Management of land and livestock contaminated with polychlorinated biphenyls

Investigations were conducted on several small neighbouring beef cattle and sheep farms that were found to be contaminated with polychlorinated biphenyls (PCBs). The residues detected contained about 62% w/w chlorine and soil concentrations ranged from 0.35 to 1.9 mg/kg. Beef cattle and sheep grazing the contaminated land had PCB concentrations in their fat of 0.3 to 1.7 mg/kg and 0.19 to 0.45 mg/kg, respectively. The concentration of PCBs in the caudal fat of cattle was 0.3 to 2 times the concentration of PCBs in the land they were grazing and was positively related to stocking rates. PCBs were present in milk fat from cattle at about the same concentration as in caudal fat, and lactation appeared to contribute to decontamination. Wool grease from sheep contained about 1 to 2 times the concentration of PCBs in subcutaneous fat. Calves of contaminated cows also became contaminated. The half-life for decontamination of PCBs in a group of 8 young female beef cattle was calculated at 13 months. PCBs were detected in pasture samples at concentrations ranging from less than 0.01 mg/kg to 0.12 mg/kg. However, PCBs were not detected in any sample of hay cut from these paddocks. In 4 sheep fed a sole ration of this hay, traces of PCBs were detected in their fat following 89 days of feeding. Grazing livestock for meat production on land contaminated with PCBs is not recommended because livestock readily acquire residues, and PCBs persist in soil and livestock for long periods. Grazing sheep for wool production on land contaminated with PCBs may be an option.     

Oxygenic Photoautotrophic Growth Without Photosystem I

Contrary to the prediction of the Z-scheme model of photosynthesis, experiments demonstrated that mutants of Chlamydomonas containing photosystem II (PSII) but lacking photosystem I (PSI) can grow photoautotrophically with O2 evolution, using atmospheric CO2 as the sole carbon source. Autotrophic photosynthesis by PSI-deficient mutants was stable both under anaerobic conditions and in air (21 percent O2) at an actinic intensity of 200 microeinsteins per square meter per second. This PSII photosynthesis, which was sufficient to support cell development and mobility, may also occur in wild-type green algae and higher plants. The mutants can survive under 2000 microeinsteins per square meter per second with air, although they have less resistance to photoinhibition.     

The Seismic Structure of the Sun

Global Oscillation Network Group data reveal that the internal structure of the sun can be well represented by a calibrated standard model. However, immediately beneath the convection zone and at the edge of the energy-generating core, the sound-speed variation is somewhat smoother in the sun than it is in the model. This could be a consequence of chemical inhomogeneity that is too severe in the model, perhaps owing to inaccurate modeling of gravitational settling or to neglected macroscopic motion that may be present in the sun. Accurate knowledge of the sun's structure enables inferences to be made about the physics that controls the sun; for example, through the opacity, the equation of state, or wave motion. Those inferences can then be used elsewhere in astrophysics.     

Congenital dyserythropoietic anaemia and dyskeratosis in Australian Poll Hereford calves

Congenital dyserythropoietic anaemia (CDA) is a heterogeneous group of rare genetic disorders that in humans is characterised by ineffective haematopoiesis with morphological abnormalities in erythroid precursor cells and secondary iron overload. In the 1990s, a syndrome of CDA with dyskeratosis and progressive alopecia was reported in Poll Hereford calves in Canada and the USA. We report the clinical and pathological findings in two Poll Hereford calves with this syndrome from separate properties in South Australia. The animals had a variably severe anaemia, associated with abnormal nucleated red blood cells in peripheral blood, and large numbers of rubricytes and metarubricytes with a characteristic nuclear ultrastructure in the bone marrow. Both calves were born with a wiry hair coat and a progressively ‘dirty‐faced’ appearance associated with hyperkeratosis and dyskeratosis (apoptosis).     

Effect of adenosine infusion on isoflurane MAC in dogs.

