Epidemiology of Bovine Venereal Campylobacteriosis: Geographic Distribution and Recent Advances in Molecular Diagnostic Techniques

Bovine venereal campylobacteriosis (BVC) is a major cause of economic loss to the cattle industries in different parts of the world. Camplylobacter fetus subsp. venerealis (Cfv), the main causative agent of BVC, is highly adapted to the genital tract of cattle and is transmitted by carrier bulls. However, infertility and abortions can also be caused by the intestinal pathogens C. fetus subsp. fetus (Cff), and C. jenuni, which are not venereally transmitted. Bovine venereal campylobacteriosis, caused by Cfv associated with lowered fertility, embryo mortality and abortion, repeated returns to service, reduced pregnancy rates and extended calving intervals, has the highest prevalence in developing countries where natural breeding in cattle is widely practised. The epidemiology, pathogenesis and diagnosis of the disease have been the subject of previous reviews. The main focus of this review is to highlight the epidemiology of this disease with particular reference to geographical distribution and recent advances in molecular diagnostic techniques. It is hoped that further research interest of scientists will be stimulated with a view to finding lasting solutions to the reproductive problems associated with the disease for better livestock productivity, particularly in developing endemic countries.     

Temperature-induced momentum-dependent spectral weight transfer in Bi2Sr2CaCu2O8+delta

Angle-resolved photoemission data from the cuprate superconductor Bi2Sr2CaCu2O8+delta above and below the superconducting transition temperature Tc reveal momentum-dependent changes that extend up to an energy of about 0.3 electron volt, or 40kTc (where k is the Boltzmann constant). The data suggest an anomalous transfer of spectral weight from one momentum to another, involving a sizable momentum transfer Q approximately (0.45pi, 0). The observed Q is intriguingly near the charge-order periodicity required if fluctuating charge stripes are present.     

Pb isotopic variability in melt inclusions from oceanic island basalts, polynesia

Previous studies have suggested that melting processes are responsible for the trace element variability observed in olivine-hosted basaltic melt inclusions. Melt inclusions from three individual lava samples (two from Mangaia, Cook Islands, and one from Tahaa, Society Islands) have heterogeneous Pb isotopic compositions, even though the erupted lavas are isotopically homogeneous. The range of Pb isotopic compositions from individual melt inclusions spans 50 percent of the worldwide range observed for ocean island basalts. The melt inclusion data can be explained by two-component mixing for each island. Our data imply that magmas with different isotopic compositions existed in the volcanic plumbing system before or during melt aggregation.     

Effect of restriction of silage intake and the provision of an alternative forage on the performance of dairy cows

In three experiments the effects of restricting the silage ration of dairy cows and of offering alternative forages as buffer feeds were investigated.
In the first experiment of changeover design with 3-week periods, restricting the intake of low-quality silage to 0.62 of ad libitum had no significant effect on milk yield in spite of the large energy deficit. Offering high-quality hay as a buffer feed increased total DM intake and milk production of cows receiving either restricted or ad libitum silage.
In the second experiment of similar design, restricting the DM intake of high-quality silage to 0·58 of ad libitum significantly reduced milk yield and was associated with a large negative energy balance. Offering straw or ammonia-treated straw with the restricted silage diet did not restore milk production to the level achieved with ad libitum silage but these supplements slightly reduced the energy deficit of the cows. In the third experiment of continuous design lasting 7 weeks, restricting the silage ration to 0.85 of ad libitum had no significant effect on milk production. Offering a strawmix based on straw, barley, molasses and soya with the restricted silage ration restored total DM intake to the ad libitum silage level.
In all three experiments milk protein content was reduced by restricting the silage ration and partially restored by offering alternative forages. There were no significant effects on milk fat content and milk lactose content was only reduced by the severest restriction in Experiment 2. It is concluded that short-term minor restrictions of silage intake can be partly sustained by body fat mobilization but more severe restrictions will result in loss of milk yield. Good-quality hay and a strawmix were of benefit in restoring DM and metabolizable energy intakes, whereas straw and ammonia-treated straw were of little value.     

