Megaesophagus in a cow

Megaesophagus developed subsequent to presumed pharyngeal trauma in a cow. Signs resolved after prolonged antibiotic treatment and supportive care.     

Nasal obstruction caused by cystic nasal conchae in cattle

Four Holstein heifers were found to have partial nasal obstruction caused by bilateral cystic conchae. Three of the heifers (age range, 4 to 6 months) had a history of progressive nasal obstruction since near birth, were affected severely, and required surgical management. Each of 2 surgical procedures, a bilateral dorsolateral nasal flap approach and a dorsal nasal flap approach, was used successfully. The fourth heifer, which was 15 months old, had signs of nasal obstruction since shortly after birth, but was affected only mildly and was not treated. Follow-up information obtained 10 to 37 months later revealed that all cattle were considered normal and had no signs of nasal obstruction. In each case, a developmental problem or malformation of the ventral nasal concha resulting in cystic enlargement was suspected. The onset of clinical signs early in life and the bilateral nature suggested that the defect was of congenital origin.     

Reproductive disease and congenital malformations caused by Menangle virus in pigs

OBJECTIVE: To describe a new syndrome characterised by embryonic mortalities, stillbirths, mummified foetuses and congenital malformations in a herd of intensively farmed pigs. DESIGN: Field observations, laboratory investigations and examination of breeding records. PROCEDURE: Pathology examinations were performed on mummified and congenitally deformed piglets during an outbreak of reproductive disease at a 2600 sow intensive piggery in New South Wales from April to October 1997. Reproductive performance was monitored during the outbreak and breeding records were examined retrospectively. Serum and tissue samples from pigs were tested for evidence of infection with known porcine pathogens and for a new virus, Menangle virus, isolated from stillborn piglets with deformities from the affected piggery in August 1997. RESULTS: Reproductive disease occurred sequentially in all four breeding units at the affected piggery over a period of 21 weeks. The farrowing percentages in each unit decreased from 80 to 82% before the outbreak to 63 to 78% during the outbreak and the number of live piglets per litter declined from a mean of 9.6 to 9.8 before the outbreak to 7.2 to 8.9 during the outbreak. The proportion of affected litters (litters with less than six liveborn piglets) was highest (64%) in the sixth week of the outbreak. Mummified foetuses, stillborn piglets with arthrogryposis, craniofacial deformities and degeneration of the brain and spinal cord, were observed along with occasional abortions. Sera from sows that produced affected litters contained neutralising antibodies against Menangle virus and there was evidence that this virus had been introduced to the piggery in February 1997. CONCLUSIONS: Reproductive disease in pigs due to Menangle virus was characterised by stillbirths, mummification, embryonic death and infertility, along with abortions, skeletal deformities and degeneration of the brain and spinal cord in affected foetuses and stillborn piglets.     

Degradation of four phenylurea herbicides by mixed populations of microorganisms from two soil types

The metabolism of four substituted urea herbicides by microbial populations from two soils was investigated. The herbicides were two dimethylurea herbicides (fluometuron and chloroxuron) and two methoxymethylphenylurea herbicides (metobromuron and chlorbromuron), and the two soils used were Louisiana Commerce Loam and Indiana Silt Loam. The dimethyl compounds were successively N-demethylated by microorganisms from both soils. N-demethylation of the methoxymethyl herbicides, however, was significant only in the Louisiana soil, while N-demethoxylation was found in only trace amounts in all the cultures. Metabolism of these herbicides apparently was predominantly via direct hydrolysis to the aniline, which in turn underwent further transformations.     

Arthropods in coarse woody debris in jarrah forest and rehabilitated bauxite mines in Western Australia

? Coarse woody debris (CWD) is returned to Alcoa’s rehabilitated mined areas in the jarrah forest as potential vertebrate fauna habitat, however, its value for invertebrate fauna has not been investigated. We sought to determine if CWD in rehabilitated areas supported a similar arthropod fauna to that on fallen logs in the adjacent unmined jarrah forest.

