Pop hole use by hens with different keel fracture status monitored throughout the laying period     

Richards GJ  Wilkins LJ  Knowles TG  Booth F  Toscano MJ  Nicol CJ  Brown SN 《The Veterinary record》2012,170(19):494

The aim of this work was to study the effect of keel fractures on the extent to which free-range hens access the range through pop holes. Over two consecutive laying periods (two production years) a total of 1100 individual birds from one half of a house, divided into four separated flocks, were caught at 25, 35, 45, 55 and 65 weeks, palpated to assess the prevalence and severity of keel fractures and tagged with RFID transponders. Their use of pop holes was subsequently monitored in some cases from week 25 to end of lay at 68 to 70 weeks. At regular intervals (every 10 weeks), the tagged birds were re-caught to assess changes in keel fracture prevalence and severity. The average percentage of birds with fractured keels at 25, 35, 45, 55, 65 and at end of lay (68 to 70 weeks of age) was 5.5, 25.5, 49, 63, 66.5 and 78.5, respectively, across both production years. The effect of keel score on pop hole use was modelled statistically, adjusting for weather conditions and age of the birds. There were significant effects of most of the weather variables recorded, as well as age of the bird, on use of pop holes and also a significant effect of keel score. Higher keel scores resulted in a reduction in pop hole use. A significant statistical interaction between keel score and ambient temperature revealed an accelerated reduction in use as the temperature decreased and keel score increased. It is concluded that the occurrence of keel fractures may affect the birds' ability or willingness to utilise the outdoor range provided by free-range housing systems, thereby reducing the potential welfare advantages of this type of housing.  相似文献   

Lack of production response in grazing dairy cows supplemented with long-acting injectable vitamin B12     

Grace ND  Knowles SO 《New Zealand veterinary journal》2012,60(2):95-99

  相似文献   

Acute phase response to Mycoplasma haemofelis and 'Candidatus Mycoplasma haemominutum' infection in FIV-infected and non-FIV-infected cats     

RM Korman  JJ Cerón  TG Knowles  EN Barker  PD Eckersall  S Tasker 《Veterinary journal (London, England : 1997)》2012,193(2):433-438

The pathogenicity of Haemoplasma spp. in cats varies with 'Candidatus Mycoplasma haemominutum' (CMhm) causing subclinical infection while Mycoplasma haemofelis (Mhf) often induces haemolytic anaemia. The aims of this study were to characterise the acute phase response (APR) of the cat to experimental infection with Mhf or CMhm, and to determine whether chronic feline immunodeficiency virus (FIV) infection influences this response. The acute phase proteins serum amyloid A (SAA), haptoglobin (Hp) and α-1-acid glycoprotein (AGP) concentrations were measured pre-infection and every 7-14days up to day 100 post-infection (pi) in cats infected with either Mhf or CMhm. Half of each group of cats (6/12) were chronically and subclinically infected with FIV. Marbofloxacin treatment was given on days 16-44 pi to half of the Mhf-infected cats, and on days 49-77 pi to half of the CMhm-infected cats. FIV-infected animals had significantly lower AGP concentrations, and significantly greater Hp concentrations than non-FIV-infected cats when infected with CMhm and Mhf, respectively. Both CMhm and Mhf infection were associated with significant increases in SAA concentrations, while AGP concentrations were only significantly increased by Mhf infection. Mhf-infected cats had significantly greater SAA concentrations than CMhm-infected animals. Both Mhf and CMhm infections were associated with an APR, with Mhf infection inducing a greater response. Chronic FIV infection appeared to modify the APR, which varied with the infecting Haemoplasma species.  相似文献   

Induction of hyperactivity in larvae of the cattle tick Boophilus microplus by formamidines and related compounds     

P.W. Atkinson  C.O. Knowles 《Pesticide biochemistry and physiology》1974,4(4):417-424

