Salmonella Typhimurium persistence in a Hunter Valley dairy herd

OBJECTIVE: An epidemiological study was undertaken at a Hunter Valley dairy with persistent Salmonella Typhimurium infection. The aim of the study was to identify cattle currently or previously infected with Salmonella, possible sources of the organism, patterns of spread, and husbandry practices that could be improved. METHODOLOGY: Faecal samples, feed, water and environmental samples were cultured for Salmonella and blood samples were tested for antibodies against Salmonella (Dublin and Typhimurium). A questionnaire was designed to identify possible risk factors associated with Salmonella excretion. RESULTS: S Typhimurium was apparently introduced from an old to a new dairy through manure spread as fertiliser. Salmonella apparently persisted in the effluent pond, and the following year clinical cases occurred after pasture, irrigated with water from the pond, was grazed by dry cows, and adult cattle became clinically ill with salmonellosis. The disease spread to other cows and calves. Poor design of calf pens assisted spread of Salmonella from sick to healthy calves. In addition, there was suspected transmission to the dairy farmer's 9-month-old daughter. Salmonellosis on a farm is a potential zoonotic risk to farm workers and their families. There is also the risk that cull cows may carry Salmonella to the abattoir and subsequently into the human food chain. Methods of waste management, and the design of calf pens, were identified as major risk factors that could be improved to minimise the spread of salmonellosis on this property.     

Significant suppression of invasive emerald ash borer by introduced parasitoids: potential for North American ash recovery

Journal of Pest Science - Successful management of invasive forest pests with sustainable approaches, such as biological control, is critical to the restoration of the affected or damaged forest...     

A collective navigation hypothesis for homeward migration in anadromous salmonids

Anadromous salmon (genera Oncorhynchus and Salmo) spend much of their lives feeding in productive northern oceans and then return home to natal sites for reproduction with remarkable accuracy. The mechanisms used for navigation by individuals during migrations are thought to include geomagnetic, celestial and olfactory cues, but rarely are social interactions between individuals considered. Mounting evidence from other taxa indicates that individuals in larger groups can better sense and respond to environmental cues, thus potentially increasing their ability to navigate. Here, we propose that salmon might similarly benefit from collective navigation on their homeward journey. To explore this, we compiled data from multiple studies and found strong evidence that rates of successful homing increase with population abundance, consistent with collective navigation. We then discuss how collective navigation could benefit salmon during each stage of their seaward and homeward migrations, and complement this with a review of salmon sociality. Next, we analyse historic high‐seas catch records and provide new insight into schooling structure of salmon in the marine environment. We argue that collective navigation likely represents a presently under‐appreciated mechanism enhancing the navigational ability of salmon as well as other migratory species, and outline critical tests of our hypothesis.     

Voluntary intake and digestibility of reed canarygrass and timothy hay fed to horses

Thousands of hectares of timothy (Phleum pretense L.) grown in the Mid-Atlantic region are infected by cereal rust mite (Abacarus hysterix) that causes discoloration and curling of leaves, decreased nutritional quality, and substantial decreases in yield. A decline in production of timothy hay can lower income for hay producers and cause horse owners to search for alternative hays. Low alkaloid reed canarygrass (Phalaris arundinacea L.) hay has potential as an alternative to timothy hay because it grows well in the Mid-Atlantic region, is believed to have a similar nutrient quality to timothy, and is not as susceptible to cereal rust mite. Eleven mature, stalled Thoroughbred geldings (549 +/- 12.1 kg) that were exercised daily were used to compare voluntary DMI and apparent nutrient DM digestibility of timothy and low-alkaloid Chiefton variety reed canarygrass hay. Horses were paired by age and BW and randomly assigned to timothy or reed canarygrass hay during a 14-d period to measure voluntary DMI followed by a 4-d period to measure apparent DM digestibility. Both hays met the minimum requirements for DE, CP, Ca, P, K, Fe, and Mn, but they did not meet the minimum requirements for Cu, Zn, and Na for horses at maintenance and averaging 550 kg of BW. Timothy hay seemed to have a lower CP concentration (14.4%) compared with reed canarygrass hay (17.1%) and a more desirable Ca:P ratio at 1.6:1 compared with 0.8:1 for reed canarygrass hay. Horses fed timothy consumed more hay (P <0.001) during the voluntary DMI period compared with horses fed reed canarygrass. Greater voluntary DMI of timothy occurred on d 1, 3, and 5 (P <0.05), but DMI was similar for other days. Apparent DM digestibility was greater in horses fed timothy hay by 9.6% compared with horses fed reed canarygrass hay (P <0.05). Horses fed timothy had greater DM digestibility of ADF (P = 0.001), NDF (P = 0.001), sugar (P = 0.05), and Ca (P = 0.001) but lower apparent DM digestibility of CP (P = 0.012) and crude fat (P = 0.004). Timothy hay was superior in voluntary DMI and apparent DM digestibility compared with low-alkaloid reed canarygrass hay fed to horses.     

