Lymphosarcoma of the pharyngeal region in a 7-month-old beef steer

A steer presented for retropharyngeal swelling and dyspnea. Biopsy of the swelling indicated lymphoblastic lymphosarcoma, and necropsy revealed involvement of regional veins and arteries. The tumor was classified as a non-T, non-B lymphoma based on CD3 polyclonal antibody stains. Lymphosarcoma is unusual in this location, but should be considered with retropharyngeal swelling.     

Association of serologic status for Neospora caninum with postweaning weight gain and carcass measurements in beef calves

OBJECTIVE: To determine the seroprevalence for Neospora caninum in a population of beef calves in a feedlot and the association of serologic status with postweaning weight gain and carcass measurements. DESIGN: Longitudinal observational study. ANIMALS: 1,009 weaned beef steers from 92 herds. PROCEDURE: Samples were obtained from all steers at time of arrival at a feedlot. Serologic status for Neospora spp was determined, using an agglutination test. Results of serologic testing were compared with calf growth and carcass data, using multivariate regression with generalized estimating equations. RESULTS: Of 1,009 calves, 131 (12.98%) were seropositive, and 54 of 92 (58.7%) consignments had > or = 1 seropositive calf. Median within-consignment prevalence for consignments in which there was > or = 1 seropositive calf was 20%. Seropositive status was associated with significant reductions in average daily gain, live body weight at slaughter, and hot carcass weight and an increase in ribeye area-to-hot carcass weight ratio. Seropositive status also was associated with significant increases in cost of treatment and significant reductions in income. Sick seropositive calves had the highest cost of treatment. An economic loss of $15.62/calf was projected for seropositive calves. CONCLUSIONS AND CLINICAL RELEVANCE: Significant reductions in postweaning weight gain, carcass weight, and economic return were associated with detection of antibodies to N caninum in beef calves in a feedlot.     

Cryptosporidium meleagridis in an Indian ring-necked parrot (Psittacula krameri)

OBJECTIVE: To perform a morphological and genetic characterisation of a Cryptosporidium infection in an Indian ring-necked parrot (Psittacula krameri) and to compare this with C meleagridis from a turkey. DESIGN: Tissue and intestinal sections from an Indian ring-necked parrot were examined microscopically for Cryptosporidium. The organism was also purified from the crop and intestine, the DNA extracted and a portion of the 18S rDNA gene amplified, sequenced and compared with sequence and biological information obtained for C meleagridis from a turkey as well as sequence information for other species of Cryptosporidium. RESULTS: Morphological examination of tissue sections from an Indian ring-necked parrot revealed large numbers of Cryptosporidium oocysts attached to the apical border of enterocytes lining the intestinal tract. Purified Cryptosporidium oocysts measured about 5.1 x 4.5 microns, which conformed morphologically to C meleagridis. The sequence obtained from this isolate was identical to sequence information obtained from a C meleagridis isolate from a turkey. CONCLUSION: Cryptosporidium meleagridis was detected in an Indian ring-necked parrot using morphological and molecular methods. This is the first time that this species of Cryptosporidium has been reported in a non-galliform host and extends the known host range of C meleagridis.     

Fatigue in wood-based panels. Part 1: The strength variability and fatigue performance of OSB, chipboard and MDF

Wood-based panels used as floor decking can be exposed to fatigue as well as creep loading. The strength and fatigue performances of three wood-based panel products OSB, chipboard and MDF have been determined in four-point bending. The mean bending strengths were found to decrease in the following order MDF>OSB>chipboard. The bending strength variation within the OSB was considerably greater than that for chipboard and MDF. Normalised with respect to the static strengths, the fatigue performance of the chipboard was superior to that of the OSB, although the two materials have very similar performances at low stress levels. Normalised with respect to the static strengths, the fatigue performance of the MDF was inferior to both materials and at lower stress levels the fatigue performance deteriorated to a greater extent. However, in terms of absolute applied stress, the fatigue performance of the MDF was superior to that of the OSB, which was superior to that of the chipboard. However, as the stress was reduced the difference between the three materials reduced. At low stresses the performances of the three materials were quite similar. Received 5 August 1999     