Adenosine is a potent analgesic in people and reduces the MAC of halothane in dogs. The purpose of this study was to determine whether adenosine reduces the MAC of isoflurane in dogs. Seven beagles (four males and three females) were anesthetized and randomly assigned to receive adenosine (0.3 mg kg^–1 minute^–1; 6 mL kg^–1 hour^–1, IV) or saline (0.9%, 6 mL kg^–1 hour^–1IV). After an interval of ≥7 days, each dog was reanesthetized and treated with the alternate infusion. Anesthesia was induced and maintained with isoflurane in oxygen. Dogs were intubated and instrumented for measurement of mean systemic arterial blood pressure and airway concentration of isoflurane and end‐tidal partial pressure of carbon dioxide. The MAC for isoflurane was determined using the tail‐clamp technique. Baseline MAC values were 1.25 (1.15, 1.35)% [median (minimum, maximum)] and 1.25 (1.05, 1.45)% before the saline and adenosine treatments, respectively. After 2 hours of infusion with saline or adenosine, MAC values were not different (p = 0.156) and were 1.25 (0.95, 1.35)% and 1.05 (1.00, 1.25)%, respectively. Two hours following the end of each infusion, the MAC values for saline and adenosine treatment groups differed significantly (p = 0.015), but by no more than the normal variation inherent in this study, and were 1.15 (1.15, 1.35)% and 1.05 (1.05, 1.25)%, respectively. Mean arterial blood pressure was 93 (74, 123) mm Hg for saline treated dogs and 67 (52, 72) mm Hg (p = 0.008) during adenosine infusion. End‐tidal carbon dioxide was not different between the two treatment groups. We conclude that adenosine administered at 0.3 mg kg^–1 minute^–1had no effect on isoflurane MAC in dogs, but decreased mean arterial blood pressure.     

Effects of increasing dose of live cultures of Lactobacillus acidophilus (Strain NP 51) combined with a single dose of Propionibacterium freudenreichii (Strain NP 24) on performance and carcass characteristics of finishing beef steers

Two experiments, each with a randomized complete block design, were conducted to evaluate the effects of feeding live cultures of Lactobacillus acidophilus plus Propionibacterium freudenreichii on performance and carcass characteristics of feedlot cattle. British and British x Continental steers (240 steers in each experiment; 12 pens/treatment in each study; average initial BW = 370 +/- 6 kg) were fed a 92% concentrate diet based primarily on steam-flaked corn. Four treatments were evaluated, which included a control diet (lactose carrier only) or diets containing 1 x 10(9) cfu/(steer x d) of P. freudenreichii (strain NP 24) with 1 x 10(7) (L), 1 x 10(8) (M), or 1 x 10(9) (H) cfu of L. acidophilus strain NP 51/(steer x d). Data were pooled for the 2 experiments. No differences (P > 0.10) were detected among treatments for final BW, final BW based on HCW, or DMI during various stages of the feeding period or overall. Likewise, no differences among treatments were observed for either ADG or carcass-adjusted ADG (P > 0.10), except for the tendency for a quadratic effect of NP 51 dose for the overall feeding period (P = 0.10), in which cattle fed M had a lower ADG than those fed L and H. Gain efficiency on a live BW basis was improved (P = 0.02) by NP 51 treatments compared with the control, with G:F responding quadratically to NP 51 dose for the overall feeding period (P = 0.05). In contrast to G:F based on live BW, carcass-adjusted G:F tended (P = 0.14) to decrease linearly with increasing NP 51 dose because the dressing percent tended (P = 0.12) to be less for steers fed direct-fed microbial compared with control cattle. Within the direct-fed microbial treatments, there also was a tendency (P = 0.13) for a linear decrease in the dressing percent as the NP 51 dose increased. No differences were observed in other carcass characteristics (P > 0.10), except tendencies for a quadratic increase in marbling score (P = 0.11) and percentage of USDA Choice cattle (P = 0.10). These data indicate that live cultures of L. acidophilus strain NP 51 plus P. freudenreichii strain NP 24 increased G:F of feedlot cattle fed steam-flaked corn-based diets by approximately 2%, but the effects depended on the dose of Lactobacillus.     

A pilot study examining a proprietary herbal blend for the treatment of canine osteoarthritis pain

Osteoarthritis is the most common joint disease in dogs. Despite the use of nonsteroidal anti-inflammatory drugs (NSAIDs), many owners seek natural therapies; either to augment the response to NSAIDs, or as a replacement. Substantial research has been directed to investigation of novel therapies. A randomized, double-blinded, controlled study was conducted to assess the efficacy of a herbal remedy for treatment of canine osteoarthritis pain. Client-owned dogs (N = 24) with osteoarthritis were enrolled between 2 veterinary hospitals. Each dog underwent veterinary and owner assessment at 0, 4, and 8 weeks, using the Canine Brief Pain Inventory and Hudson activity scale. Blood was collected for a complete blood (cell) count (CBC) and serum chemistry analysis. The product was deemed to be safe and well-tolerated at the manufacturer recommended dosage, with no significant changes seen in the CBC or serum biochemical analyses. Aside from1 dog that developed gastrointestinal upset, all other dogs tolerated the supplement without complication. The supplement did not statistically improve clinical signs in dogs based on veterinary or owner assessments of lameness. There was a treatment/time effect when assessing veterinary pain scores; however, post-hoc analysis suggests no observable benefit of treatment compared with the placebo group at any time point.