The effect of chlordimeform and 18 related compounds on the aggregation behavior of the negatively geotactic larvae of the cattle tick, Boophilus microplus was investigated. Aggregations were treated and hyperactivity in the forms of immediate dispersal, delayed dispersal, and prolonged leg waving evaluated. A marked structure-activity relationship with delayed dispersal resulted; most active were the N-monomethyl formamidines, N′-(2,4-dimethylphenyl)-N-methylformamidine and demethylchlordimeform. Other compounds, including chlordimeform, with structures compatible with metabolism to N-monomethyl formamidines were also active. Delayed dispersal caused by those possessing the N,N-dimethyl moiety was antagonized after inhibition of oxidative N-demethylation to N-monomethyl analogs by piperonyl butoxide. Since the N-monomethyl moiety had already been reported as important in the killing action of the formamidines in cattle tick larvae, the possibility of a relationship between delayed dispersal and acaricidal effectiveness was examined and percentage mortality at 24 hr found to correlate positively with the rate of onset of dispersal.Delayed dispersal was not characteristic of the responses to other acaricides such as lindane, allethrin, carbaryl, and coumaphos. In addition, the monoamine oxidase inhibitors, tranylcypromine, pargyline, and nialamide, did not induce delayed dispersal and showed no lethal effects.  相似文献   

The clinical efficacy of EMLA cream for intravenous catheter placement in client-owned dogs     

Hugo van Oostrom  Toby G. Knowles 《Veterinary anaesthesia and analgesia》2018,45(5):604-608

Objective

To assess the reaction of client-owned dogs to intravenous (IV) catheter placement after applying a local anaesthetic (EMLA) or placebo cream for either 30 or 60 minutes.

Study design

Prospective, randomized, blinded, placebo-controlled, clinical trial.

Animals

A total of 202 client-owned dogs of various breeds.

Methods

With owner consent, dogs were randomly allocated to one of four treatment groups: EMLA 60 minutes, EMLA 30 minutes, Placebo 60 minutes and Placebo 30 minutes. After the cream was applied for the allocated time, an IV catheter was placed and the behavioural reaction of the dog was scored. The reaction score was analysed using a Kruskal–Wallis test followed by Mann–Whitney U tests of the multiple pairwise comparisons, with Bonferroni correction.

Results

A large number of dogs, even in the placebo groups, did not react to IV catheter placement. However, the Kruskal–Wallis test showed an overall difference between treatment groups (χ2 = 11.029, df = 3, p = 0.012). The pairwise comparisons showed a lower overall reaction score in the EMLA 60 group than in the EMLA 30 and Placebo 60 groups (adjusted p = 0.018 and adjusted p = 0.044, respectively).

Conclusions and clinical relevance

This study shows that EMLA cream applied for 60 minutes reduces the behavioural reaction of dogs to IV catheter placement; therefore, this intervention can be advocated for routine use in veterinary medicine to enhance the welfare of dogs undergoing IV catheter placement.  相似文献   

Tracking the evolution of a hydrothermal event plume with a RAFOS neutrally buoyant drifter     

JE Lupton  ET Baker  N Garfield  GJ Massoth  RA Feely  JP Cowen  RR Greene  TA Rago 《Science (New York, N.Y.)》1998,280(5366):1052-1055

The migration and evolution of a deep ocean hydrothermal event plume were tracked with a neutrally buoyant RAFOS float. The float remained entrained in the plume for 60 days, and the plume vorticity was calculated directly from the anticyclonic motion of the float. Concentrations of suspended particles, particulate iron, and dissolved manganese in the plume did not decay significantly during the 60 days, which indicates that event plumes would be easily detectable a year after formation.  相似文献   

Paleolithic population growth pulses evidenced by small animal exploitation   总被引：1，自引：0，他引：1  

MC Stiner  ND Munro  TA Surovell  E Tchernov  O Bar-Yosef 《Science (New York, N.Y.)》1999,283(5399):190-194

Variations in small game hunting along the northern and eastern rims of the Mediterranean Sea and results from predator-prey simulation modeling indicate that human population densities increased abruptly during the late Middle Paleolithic and again during the Upper and Epi-Paleolithic periods. The demographic pulses are evidenced by increasing reliance on agile, fast-reproducing partridges, hares, and rabbits at the expense of slow-reproducing but easily caught tortoises and marine shellfish and, concurrently, climate-independent size diminution in tortoises and shellfish. The results indicate that human populations of the early Middle Paleolithic were exceptionally small and highly dispersed.  相似文献   

Nitrogen monoxide production and consumption in an organic soil   总被引：2，自引：0，他引：2  

