prepartum period as key in the development of the disorder. Indicators of
prepartum energy status, such as depressed dry matter intake (DMI) and elevated plasma
non-esterified fatty acid (NEFA) concentrations have been associated with the occurrence
of ketosis. The objective of this study was to investigate the role of phosphoenolpyruvate
carboxykinase (PEPCK) in the periparturient and ketotic cow. The enzyme PEPCK
catalyzes the rate limiting step in gluconeogenesis in hepatocytes. Whereas, in adipocytes,
it has been suggested that PEPCK functions in the synthesis of glycerol for the formation
of triacylglycerol (TAG) when plasma glucose concentrations are low. Thirty-four
pregnant multiparous Holstein dairy cows were fed a single prepartum ration that
consisted of 50% oat hay, 18% corn silage and 32% grain mix (DM basis). The ration
was formulated to meet or exceed NRC requirements of 14% CP and 1.6 Mcal/kg NE[subscript L].
At calving, cows were transitioned onto one of two postpartum diets: control (n=14) or
3.5% supplemental fat (n=20). The postpartum diets, fed from wk 1 to 3, were
formulated to isonitrogenous and to meet NRC requirements. Both diets consisted of
25% alfalfa, 25% corn silage and 50% grain mix. The control and fat diets contained 17.2
and 17.6% CP and 1.67 and 1.74 Mcal/kg NE[subscript L] respectively. Liver biopsies from 28 cows and adipose tissue biopsies from 6 cows were collected at -14, 2 or 3 and 14 d relative to calving. Tissue samples were analyzed for PEPCK mRNA and activity. All results were analyzed by period: prepartum (-21 to -2 d), freshening (2 to 7 d) and postpartum (8 to 21 d). In a previous study in our lab, 25 and 75% cows on the control and fat diets, respectively, experienced ketosis. In the current study there a 40% occurrence of ketosis for both control and fat diet groups. The high occurrence in both diets may be attributed to the rapid transition from the dry cow ration (70:30 forage to concentrate ratio, DM basis) to the lactating cow ration (50:50 forage to concentrate ratio, DM basis). The cows on the fat diet had lower serum glucose at freshening. Cows with ketosis had higher prepartum body weights (788 kg) than non-ketotic cows (743 kg; P<.1). No prepartum differences were seen in body condition score, DMI, NE[subscript L] balance, NEFA, glucose or ��-hydroxybutyrate concentrations were detected between ketotic and non-ketotic cows. Expression of adipose PEPCK mRNA was not different between ketotic and non-ketotic cows. However, hepatic PEPCK mRNA expression was higher in non-ketotic cows at freshening when compared to ketotic cows. Cows that experienced ketosis had lower hepatic PEPCK activity prepartum (6.6 vs. 9.3 units /min/g protein) and postpartum (7.6 vs. 10.2 units/min/g protein; P<0.5) when compared to non-ketotic cows. Our data indicated that hepatic PEPCK is a useful prepartum predictor of a cows susceptibility to
ketosis.<br>Graduation date: 1998
50
Chamberlin, RaeAnne. "Partial characterization of gelatinases produced by preimplantation porcine, ovine and bovine embryos." Thesis, 1995. http://hdl.handle.net/1957/34890.
Testo completo