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71.
72.
R N Arnold K K Scheller S C Arp S N Williams D R Buege D M Schaefer 《Journal of animal science》1992,70(10):3055-3065
Three experiments were conducted to examine the effects of vitamin E supplementation on feedlot cattle. Vitamin E supplementation did not affect feedlot performance or carcass characteristics of cattle fed a high-concentrate diet (P greater than .1). The major finding was the effectiveness of vitamin E in extending the color stability of displayed beef (P less than .01). Color stability during display of longissimus lumborum steaks from cattle supplemented with 300 IU/d for 266 d, 1,140 IU/d for 67 d, or 1,200 IU/d for 38 d was extended by 2.5 to 4.8 d. Gluteus medius steaks had an extended color display life of 1.6 to 3.8 d. The accumulation of lipid oxidation products, but not aerobic microbes, associated with displayed longissimus lumborum was suppressed for muscle from vitamin E-supplemented steers. Taste panelists detected no difference among longissimus lumborum steaks from control and vitamin E-supplemented steers but found (P less than .01) steaks aged for 21 d to be more tender than steaks aged for 7 d. Supplementing cattle with vitamin E should reduce economic losses associated with discolored beef during retail display. 相似文献
73.
D Werling F Sutter M Arnold G Kun P.C.J Tooten E Gruys M Kreuzer W Langhans 《Research in veterinary science》1996,61(3):252-257
The effect of a prolonged low dose infusion of bacterial lipopolysaccharide (LPs) on acute phase-like reactions was examined in heifers. LPS (2 μg kg−1 dissolved in 100 ml water), or saline was infused (at 1 ml min−1) intravenously for 100 minutes and blood samples were taken at various times before, during and after the infusion. The serum concentrations of tumour necrosis factor-alpha(TNFα), interleukin-Ibeta (IL-1β), interleukin-6 (IL-6) and serum amyloid A (SAA) and the rectal temperature increased in response to the LPS infusion. Serum TNFα increased before the increases in IL-1β and IL-6 and remained high from 20 minutes after the onset of the infusion until the end of the sampling period (six hours). The LPS-induced increases in serum IL-1β and IL-6 were biphasic. Plasma cortisol and lactate concentrations also increased, and plasma glucose and B-hydroxybutyrate concentrations decreased in response to the LPS infusion. The similarity of these reactions to changes observed in response to bacterial infections shows that the prolonged infusion of low doses of LPS is a good model for studying the acute phase response to Gramnegative bacterial infection in heifers. 相似文献
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The volume of water in the rumen of four steers was increased (P less than .01) 47% when the level of ground cobs in the diet fed to the steers was changed from 10% to 50%. The difference in gut water content due to diet was not accurately (P greater than .10) estimated by deuterium oxide dilution using either one-, two- or three-compartmental models. Gut water was overestimated and empty body water underestimated when calculated by two-compartment models. The proportions of total body water within each compartment of a three-compartment model were quite variable among steers. When the two-compartment model was solved on the basis of measurements taken from either compartment, different compartment volumes were obtained. This indicated that the two-compartment model did not accurately describe the water equilibration process. Water in the contents of the proximal duodenum and terminal ileum equilibrated with blood in 30 min (range, 10 to 75 min), fecal water equilibrated in 4.3 h (range, 1.7 to 6.7 h) and water in rumen contents equilibrated in 8.3 h (range, 3.8 to 12.5 h). Diet did not affect (P greater than .10) equilibration time or the mean retention time of water in the gastrointestinal tract. Mean retention time was much longer than equilibration time; thus, the equilibration of water in the gastrointestinal tract contents was primarily dependent upon movement of water across the gut mucosa and not upon the flow of water through the gut. One-third of the water in the contents of the gastrointestinal tract was located outside the rumen. Compartmental modeling based only upon D2O disappearance from blood did not enable either gut water or rumen water to be accurately estimated. 相似文献
