Gross postmortem and histologic examination findings from abortion losses and calf mortalities in western Canadian beef herds

Production losses from abortions, stillbirths, and early calf mortality were described for the 2002 calf crop in 203 beef herds in western Canada. A total of 1689 calves were examined. A summary diagnosis was reported for 64% of aborted calves, 78% of stillborn calves, 88% of neonatal calves, and 94% of the calves > 3 d of age. Diagnoses for aborted calves included: thyroid gland lesions, pneumonia, developmental anomalies, placentitis, and myocardial necrosis or myopathy. For stillborn calves, diagnostic findings included: dystocia, thyroid gland lesions, myocardial necrosis or myopathy, developmental anomalies, and skeletal myopathy or necrosis. The most common diagnoses for neonatal calves (≤ 3 d) were: pneumonia, skeletal myopathy or necrosis, myocardial necrosis or myopathy, accident or trauma, and septicemia. For older calves (3 d to 3 mo), the most common diagnoses included: starvation, abomasal ulcer or perforation, enteritis or colitis, pneumonia, and intestinal volvulus, obstruction, or perforation.     

Relationships between bole and crown size for young urban trees in the northeastern USA

Knowledge of allometric equations can enable urban forest managers to meet desired economic, social, and ecological goals. However, there remains limited regional data on young tree growth within the urban landscape. The objective of this study is to address this research gap and examine interactions between age, bole size and crown dimensions of young urban trees in New Haven, CT, USA to identify allometric relationships and generate predictive growth equations useful for the region. This study examines the 10 most common species from a census of 1474 community planted trees (ages 4–16). Regressions were applied to relate diameter at breast height (dbh), age (years since transplanting), tree height, crown diameter and crown volume. Across all ten species each allometric relationship was statistically (p < 0.001) significant at an α-level of 0.05. Consistently, shade trees demonstrated stronger relationships than ornamental trees. Crown diameter and dbh displayed the strongest fit with eight of the ten species having an R² > 0.70. Crown volume exhibited a good fit for each of the shade tree species (R² > 0.85), while the coefficients of determination for the ornamentals varied (0.38 < R² < 0.73). In the model predicting height from dbh, ornamentals displayed the lowest R² (0.33 < R² < 0.55) while shade trees represented a much better fit (R² > 0.66). Allometric relationships can be used to develop spacing guidelines for commonly planted urban trees. These correlations will better equip forest managers to predict the growth of urban trees, thereby improving the management and maintenance of New England's urban forests.     

The development of a novel percutaneous lung biopsy procedure for use on feedlot steers

The purpose of this study was to develop a percutaneous lung biopsy technique to be used on steers in a commercial feedlot setting. Thirty-four crossbred steer and heifer calves from a commercial feedlot in southern Alberta were used in this study. The calves originated from the auction market and all were chronically affected with bovine respiratory disease (BRD). A technique was developed to obtain a lung sample from the right cranioventral lung lobe, intercostal space (ICS) 2, using a manual or an automatic biopsy instrument with a 14- or 12-gauge (ga) biopsy needle. Overall, lung parenchyma was successfully harvested in 55.9% of experimental animals and in 55.0% of lung biopsy trials. Compared with postmortem diagnosis, the biopsy resulted in the same pathologic diagnosis for 75% of biopsy samples when evaluated using standardized criteria by the same veterinary pathologist. The success rate was 61.5% and 42.9% in a hospital or field setting, respectively. With an automatic instrument, lung was recovered from 57.9% and 37.5% of samples obtained using a 12- or 14-ga biopsy needle, respectively. One experimental animal or 2.9% of the total had fatal complications from the procedure. In a commercial feedlot setting, the procedure took 20 min for each animal. Percutaneous lung biopsy of the right cranioventral lung lobe may be a viable technique when used on feedlot steers affected with chronic pneumonia. These findings suggest that using an automatic instrument with either a 14- or 12-ga biopsy needle may yield lung samples that are suitable for histopathological evaluation. However, this technique needs to be further evaluated in a field setting.     

Atypical hypoadrenocorticism in a Birman cat

A 1-year-old female spayed Birman cat was presented with a history of inappropriate urination and defecation, lethargy, anorexia, and weight loss. After intermittent responses to non-specific therapy she was diagnosed with atypical hypoadrenocorticism from the results of an adrenocorticotropic hormone stimulation test.     

Prevalence of selected zoonotic and vector-borne agents in dogs and cats in Costa Rica

To estimate the prevalence of enteric parasites and selected vector-borne agents of dogs and cats in San Isidro de El General, Costa Rica, fecal and serum samples were collected from animals voluntarily undergoing sterilization. Each fecal sample was examined for parasites by microscopic examination after fecal flotation and for Giardia and Cryptosporidium using an immunofluorescence assay (IFA). Giardia and Cryptosporidium IFA positive samples were genotyped after PCR amplification of specific DNA if possible. The seroprevalence rates for the vector-borne agents (Dirofilaria immitis, Borrelia burgdorferi, Ehrlichia canis, and Anaplasma phagocytophilum) were estimated based on results from a commercially available ELISA. Enteric parasites were detected in samples from 75% of the dogs; Ancylostoma caninum, Trichuris vulpis, Giardia, and Toxocara canis were detected. Of the cats, 67.5% harbored Giardia spp., Cryptosporidium spp., Ancylostoma tubaeforme, or Toxocara cati. Both Cryptosporidium spp. isolates that could be sequenced were Cryptosporidium parvum (one dog isolate and one cat isolate). Of the Giardia spp. isolates that were successfully sequenced, the 2 cat isolates were assemblage A and the 2 dog isolates were assemblage D. D. immitis antigen and E. canis antibodies were identified in 2.3% and 3.5% of the serum samples, respectively. The prevalence of enteric zoonotic parasites in San Isidro de El General in Costa Rica is high in companion animals and this information should be used to mitigate public health risks.     