The Anatomy of Softwoods and its Influence on Timber Quality

Considers first the gross natural features which govern timberquality. Then the effect of rate of growth on structure andquality, particularly density and fibre length, and ends witha note on the work being done and the prospects of success inselecting improved strains of trees for future timber production.     

THE EFFECT OF RATE OF GROWTH (RING WIDTH) ON THE DENSITY OF SOFTWOODS

The relation between rate of growth and density has been examinedin fairly wide-ringed Douglas fir (Pseudotsugo taxifolia) andCorsican pine (Pinus nigra var. calabrica) grown in the southof England. A comparison between wood formed early in the lifeof the tree and wood of similar ring width formed later hasshown that the latter is invariably denser, indicating thatthe higher density of older wood is due to an age effect ratherthan to diminishing ring width. It is concluded that after acertain age rapid growth can produce wood of reasonably highdensity. This confirms that Turnbull's findings on widely spacedexotic softwoods grown in South Africa apply, with reservations,to trees grown in this country under conditions where rapidgrowth can be maintained.     

The relationship of scrotal circumference to testicular weight in rams

Scrotal circumference (SC), testicular diameter (TD) and testicular weight (TW) were measured at necropsy of 148 Merino rams of varying age (yearling: 110, 2- to 3-year-old: 5, 4-year-old: 28, greater than 7-year-old: 5). These rams, although culled from flocks in north western Queensland for poor conformation or advancing age, had no clinically palpable or gross necropsy lesions of the genitalia. Despite the fact that SC measurement was performed at necropsy on scrota with greatly varying wool cover and its diverse content of plant material (burrs and grass seeds), the correlation of SC with TW was positive, high and significant (r = 0.92, P less than 0.01). This correlation was greater than that between TD and TW (r = 0.91, P less than 0.01) even though both were measured after dissection of the scrotal contents. The clinically convenient SC measurement deserves wider application as an estimate of testicular weight and therefore fertility in rams.     

Antibiotic prophylaxis of lower respiratory tract contamination in horses confined with head elevation for 24 or 48 hours

Objective To evaluate the administration of procaine penicillin prior to or during confinement with head elevation as a means of reducing the associated accumulation of inflammatory lower respiratory tract secretions and increased numbers of bacteria within the lower respiratory tract of confined horses. Design and Procedure Two experiments were conducted to evaluate the efficacy of different dose rates and dosing frequencies. In experiment A a single low dose (15,000 IU/kg) of procaine penicillin was administered to four horses immediately prior to confinement with head elevation for 48 hours. The systemic leucocyte response, gross and cytologic characteristics of transtracheal aspirate and bacterial numbers in lower respiratory tract samples were compared with corresponding samples from two horses confined with heads elevated but not given penicillin. The efficacy of higher dose rates (20,000 IU/kg and 40,000 IU/kg) given before and during confinement with heads elevated for 24 hours was evaluated in experiment B. Results Treatment with procaine penicillin had no effect on the systemic leucocyte response or on the accumulation of inflammatory lower respiratory tract secretions at any of the dosing schedules evaluated. The number of bacteria isolated from trans-tracheal samples was reduced at 12 hours for treated horses in experiment A and at 24 hours for experiment B. β-haemolytic Streptococcus spp were not isolated from treated horses in either experiment. Bacterial species isolated from treated horses were predominantly Pasteurella and/or Actinobacillus spp, however, members of the family Enterobacteriaceaé and a Staphylococcus sp were isolated from treated horses. One treated horse in experiment A developed clinically apparent pulmonary disease. Conclusions The prophylactic administration of penicillin before or during confinement did not reliably reduce bacterial numbers or prevent the accumulation of purulent lower respiratory tract secretions in horses confined with their heads elevated. Numbers of β-haemolytic Streptococcus spp were reduced following treatment, suggesting that the repeated administration of procaine penicillin may have some merit as part of a strategy to prevent transport-associated respiratory disease. However, methods directed at minimising the duration of confinement with head elevation, augmentation of the clearance of accumulated secretions and prompt identification of animals in which airway inflammation has extended to the pulmonary parenchyma remain the best ways of minimising transport-associated respiratory disease.