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201.
Tanja M. Hess Jill Rexford Diana Karen Hansen Nicolette Schauermann Ahrens Mary Harris Terry Engle Trinette Ross Kenneth G. Allen 《Journal of Equine Veterinary Science》2013
The objective of this study was to examine the effects of dietary ω-3 fatty acid supplementation on insulin sensitivity (SI) in horses. Twenty-one mares were blocked by age, body weight (BW), and body condition score (BCS) and randomly assigned to one of three dietary treatments. Treatments consisted of (1) 38 g of n-3 fatty acids via fish and algae supplement and diet (MARINE), (2) 38 g of n-3 fatty acids via a flaxseed meal from the supplement and diet (FLAX), and (3) control (CON) no supplemental fatty acid. Treatments were supplemented for 90 days. Frequent sampling intravenous glucose tolerance tests were performed on days 0, 30, 60, and 90. Blood samples were analyzed for glucose and insulin. The minimal model was applied for the glucose and insulin curves using MinMod Millennium. SI increased 39% (P < .007) across all treatment groups. Acute insulin response to glucose decreased 22% (P < .006) between days 30 and 60 and increased (P = .040) again at day 90. Disposition index (combined SI and β pancreatic response) increased (P = .03) by 53% in the MARINE- and 48% in the FLAX-supplemented horses and did not change with time in the CON group. In insulin-resistant mares, MARINE- and FLAX-treated horses had an increase in SI (P = .09). It would be interesting to test this supplement in a larger group of insulin-resistant horses. If proven effective, supplementation with ω-3 fatty acids would help to reduce problems associated with insulin resistance in horses. 相似文献
202.
M. G. G. Chagunda D. Ross J. Rooke T. Yan J.-L. Douglas L. Poret 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2013,63(2):68-75
Abstract This study investigated the effectiveness of the proprietary laser methane detector (LMD) in enteric methane monitoring from individual dairy cows and sheep. Three experiments were carried out. First, the relationship between LMD and indirect open-circuit respiration calorimetric chamber measurements was tested. Sensitivity and specificity for cows were 95.4% and 96.5%. For sheep, sensitivity was 93.8% and specificity was 78.7%. Second, the effect of cow's activity on enteric methane emissions was investigated. During drinking and feeding, cows produced significantly more (p<0.001) methane emissions than when idle. Third, effect of different micrometeorological factors on LMD measurements under outdoor grazing conditions was investigated. Wind speed, relative humidity, pressure and wind direction relative to methane point-source had significant effect on methane measurements (p<0.001) under outdoor conditions. With further validation, the LMD has potential to provide reliable estimates from ruminants and hence provide a useful technique for on-farm monitoring and decision support for greenhouse gas mitigation strategies. 相似文献
203.
Counts of bushbuck tracks were used to estimate their population densities. Good correlations were obtained between various indices of track frequency and estimated absolute population density. The technique is therefore recommended for assessing the absolute density of a population. High sampling costs, however, disqualify the technique for detecting small changes in density. 相似文献
204.
H.S. Cameron D.V.M. Ph.D. 《New Zealand veterinary journal》2013,61(3):41-44
Extract First let me express my appreciation of being the recipient of a Fulbright Fellowship for research in New Zealand and also for the privilege of discussing brucellosis before the New Zealand Veterinary Association. 相似文献
205.
206.
Bou R Guardiola F Codony R Faustman C Elias RJ Decker EA 《Journal of agricultural and food chemistry》2008,56(20):9612-9620
Myoglobin (Mb) and its iron have been proposed to be major prooxidants in cooked meats. To understand the mechanisms and differentiate between the prooxidant and antioxidant potential of oxymyoglobin (OxyMb) and metmyoglobin (MetMb), their prooxidant activity, iron content, solubility, free radical scavenging activity, and iron binding capacity were determined as a function of thermal processing. The ability of native and heat denatured OxyMb and MetMb to promote the oxidation of muscle microsomes was different. MetMb promoted lipid oxidation in both its native and denatured states. Conversely, OxyMb became antioxidative when the protein was heated to temperatures >or=75 degrees C. The increased antioxidant activity of heat denatured OxyMb was likely due to a decrease in its prooxidative activity due to its loss of solubility. These data show that the impact on oxidative reactions of Mb is the result of the balance between its antioxidant and prooxidant activities. 相似文献
207.
