Longevity of protective immunity to experimental bovine herpesvirus-1 infection following inoculation with a combination modified-live virus vaccine in beef calves

OBJECTIVE: To determine whether a combination viral vaccine containing modified-live bovine herpesvirus-1 (BHV-1) would protect calves from infection with a recent field isolate of BHV-1. DESIGN: Randomized controlled trial. ANIMALS: Sixty 4- to 6-month-old beef calves. PROCEDURE: Calves were inoculated with a placebo 42 and 20 days prior to challenge (group 1; n = 10) or with the combination vaccine 42 and 20 days prior to challenge (group 2; 10), 146 and 126 days prior to challenge (group 3; 10), 117 and 96 days prior to challenge (group 4; 10), 86 and 65 days prior to challenge (group 5; 10), or 126 days prior to challenge (group 6; 10). All calves were challenged with BHV-1 via aerosol. Clinical signs, immune responses, and nasal shedding of virus were monitored for 14 days after challenge. RESULTS: Vaccination elicited increases in BHV-1-specific IgG antibody titers. Challenge with BHV-1 resulted in mild respiratory tract disease in all groups, but vaccinated calves had less severe signs of clinical disease. Extent and duration of nasal BHV-1 shedding following challenge was significantly lower in vaccinated calves than in control calves. In calves that received 2 doses of the vaccine, the degree of protection varied with the interval between the last vaccination and challenge, as evidenced by increases in risk of clinical signs and extent and duration of viral shedding. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that this combination vaccine provided protection from infection with virulent BHV-1 and significantly reduced nasal shedding of the virus for at least 126 days after vaccination.     

Measurement of the Lateral Thoracic Reflex Latency in Ponies

Lateral thoracic nerve reflex latencies values were measured in ponies using a simple, non-invasive technique. The reflex was elicited using an external triggering hammer attached to an electrodiagnostic unit. The resulting evoked, compound muscle action potentials were recorded with electrodes, which were placed over the 6th ribs or 11th rib level with the axilla. Two superimposed repeats of 4 signal-averaged sweeps of 50 or 100 milliseconds were recorded and the estimated reflex pathway was measured for each subject in order to calculate the reflex latencies and latency velocities. Mean left and right 6th rib peak latencies were not significantly different from each other ( P = .609), but left 6th rib latencies were shorter than those recorded from the 11th rib ( P < .0001), substantiating the existence of an indirect (central) pathway to the reflex. The calculated left and right 6th rib latency velocities were not significantly different from each other ( P = .58) but left 6th rib latency velocities were different from left 11th rib ( P = .009). The calculated latency velocities were within the broad range for corticospinal tract motor conduction velocities and comparable to magnetic motor evoked latency velocities. The use of lateral thoracic reflex latency measurements to objectively identify the site of spinal cord lesions is discussed.     

A preliminary equine abuse policy with potential application to veterinary practice

An equine abuse policy was developed as an adjunct to an equine management survey. If at least 3 of 5 categories caused concern, a report to the authorities was indicated. The policy was not used but, in the absence of other guidelines, it might assist veterinarians considering potential abuse cases.     

Meniscal Mineralization in Domestic Cats

Objective: To (1) determine prevalence of radiographically detectable meniscal mineralization in domestic cats and (2) to evaluate the association between meniscal mineralization and degenerative joint disease (DJD). Study Design: Prospective study. Animals: Client‐owned cats (n=100) and 30 feline cadavers. Methods: Randomly selected client‐owned cats were used to determine the prevalence of meniscal mineralization. Stifles from feline cadavers were used to evaluate the relationship between meniscal mineralization (using high‐resolution X‐ray), radiographic DJD, and cartilage damage. Menisci were evaluated histologically. Results: Forty‐six percent of the client‐owned cats had meniscal mineralization detected in 1 or both stifles. Pain scores were not significantly different between stifles with meniscal mineralization and those with no radiographic pathology (P=.38). Thirty‐four of 57 cadaver stifles had meniscal mineralization, which was always located in the cranial horn of the medial meniscus. Percentage mineralization of the menisci was significantly correlated with the cartilage damage score of the medial femoral (r²=0.6; P<.0001) and tibial (r²=0.5; P<.0001) condyles as well as with the total joint cartilage damage (r²=0.36; P<.0001) score and DJD score (r²=0.8; P<.0001). Conclusion: Meniscal mineralization is a common condition in domestic cats and seems to indicate medial compartment DJD. Clinical Relevance: Clinical significance of meniscal mineralization is uncertain. Further work is needed to determine if the meniscal mineralization is a cause, or a consequence of joint degeneration.     