Comparison of wetland and agriculture drainage as sources of biochemical oxygen demand to the San Joaquin River, California

For many years, the San Joaquin River (SJR) has had low dissolved oxygen conditions intermittently during the late summer and early fall. The low dissolved oxygen conditions are impacting critical fish habitat and the SJR is being regulated under a state of California remediation plan that includes the development of a total maximum daily load (TMDL) allocation for oxygen demanding substances. In support of the development of a scientific TMDL allocation, studies are being conducted to characterize water quality in the many tributaries of the SJR. This study identified the sources of biochemical oxygen demand (BOD) in two western tributaries of the SJR, Mud Slough and Salt Slough, and measured the loads of BOD, algae, and ammonia entering the SJR from wetland and agricultural sources.

Mud and Salt Sloughs drain the Grassland Watershed. The watershed contains seasonal wetlands, irrigated farmland, and other agricultural lands. This drainage is under close regulatory scrutiny, because it produces a majority of the selenium and boron entering the SJR. In this study, wetland and irrigated agricultural drainage were sampled separately and a comparison was made to determine differences in water quality. In addition, water entering the study area was compared to water exiting the study area to determine the effect of water use in the region on water quality.

This study demonstrated that BOD loads from the Grassland Watershed to the SJR were proportional to flow during June–October, the most critical time for dissolved oxygen deficits in the lower SJR. This indicates that Mud and Salt Sloughs are not producing more BOD than other tributaries in the region that are not under close regulatory scrutiny. The BOD concentration of wetland drainage is higher than that of agricultural drainage, but the higher agricultural drainage flows result in a higher mass loading of BOD. Wetland flooding and irrigation of crops both had a negative impact on water quality. Algal growth was identified as the major source of BOD in agricultural drainage and locations where BOD control could potentially be implemented were identified.     

Basic Beliefs About Wildlife and Migration: The Influence of the Prior State of Residence

This study compared mean scores on four items from the appropriate use basic belief dimension of the domination wildlife value orientation scale between life-long Alaska residents and migrants to Alaska from the western United States. Basic beliefs were compared among the migrant-sourcing states. Data were collected through a mail survey; 2,264 questionnaires were completed (27% response rate) and 1,673 responses were included in this analysis. When aggregated, migrants scored lower on the appropriate use basic beliefs than life-long Alaskans (M = 4.8 vs. 4.2), but no significant differences were found among the migrant-sourcing states. Among the migrants, length of time living in Alaska and education were predictors of basic belief scores. Although migrants might be exerting a slightly less utilitarian force on Alaska’s dominant orientation toward wildlife, results also allow for the possibility that migrants with utilitarian-leaning views are choosing to move to Alaska.     

Neutrophil recruitment in endotoxin-induced murine mastitis is strictly dependent on mammary alveolar macrophages

Mastitis, inflammation of the mammary tissue, is a common disease in dairy animals and mammary pathogenic Escherichia coli (MPEC) is a leading cause of the disease. Lipopolysaccharide (LPS) is an important virulence factor of MPEC and inoculation of the mammary glands with bacterial LPS is sufficient to induce an inflammatory response. We previously showed using adoptive transfer of normal macrophages into the mammary gland of TLR4-deficient C3H/HeJ mice that LPS/TLR4 signaling on mammary alveolar macrophages is sufficient to elicit neutrophil recruitment into the alveolar space. Here we show that TLR4-normal C3H/HeN mice, depleted of alveolar macrophages, were completely refractory to LPS intramammary challenge. These results indicate that alveolar macrophages are both sufficient and essential for neutrophil recruitment elicited by LPS/TLR4 signaling in the mammary gland. Using TNFα gene-knockout mice and adoptive transfer of wild-type macrophages, we show here that TNFα produced by mammary alveolar macrophages in response to LPS/TLR4 signaling is an essential mediator eliciting blood neutrophil recruitment into the milk spaces. Furthermore, using the IL8 receptor or IL1 receptor gene-knockout mice we observed abrogated recruitment of neutrophils into the mammary gland and their entrapment on the basal side of the alveolar epithelium in response to intramammary LPS challenge. Adoptive transfer of wild-type neutrophils to IL1 receptor knockout mice, just before LPS challenge, restored normal neutrophil recruitment into the milk spaces. We conclude that neutrophil recruitment to the milk spaces is: (i) mediated through TNFα, which is produced by alveolar macrophages in response to LPS/TLR4 signaling and (ii) is dependent on IL8 and IL1β signaling and regulated by iNOS-derived NO.     

