Vascular lesions of Dirofilaria immitis in the red fox

Dirofilaria immitis was found in the right ventricle, pulmonary artery, and lungs of 2 red foxes (Vulpes fulva) in Connecticut. The most significant lesions occurred in the pulmonary artery and consisted of focal atheromatous-like intimal plaques, diffuse subintimal accumulations of inflammatory cells, and marked villose endarteritis in the elastic portion of the pulmonary artery. Medial hyperplasia of the muscular branches, along with periarteritis, was found in 1 fox. These 2 cases may be a further indication of the increased incidence of this disease in Carnivora in the State of Connecticut.     

Effect of level of beef cow milk production on pre- and postweaning calf growth

Three groups of beef cows that were similar in growth and mature size, but different in genetic potential for level of milk provided to their calves, were studied. A procedure for fitting grafted polynomials based on calf suckling data was used to estimate the total amount of milk produced by each cow during 205-d lactations. Estimated 205-d milk production of the high milk group exceeded that of the medium and low milk groups by 186 and 561 kg, respectively. Differences in milk production of the three groups tended to increase as dams got older. The pooled, within milk-group correlation between calf gain to 205 d and milk intake was .60. Calves suckling dams with low milk production relied earlier and to a greater extent on alternative food sources of lower nutritional value than milk. Calves suckling high milk-group dams had 16.9 kg greater 205-d weaning weight than those suckling low milk-group dams, solely because of differences in maternal environment. Calves from the high milk group maintained 63% of the advantage over those in the low milk group in 205-d weight through a fairly rapid postweaning growth period to slaughter.     

Seasonal Variation in Habitat Selection by Free-Ranging Feral Horses Within Alberta’s Forest Reserve

Little is known about habitat selection by free-ranging feral horses in Montane environments, including how horse use may vary seasonally throughout the year. We tracked four global positioning system collared horses in four separate harems between November 2008 and October 2010 for a portion of the Rocky Mountain Forest Reserve in southwest Alberta, Canada. We assessed seasonal habitat selection for the study period by combining locational data with landscape data (including vegetation types) in an information theoretic framework. Home ranges for horses varied from 12.4 to 90 km² and were confined to local watersheds. Horses selected most for lowland grasslands across all seasons, with shrublands increasingly selected in spring and summer. Harvested conifer forests were only selected by horses during winter. Resource selection functions indicated that in addition to vegetation type, horses were selecting for a variety of habitat characteristics (i.e., distance to forest and solar radiation), while water availability, topographic accessibility, and disturbance features (e.g., distance to roads, recreational trails, and seismic lines associated with energy exploration) had little or no influence on horse selection. Overall, horses demonstrated selection for habitats covering 14% of the study area while avoiding 42% of habitats: remaining areas were used in proportion to their availability. Concentration of horse use within sparse vegetation types (grassland and shrubland), particularly during one or more times of the year, help identify critical horse habitat including areas where multiple, overlapping land uses interact on public land.     

Assessment of the human risk associated with use of pork with possible presence of Salmonella typhimurium DT104 for dry-cured sausages

We examined whether pork with suspected content of Salmonella Typhimurium DT104 (DT104) could be used for production of dry-cured sausages without jeopardizing consumer safety. The results of the risk assessment showed, that if Salmonella is present in raw pork, it is usually in low numbers. Additionally, during processing, an eventual presence of Salmonella will be reduced with at least two log units. The simulations showed that only 1-2 DT104 would be present in dry-cured sausages made by Danish pork, and this extremely seldom. Likewise, up to 4 DT104 would be present in dry-cured sausages made by foreign pork. It is not clear whether these low numbers of DT104 are capable of producing disease at all. However, if higher numbers are present, disease might occur. Therefore, we set up a monitoring and managing program, including a list with demands to processing in order to achieve minimum two-log reduction of any DT104 bacteria. The suggested scheme implies a far better and more systematic monitoring than the current system, ensuring the consumer a higher degree of food safety.     

A review of enzyme immunoassay for detection of antibody to Brucella abortus in cattle

Enzyme immunoassay has gained wide acceptance for serological diagnosis of bovine brucellosis because of its ability to detect antibody of all isotypes unlike the conventional tests. The indirect enzyme immunoassay, however, presents several parameters that require careful analysis. These parameters include the choice of antigen and antiglobulin-enzyme conjugate reagents for use in the assay, dealing with the large amount of data the semi-automatic or automatic assay can generate and the inter- and intralaboratory standardization and quality control. This review considers the various methods described in the literature and, briefly, how some of the problems have been overcome or how they might be dealt with.     

