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51.
52.
Suraj Gunawardana Dulari Thilakarathne Indra S. Abegunawardana Preeni Abeynayake Colin Robertson Craig Stephen 《Tropical animal health and production》2014,46(7):1105-1112
A study of the risk factors associated with mastitis in Sri Lankan dairy cattle was conducted to inform risk reduction activities to improve the quality and quantity of milk production and dairy farmer income. A cross-sectional survey of randomly selected dairy farms was undertaken to investigate 12 cow and 39 herd level and management risk factors in the Central Province. The farm level prevalence of mastitis (clinical and subclinical) was 48 %, similar to what has been found elsewhere in South and Southeast Asia. Five cow level variables, three herd level variables, and eight management variables remained significant (p?0.05) in the final logistic regression analysis. Expected risk factors relating to unhygienic environments and inadequate knowledge or practice of mastitis control were found. Other factors included parity, milk yield, milking practices, access to veterinary services, use of veterinary products, stall structure, and stall hygiene. Many of the risk factors could be addressed by standard dairy cattle management techniques, but implementation of mastitis control programs as a technical approach is likely to be insufficient to achieve sustainable disease control without consideration of the social and political realities of smallholder farmers, who are often impoverished. 相似文献
53.
Lori Robertson William Bray Joanna Leung-Trujillo Addison Lawrence 《Journal of the World Aquaculture Society》1987,18(3):180-185
Molt staging has many applications in penaeid aquaculture as a routine procedure. Using criteria developed for various crustaceans, a method of rapid molt staging was applied to Penaeus stylirostris and Penaeus setiferus adults. The most useful characters were the degree of epidermal retraction from the setal bases and epidermal retraction from the cuticle coupled with the development of new setae. The duration of the molt cycle of P. stylirostris was 11.5 ± 1.0 days ( N = 5) at 27–29 C. The early postmolt, late postmolt, intermolt, early premolt and late premolt stages were readily determined. For P. stylirostris , the duration of postmolt was 27% of the cycle; intermolt, 17%; and premolt, 56%. The length of the molt cycle of P. setiferus at 27–29 C was 13.6 ± 1.0 days ( N = 21) with postmolt occupying 22% of the cycle; intermolt, 19%; and premolt, 59%. Unilaterally eyestalk enucleated P. setiferus had a significantly shorter molt cycle than intact P. setiferus (11.7 ± 1.21 days vs. 13.6 ± 1.02 days, P < 0.05). There were no differences in molt cycle duration between the sexes, whether enucleated or intact ( P > 0.05). A series of illustrations identifies the key characteristics for determining stage of molt in these penaeids. 相似文献
54.
Valeria Hidalgo-Ruz Guillermo Luna-Jorquera Marcus Eriksen Hanna Frick Diego Miranda-Urbina Matias Portflitt-Toro Marcelo M. Rivadeneira Christopher J.R. Robertson R. Paul Scofield Juan Serratosa Cristián G. Suazo Martin Thiel 《水产资源保护:海洋与淡水生态系统》2021,31(2):389-407
- While floating near the sea surface plastic debris interacts with a number of external factors, including many different organisms. Seabirds have the most extensive documented history of interactions with plastics, through ingestion, entanglement, and nest construction.
- In the present study, eight seabird species from the South Pacific Ocean were used as a proxy to determine potential patterns of removal of marine plastic debris, and three hypotheses were tested in relation to their feeding habits and nesting areas.
- Plastics from abiotic compartments (Chilean continental coast, South Pacific Gyre, and Rapa Nui beaches) and biotic compartments (surface-feeding seabirds, diving seabirds, and nesting areas) were compared, according to their type, colour, shape, and density.
- Continental beaches had a relatively wide range of colours and shapes, with many non-buoyant plastics. Samples from the South Pacific Gyre (SPG) and Rapa Nui (Easter Island) beaches comprised mainly hard, rounded, buoyant, and white/grey plastics.
- These results indicate that the composition of floating plastics from terrestrial sources changes during transport with oceanic currents, reducing the proportion of prey-like plastics present in the subtropical gyres.
- The stomach contents of surface-feeding and diving seabirds were dominated by hard, white/grey, and round plastic items, similar to plastics from the SPG, suggesting non-selective (accidental or secondary) ingestion.
- Nesting areas had a more variable composition of brightly coloured plastics, suggesting a pattern of selective removal of plastics by seabirds, probably from oceanic sources.
- The present study reveals extensive interactions of seabirds with plastics on a broader scale, which is highly relevant given that the impacts of plastics on seabirds are increasing worldwide, compromising their efficient conservation.
55.
