Hydrogen radicals, nitrogen radicals, and the production of O3 in the upper troposphere

The concentrations of the hydrogen radicals OH and HO2 in the middle and upper troposphere were measured simultaneously with those of NO, O3, CO, H2O, CH4, non-methane hydrocarbons, and with the ultraviolet and visible radiation field. The data allow a direct examination of the processes that produce O3 in this region of the atmosphere. Comparison of the measured concentrations of OH and HO2 with calculations based on their production from water vapor, ozone, and methane demonstrate that these sources are insufficient to explain the observed radical concentrations in the upper troposphere. The photolysis of carbonyl and peroxide compounds transported to this region from the lower troposphere may provide the source of HOx required to sustain the measured abundances of these radical species. The mechanism by which NO affects the production of O3 is also illustrated by the measurements. In the upper tropospheric air masses sampled, the production rate for ozone (determined from the measured concentrations of HO2 and NO) is calculated to be about 1 part per billion by volume each day. This production rate is faster than previously thought and implies that anthropogenic activities that add NO to the upper troposphere, such as biomass burning and aviation, will lead to production of more O3 than expected.     

Sensitivity of boreal forest carbon balance to soil thaw

We used eddy covariance; gas-exchange chambers; radiocarbon analysis; wood, moss, and soil inventories; and laboratory incubations to measure the carbon balance of a 120-year-old black spruce forest in Manitoba, Canada. The site lost 0.3 +/- 0.5 metric ton of carbon per hectare per year (ton C ha-1 year-1) from 1994 to 1997, with a gain of 0.6 +/- 0.2 ton C ha-1 year-1 in moss and wood offset by a loss of 0.8 +/- 0.5 ton C ha-1 year-1 from the soil. The soil remained frozen most of the year, and the decomposition of organic matter in the soil increased 10-fold upon thawing. The stability of the soil carbon pool ( approximately 150 tons C ha-1) appears sensitive to the depth and duration of thaw, and climatic changes that promote thaw are likely to cause a net efflux of carbon dioxide from the site.     

Comparison of haymaking strategies for cow-calf systems in the Salado Region of Argentina using a simulation model. 2. Incorporation of flexibility into the decision rules

In pastoral farming systems, pasture production normally exceeds demand in the spring–summer period. Consequently, conserving forage at this time for use during the following winter is a widespread practice. The objective of this study was to assess the possible advantages of incorporating flexibility into a calendar‐based haymaking policy. A range of flexible haymaking strategies were simulated and compared against a calendar‐based strategy by using a simulation model to estimate long‐term performance of cow‐calf farm systems under each strategy. The results suggest that controlling haymaking in a flexible fashion, basing the decisions of closing, releasing and cutting paddocks on a simple pasture budget, could give the system productive advantages over using a calendar‐based approach. In terms of liveweight production per hectare, compared at the same area harvested, the flexible approach had higher average annual calf liveweight production (an increase of up to 0.15) and lower system variability [a reduction of 0.10 in the coefficient of variation (CV)] depending on the stocking rate. The results indicated that allocating more than 0.50–0.60 of the farm area to conservation would only be advantageous at very high stocking rates. In contrast to the calendar‐based strategy, making more hay than required for the immediate next winter, where possible, can reduce system variability.     

Application of quantitative PCR assays for diagnosing Ikeda and other Theileria orientalis types to examine associations between severity of anaemia and parasitaemia in bovine anaemia outbreaks

AIMS: To use quantitative PCR assays to detect Theileria orientalis Ikeda type in cattle presumed infected with T. orientalis, to examine the relationship between theilerial piroplasm count and haematocrit (HCT), and the relationship with quantification cycle threshold (Cq) values.

METHODS: Blood samples in EDTA (n=1,024), derived from herds affected by anaemia associated with T. orientalis infection (TABA) between April and October 2013, were submitted for testing using quantitative PCR (qPCR) assays for T. orientalis and Ikeda type. Nucleotide sequencing of the major piroplasm surface protein (MPSP) gene was performed on 16 samples to identify T. orientalis types. Blood smear and/or HCT results were supplied with most samples. For data analysis, the number of theilerial piroplasm per 1,000 erythrocytes counted was categorised as negative (0), low (1–9), moderate (10–100) or high (>100). HCT was categorised as severely anaemic (<0.15 L/L), mildly anaemic (0.15–0.24 L/L) or not anaemic (>0.24 L/L). Differences between categories in proportion of samples positive for Ikeda type or mean Cq value were examined using χ² tests or analysis of variance, respectively.

