Foot rot in cattle; a small controlled experiment     

ROBERTS SJ  KIESEL GK  LEWIS NF 《The Cornell veterinarian》1948,38(2):122-130

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A model for the effect of constant photoperiods on the rate of sexual maturation in pullets     

P.D. LEWIS  T. R. MORRIS  G. C. PERRY 《British poultry science》1998,39(1):147-151

1. This paper reviews evidence from 15 experiments, reported over a span of 44 years, in which pullets were reared from hatching to sexual maturity on 2 or more constant photoperiods. 2. The evidence strongly indicates that earliest age at first egg (AFE) was observed when pullets were held on constant 10 h days (though earlier maturity is easily induced by increasing the photoperiod during rearing). The pair of equations which best describe the relationship between AFE (y,d) and photoperiod (x,h) are for x < 10 h, y = 175.8- 1.731x; for x > 10 h, y=155.5 + 0.301x. 3. This 2-straight-line model, hinged at 10 h, should be used in preference to curvilinear models published earlier, which wrongly predict that pullets reared on long days (14h to 17h) mature faster than birds reared on constant 10 h.  相似文献   

Attitudes toward Accelerated Urban Development in Low-Population Areas     

W. CRIS LEWIS  STAN L. ALBRECHT 《Growth and change》1977,8(1):22-28

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Variation in host range, systemic infection and epidemiology of Leptosphaeria maculans   总被引：2，自引：0，他引：2  

R. D. JOHNSON  B. G. LEWIS 《Plant pathology》1994,43(2):269-277

The A and B groups (aggressive and non-aggressive) of Leptosphaeria maculans were compared in studies of host range, infection phenotypes and epidemiology. Isolates of both groups infected a wide range of cruciferous hosts including Brassica napus, B. rapa, B. oleracea, B. juncea, B. carinata. B. nigra, Thlaspi arvense and Raphanus sativus. On cotyledons, B-group isolates were generally more aggressive than A-group isolates, causing local lesions and subsequent systemic invasion of the majority of test species. On susceptible stems, A-group isolates caused cortical lesions; B-group isolates, if they reached the stem, usually caused pith lesions with no external symptoms. In a susceptible line of B. napus , CrGC5, systemic infections of the leaf and petiole were similar with both groups, but the B-group rarely entered the stem to form cortical lesions or cankers. At two different field locations, natural epidemics caused by the two groups on oilseed rape leaves were similar in overall pattern, B-group lesions occurred slightly later but the incidence increased more rapidly and reached a maximum slightly earlier than that of the A group. The two groups differed markedly in stem infection patterns. Infection of the cortex near the base of the stem and the development of a typical stem canker was caused entirely by the A group. However the B group often caused considerable damage to the pith. Superficial chlorotic lesions on stems and inflorescences were mainly attributable to the B group. In view of the stem pith infection by the B group without external symptoms, its importance on oilseed rape may have been underestimated previously.  相似文献   

A Biomechanical Evaluation and Assessment of the Accuracy of Reduction of Two Methods of Acetabular Osteotomy Fixation in Dogs   总被引：1，自引：0，他引：1  

W. PRESTON STUBBS DVM  Diplomate ACVS    DANIEL D. LEWIS DVM  Diplomate ACVS    GARY J. MILLER PhD    CHARLES QUARTERMAN BS  GISELLE HOSGOOD BVSc  MS  Diplomate ACVS 《Veterinary surgery : VS》1998,27(5):429-437

Objective—To compare the accuracy of reduction, biomechanical characteristics, and mode of failure of two methods of acetabular osteotomy repair. Study Design—Acetabular osteotomies were created in 16 paired hemipelves and stabilized with a screw/wire/polymethylmethacrylate composite fixation technique (SWP) or a 2-mm veterinary acetabular plate (VAP). Eight intact hemipelves were used as controls. Sample Population—Twelve canine cadavers. Methods—Accuracy of osteotomy reduction was evaluated grossly and by measurement of articular incongruencies formed in polyvinylsiloxane impression casts. Acetabula were loaded in modified bending until failure using a universal testing machine. Data from load-deformation curves were used to determine the biomechanical characteristics of the repaired and intact acetabula. Mode of failure was evaluated grossly and radiographically. Results—Osteotomy reduction was superior in acetabula stabilized with SWP. Mean values ± standard deviation for load at failure and stiffness of the intact acetabula were 2,796 ± 152.9 N and 267.5 ±61.9 N/mm. Corresponding values for SWP and VAP were 1,192 ± 202.7 N and 136.3 ± 76.5 N/mm, and 1,100.5 ± 331.6 N and 110.0 ± 51.3 N/mm, respectively. The mean load at failure and stiffness of intact acetabula was significantly greater than acetabula stabilized with SWP or VAP. There was no significant difference between SWP and VAP for load at failure or stiffness. Failure of acetabula stabilized with SWP occurred by fracture of the polymethylmethacrylate and ventrolateral bending of the wires. Acetabula stabilized with VAP failed by ventrolateral twisting of the plate and bending of the caudal screws. Conclusions—SWP and VAP provide comparable rigidity, however, the SWP facilitates more accurate osteotomy reduction. Clinical Relevance—These findings support the use of the SWP technique as an alternative method of acetabular fracture repair.  相似文献   