Germination and seedling growth of <Emphasis Type="Italic">Dimorphandra jorgei</Emphasis> MF Silva and <Emphasis Type="Italic">Swartzia macrostachya</Emphasis> Benth. var. <Emphasis Type="Italic">riedelii</Emphasis> Cowan

Dimorphandra jorgei MF Silva (Caesalpinaceae) and Swartzia macrostachya Benth. var. riedelii Cowan (Fabaceae) are tree species from the southern Bahian Atlantic Forest, identified for the restoration of degraded areas. The objective of this research is to study their seed germination and seedling growth to develop simple methods for seedling production in small scale nurseries. Because the species have distinct dormancy and germination characteristics, the seeds were submitted to different treatments. D. jorgei seeds were immersed in hot water, scarified and stored for 12 weeks in the laboratory environment (25°C). S. macrostachya seeds were submitted to different combinations of drying and storage in the laboratory environment or refrigerator (4°C). Seedlings were submitted to two light treatments for 3 months: partial shade (52% of full sun) and full shade (12% of full sun). In D. jorgei, the highest germination occurred for scarified seeds (87%) and for seeds stored for 12 weeks and then scarified (69%). In S. macrostachya the undried control seeds had the highest germination, followed by that of the refrigeration storage treatment, without predrying (99% and 97%, respectively). The average values for the growth parameters were greater in full shade for D. jorgei, while S. macrostachya seedlings showed greater growth rates in partial shade. Two months growth is recommended before D. jorgei seedlings are of the sufficient size and leaf number for field planting. On the other hand, a period of 4 months is recommended for S. macrostachya, due to its relatively slow growth.     

Modeling mid-rotation fertilizer responses using the age-shift approach

Growth and yield modelers have incorporated mid-rotation fertilizer responses by: modifying site index; developing new models to include fertilizer responses directly; using multipliers or additional terms to scale existing models. We investigated the use of age-shifts to model mid-rotation fertilizer responses. Age-shift prediction models were constructed from 43 installations of a nitrogen (0, 112, 224 and 336 kg ha⁻¹ elemental) by phosphorus (0, 28 and 56 kg ha⁻¹ elemental) factorial experiment established in mid-rotation loblolly (Pinus taeda L.) pine stands in the southeastern US. Age-shifts for dominant height and basal area increased with time after fertilization, to a maximum and then either remained fairly constant, or declined. The initial rate of increase, maximum age-shift and decline were functions of the rate and combinations of fertilizers applied, as well as stand density and age at fertilization. Volume age-shifts increased linearly throughout the 10-year measurement period for most treatments with the rate of increase being a function of the elements applied, stocking, site index and age at fertilization. A mid-rotation fertilizer application of 224 and 28 kg ha⁻¹ elemental N and P, respectively, resulted in age-shifts of 1.1, 1.9 and 2.4 years for dominant height, basal area and volume, respectively, 10 years after fertilization. The age-shifts were incorporated into growth and yield models.     

Histopathologic and immunohistochemical findings in two white-tailed deer fawns persistently infected with Bovine viral diarrhea virus.

Bovine viral diarrhea virus (BVDV) is an important pathogen of domestic cattle. Serologic, experimental, and individual case studies explored the presence and pathogenesis of the virus in wild ungulates; however, there remain large gaps in knowledge regarding BVDV infection in nonbovine species. Live twins were born from a white-tailed deer (Odocoileus virginianus) doe infected with noncytopathic BVDV during its first trimester of pregnancy. The twins died at 1 day of age from trauma unrelated to the infection, and tissues were collected for histologic and immunohistochemical examination. The most significant histologic abnormality was diffuse depletion of B-lymphocytes in both fawns. The BVDV antigen was distributed widely throughout many tissues and cell types, most notably epithelium and vascular endothelium, consistent with that reported in cattle. In contrast to cattle, lymphocytes exhibited only very rare positive staining.     

Parametric distance weighting of landscape influence on streams

We present a parametric model for estimating the areas within watersheds whose land use best predicts indicators of stream ecological condition. We regress a stream response variable on the distance-weighted proportion of watershed area that has a specific land use, such as agriculture. Distance weighting functions model the declining influence of landscape elements as a function of their flowpath distances, first to the stream channel (to-stream distance), and then down the channel to the location at which stream condition was sampled (in-stream distance). Model parameters specify different distance scales over which to-stream and in-stream influences decline. As an example, we predict an index of biotic integrity (IBI) for the fish communities in 50 small streams of the Willamette Basin of Oregon, USA, from distance-weighted proportions of agricultural or urban land use in their watersheds. The weighting functions of best-fitting models (R ² = 0.57) represent landscape influence on IBI as extending upstream tens of kilometers along the stream channel network, while declining nearly to zero beyond a distance of 30 m from the channel. Our example shows how parametric distance weighting can identify the distance scales, and hence the approximate areas within watersheds, for which land use is most strongly associated with a stream response variable. In addition, distance-weighting parameters offer a simple and direct language for comparing the scales of landscape influence on streams across different land uses and stream ecosystem components.