Water relations of co-occurring understory saplings of Quercus ellipsoidalis E.J. Hill, an early successional, xeric species, Populus tremuloides Michx., an early successional, mesic species, and Acer rubrum L., a late successional species that occurs on both wet and dry sites, were evaluated on four dates during the 1986 growing season. The understory was characterized by high soil water content, low irradiance and low vapor pressure deficit throughout the growing season. Stomatal conductance and calculated transpiration flux were lowest for A. rubrum and highest for P. tremuloides and Q. ellipsoidalis. Except early in the growing season, leaf water potentials were lower in P. tremuloides than in the other species. Populus tremuloides had the highest bulk modulus of elasticity, Q. ellipsoidalis the lowest. Over the growing season, Populus tremuloides and Q. ellipsoidalis, but not A. rubrum, exhibited a decrease in osmotic potential at both full and zero turgor. Of the three species, Populus tremuloides exhibited the sharpest decrease in leaf water potential and turgor pressure with decreasing relative water content. 相似文献
In a balance trial with 10 pigs (mean body mass 50 kg) the influence of a bacterial protein supplement (Alcaligenes eutrophus) on N-metabolism was investigated. The bacteria were included into the diet at levels of 7 and 14% at the expense of extracted soyabean meal. Thus bacterial "pure protein" (bacterial non-nucleic acid N X X 6.25) amounted to 30 and 60% of the protein of the ration. Consuming 2 kg of feed dry matter per day the animals of the control group (I) and the experimental groups (II and III) ingested 48 g, 52 g and 55 g of total N respectively. The difference in N-intake is explained by the additional nucleic acid-N, amounting to 19,8% of total bacterial N. Daily weight gain (on average 1054 g) and feed conversion efficiency (feed ingested/weight gain; on average 1,9) were relatively improved at the highest dietary level of bacterial cell mass. Faecal N-excretion was increased significantly, whereas renal N-excretion remained unchanged. Mean apparent N-digestibility was 87,4% showing no significant difference between the experimental groups. N-balance values were noticibly increased following the intake of the bacterial protein supplement. The excretion of urinary urea-N was slightly reduced whereas 4-6 times as much allantoin-N was excreted when bacteria were fed. It is calculated that about 80% of the bacterial purines are renally excreted as allantoin and uric acid. 相似文献
Salmon poisoning disease in dogs has previously been reported in North America only along the western coast of the U.S.A. This paper presents the findings from eight affected dogs recently diagnosed on Vancouver Island, Canada. The clinical signs shown by these dogs were lethargy, anorexia, pyrexia and lymph node enlargement. The causative agent, Neorickettsia helminthoeca was observed in macrophages obtained from lymph node aspirates. This organism is transmitted to dogs in cysts of the fluke Nanophyetus salmincola salmincola within the tissues of the salmon or trout. The presence of fluke eggs in the feces of dogs showing typical signs is very suggestive of a diagnosis of salmon poisoning disease. Appropriate treatment, including chloramphenicol or oxytetracycline and fluid therapy, resulted in recovery. Prevention of salmon poisoning disease in endemic areas can be achieved by advising owners against allowing their dogs to eat raw salmon or trout. We suggest, based on the diagnoses made in these eight dogs, that Vancouver Island now be considered an endemic area for salmon poisoning disease. 相似文献
A two year old Thoroughbred gelding, presented with guttural pouch hemorrhage, had the internal and external carotid arteries ligated. Guttural pouch mycosis was detected on endoscopic examination. After one month of topical antifungal therapy, the horse was returned and euthanized because of recurrent epistaxis. A bacterial infection of the guttural pouch with associated ulceration and hemorrhage from the maxillary artery was found at necropsy.
A two year old grade gelding had ulceration and hemorrhage from the external carotid artery. Utilizing balloon-tipped catheters and arterial ligation, hemestasis was achieved in the internal carotid artery and the external carotid artery and its branches. Mycotic ulceration of the internal carotid artery was detected endoscopically and treated with local antifungal therapy for one month. Thirty-three days postoperatively the horse returned, bleeding from a lesion in the maxillary artery. The rationale for surgical intervention to prevent epistaxis associated with guttural pouch mycosis and possible etiologies for postsurgical epistaxis are discussed.
A nine year old Hereford crossbred cow with a history of progressive neurological signs was referred to the Western College of Veterinary Medicine, Saskatoon. A large intracranial mass, histologically identified as a schwannoma, was found to be compressing the left brain stem and appeared to have arisen from the left fifth cranial nerve. 相似文献
A retrospective morbidity and mortality study was carried out on 125 case records of cattle involving xylazine/halothane anesthesia at the Ontario Veterinary College, Guelph between May 1979 and February 1983. 相似文献