? Using emergence tents, sampling from logs in 5-year old and 15-year old rehabilitated forest, and in unmined forest, yielded 2266 specimens from 187 taxa. Collembola (43% of total) and Acarina (32%) were the most abundant groups, followed by Diptera (11%), Araneae (4%) and Coleoptera (3%).

? There were no significant differences in either taxa richness or overall abundance among the three forest types. However, community composition varied significantly. Species richness from the Araneida, Coleoptera and Diptera was highest in the 5-year old rehabilitated forest, while Collembola and Acarina were better represented in the unmined forest; this was related to changes in the environment surrounding the logs as rehabilitated forest develops, and to log condition. The composition of arthropods on logs in the 15-year old rehabilitated forest was intermediate, indicating a trend of increasing similarity to the unmined forest in arthropod fauna as the rehabilitated forest ages.

? We suggest that over longer time periods, CWD in rehabilitated forest will support arthropod communities similar to those found in unmined forest. Future work should determine if returning logs to mined areas facilitates the return of CWD-dependent taxa.

     

Effect of 7-year application of a nitrification inhibitor, dicyandiamide (DCD), on soil microbial biomass, protease and deaminase activities, and the abundance of bacteria and archaea in pasture soils

Purpose

The nitrification inhibitor dicyandiamide (DCD) has been shown to be highly effective in reducing nitrate (NO₃ ^?) leaching and nitrous oxide (N₂O) emissions when used to treat grazed pasture soils. However, there have been few studies on the possible effects of long-term DCD use on other soil enzyme activities or the abundance of the general soil microbial communities. The objective of this study was to determine possible effects of long-term DCD use on key soil enzyme activities involved in the nitrogen (N) cycle and the abundance of bacteria and archaea in grazed pasture soils.

Materials and methods

Three field sites used for this study had been treated with DCD for 7 years in field plot experiments. The three pasture soils from three different regions across New Zealand were Pukemutu silt loam in Southland in the southern South Island, Horotiu silt loam in the Waikato in the central North Island and Templeton silt loam in Canterbury in the central South Island. Control and DCD-treated plots were sampled to analyse soil pH, microbial biomass C and N, protease and deaminase activity, and the abundance of bacteria and archaea.

Results and discussion

The three soils varied significantly in the microbial biomass C (858 to 542 μg C g^?1 soil) and biomass N (63 to 28 μg N g^?1), protease (361 to 694 μg tyrosine g^?1 soil h^?1) and deaminase (4.3 to 5.6 μg NH₄ ⁺ g^?1 soil h^?1) activity, and bacteria (bacterial 16S rRNA gene copy number: 1.64?×?10⁹ to 2.77?×?10⁹ g^?1 soil) and archaea (archaeal 16S rRNA gene copy number: 2.67?×?10⁷ to 3.01?×?10⁸ g^?1 soil) abundance. However, 7 years of DCD use did not significantly affect these microbial population abundance and enzymatic activities. Soil pH values were also not significantly affected by the long-term DCD use.

Conclusions

These results support the hypothesis that DCD is a specific enzyme inhibitor for ammonia oxidation and does not affect other non-target microbial and enzyme activities. The DCD nitrification inhibitor technology, therefore, appears to be an effective mitigation technology for nitrate leaching and nitrous oxide emissions in grazed pasture soils with no adverse impacts on the abundance of bacteria and archaea and key enzyme activities.     

The effect of transfer factor treatment on two challenge infections ofHaemonchus contortus in immuno-competent 7-month-old lambs

A number of immuno-competent Blackface lambs were infected with 10,000Haemonchus contortus third stage larvae and were later challenged with a second dose of 10,000H. contortus third stage larvae. One group of lambs was treated with dialysed transfer factor prior to the second challenge dose.Histological changes in the abomasal wall, reductions in abomasal worm burdens at slaughter and faecal egg counts monitored throughout the experiment suggested the presence in some animals of (1) an innate resistance, (2) a self curing effect, (3) an enhancement of this self curing effect in the transfer factor treated group and (4) a response in one transfer factor treated animal comparable to classical self cure.     