RESULTS: Of 1,022 samples containing amplifiable DNA, 916 (90%) were positive for T. orientalis and 789 (77%) were positive for Ikeda type. Nucleotide sequencing of MPSP amplicons also identified the presence of Chitose and Buffeli types in 11 samples without Ikeda. Ikeda was detected in a greater proportion of severely anaemic (288/302; 95%) than mildly anaemic (227/252; 90%) cattle (p=0.02). In non-anaemic cattle, 344/406 (85%) were positive for T. orientalis and 247/406 (60%) were positive for Ikeda type. In samples from cattle that were piroplasm-positive, a greater proportion of anaemic (483/505, 96%) than non-anaemic (211/307; 69%) cattle were positive for Ikeda type (p<0.001). In piroplasm-negative cattle, 20/37 (54%) anaemic and 25/78 (32%) non-anaemic cattle were Ikeda-positive (p<0.05). The distributions of Cq values differed between piroplasm count and HCT categories (p<0.001). Mean Cq differed between high and negative, and low piroplasm categories (p<0.001), but not between high and moderate categories (p=0.81), and differed between severely anaemic and mildly anaemic (p<0.001), and non-anaemic categories (p<0.001).

CONCLUSIONS: The Ikeda type was found in a high proportion of cattle during outbreaks of TABA in New Zealand. Analysis of Cq values suggested a relationship of Ikeda parasitaemia with severity of anaemia, but further investigation is required to better understand the role of parasitaemia in the pathogenesis of TABA.     

Derivation of Canine Induced Pluripotent Stem Cells

Dogs and humans have many inherited genetic diseases in common and conditions that are increasingly prevalent in humans also occur naturally in dogs. The use of dogs for the experimental and clinical testing of stem cell and regenerative medicine products would benefit canine health and welfare and provide relevant animal models for the translation of therapies to the human field. Induced pluripotent stem cells (iPSCs) have the capacity to turn into all cells of the body and therefore have the potential to provide cells for therapeutic use and for disease modelling. The objective of this study was to derive and characterize iPSCs from karyotypically abnormal adult canine cells. Aneuploid adipose‐derived mesenchymal stromal cells (AdMSCs) from an adult female Weimeraner were re‐programmed into iPSCs via overexpression of four human pluripotency factors (Oct 4, Sox2, Klf4 and c‐myc) using retroviral vectors. The iPSCs showed similarity to human ESCs with regard to morphology, pluripotency marker expression and the ability to differentiate into derivatives of all three germ layers in vitro (endoderm, ectoderm and mesoderm). The iPSCs also demonstrated silencing of the viral transgenes and re‐activation of the silent X chromosome, suggesting full reprogramming had occurred. The levels of aneuploidy observed in the AdMSCs were maintained in the iPSCs. This finding demonstrates the potential for generating canine induced pluripotent stem cells for use as disease models in addition to regenerative medicine and pharmaceutical testing.     

Serological detection of phage infection in Chlamydia psittaci recovered from ducks

Antiserum prepared against a phage which infects a Chlamydia psittaci isolate recovered from domestic ducks was used to screen other recent avian C psittaci isolates by indirect immunofluorescence. Two more phage infected strains from ducks were discovered. However, phage was not detected in every isolate examined from common source ducks, although such birds are likely to be infected with the same C psittaci strain. Moreover, phage could not always be demonstrated by indirect immunofluorescence in McCoy cell monolayers infected with the phage-containing strain. The results suggest that phage infection is probably an integral part of duck chlamydiosis in the United Kingdom at present, but that the infection is often cryptic.     

Epidemiology of the epidemic of bovine anaemia associated with Theileria orientalis (Ikeda) between August 2012 and March 2014

AIMS: To describe the epidemiology of the epidemic of bovine anaemia associated with Theileria orientalis infection (TABA) in New Zealand between 30 August 2012 and 4 March 2014.

METHODS: Blood samples and associated data were obtained from cases of TABA. The case definition for TABA was met when piroplasms were present on blood smears and the haematocrit was ≤0.24?L/L. Samples were analysed using quantitative PCR (qPCR) assays for the detection of T. orientalis Ikeda type. Only cases that were positive in the qPCR assays were included in the analysis. A case herd was defined as a herd that had ≥1 animal positive for T. orientalis Ikeda.

Movement records for farms were accessed through the national animal identification and tracing scheme. The OR for cattle movements onto a case farm compared to a non-case farm was estimated using a generalised estimating equation model and the geodesic distance for movements onto case and non-case farms compared using Student's t-test. The kernel-smoothed risk of disease at the farm level was calculated using an extraction map and the clustering of diseased farms in time and space was measured using the spatial temporal inhomogeneous pair correlation function.

