Pathogen Inactivation In Cow Manure Compost

During aerobic composting of animal manure, microbial activity within the mixture generates heat and metabolic by-products that inactivate zoonotic pathogens. Although it is recognized that the type and level of microbial activity will vary with the nutrient availability of different compost ingredients, the degree to which these changes could impact pathogen inactivation is of interest. Towards that goal, the purpose of this study was to determine inactivation of Escherichia coli O157:H7 and Listeria monocytogenes in compost laboratory-scale bioreactor systems formulated to different initial carbon:nitrogen (C:N) ratios with cow manure, straw, and cottonseed meal. The C:N ratio did not significantly affect the time to inactivation of Listeria monocytogenes. In contrast, Escherichia coli O157:H7 survived for significantly (P < 0.05) longer periods of time in 40:1 C:N systems than in 30:1 or 20:1 systems even though the cumulative heat exposures were statistically similar in the systems. An increase of pH values to 8 to 9 occurred initially for 40:1 C:N systems, whereas the pH of the 20:1 and 30:1 systems initially declined to 5.5 to 6 before increasing to 8 to 9 after 2 days of composting.     

Monitoring distances travelled by horses using GPS tracking collars

Objective The aims of this work were to (1) develop a low-cost equine movement tracking collar based on readily available components, (2) conduct preliminary studies assessing the effects of both paddock size and internal fence design on the movements of domestic horses, with and without foals at foot, and (3) describe distances moved by mares and their foals. Additional monitoring of free-ranging feral horses was conducted to allow preliminary comparisons with the movement of confined domestic horses. Procedures A lightweight global positioning system (GPS) data logger modified from a personal/vehicle tracker and mounted on a collar was used to monitor the movement of domestic horses in a range of paddock sizes and internal fence designs for 6.5-day periods. Results In the paddocks used (0.8–16 ha), groups of domestic horses exhibited a logarithmic response in mean daily distance travelled as a function of increasing paddock size, tending asymptotically towards approximately 7.5 km/day. The distance moved by newborn foals was similar to their dams, with total distance travelled also dependent on paddock size. Without altering available paddock area, paddock design, with the exception of a spiral design, did not significantly affect mean daily distance travelled. Feral horses (17.9 km/day) travelled substantially greater mean daily distances than domestic horses (7.2 km/day in 16-ha paddock), even when allowing for larger paddock size. Conclusions Horses kept in stables or small yards and paddocks are quite sedentary in comparison with their feral relatives. For a given paddock area, most designs did not significantly affect mean daily distance travelled.     

Do Thoroughbred and Standardbred horses have similar increases in pulmonary vascular pressures during exertion?

To test the hypothesis that the pulmonary vascular pressures of Thoroughbred and Standardbred horses behave similarly during exertion. Measurements were made on 5 Thoroughbred and 5 Standardbred horses on a treadmill at rest and during 3-minute exercise intervals at speeds predicted to produce 75%, 90%, and 100% maximal heart rate. Left forelimb acceleration, heart rate, esophageal pressure, and pulmonary artery pressure were measured continuously. Pulmonary capillary and wedge pressures were measured during intermittent occlusion of the pulmonary artery. Breathing rate and gait frequency were the fundamental frequencies of the esophageal pressure and limb acceleration signals respectively. The ratio of speed:gait frequency gave stride length. The effects of exertion and breed were evaluated using two-way analysis of variance. Exertion produced significant increases in pulmonary artery (P = 0.001), capillary (P= 0.002), and wedge (P= 0.005) pressures. No significant effect of breed was detected on pulmonary artery pressure, but at exertion pulmonary capillary and wedge pressures were 15% (P= 0.03) and 23% (P= 0.04) greater in Thoroughbreds, respectively. Treadmill speed was ~12% greater (P= 0.04), stride length was ~25% greater (P= 0.0003), gait frequency was ~10% less (P= 0.006), breathing rate was ~10% less (P= 0.001), and heart rate was ~6% less (P= 0.06) for Thoroughbreds. There was no effect of breed on inspiratory or expiratory esophageal pressure although mean esophageal pressure was ~2 mmHg greater (P= 0.03) in exercising Standardbreds. In conclusion, pulmonary capillary and wedge pressures are greater in Thoroughbreds than in Standardbreds at similar fractions of maximal heart rate. This is compatible with the higher incidence of exercise-induced pulmonary hemorrhage observed in Thoroughbreds.     

Monoclonal antibodies for coagglutination of Streptococcus suis type 1

Monoclonal antibodies (MAbs) were sought that would identify Streptococcus suis. Spleen cells from Balb/c mice immunized with formalin-killed S. suis were fused with the murine cell-line SP-2/0. Hybridomas positive for S. suis were identified by a solid-phase radioimmunoassay with a mixture of all available serotypes of S. suis. On further screening with individual serotypes of S. suis (Types 1,2,1/2,3,4,5,7,8,9 and 12) and other related and unrelated bacteria, a hybridoma specific for Type 1 was identified. Another hybridoma was positive for all serotypes of S. suis. S. suis Type 1-specific MAbs in the form of ascites fluid was used in a coagglutination test. Agglutination with S. suis Type 1 was observed within 45 s, while there was no reaction with other serotypes of S. suis or other bacteria, during the 5-min observation period. A library of type-specific MAbs should help in rapid and accurate serotyping of S. suis isolates.     

Do Abrasion- or Temperature-Based Techniques More Effectively Relieve Physical Dormancy in Seeds of Cold Desert Perennials?

Seed dormancy can present a significant barrier to restoration outcomes in dryland systems. Physical and combinational (physical + physiological) dormancy are prevalent among seeds of many herbaceous perennials used in restoration of drylands throughout the western United States. Although many techniques designed to alleviate these dormancy traits exist, their efficacy is species specific, may result in embryo damage, and may have limited large-scale application. To identify the most effective means of dormancy alleviation with the potential to be used on an operational scale, we examined the effects of 16 temperature-based techniques (altering temperature and duration of wet heat, freezing and wet heat, and freeze-thaw cycles) and 6 abrasion-based techniques (altering pneumatic scarification length or using a single duration of manual scarification) on the enhancement of seed permeability among two physically dormant (western prairie clover [Dalea ornata {Douglas} Eaton & Wright] and Munro’s globemallow [Sphaeralcea munroana {Douglas} Spach]) and two combinationally dormant species (basalt milkvetch [Astragalus filipes Torr. ex A. Gray] and longspur lupine [Lupinus arbustus {Douglas} ex Lindl.]). We first assessed seed imbibition following exposure to all temperature- and abrasion-based techniques to identify those most successful at promoting seed permeability and then evaluated the effectiveness of those techniques through a series of germination experiments. For combinationally dormant species, we also tested whether exposure to GA₃ enhanced germination. Abrasion-based techniques were more effective than temperature-based techniques at improving water uptake across all species. Pneumatic scarification significantly improved germination, but optimal treatment durations were species specific. GA₃ did not enhance germination under the tested conditions. We conclude that pneumatic scarification is a fast, safe, and effective method for alleviating physical seed dormancy with a potential to be scaled up for operational use in restoration.