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341.
342.
ABSTRACT

Consumers perceive pasture-based systems of milk production as natural and therefore better for cow welfare than confinement systems. However both systems are heterogeneous and continually evolving, varying from total confinement to total pasture with many hybrid intermediaries. To compare the welfare of dairy cows in these various systems, we use the three spheres framework, comprising biological functioning, natural behaviour and affective states. Considering biological functioning, pasture-based cows are less at risk of subclinical and clinical mastitis, claw lesions, lameness, metritis, early embryonic mortality, culling and mortality, but at more risk of internal parasitism, malnutrition and delayed onset of oestrous activity postpartum than confined cows. Regarding natural behaviours, pasture-based cows exhibit less agonistic behaviour, better lying behaviour, more normal oestrous behaviours and better synchronicity of behaviours than confined cows. They also have the opportunity to graze, which is one of the main features of the behavioural repertoire of dairy cows, but, they may also experience long periods away from pasture in larger herds, and severe climatic stresses which will become increasingly important as the climate changes. Our current ability to assess the affective state of dairy cows is poor. For example, hunger is an important subjective state that cannot be measured directly. The growing focus on ensuring that animals have lives worth living, means that dairy cows should garner some positive emotions from their lives, and it seems clear that pasture access is essential for this. Clearly measurement of affective state is an important challenge for future dairy cow welfare research. At the extremes of management systems, there can be major differences in animal welfare but in hybrid systems, dairy cows experience elements of both confinement and pasture which may ameliorate the negative effects of each on cow welfare. Ultimately, the optimal system gives cows an element of choice between both environments. Moreover management of the system, whether it is confinement or pastured-based, may be as important as the system of management in ensuring good dairy cow welfare and addressing societal concerns.

Abbreviations: BCS: Body condition score; TMR: Total mixed ration  相似文献   
343.
Cerebral microbleeds in people are small foci of hemosiderin-containing macrophages in normal brain parenchyma. They are the remnant of previous hemorrhage and occur with greater frequency in older individuals. Our purpose was to describe the magnetic resonance (MR) appearance of cerebral microbleeds in four dogs. These lesions appeared as round, hypointense foci measuring ≤4 mm on T2*-gradient-recalled echo images. They were less conspicuous or absent on T2-weighting, being iso- or hypointense, and uniformly invisible on T1-weighted images. No contrast enhancement was seen in any of the cerebral microbleeds. Necropsy-derived histopathologic analysis of one brain confirmed these lesions to be chronic cerebrocortical infarcts containing hemosiderin. The MR changes seen in dogs were analogous to what has been described in people and will be helpful in distinguishing cerebral microbleeds from other brain lesions.  相似文献   
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Salmonella continues to be a significant human health threat, and the objective of this study was to identify microorganisms with the potential to improve porcine food-safety through their antagonism of Salmonella. Anaerobic culture supernatants of 973 bacterial isolates from the gastrointestinal tract and feces of swine were screened for their capacity to inhibit the growth of Salmonella enterica serovar Typhimurium. Growth inhibition of 1000-fold or greater was observed from 16 isolates, and 16S rRNA sequencing identified the isolates as members of the genera Mitsuokella, Escherichia/Shigella, Anaerovibrio, Selenomonas, and Streptococcus. Four isolates were identified as Mitsuokella jalaludinii, and the mechanism of Salmonella Typhimurium growth inhibition by M. jalaludinii was further investigated. M. jalaludinii stationary phase culture supernatants were observed to significantly inhibit growth, and featured the production of lactic, succinic, and acetic acids. Aerobic and anaerobic S. Typhimurium growth was restored when the pH of the culture supernatants (pH 4.6) was increased to pH 6.8. However, S. Typhimurium growth in fermentation acid-free media was the same at pH 4.6 and pH 6.8 - indicating a synergistic effect between fermentation acid production and low pH as the cause of S. Typhimurium growth inhibition. Furthermore, exposure of S. Typhimurium to M. jalaludinii culture supernatants inhibited Salmonella invasion of HEp-2 cells by 10-fold. The results identify M. jalaludinii as a possible inhibitor of Salmonella growth and invasion in swine, and thus a potential probiotic capable of improving food safety.  相似文献   
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Surveys determining amounts of acrylamide formed as a byproduct of cooking in frequently consumed fried and baked foods have sometimes found variability in the levels, even when comparing items having similar ingredients and cooking procedures. To better understand the sources of variability, the effects of different ingredients on formation and elimination of acrylamide were studied in a model system based on wheat flour and water, that resembled crackers. It was found that NaHCO3 eliminated acrylamide. To a lesser extent, NH4HCO3, cysteine, sodium bisulfite, and ascorbate also enhanced elimination. Some ingredients, including citric acid, ferulic acid, and NaCl, were found to decrease the amount of acrylamide produced while having little or no effect on elimination. Asparagine, but not reducing sugar, caused a large increase in acrylamide formation.  相似文献   
348.
