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1.
Estuarine habitats provide rearing opportunities for the juvenile life stage of anadromous fishes. Because survival is positively correlated with juvenile performance, these estuarine habitats play an important role in population abundance and productivity. To provide information for the recovery of several depressed stocks of Chinook salmon in the Columbia River Basin, we sought to identify the factors that explain variability in performance. Using otolith‐derived estimates of juvenile somatic growth rate as an index of recent performance, we observed a negative nonlinear relationship between growth rate and day of year, and a decreasing and increasing trend of growth rate over the 8 years of this study and distance from the river mouth respectively. Using a generalised linear modelling approach, we found that variability in juvenile somatic growth rate was best explained by where and when individuals were collected, their body size, contaminant loads, stock of origin, and whether a fish was hatchery produced or unmarked. Lastly, we argue that a considerable improvement to the growth rate of juveniles in estuarine habitats is physiologically possible. The results of this 8‐year study provide a baseline of the performance of juvenile Chinook salmon to evaluate habitat restoration programs and to compare against future anthropogenic conditions.  相似文献   
2.
The aim of this study was to investigate the effect of dietary supplementation with the docosahexaenoic acid (DHA )‐rich microalgae, Aurantiochytrium limacinum (AURA ), on a variety of health and productivity parameters in lactating cows. Twenty‐four cows were blocked by parity and number of days in milk and then randomly assigned to a control (CON ; n  = 12) group with no algal supplementation, or a treatment group (AURA ; n  = 12) provided with 100 g AURA  cow?1 day?1 or 16 g DHA  cow?1 day?1. A variety of health and productivity measurements were taken, and results indicated that supplementation had no negative effects on animal health in terms of somatic cell count, haematological and biochemical blood parameters, while body condition was marginally improved by algal supplementation. No differences were found for the various production parameters measured; however, a tendency towards increased milk production was observed for the AURA group during the final stage of the study (+4.5 kg cow?1 day?1, day 78–84). The fatty acid profile of milk was improved by supplementation, with significantly lower saturated fatty acids, significantly higher omega‐3 fatty acids and an improved omega‐3/omega‐6 ratio observed when compared to the control group. The amount of DHA in the milk of cows provided 105 g AURA  head?1 day?1 was 4.7 mg/100 g milk with a peak transfer efficiency from feed to milk at day 49 of 8.3%. These results indicate that supplementation with 105 g AURA  head?1 day?1 resulted in the successful enrichment of milk with DHA without negatively impacting the health or productivity of the animals.  相似文献   
3.
Two 125‐day experiments of the same design were conducted to evaluate the effects of a heterotrophically grown microalgae (AURA) containing docosahexaenoic acid (DHA) on pig performance, carcass traits and the fatty acid composition of lean and adipose tissue. In each experiment, 144 Hypor pigs were blocked by sex, allocated to three treatment groups, and fed 0, 0.25% or 0.50% AURA in isonutritive, isocaloric diets. Pigs were weighed on days 0, 28, 56, 84 and 112. Feed and water intakes were measured every 28 days. Pigs were slaughtered on day 125. Data from the two studies were analysed as a single data set. Performance and carcass traits did not differ between treatments. Both microalgae treatment levels enriched (< .05) Longissimus lumborum (LL) and backfat in DHA and improved (< .05) their ratios of n‐6 to n‐3 fatty acids.  相似文献   
4.
Summary Airborne measurements of reflected solar and emitted thermal radiation were combined with ground-based measurements of incoming solar radiation, air temperature, windspeed, and vapor pressure to calculate instantaneous evaporation (LE) rates using a form of the Penman equation. Estimates of evaporation over cotton, wheat, and alfalfa fields were obtained on 5 days during a one-year period. A Bowen ratio apparatus, employed simultaneously, provided ground-based measurements of evaporation. Comparison of the airborne and ground techniques showed good agreement, with the greatest difference being about 12% for the instantaneous values. Estimates of daily (24 h) evaporation were made from the instantaneous data. On three of the five days, the difference between the two techniques was less than 8%, with the greatest difference being 25%. The results demonstrate that airborne remote sensing techniques can be used to obtain spatially distributed values of evaporation over agricultural fields.  相似文献   
5.