Transovarial Effect of Novaluron on Tribolium castaneum (Coleoptera: Tenebrionidae) After Termination of Direct Contact

The insect growth regulator novaluron (Rimon 10 EC, Makhteshim-Agan Ltd, Israel) is used against many field pests on corn, vegetables, orchards, forests, and cotton plantations. Previously, we studied various effects of novaluron on stored grain pests. Termination in Tribolium castaneum (Herbst) eggs hatching after treating adults with novaluron and following restoration after adult transfer to untreated media was observed. The objective of this study was to investigate the restoration of T. castaneum egg hatch following transfer of adults from treated media to untreated favorable and unfavorable media. The time needed for hatching restoration of 50% of eggs laid by adults transferred from novaluron (1 ppm) treated flour to untreated flour (RT₅₀) was 2.7 d. RT₅₀ for those transferred to untreated wheat grain was 4.1 d. RT₉₀ in flour was 3.6 d, in grain—6.1 d. Varieties of RTs in grain and in flour with nonoverlapping confidence intervals indicate that RTs were significantly different. Delay of eggs hatching restoration for adults transferred from treated flour to unfavorable media (Petri dishes with limited amount of flour, lying of eggs not detected) was observed. RT₅₀ in flour was 2.1 d and RT₉₀—3.1 d, while RT₅₀ in the unfavorable media was 3.4 d and RT₉₀ 6.5 d. Delayed effect of egg hatching restoration after adult transfer to unfavorable media provides evidence of the significant role of insect physiological state in novaluron excretion and (or) degradation by T. castaneum females.     

Manganese (Mn2+)-dependent storage stabilization of Rhodotorula glutinis phenylalanine ammonia-lyase activity

Phenylalanine ammonia-lyase (PAL; E C 4.3.1.5) reverse reaction has been exploited for the commercial production of optically pure l-phenylalanine from trans-cinnamic acid. Optimal conditions for the growth and PAL activity of Rhodotorula glutinis cells and an improved method for the synthesis of l-phenylalanine have been reported. A major problem encountered during these studies was rapid loss of PAL activity during storage of the yeast cells, which were therefore unsuitable for long-term and repeated use. Enhancement of enzyme stability in the presence of various additives including polyhydric compounds and metal ions is described. Whole cells retained nearly 85% of the original enzyme activity for at least 12 weeks when a low concentration of Mn2+ (0.01%) was included in the storage buffer medium (50 mM Tris-HCl, pH 8.8). In contrast, <3.0% activity was present in the control within 4 weeks. Mn2+-dependent stabilization of PAL was also observed with an isolated enzyme preparation (73% retention in activity for 12 weeks) obtained by ultrasonication of R. glutinis whole cells. The data suggest that Mn2+ ions may be responsible for the specific stabilization of a more active conformation of the enzyme. In addition, enzyme stability as a function of temperature was studied, and the optimal temperature for maximal activity retention was 0-2 degrees C. The effects of various additives on the induction of PAL have also been examined. These results could have direct implications in studies on activity, inhibition, and reaction mechanism of this biotechnologically important enzyme.     

Performance of finishing beef steers in response to anabolic implant and zilpaterol hydrochloride supplementation

Our objectives were to evaluate the dose/payout pattern of trenbolone acetate (TBA) and estradiol-17β (E(2)) implants and feeding of zilpaterol hydrochloride (ZH) on performance and carcass characteristics of finishing beef steers. A randomized complete block design was used with a 3 × 2 factorial arrangement of treatments. British × Continental steers (n = 168; initial BW = 362 kg) were blocked by BW and allotted randomly to 42 pens (7 pens/treatment; 6 pens/block; 4 steers/pen). The main effects of treatment were implant [no implant (NI); Revalor-S (REV-S; 120 mg of TBA + 24 mg of E(2)); and Revalor-XS (REV-X; 200 mg of TBA + 40 mg of E(2))] and ZH (0 or 8.3 mg/kg of DM for 20 d with a 3-d withdrawal before slaughter). Blocks were split into 2 groups, and block groups were fed for either 153 or 174 d. No implant × ZH interactions were noted for cumulative performance data. Overall, shrunk final BW (567, 606, and 624 kg for NI, REV-S, and REV-X, respectively), ADG (1.25, 1.51, and 1.60 kg), and G:F (0.14, 0.16, and 0.17) increased (P < 0.05) as TBA and E(2) dose increased. Implanting increased (P < 0.05) DMI, but DMI did not differ (P > 0.10) between REV-S and REV-X (8.8 for NI vs. 9.4 kg/d for the 2 implants). From d 1 to 112 of the feeding period, implanting increased (P < 0.05) ADG and G:F, but REV-S and REV-X did not differ (P > 0.10). From d 112 to end, ADG increased by 19% (P < 0.05) and G:F was 18% greater (P < 0.05) for REV-X vs. REV-S. Carcass-adjusted final BW (29-kg difference), ADG (0.2-kg/d difference), and G:F (0.02 difference) were increased (P < 0.05) by ZH, but daily DMI was not affected by feeding ZH. Hot carcass weight was increased (P < 0.05) by ZH (19-kg difference) and implant, with REV-X resulting in the greatest response (HCW of 376 for NI vs. 404 and 419 kg for REV-S and REV-X, respectively; P < 0.05). An implant × ZH interaction (P = 0.05) occurred for dressing percent (DP). Without ZH, implanting increased DP, but DP did not differ (P > 0.10) between REV-X and REV-S. With ZH, REV-X increased (1.7%; P < 0.05) DP vs. NI and REV-S. Marbling score, 12th-rib fat, and KPH were not affected (P > 0.10) by implant or ZH. Overall, treatment increased steer performance and HCW in an additive fashion, suggesting different mechanisms of action for ZH and steroidal implants. In addition, a greater dose of TBA + E(2) and extended payout improved steer performance and HCW.