B S Beale R L Goring M Schaer S A Robertson 《Journal of the American Veterinary Medical Association》1991,198(2):281-285
Modified choledochoduodenostomy and gastrojejunostomy were used successfully to treat extensive duodenal ulceration and perforation in a dog. Concomitant pyometra, simultaneously managed by ovariohysterectomy, may have predisposed the dog to stress ulceration. Choledochoduodenostomy was performed by transplantation of the entire common bile duct and associated major duodenal papilla to a more distal duodenal location. An indwelling choledochostomy tube was used to stent the anastomotic site, externally divert bile flow, and allow postoperative cholangiography. Early postoperative complications included presumed metronidazole-induced neurotoxicosis, choledochostomy tube obstruction, and pancreatitis, all of which resolved within 2 weeks. The dog was clinically normal and medication (ranitidine and sucralfate) was discontinued 35 months later. 相似文献
56.
57.
Guy R. Alexander BVSc Cert VR Katherine T. Gibson BVSc MS Diplomate ACVS Robert E. Day MBiomedEng BEng CPEng Ian D. Robertson BVSc PhD MACVSc 《Veterinary surgery : VS》2001,30(6):522-527
OBJECTIVE: To measure the effects of transection of the accessory ligament of the superficial digital flexor (SDF) muscle (superior check desmotomy) on flexor tendon and suspensory ligament (SL) strain in vitro. STUDY DESIGN: In vitro experimental biomechanical investigation. ANIMALS USED: Ten equine cadaver forelimbs. METHODS: The effects of superior check desmotomy were determined using equine cadaver forelimbs secured in a servocontrolled hydraulic testing machine. Strain sensors were used to measure strain on the superficial and deep digital flexor tendons and SL, and a goniometer was used to measure joint angles when the limb was loaded at 890 N and 3,115 N before desmotomy, and at 3,115 N after desmotomy. RESULTS: Superior check desmotomy was associated with significantly increased strains on the SDF tendon and SL, and significant alterations in the angles of the metacarpophalangeal and carpal joints. CONCLUSIONS: The superior check ligament has an important role in maintaining joint angles and load distribution in the forelimb. Lengthening of the SDF musculotendinous unit after superior check desmotomy may be associated with increased strain on the SL. CLINICAL RELEVANCE: Transection of the accessory ligament of the SDF muscle may predispose horses to SL desmitis postoperatively. 相似文献
58.
D. A. Bond G. J. Jellis G. G. Rowland J. Le Guen L. D. Robertson S. A. Khalil L. Li-Juan 《Euphytica》1993,73(1-2):151-166
Progress is being made, mainly by ICARDA but also elsewhere, in breeding for resistance to Botrytis, AScochyta, Uromyces, and Orobanche; and some lines have resistance to more than one pathogen. The strategy is to extend multiple resistance but also to seek new and durable forms of resistance. Internationally coordinated programs are needed to maintain the momentum of this work.Tolerance of abiotic stresses leads to types suited to dry or cold environments rather than broad adaptability, but in this cross-pollinated species, the more hybrid vigor expressed by a cultivar, the more it is likely to tolerate various stresses. 相似文献
59.
A. Soltani M. J. Robertson A. Rahemi-Karizaki J. Poorreza H. Zarei 《Journal of Agronomy and Crop Science》2006,192(5):379-389
Quantitative information regarding biomass accumulation and partitioning in chickpea (Cicer arietinum L.) is limited or inconclusive. The objective of this study was to obtain baseline values for extinction coefficient (KS), radiation use efficiency (RUE, g MJ?1) and biomass partitioning coefficients of chickpea crops grown under well‐watered conditions. The stability of these parameters during the crop life cycle and under different environmental and growth conditions, caused by season and sowing date and density, were also evaluated. Two field experiments, each with three sowing dates and four plant densities, were conducted during 2002–2004. Crop leaf area index, light interception and crop biomass were measured between emergence and maturity. A KS value of 0.5 was obtained. An average RUE of 1 g MJ?1 was obtained. Plant density had no effect on RUE, but some effects of temperature were detected. There was no effect of solar radiation or vapour pressure deficit on RUE when RUE values were corrected for the effect of temperature. RUE was constant during the whole crop cycle. A biphasic pattern was found for biomass partitioning between leaves and stems before first‐seed stage. At lower levels of total dry matter, 54 % of biomass produced was allocated to leaves, but at higher levels of total dry matter, i.e. under favourable and prolonged conditions for vegetative growth, this portion decreased to 28 %. During the period from first‐pod to first‐seed, 60 % of biomass produced went to stems, 27 % to pods and 13 % to leaves. During the period from first‐seed to maturity, 83 % of biomass was partitioned to pods. It was concluded that using fixed partitioning coefficients after first‐seed are not as effective as they are before this stage. Environmental conditions (temperature and solar radiation) and plant density did not affect partitioning of biomass. 相似文献
60.