S. Moran 《Phytoparasitica》1991,19(2):95-101
Modified Australian crow traps effectively protected crops, mainly in pecan orchards and watermelon fields, from the hooded crow, Corvus corone sardonius Kleinschmidt (Corvidae). The effects of modifications in trap construction and operation methods on trapping efficiency were studied. It was essential to use a lure crow, whereas the importance of bait was doubtful.  相似文献   
6.
鸡传染性喉气管炎(ILT)是由鸡传染性喉气管炎病毒引起的以剧烈咳嗽、气喘、高度呼吸困难和气管内有血样渗出物等为特征的一种急性呼吸道传染病.育成蛋鸡感染该病多有报道,而蛋雏鸡感染发病比较少见.本文以一起48日龄海兰褐蛋雏鸡传染性喉气管炎病例为题材,从发病情况、临床症状、病理剖检变化、诊断、防治等几个方面对该病做了详尽阐述.  相似文献   
7.
猪败血性链球菌病是猪链球菌感染引起的一种急性败血性传染病,猪附红细胞体病是由猪附红细胞体寄生于猪红细胞而引起的一种散在的热性、溶血性传染病.本文以某猪场这2种病混合感染病例为题材,从发病基本情况、临床症状、剖检变化、实验室检验、防治措施等6个方面对该混合感染病例做了详尽的阐述.  相似文献   
8.
Crocodile morphometric (head, snout‐vent and total length) measurements were recorded at three stages during the production chain: hatching, inventory [average age (±SE) is 265.1 ± 0.4 days] and slaughter (average age is 1037.8 ± 0.4 days). Crocodile skins are used for the manufacture of exclusive leather products, with the most common‐sized skin sold having 35–45 cm in belly width. One of the breeding objectives for inclusion into a multitrait genetic improvement programme for saltwater crocodiles is the time taken for a juvenile to reach this size or age at slaughter. A multivariate restricted maximum likelihood analysis provided (co)variance components for estimating the first published genetic parameter estimates for these traits. Heritability (±SE) estimates for the traits hatchling snout‐vent length, inventory head length and age at slaughter were 0.60 (0.15), 0.59 (0.12) and 0.40 (0.10) respectively. There were strong negative genetic (?0.81 ± 0.08) and phenotypic (?0.82 ± 0.02) correlations between age at slaughter and inventory head length.  相似文献   
9.
Two methyl anthranilate formulations, ReJex‐iT® TP‐40 and AG‐36, were tested as bird‐repelling agents for animal feed and vegetable sprouts, respectively. Feral pigeons (Columba livia) and house sparrows (Passer domesticus) are important pests of animal husbandry and field crops in Israel. In each 4‐day experiment, four birds were held together in an aviary, and were offered four trays or dishes with animal feed or cauliflower sprouts in four corners of the cage. The trays and dishes were transposed daily in a Latin square sequence. Pigeons consumed significantly more untreated feed than treated feed. When no alternative untreated food was offered, there was no significant repellency. Treatment of animal feed with TP‐40 to give 2.0 ml methyl anthranilate kg?1 or less had no repellent effect on sparrows. Concentrations of 4.0 ml kg?1 or more repelled the sparrows significantly. When no untreated feed was presented, pigeons and sparrows preferred the lowest concentration of methyl anthranilate presented. When AG‐36 was tested on vegetable sprouts, the sparrows tended significantly to avoid the highest concentration used—14.5 ml methyl anthranilate litre?1 spray. The inter‐specific differences between the birds indicate that the efficacy of methyl anthranilate formulations as a repellent has to be specified for every species. This study did not determine (1) the possibility of developing habituation, (2) the behaviour of birds under natural conditions in the field, or (3) the influence of the feeding behaviour of a sympatric bird species on the repellency of methyl anthranilate to other species. © 2001 Society of Chemical Industry  相似文献   
10.
A 6-year-old female Alaska Malamute dog was presented for evaluation of abdominal enlargement referred by a local veterinarian. On the history, the owner complained of chronic abdominal enlargement initiated more than 4 months ago, reduced appetite, occasional vomiting and general dullness. He also complained of greenish mucous intermittent vaginal discharge starting 10 days ago. The bitch was chronically treated with medroxiprogesterone acetate. A laparatomy was performed and fluid in the abdomen was found and aspirated during the surgery. Also a very fluid-filled distended uterus and a mass in the distal part of the left uterine horn were found. The mass was encapsulated by the omentum, but areas of necrosis and calcification were identified. Histopathological diagnosis was endometrial adenocarcinoma.  相似文献   
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