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This study was conducted to ascertain the effect of autoclaving, source of calcium and phosphate, vitamin D3 level and strain of turkey poults on the rachitogenic activity of isolated soybean protein (C‐1 protein‐Skidmore). One‐day‐old poults were fed purified diets of the glucose—C‐1 protein type. The diets contained calcium, phosphorus and vitamin D3 at levels equal to or greater than the National Research Council's (1960) recommendations. The findings demonstrate that USP hydrated dicalcium phosphate was more effective than food‐grade dicalcium phosphate in overcoming the rachitogenic activity of the C‐1 protein. Autoclaving the C‐1 protein for 80 min destroyed its rachitogenic activity: Vitamin D3 was also effective in reducing the rachitogenic effect of C‐1 protein. The Broad Breasted White strain proved to be more susceptible to the rachitogenic property of C‐1 protein than the Wrolstad Small White strain. Substituting USP hydrated dicalcium phosphate for food‐grade dicalcium phosphate, autoclaving the C‐1 protein or increasing the vitamin D3 level increased body weight gains and tibia ash values. The interactions which were shown to exist between source of calcium and phosphate × autoclaving, strain × autoclaving, and vitamin D3 level × strain demonstrate an interrelationship between these factors. 相似文献
79.
Arnold JE 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2005,34(2):115-123
BACKGROUND: Standardized hematologic methods and reference intervals have not been established for cartilaginous fishes (sharks, skates, and rays) despite the large number of animals displayed in zoos and aquariums worldwide. OBJECTIVE: The focus of this study was to validate CBC methods for sandbar shark (Carcharhinus plumbeus) blood, based on criteria established in human medicine, for the following tests: RBC count, total WBC count, PCV, hemoglobin (Hgb) concentration, and WBC differential percentages. METHODS: Replicate CBCs were performed using blood samples from 5 captive sandbar sharks. Three protocols for RBC and total WBC counts were compared, as were different centrifugation times for PCV determination, and 2 methods for Hgb concentration. Means, minimum and maximum values, and CVs were compared to CAP and CLIA performance guidelines for human tests. RESULTS: Total WBC counts in a diluent modified for elasmobranch blood, Hgb concentration by the cyanmethemoglobin method after removal of nuclei, and WBC differential percentages showed acceptable performance. PCV results were acceptable when tubes were centrifuged for at least 5 minutes. Total RBC counts by all 3 methods exceeded the acceptable error for manual counts of human cells. CONCLUSIONS: Standardized CBC tests can be used as health assessment tools for elasmobranchs. Total RBC counts should be viewed as estimates. 相似文献
80.
Students in veterinary schools can experience stress in balancing the different demands on them-academic, interpersonal, intrapersonal, and professional or work related-as well as managing potential conflict between animal and human interests. Practicing veterinarians report many similar stressors and reactions. Stressful stimuli produce stress reactions that can be inimical to physical and psychological well-being, and students' performance in veterinary programs can be adversely affected if they do not have coping resources. While there has been some research into stress among university students in general, and among medical students in particular, there is little on the experience of veterinary students. This article describes a study by the School of Psychology, commissioned by the Department of Veterinary Clinical Sciences, at Murdoch University in Western Australia. It was designed to investigate the levels and causes of stress among, and the frequency and type of coping strategies used by, fourth- and fifth-year students. Results indicate that the students in this cohort faced frequent stressors and felt at least moderately stressed but did not routinely and systematically use a range of coping strategies. Academic stressors and perceived responsibilities attached to moving into practical or professional areas figured strongly and were associated with higher levels of stress in the students, in particular physical sequelae. Though the numbers were small, it is of concern that some students were using measures that were potentially harmful. Some recommendations are made here about measures that veterinary programs may be able to incorporate to address stress in their students. Information is included on current strategies within the curriculum to manage potential stressful situations as part of students' professional development. 相似文献