P. F. Dunfield  R. Knowles 《Biology and Fertility of Soils》1999,30(1-2):153-159

 Factors controlling NO production, consumption, and emission rates were examined in an organic soil. Emission rates were measured in the enclosed headspaces of intact soil cores under three fertilisation treatments (unfertilised or 100 kg N ha^–1 as NH₄Cl or as NaNO₃), with and without the nitrification inhibitor C₂H₂ (20–70 μl l^–1). Nitrification was always the main source of NO emitted across the soil surface, even when the soil was nearly saturated. Fertilisation of soil with NH₄Cl increased NO emission both by stimulating NO production from nitrification, and by decreasing the NO consumption rate constant. Addition of NaNO₃ also stimulated the production of NO and N₂O during nitrification in aerobic soil slurry experiments. This effect was eliminated by adding C₂H₂ and was therefore not related to denitrification. In loose soil samples, the increase in NO-N production after NH₄Cl addition represented as much as 26% of the added N. However, in intact cores, 95% of the NO produced through nitrification was oxidised within the soil column rather than emitted to the atmosphere. We concluded that nitrification is the primary NO source from this organic soil, that surface NO emissions are much lower than gross NO production rates, and that gaseous N oxide (NO and N₂O) losses during nitrification can be affected by both soil NH₄ ⁺ and NO₃ ^–. Received: 15 December 1998  相似文献   

壳聚糖对动物脂肪代谢及生长性能的影响   总被引：7，自引：2，他引：5  

丁晓岚  闫素梅  塔娜 《饲料工业》2005,26(12):8-9

壳聚糖(chifosan),是甲壳素的衍生物．又名可溶性甲壳素、脱乙酰甲壳素、甲壳胺、几丁聚糖．是通过甲壳素一定程度的脱乙酰而得到．通常将脱乙酰度55％以上的甲壳素称作壳聚糖,化学名称是(1．4)-2-氨基-2-脱氧-β-D-葡聚糖。在众多的天然多糖中,甲壳素及其主要衍生物壳聚糖是唯一的碱性多糖．具有生物相容性、可食用性、可抗菌性、  相似文献   

Efficacy of Seed Aging and Gibberellin Treatments for Manipulating Apical Dominance,Tuber Set and Size Distribution of cv. Shepody     

Cody J. Dean  Lisa O. Knowles  N. Richard Knowles 《American Journal of Potato Research》2018,95(5):526-538

The cultivar Shepody has excellent early processing qualities and produces above average tuber yields but sets relatively few tubers that often become excessively large relative to market demand. Optimizing tuber set and size of Shepody for seed and frozen processing markets currently entails adjusting in-row spacing and vine kill date. However, arresting tuber growth by vine killing for size control sacrifices yield potential. Aging seed by storing at 12, 22, and 32°C for 80-, 450-, and 900-degree days, or gibberellin (GA) treatments, were evaluated as more direct approaches for modulating stem number (apical dominance), tuber set, and size distribution relationships. Shepody proved to be inherently resistant to high temperature-induced age-priming treatments. In contrast to other cultivars studied previously, age-priming Shepody seed during storage had no effect on plant emergence and the resulting increases in stem number, tuber set, and associated decreases in average tuber weight were marginal. By contrast, GA applied as seed dip or spray effectively hastened plant emergence, reduced apical dominance, increased tuber set, and decreased average tuber size. The magnitude of these GA-induced effects depended on concentration and application technique (seed dip versus spray). For frozen processing, GA applied as a seed dip at 1 mg L^-1 added an additional tuber per plant and decreased average tuber size by 15% without affecting U.S. No. 1 tuber yields and gross returns; however, 2 and 3 mg L^-1 GA decreased U.S. No. 1 tuber yields and crop value by an average of 16 and 14%, respectively. Spray applications of 2–6 mg L^-1 GA also reduced U.S. No. 1 tuber yield and frozen processing value. Conversely, the increase in tuber set (1.5 tubers plant^-1) and associated 25% reduction in average tuber weight induced by 2 mg L^-1 GA applied as either dip or spray increased gross crop values on a seed contract by 25 and 38%, respectively. The differential efficacies of dip versus spray applications of GA on tuber set and size distribution were likely attributable to differences in GA deposition on the seed. Applying low concentrations of GA to cut seed of Shepody as either a dip (1–2 mg L^-1) or spray (2 mg L^-1) effectively modulated tuber set and size to significantly increase gross returns for seed, and to better satisfy the needs of processors for more moderate size tubers.  相似文献