Evaporation from fetch-limited water bodies

An analytic model to calculate evaporation from fetch-limited water bodies is described. By modifying the surface boundary condition to an analytic solution to the advection-diffusion equation for specific humidity in the air flow over a water body, we are able to solve for the entire specific humidity field q (x, z) from a single measurement of humidity, surface temperature, and wind speed. Comparisons of model predictions with measurements from Rushy Billabong, a small turbid lake, over a 146 day period show that on average the model underestimates evaporation rates by 12%. We believe that the evaporation shortfall is due to the downwind advection of heat within the billabong when the billabong is highly stratified in temperature. When the thermal stratification is weak, the advection of heat within the water column is less important and the model is an accurate predictor of evaporation.     

Detection of antibiotic residues and association of cefquinome residues with the occurrence of Extended-Spectrum β-Lactamase (ESBL)-producing bacteria in waste milk samples from dairy farms in England and Wales in 2011

Waste milk samples from 103 farms in England and Wales were examined for the presence of β-lactam antibiotics and ESBL-producing Enterobacteriaceae. Approximately 10 months after the initial sampling, further waste milk, environmental and faecal samples from farms shown to be positive for CTX-M Escherichia coli were investigated further. Isolates with an ESBL phenotype were tested by PCR for the presence of bla_CTX-M, bla_OXA, bla_SHV and bla_TEM genes. Isolates positive for bla_CTX-M were sequenced to determine CTX-M type. Representative isolates were further examined by PFGE, plasmid replicon typing and serotyping. Of particular interest, 21.4% of waste milk samples contained residues of the cephalosporin cefquinome, which was significantly associated with CTX-M bacteria. Such bacteria occurred in 5.8% of the waste milk samples (including 3.9% CTX-M E. coli). CTX-M types identified were 1, 14, 14b and 15, but none of the E. coli were serotype O25, the serotype of the human pandemic strain.     

Contribution of White Clover Varieties in High-Productivity Systems under Grazing and Cutting

Two medium leaf size varieties of white clover (Trifolium repens L.) were grown in mixture with a range of grass species and varieties in a field experiment conducted over 4 years. The clovers were grown singly or as a blend in swards with a tetraploid perennial ryegrass (Lolium perenne L.), a diploid Italian ryegrass (Lolium multiflorum L.) or tetraploid hybrids between these two species (Lolium x boucheanum Kunth). These grasses were also grown in monoculture. Swards were managed in a regime involving two periods of sheep grazing, two periods of cattle grazing and a silage cut in the same year for 4 years. The objectives of this experiment were 3‐fold: (1) to examine the yield and persistency of white clover in highly productive systems with modern perennial, hybrid and Italian ryegrasses; (2) to compare the performance of white clover varieties grown singly in mixture with grasses with their performance together as a blend, and (3) to examine the persistency of new Italian ryegrass varieties, exemplified by AberComo. The clover content of the sward remained high throughout the experiment, with a mean of 31 % overall. Differences in clover yield between plots were largely attributable to the effects of companion grasses. Total yields were very similar in plots containing different clover varieties and in plots where these varieties had been grown singly or as a blend. Grass yields in mixture were greater than those in monoculture but showed similar relative rankings. The diploid Italian ryegrass variety AberComo showed an unexpectedly high yield in the 4th year of the experiment. The implications of these results for strategies for productive, sustainable agriculture using modern white clover and ryegrass varieties are discussed.     

Influence of pH and temperature on force development and shortening velocity in skinned muscle fibres from fish

Three species of fish were studied: Atlantic cod (Gadus morhua), sculpin (Myoxocephalus scorpius) (from the North Sea, temperature 2 to 12°C) andNotothenia neglecta (from Antarctica, temperature –2 to +2°C). Single fast muscle fibres were isolated from anterior myotomes and skinned with detergent in order to directly determine the effects of pH and temperature on force production and shortening velocity.In all species maximum force production (Po) was independent of pH over the range 7.3–8.0. Decreasing the pH from 7.3 to 6.6 reduced maximum force by 28% in fibres fromG. morhua andN. neglecta but had no effect on fibres fromM. scorpius. The depression in maximum force with acidosis was accompanied by a proportional decrease in stiffness and an increase in the rate of force recovery after stretch.Unloaded contraction velocity of cod fibres (Vmax) showed a pH optimum at around pH 7.6 decreasing by 31% at pH 6.6. Vmax of fibres from the other species was independent of pH over the range 6.6–8.0.The effects of pH on Po and Vmax were similar at 0 and 10°C. Thus for maximally activated fibres both force and contraction velocity are independent of temperature induced changes in pH. In some species acidosis depresses contractility and is likely to be a contributory factor to muscle fatigue.