The persistence of foot-and-mouth disease virus on wool   总被引：1，自引：0，他引：1  

KA McCOLL  HA WESTBURY  RP KITCHING†  VM LEWIS 《Australian veterinary journal》1995,72(8):286-292

SUMMARY Five Suffolk sheep, held in a high-security isolation room, were exposed for 2 hours to the aerosol of 3 mature pigs that had been infected with foot-and-mouth disease virus (FMDV), strain O₁-BFS. The fleeces of 3 of the sheep were contaminated with FMDV at 2 days post exposure (dpe), while at 5 dpe the fleeces of all 5 sheep were more extensively, and more heavily, contaminated. The persistence of FMDV on contaminated wool was examined in vitro using multiple 0.5 g samples of Merino wool that were each contaminated with one of 3 strains of FMDV in tissue-culture medium: O₁-BFS, O-Morocco (O-MOR 9/91) or an Asia 1 strain (TAI 1/90). Wool samples were held at either 4°C, 18°C or 37°C, and decay curves were established for each virus at each temperature. These curves predicted that O₁-BFS, O-MOR 9/91 and TAI 1/90 would fall below detect-able levels at 72, 70 and 48 days post contamination (pc), respectively, for wool stored at 4°C; at 11, 12 and 12 days pc, respectively, for wool stored at 18°C; and at 57, 68 and 33 hours pc, respectively, for wool stored at 37°C. For wool contaminated with O₁-BFS-infected sheep faeces, urine or blood, or with O₁-BFS-infected cattle saliva, decay curves predicted virus to persist for 5 to 11 days pc at 18°C. We demonstrated that the simulated scouring of FMDV-contaminated wool at 60° to 70°C would usually reduce virus to below detectable levels. The detergent component of the scouring process had little, if any, antiviral activity, and scouring at 20°C or 50°C had limited impact on FMDV titres . We recommend that either (1) simple storage of FMDV-contaminated wool for 4 weeks at temperatures of 18°C or higher, or (2) scouring of contaminated wool at 60° to 70°C would be sufficient to remove the threat of FMDV-contaminated wool being infectious to other animals .  相似文献   

Bovine cranial zygomycosis caused by Saksenaea vasiformis     

BD HILL  PF BLACK  M KELLY  D MUIR  WAJ MC DONALD 《Australian veterinary journal》1992,69(7):173-174

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Interactions between pesticide treatment, cutting frequency and rate of N fertilizer on white clover grown in mixture with perennial ryegrass     

G. C. LEWIS 《Grass and Forage Science》1991,46(4):399-403

The effects of a combined pesticide and fungicide (P + F) treatment on the proportion of white clover in an established perennial ryegrass/white clover sward were assessed on six occasions during 1988 and 1989, under two cutting frequencies (2- or 6-week intervals) and with or without N fertilizer (120 kg ha^-1 per annum). In 1988 P + F treatment significantly increased the proportion of clover in August and October, with an increase at the latter harvest being much greater where N was also applied. There was no significant interaction between P + F treatment and cutting frequency, although less frequent cutting increased significantly the proportion of clover in October where N was not applied.
In 1989, drought prevented the proportion of clover from exceeding 1% throughout, regardless of management factors. P + F treatment significantly increased the proportion of clover in August, and significantly reduced populations of slugs, foliar-feeding insects (mainly Collembola; Sminthuridae) and the area of clover leaf damaged by pests. No marked effect of P + F treatment on populations of plant parasitic nematodes was detected. No appreciable incidence of fungal diseases was observed in either year.  相似文献   

Control of stem nematode (Ditylenchus dipsaci) in strawberry by granular nematicides     

SERFIAH LEWIS 《Plant pathology》1979,28(4):191-196

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PROCEDURES FOR THE DIAGNOSIS OF RABIES IN AUSTRALIA     

H. GELDARD B. V. Sc.  P. F. LEWIS  B. V. Sc.  M. A. C. V. Sc. 《Australian veterinary journal》1977,53(6):297-297

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