Intravenous infusion of glucose improved farrowing performance of hyperprolific crossbred sows

The sow at parturition is challenged with respect to energy status due to increases in energetic expenses associated with 1) nest building 2) uterine contractions, and 3) colostrum production. A previous study indicated that sows were depleted of glucogenic energy around farrowing. The aim was to investigate whether intravenous infusion of glucose from observed nest-building behavior to 24 h postpartum affected the farrowing kinetics and colostrum production in sows. Ten multiparous sows (DanBred landrace × DanBred Yorkshire) were fitted with a jugular vein catheter on each side (one for infusion and the other one for blood sampling). Sows were infused with either 0.9% saline (CON; n = 5) or 10% glucose (GLU; n = 5) solution at a constant rate of 125 mL/h. From day 108 of gestation, sows were fed once daily with 3.33 kg of a standard lactation diet. During farrowing, sows were monitored to register the onset of farrowing, time of birth, birth status (live or dead), sex, stillbirth rate (SR), and weight of newborn piglets. Farrowing assistance (FA) was provided when the birth interval exceeded 60 min. In late gestation, 1 mL of blood was collected every third hour for blood gas analysis and every sixth hour for harvesting plasma. During farrowing, 1 mL (for blood gas) and 9 mL of blood were collected at 0, 3, 6, 9, 12, 15, 18, 21, and 24 h in milk (HIM). Colostrum and milk samples were collected at 0, 6, 12, 18, 24, and 36 HIM and also at 3, 10, 17, and 24 d in milk. Compared with CON sows, GLU infusion decreased the SR (16.1% vs. 7.4%; P = 0.03), FA (21% vs. 9.0%; P = 0.01), and surprisingly also blood glucose at the onset of farrowing (5.53 vs. 5.09 mmol/L; P = 0.03), respectively. A tendency to higher plasma lactate at the onset of farrowing (P = 0.05) but decreased piglet survival from 0 to 24 h (P = 0.06) was also found for GLU sows. No effects of treatment on farrowing duration or mean birth intervals were found. Lactate in whole blood (P = 0.003) and plasma (P = 0.002) was increased for GLU sows as compared with CON sows during the colostrum period. No effect of GLU infusion was seen on colostrum and milk composition and yield. The increase in lactate was most likely due to a shift toward a greater proportion of glucose oxidation and insufficient O₂ supply to fuel uterine contractions. In conclusion, infusion of glucose reduced the frequency of SR and FA, and improved energy status of the sow which seems to be crucial to enhance total piglet survival.     

Experimental inoculation of late term pregnant sows with a field isolate of porcine reproductive and respiratory syndrome vaccine-derived virus.

The use of a live attenuated porcine reproductive and respiratory syndrome virus (PRRSV) vaccine in piglets has been associated with reproductive disorders in non-vaccinated sows. Vaccine-derived virus (VDV) has been isolated from foetuses, stillborn pigs, and dead piglets, indicating that the live vaccine spread from vaccinated piglets to non-vaccinated sows, and that the virus might be implicated in the severe reproductive problems observed. In the present study, one such VDV isolate was used to experimentally infect pregnant sows in the last trimester. The chosen isolate, which had more than 99.6% identity to the attenuated vaccine virus, originated from the lungs of a stillborn pig from a swine herd with a sudden high level of stillborn pigs and increased piglet mortality in the nursing period. Intranasal inoculation of sows with the virus isolate resulted in congenital infection, foetal death, and preweaning pig mortality. As such, the present study showed that vaccine-derived PRRSV can cause disease in swine consistent with PRRS.     

Failure of bovine complement levels measured by radial hemolysis to correlate with tube titration

Hemolytic complement levels in 30 duplicate samples of normal bovine sera were determined by a tube titration method (CH50) and by a radial hemolysis in gel assay. Significant correlation was not observed between the values obtained by the 2 tests. This lack of correlation could be a result of considerable error observed in values obtained for duplicate samples in the CH50 method or to the relative insensitivity of the hemolysis in gel test. The hemolytic reaction in gel was found to depend on Mg2+, thus raising questions (i) about its validity in determining total hemolytic complement or (ii) about bovine C1q depending on Mg2+ rather than Ca2+ for binding to immune complexes.     

Effects of various treatments of bovine complement on its lytic efficacy measured by two different tests

Bovine complement was treated with various agents known to activate or inactivate one or more of the cascade components. The treated complement was then assessed for remaining hemolytic activity by a tube titration test and a radial hemolysis method. Divalent cation chelators (EDTA and EGTA); immune complexes prepared with serum and IgM, IgG1, IgG2, and IgA isotypes; smooth and rough lipopolysaccharides and lipid A; hydrazine; zymosan; cobra venom factor and brown recluse spider venom caused depletion of complement as determined in the tube titration test. Immune complexes (prepared with serum); hydrazine; cobra venom factor; EDTA and smooth lipopolysaccharide caused loss of hemolytic activity in the radial hemolysis test. This evidence suggests that the radial hemolysis test assessed complement consumed by the alternate pathway, while the tube titration method measured classical pathway consumption.