Osseous sequestration in cattle: 110 cases (1987-1997)

OBJECTIVE: To determine risk factors for development of sequestra in cattle and identify factors associated with a successful outcome. DESIGN: Retrospective study. ANIMALS: 110 cattle. PROCEDURE: Medical records of cattle treated at veterinary teaching hospitals in North America were reviewed. To determine risk factors for osseous sequestration, breed, age, and sex of cattle with osseous sequestration were compared with breed, age, and sex of all other cattle admitted during the study period. RESULTS: 110 cattle were included in the study. Three had 2 sequestra; thus, 113 lesions were identified. Most sequestra were associated with the bones of the extremities, most commonly the third metacarpal or third metatarsal bone. Ninety-two animals were treated surgically (i.e., sequestrectomy), 7 were treated medically, 3 were initially treated medically and were then treated surgically, and 8 were not treated. Follow-up information was available for 65 animals treated surgically and 6 animals treated medically. Fifty-one (78%) animals treated surgically and 5 animals treated medically had a successful outcome. Cattle that were 6 months to 2 years old had a significantly increased risk of developing a sequestrum, compared with cattle < 6 months old. Cattle in which sequestrectomy was performed with the aid of local anesthesia were significantly more likely to undergo 2 or more surgical procedures than were cattle in which sequestrectomy was performed with the aid of general anesthesia. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that sequestrectomy will result in a successful outcome for most cattle with osseous sequestration.     

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.     

Postoperative radiotherapy for canine soft tissue sarcoma

Thirty-five dogs with 37 soft tissue sarcoma tumors that were incompletely excised and treated with radiotherapy in the postoperative, adjuvant setting were reviewed. Variables evaluated included age, sex, tumor site, tumor histology, total tumor radiation dose, radiotherapy field size. time to recurrence, and survival. The majority of tumors were fibrosarcomas and hemangiopericytomas, but small numbers of other tumor types were also represented. Total tumor radiation dose ranged from 42 to 57 Gy given in 3- to 4.2-Gy daily fractions on a Monday through Friday schedule. Overall median survival was 1,851 days. Median time to local recurrence was greater than 798 days. Soft-tissue sarcoma tumors at oral sites had a statistically significant lower median survival (540 days) as compared to other tumor sites (2,270 days). Radiotherapy may be a useful adjuvant therapy for incompletely excised soft-tissue sarcomas with a reasonable expectation for long-term patient survival.     

It may be a dog's life but the relationship with her owners is also key to her health and well being: communication in veterinary medicine.

Effective communication is necessary for achieving important outcomes in veterinary practice, including patient health, accuracy, efficiency, and economic viability. Communication is a series of learned skills. Daily practice, feedback, and refinement are the ingredients for continued practice success.     

Adaptive significance of intermittent shoot growth in Douglas-fir seedlings

We tested the hypothesis that intermittent (lammas) shoot growth in Douglas-fir (Pseudotsuga menziesii var menziesii (Mirb.) Franco) seedlings from dry regions of southwest Oregon is adaptively significant. Seedlings from open-pollinated families (160 total) from two inland (dry) and two coastal (wet) sources were grown under either well-watered or intermittent drought conditions (temporary drought followed by rewatering) for two growing seasons. In the first growing season, the results supported the hypothesis: the frequency of a second flush was genetically controlled (although weakly, h(f) (2) 相似文献   

Virulence and double‐stranded RNA in Sphaeropsis sapinea

Forty wildtype isolates of Sphaeropsis sapinea were grouped into the morphotypes A and B based on previously defined differences in cultural and morphological criteria as well as restriction sites for Dde I and Bst UI endonucleases in nuclear ribosomal DNA amplicons. Thirteen of 20 type A isolates and nine of 20 type B isolates contained detectable dsRNA (55%) of different molecular weight and size. dsRNA was transmitted into conidia at a frequency of 71–100%. By selecting single conidia, dsRNA‐free subcultures were obtained from six of 22 isolates containing dsRNA. Pathogenicity tests on expanding buds of landscape trees of three species of Pinus showed highly significant statistical interactions between isolate virulence, Pinus species, and year. Pine species‐year had a profound impact on virulence. The pattern in the interactions was revealed by principal component analysis of the interaction sums of squares of the anova (Additive Main Effects and Multiplicative Interaction; AMMI). Pinus sylvestris was highly interactive in its susceptibility to S. sapinea with seasonal effects. P. nigra and P. resinosa were more stable. The interactivity analysis was used to apportion interaction to specific isolates to improve the accuracy of the estimates of virulence. Estimates of the relative virulence of isolates were predicted over five different Pinus species‐years. Isolates were ranked in virulence and interactivity using the AMMI model. This model permitted mean separation tests of the relative virulence among isolates over the combined Pinus species‐years. One isolate was identified as potentially having dsRNA‐mediated hypovirulence based on the significantly greater virulence of its isogenic, dsRNA‐free subculture, as expressed over the three Pinus species and 2 years. Type A isolates containing dsRNA ranged from stable to highly interactive and from low to high in virulence. Type B isolates containing dsRNA were similar in interactivity but virulence ranged from avirulent to moderate, seldom exceeding the mean for S. sapinea. dsRNA‐free isogenic subcultures tended not to express higher virulence than their dsRNA‐containing parent strains but often changed in interactivity. Therefore, in one year a dsRNA‐free subculture might be more virulent than its dsRNA‐containing parent. In another year the dsRNA‐free subculture might be less virulent.     

An improved heat pulse method to measure low and reverse rates of sap flow in woody plants

The compensation heat pulse method (CHPM) is of limited value for measuring low rates of sap flow in woody plants. Recent application of the CHPM to woody roots has further illustrated some of the constraints of this technique. Here we present an improved heat pulse method, termed the heat ratio method (HRM), to measure low and reverse rates of sap flow in woody plants. The HRM has several important advantages over the CHPM, including improved measurement range and resolution, protocols to correct for physical and thermal errors in sensor deployment, and a simple linear function to describe wound effects. We describe the theory and methodological protocols of the HRM, provide wound correction coefficients, and validate the reliability and accuracy of the technique against gravimetric measurements of transpiration.     

Family variation for fall cold hardiness in two Washington populations of coastal Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco)

In order to assess the genetics of fall cold hardiness in coastal Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco), shoot cuttings were collected in October from saplings (9-year-old trees) of open-pollinated families in two progeny tests in each of two breeding zones in Washington, one in the Coast range (80 families) and one on the west slope of the Cascade Mountains (89 families). Samples from over 5500 trees were subjected to artificial freezing and visually evaluated for needle, stem and bud tissue injury. The extent to which cold injury is genetically related to tree height and shoot phenology (timing of bud burst and bud set) was also evaluated.

Significant family variation was found for all cold hardiness traits; however, individual heritability estimates were relatively low (ranging from 0.09 to 0.22). Significant family-by-test site interaction was detected for needle injury in the Cascade breeding zone, but not in the coastal zone. Genetic correlations (r_A) among needle, stem and bud tissues for cold damage were weak (0.16 ≤ r_A ≤ 0.58) indicating that genes controlling fall hardening are somewhat different for different tissues. Timing of bud burst and bud set were only weakly correlated with cold injury (r_A ≤ 0.49). Thus, bud phenology is a poor predictor of fall cold hardiness in this species. There was no consistent relationship between tree height and cold injury in the coastal zone. In the Cascade zone, taller trees appeared to be more susceptible to cold injury, but the association was weak (mean r_A = 0.38, range 0.20 – 0.72).