Effect of two relative humidity environments on the performance properties of MDF, OSB and chipboard

The static strength, stiffness and fatigue life of MDF, OSB and chipboard have been measured in a 65%RH environment and a 85%RH environment. Chipboard is commonly utilised as a flooring material and OSB is also used in structural applications, for example floor decking and webs of I-beams. The mean static strengths of MDF, OSB and chipboard at 65%RH were 47.9 MPa, 27.9 MPa and 21.0Mpa, respectively, compared with 34.59 MPa, 21.70 MPa and 10.61 MPa at 85%RH. However, MDF has mostly been used in non-structural applications, such as furniture, so its resistance to fatigue loads as a structural panel is of considerable interest. In a 65%RH environment dynamic modulus values showed that whilst MDF and chipboard exhibit similar stiffness values (4 GPa), OSB is approximately 50% stiffer. However, at 85%RH MDF was the stiffest of the three materials, followed by OSB and chipboard. The fatigue life performance of all three panel products was markedly lower at 85%RH compared with 65%RH. Overall, the high RH environment had a noticeably detrimental effect on the MOE (modulus of elasticity), MOR (modulus of rupture) and fatigue lives of OSB and chipboard. This is attributed to these panels retaining more of the original characteristics of the original wood, i.e. larger particle sizes (flakes/chips) compared with the homogeneous fibrous composition of MDF. Received 5 November 1999     

Fatigue and creep in chipboard

Summary Structural grade chipboard used as floor decking can be exposed to a combination of creep loading, and fatigue loading at a wide range of frequencies. Creep loads are produced by static masses such as machinery. Fatigue loads arise from intermittent loads such as fork lift trucks in motion, people in motion, or vibrating machinery.Four-point bend tests in fatigue and creep have been performed simultaneously on matched sets of four structural grade chipboard samples. The aim was to examine the effect of frequency on the fatigue performance of chipboard by following the rate of microstrain development in each case at the same peak stress. The ratio of the minimum to the maximum fatigue stress (the R ratio) was set at R = 0.1. Fatigue tests were performed at three different frequencies classified as low, medium and high, determined by the rate of application of stress.The performance of chipboard in flooring applications is shown to be highly dependent on the loading frequency. Increasing the frequency increased the number of cycles to failure as did reducing the stress level. Using hysteresis loop capture to monitor damage accumulation during testing indicates that there is a fatigue limit for chipboard loaded at constant amplitude at some point just below 20% of its static bending strength.This research was supported by the Building Research Establishment who also supported the postgraduate case award in conjunction with the Engineering and Physical Sciences Research Council (EPSRC)     

Relationship of water to adventitious rooting in stem cuttings of Populus species

Populus species, characterized by fast growth and easy vegetative propagation, are widely used in agroforestry practices. The substantial water requirement of poplars make them interesting subjects for water balance studies. No information exists on soil moisture requirements for initial root and shoot growth of Populus cuttings. This study on leafless hardwood cuttings of Populus x euramericana (Dode) Guinier cv. Robusta examined the dynamics of water use during propagation, as influenced by two initial soil water potentials (–0.006 and –0.06 MPa). Differences in the initial water potential of the cuttings was achieved by three pretreatments i.e., fresh, soaked and dried. Initial _shoot was –1.45, –0.10 and –2.10 MPa in fresh, soaked and dried cuttings, respectively. Soil moisture had a major effect on rooting. Water-stressed cuttings took a longer time to root and had fewer roots. Pre-soaking of cuttings stimulated rooting, particularly under the drier soil moisture conditions. Initially the water potential of cuttings decreased with time and with the formation of roots it stabilized in all the pretreatments. The reduction in water potential of cuttings after planting was related to an increase in resistance to water flow in the xylem.This revised version was published online in November 2005 with corrections to the Cover Date.     