Dialkylphosphates (DAPs) in fruits and vegetables may confound biomonitoring in organophosphorus insecticide exposure and risk assessment 总被引:1,自引:0,他引:1
Zhang X Driver JH Li Y Ross JH Krieger RI 《Journal of agricultural and food chemistry》2008,56(22):10638-10645
Trace residues of organophosphorus (OP) pesticides are associated with fruits and vegetables that have been sprayed with those OP pesticides to guard against insect pests. Human dietary exposure to these OP pesticides is commonly estimated by measuring the amount of OP metabolites in urine, assuming a stoichiometric relationship between a metabolite and its parent insecticide. Dialkylphosphates (DAPs) are the OP metabolites that are most often used as markers in such biomonitoring studies. However, abiotic hydrolysis, photolysis, and plant metabolism can convert OP chemicals (OP residues) to DAP residues on or in the fruits and vegetables. To evaluate the extent of these conversions, OPs and DAPs were measured in 153 produce samples. These samples from 2 lots were known to contain OP insecticide residues based on routine monitoring by California producers and shippers. A total of 12 OPs were quantified, including mevinphos, naled, acephate, methamidophos, oxidemeton-methyl, azinphos-methyl, dimethoate, malathion, methidathion, phosmet, chlorpyrifos, and diazinon. All OP insecticide residues were below their respective residue tolerances in 2002-2004. A total of 91 of 153 samples (60%) contained more DAP residues than parent OPs. The mean mole fractions [DAPs/(DAPs + OPs)] for the first and second lots of produce were 0.62 and 0.50, respectively, and the corresponding geometric means were 0.55 and 0.34. The corresponding mean mole ratios (DAPs/OP) were 7.1 and 3.4, with geometric means of 2.1 and 0.9. Any preformed DAPs ingested in the diet that are excreted in urine may inflate the estimated absorbed OP insecticide doses in occupational and environmental studies. In subsequent prospective studies, time-dependent production of dimethylphosphate (DMP) and dimethylthiophosphate (DMTP) in strawberries and leaves following malathion sprays occurred concomitant with the disappearance of the parent insecticide and its oxon. DAPs are more persistent in plants and produce at routinely measured levels than their parent OP insecticides. 相似文献
208.
Edward W. Bork Lisa L. Raatz Cameron N. Carlyle Daniel B. Hewins Karen A. Thompson 《Soil Use and Management》2020,36(3):387-399
Grassland management aimed at enhancing carbon (C) in soil is an important tool in mitigation of rising atmospheric CO2, yet little is known of how grassland soil C changes with livestock stocking rate (SR). We relate soil organic and inorganic C mass (t ha−1 to 60 cm depth) with cattle stocking over periods of 7–27 year for 32 paddocks distributed across nine community pastures in the mixed-grass prairie of Saskatchewan, Canada. Initial analysis comparing Akaike information criterion models showed that cattle SR explained a greater proportion of variance in soil C, particularly soil organic C, than rainfall. Soil organic C mass increased with cattle SR (R2 = .293; p = .001), even when the latter was normalized to account for differences in vegetation composition and growing conditions among pastures. Normalized SR varied from 0.49 to 2.30 times recommended levels, over which SOC increased from 24.7 to 57.4 t ha−1. Increases in soil organic C under greater stocking coincided with increased abundance of introduced vegetation, particularly the rhizomatous grass Poa pratensis. Inorganic soil C accounted for 34.6% of total soil C, being particularly large below 30 cm soil depth, but did not vary with stocking rate. These findings indicate that both organic and inorganic C are important pools of C in northern temperate grassland soils, with soil organic C positively associated with long-term cattle SR. Further studies are recommended to understand more fully the mechanisms regulating grazing impacts on soil C mass in northern temperate grasslands. 相似文献
209.
Philbey AW Kirkland PD Ross AD Field HE Srivastava M Davis RJ Love RJ 《Australian veterinary journal》2008,86(11):449-454
Objective To examine flying foxes (Pteropus spp.) for evidence of infection with Menangle virus. Design Clustered non‐random sampling for serology, virus isolation and electron microscopy (EM). Procedure Serum samples were collected from 306 Pteropus spp. in northern and eastern Australia and tested for antibodies against Menangle virus (MenV) using a virus neutralisation test (VNT). Virus isolation was attempted from tissues and faeces collected from 215 Pteropus spp. in New South Wales. Faecal samples from 68 individual Pteropus spp. and four pools of faeces were examined by transmission EM following routine negative staining and immunogold labelling. Results Neutralising antibodies (VNT titres ≥ 8) against MenV were detected in 46% of black flying foxes (P. alecto), 41% of grey‐headed flying foxes (P. poliocephalus), 25% of spectacled flying foxes (P. conspicillatus) and 1% of little red flying foxes (P. scapulatus) in Australia. Positive sera included samples collected from P. poliocephalus in a colony adjacent to a piggery that had experienced reproductive disease caused by MenV. Virus‐like particles were observed by EM in faeces from Pteropus spp. and reactivity was detected in pooled faeces and urine by immunogold EM using sera from sows that had been exposed to MenV. Attempts to isolate the virus from the faeces and tissues from Pteropus spp. were unsuccessful. Conclusion Serological evidence of infection with MenV was detected in Pteropus spp. in Australia. Although virus‐like particles were detected in faeces, no viruses were isolated from faeces, urine or tissues of Pteropus spp. 相似文献
210.