Sensory Evaluation of Eleven Baked Russet-type Potato Varieties and Clones

Six hundred untrained panelists evaluated the baked sensory appeal of up to six varieties, three clones, and two Russet Norkotah (RN) strains. Panelists consumed small samples of plain baked potato and recorded their preference for aroma, flavor, texture, aftertaste and acceptance. After viewing photographs of two unidentified baked potatoes (RN and Classic Russet) sliced in half, they selected the photo that best described their visual preference of a baked potato; each potato was stored at 6.7 °C for 6 months prior to cooking. Eighty percent of panelists shown the photographs of the unidentified baked potatoes preferred the visual appearance of Classic R (white/cream - colored  flesh) to that of RN (yellow/Gy - colored flesh). Mean scores for all culinary traits averaged > 5.0 on the 1-9 scale, which indicated that panelists generally liked the culinary attributes of all trialed varieties, however, panelists were able to detect differences among varieties. Flavor and texture were addressed in written comments from panelists more frequently than other attributes. On a texture scale of 1–7, with 1 = moist/dense and 7 = dry/crumbly, most panelists preferred baked potatoes with a texture of 3 (creamy/smooth).     

Determination of sensitivity of Mycoplasma hyosynoviae to tylosin and selected antibacterial drugs by a microtiter technique.

A microtiter technique was used for determination of the sensitivity of Mycoplasma hyosynoviae to antibiotics and other drugs. Use of a biphasic agar-broth medium in microtiter plates allowed direct visualization of growth. Results were more reproducible with this system than when broth alone was used and evaluation based on color change was required. Attempts to adapt the test for use with Mycoplasma hyorhinis were not successful. Minimal inhibitory concentrations of 12 drugs and drug combinations for 12 strains of M. hyosynoviae are presented. Drugs with the lowest minimal inhibitory concentrations were tylosin (0.37 mcg/ml)and lincomycin (0.88 mcg/ml), both of which have been used for treatment and control of M. hyosynoviae arthritis. Comparison of the minimal inhibitory concentrations of tylosin for 43 isolates of M. hyosynoviae obtained in 1959 and 1960 and from 1966 through 1971 indicated the possibilty of decreasing sensitivity to the drug although differences between recent isolates and earlier ones were not statistically significant.     

Climatic factors controlling the productivity of Norway spruce: A model-based analysis

The process-based growth model, BIOMASS, was modified to incorporate low-temperature effects on photosynthetic production in Norway spruce (Picea abies) stands growing in northern Sweden. The low-temperature features incorporated in BIOMASS made it possible to simulate and estimate the reduction in photosynthetic rates caused by boreal conditions. The following four simulation-scenarios were used: (i) ‘potential' photosynthesis without boreal restrictions; (ii) reduction caused by a frozen soil; (iii) reduction caused by incomplete recovery of photosynthetic capacity during spring as a result of damage caused by low winter temperatures; and (iv) reduction as an effect of frost-induced autumn decline. Annual photosynthetic production (or gross primary production (GPP)) was simulated for three calendar years, 1990–1992, for stands with low (control) and high (irrigated and fertilized) nutrient availability. The reduction of ‘potential' GPP, caused by the low-temperature effects, ranged from 35–44% for control (C) and from 34–42% for irrigated-fertilised (IL) stands, respectively. The most pronounced loss of ‘potential' GPP originated from reduced photosynthetic capacity, in spring and early summer, which led to losses of 21–28% for C and 19–26% for IL stands. The variation between years differed mainly as an effect of differences in spring temperatures, which resulted in different rates of recovery of photosynthetic capacity. Reductions caused by frozen soil and low photosynthetic capacity during winter were similar in C and IL stands (12–13%), as were the losses resulting from severe autumn frosts (3–4%). It is concluded that, unless the effects of frozen soils and reduced photosynthetic capacity during spring and early summer are considered, large errors (ca. 40%) will be introduced into estimates of the annual photosynthetic production of boreal conifer forests.