Combined xeno/auto-grafting of a benign osteolytic lesion in a dog, using a novel bovine cancellous bone biomaterial

CASE HISTORY: A 4-year-old female Labrador Retriever was diagnosed with an osteolytic lesion of the right distal radius. CLINICAL FINDINGS: Radiographs indicated a well-circumscribed radiolucent area 18 x 15 x 8 mm, centred on the distal radial physeal scar. DIAGNOSIS: Histopathology, performed via Jamshidi needle biopsy and following surgical curettage, was inconclusive but suggested either an aneurysmal bone cyst or fibrous dysplasia. CLINICAL RELEVANCE: A novel processed cancellous bovine bone xenograft was used in conjunction with autogenous cancellous bone (at a ratio of approximately 4:1) to fill the curetted defect. There were no observed complications associated with the use of this new biomaterial. Osteointegration of the bone graft was followed using conventional radiographs and peripheral quantitative computed tomography (pQCT) for 10 months post-operatively. Radiographically, the osteolytic lesion modelled to resemble metaphyseal trabeculation. The cross-sectional area and the average bone density of the grafted lesion determined using pQCT data increased over time, suggesting healthy osteoconduction and native bone production.     

An outbreak of rickets in Corriedale sheep: evidence for a genetic aetiology

CASE HISTORY: A skeletal disease characterised by lameness, limb deformities and reduced growth rate occurred over two successive years in lambs born on a commercial sheep farm in Marlborough. A genetic aetiology was considered likely following exclusion of other known causes of rickets and because of the progressive nature of the disease, even after affected animals were transferred to another property. CLINICAL FINDINGS: Affected lambs appeared normal at birth but developed clinical signs during the first 2 months of life. The most severely affected animals either died or were euthanised within the first year of life, but some survived to breeding age. Serum biochemistry revealed hypocalcaemia, hypophosphataemia and increased concentrations of 1,25 dihydroxyvitamin D. The mean serum 25 hydroxyvitamin D concentration was similar to that of control lambs. PATHOLOGICAL FINDINGS: Gross lesions included enlarged costochondral junctions, bilateral irregularity of articular surfaces on humeral heads due to collapse of subchondral bone, thickened cortices in long bones and irregular thickening of physeal cartilages. Microscopically, tongues of hypertrophic chondrocytes extended from physes into metaphyseal regions; metaphyseal trabeculae were thick, disorganised and often lined by wide osteoid seams. Osteoclastic activity was excessive both in cortical and trabecular bone. DIAGNOSIS: Inherited rickets in Corriedale sheep. CLINICAL RELEVANCE AND CONCLUSIONS: This disease is likely to be present in several Corriedale sheep flocks in New Zealand and may have been misdiagnosed as arthritis or other diseases causing lameness and/or poor growth. A defect in end-organ responsiveness to 1,25 dihydroxyvitamin D is the likely mechanism. This disease of sheep may be a useful model for studying vitamin D metabolism and the treatment of inherited forms of rickets in human beings.     

Relationships among Puberty,Muscle and Fat,and Liveweight Gain during Mating in Young Female Sheep

Greater depths of muscle are associated with better reproductive performance in ewe lambs, but, in adult ewes, reproductive performance also seems to vary with liveweight gain during the mating period. Therefore, in a large field study with Merino ewe lambs, we tested whether the relationships among eye muscle depth (EMD), fat depth (FAT) and reproductive performance depend on liveweight gain during the mating period. We selected lambs with a wide range in phenotypic values for depths of eye muscle (EMD) and fat (FAT) and assigned them to dietary treatments designed to achieve low (LOW, n = 244) or high (HIGH, n = 237) rates of liveweight gain during a 28‐day mating period. The LOW treatment maintained live weight, whereas the HIGH treatment gained 179 ± 3.8 g/day (p < 0.001). From those ewe lambs that attained puberty, first oestrus was detected at live weight 37.8 ± 0.2 kg and age 232 days. The proportion of ewes that attained puberty increased with EMD (p < 0.01). Ewes from the HIGH treatment were more fertile (pregnant ewes per 100 ewes exposed to rams) and had a higher reproductive rate (foetuses in utero per 100 ewes exposed to rams; p < 0.001) than those from the LOW treatment. Fertility and reproductive rate were positively correlated with weight gain during mating as well as live weight at the start of mating, FAT and EMD (p < 0.05 to <0.001). We conclude that faster growth, due to either extra nutrition during mating or higher phenotypic potential for fat and muscle, will increase reproductive performance in ewe lambs mated at 8 months of age.