Four oxidized flavonoid derivatives generated from reacting quercetin (a pentahydroxylated flavone) with the peroxyl radical generator 2,2'-azobis-isobutyronitrile (AIBN) were isolated by chromatographic methods and identified by NMR and MS analyses. Compounds included 2-(3,4-dihydroxybenzoyl)-2,4,6-trihydroxy-3(2H)-benzofuranone (2); 1,3,11a-trihydroxy-9-(3,5,7-trihydroxy-4H-1-benzopyran-4-on-2-yl)-5a-(3,4-dihydroxyphenyl)-5,6,11-hexahydro-5,6,11-trioxanaphthacene-12-one (3); 2-(3,4-dihydroxybenzoyloxy)-4,6-dihydroxybenzoic acid (4); and methyl 3,4-dihydroxyphenylglyoxylate (5). Product ratios under different hydrogen ion concentrations and external nucleophiles revealed that two of the products, namely the substituted benzofuranone (2) and the depside (4), are generated from a common carbocation intermediate. Indirect evidence for the operation of a cyclic concerted mechanism in the formation of the dimeric product (3) is provided. The identification of these products supports the model that the principal site of scavenging reactive oxygen species (ROS) in quercetin is the o-dihydroxyl substituent in the B-ring, as well as the C-ring olefinic linkage.  相似文献   
349.
A 2‐year‐old female spayed Boxer dog was presented for a 1‐month history of progressive hemorrhagic diarrhea with tenesmus and weight loss despite trial courses of antibiotics and diet change. Abdominal ultrasound revealed severe, focal thickening, and loss of normal architecture of the colonic wall with abdominal lymphadenomegaly. Dry‐mount fecal cytology, performed on several consecutive days, consistently revealed numerous, round, 16‐20 μm structures with basophilic, granular content, and a thin cell wall. Transmission electron microscopy identified these structures as fungi. Culture, polymerase chain reaction (PCR), and sequencing of the internal transcribed spacer, D1/D2 regions, and DNA‐directed RNA polymerase II core subunit (RPB2) confirmed the presence of Basidiobolus microsporus in the feces. Biopsies collected via ileocolonoscopy revealed marked, multifocal, chronic, neutrophilic, and eosinophilic ileitis and colitis with ulceration, granulation tissue, and intralesional hyphae (identified with Gomori methenamine silver stain). A Pythium enzyme‐linked immunosorbent assay and Pythium‐specific PCR performed on the formalin‐fixed paraffin‐embedded biopsy specimens were positive while Basidiobolus‐specific PCR was negative, thus confirming a diagnosis of pythiosis. This report describes a fatal case of colonic and intestinal pythiosis with the presence of fecal Basidiobolus sp. spores, suggestive of concurrent gastrointestinal basidiobolomycosis.  相似文献   
350.
OBJECTIVE: To determine the electrical impulse duration thresholds (chronaxy) for maximal motor contraction of various muscles without stimulation of pain fibers in dogs. ANIMALS: 10 healthy adult Beagles. PROCEDURES: The dogs were used to assess the minimal intensity (rheobase) required to elicit motor contraction of 11 muscles (5 in the forelimb [supraspinatus, infraspinatus, deltoideus, lateral head of the triceps brachii, and extensor carpi radialis], 5 in the hind limb [gluteus medius, biceps femoris, semitendinosus, vastus lateralis, and tibialis cranialis], and the erector spinae). The rheobase was used to determine the chronaxy for each of the 11 muscles in the 10 dogs; chronaxy values were compared with those reported for the corresponding muscles in humans. RESULTS: Compared with values in humans, chronaxy values for stimulation of AA motor fibers in the biceps femoris and semitendinosus muscles and muscles of the more distal portions of limbs were lower in dogs. For the other muscles evaluated, chronaxy values did not differ between dogs and humans. CONCLUSIONS AND CLINICAL RELEVANCE: Application of the dog-specific chronaxy values when performing electrical stimulation for strengthening muscles or providing pain relief is likely to minimize the pain perceived during treatment in dogs.  相似文献   
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