RESULTS: In the first 18 months there were 496 case herds; 392 (79%) were dairy and 104 (21%) beef herds. Of 882 individual cases, 820 (93.0%) were positive for T. orientalis Ikeda in the qPCR assays. Case herds were initially clustered in the Northland, then the Waikato regions. The OR for a case farm compared to a non-case farm having ≥1 inward cattle movements was 2.03 (95% CI=1.52–2.71) and the distance moved was 26 (95% CI=20.8–31.3) km greater for case farms. The risk of disease was highest in a north, north-eastern to south, south-western belt across the Waikato region. The spatial-temporal analysis showed significant clustering of infected herds within 20–30 days and up to 15?km distant from a case farm.

CONCLUSIONS: Theileria orientalis Ikeda type is likely to have been introduced into regions populated with naïve cattle by the movement of parasitaemic cattle from affected areas. Local spread through dispersed ticks then probably became more important for disease transmission between herds once the disease established in a new area.

CLINICAL RELEVANCE: Dairy and beef farming in the North Island of New Zealand will be significantly changed in the coming years by the incursion of this new disease.     

Effect of Insemination–Ovulation Interval and Addition of Seminal Plasma on Sow Fertility to Insemination of Cryopreserved Sperm

In swine, the use of frozen-thawed (FT) sperm for artificial insemination (AI) is limited because of poor sow fertility, possibly associated with a post-thaw capacitation-like status resulting in fewer fully viable sperm. Sow fertility to AI with FT sperm may improve with deeper deposition of sperm within the female tract, insemination very close to ovulation, or reversal of cryocapacitation by seminal plasma (SP). We performed two experiments to examine these suggestions. In experiment 1, 122 multiparous Yorkshire sows received 600 IU equine chorionic gonadotrophin at weaning and 5 mg pLH 80 h later to control time of ovulation. The predicted time of ovulation (PTO) was 38 h after pLH injection. Thereafter, sows were assigned on the basis of parity to a single AI of FT sperm at 2 h before PTO, or at 12 h before PTO, or FT sperm supplemented with 10% SP at 12 h before PTO. Control sows received fresh semen at 12 h before PTO. All semen doses were adjusted to 3 x 10(9) live cells and deposited into the cervix. Experiment 2 employed 99 multiparous crossbred sows and repeated the treatments of experiment 1 except that all FT inseminations were intrauterine. In both experiments, farrowing rates were lower (p < 0.01) following FT inseminations with no effect of time of insemination or of supplemental SP. In experiment 1, litter size was smaller following FT insemination (p < 0.05), but no effect on litter size was evident in experiment 2. Supplemental SP had no effect on litter size in either experiment. The lack of effect of either SP or timing of FT insemination on sow fertility suggests that the non-lethal sperm cryoinjury affecting fertility involves more than just cryocapacitation.     

Echinococcus granulosus in the Northern Territory,Australia: hydatid disease reported in beef cattle from the region

Hydatid disease in beef cattle has been reported to be widespread throughout Australia, but cattle bred and raised in the Northern Territory were previously believed to be free of the disease. Between 2010 and 2016, 1061 cattle from the Northern Territory were slaughtered at a New South Wales abattoir and inspected for hydatid disease. The proportion of cattle reported infected with hydatid disease was 3.5%. Individual cattle identification numbers indicated that the cattle included in the study had most likely remained within the Northern Territory from birth until immediately prior to slaughter, so were assumed to have become infected within the region. We suspect that the sylvatic cycle of Echinococcus granulosus transmission could be responsible for infection of cattle in this region.     

Further investigation of lead exposure as a potential threatening process for a scavenging marsupial species

There is a growing recognition of the harmful effects of lead exposure on avian and mammalian scavengers. This can lead to both lethal and non-lethal effects which may negatively impact wildlife populations. Our objective was to assess medium-term lead exposure in wild Tasmanian devils (Sarcophilus harrisii). Frozen liver samples (n = 41), opportunistically collected in 2017–2022, were analysed using inductively coupled plasma mass spectrometry (ICP-MS) to determine liver lead concentrations. These results were then used to calculate the proportion of animals with elevated lead levels (>5 mg/kg dry weight) and examine the role of explanatory variables that may have influenced the results. The majority of samples analysed were from the south-east corner of Tasmania, within 50 km of Hobart. No Tasmanian devil samples were found to have elevated lead levels. The median liver lead concentration was 0.17 mg/kg (range 0.05–1.32 mg/kg). Female devils were found to have significantly higher liver lead concentrations than males (P = 0.013), which was likely related to lactation, but other variables (age, location, body mass) were not significant. These results suggest that wild Tasmanian devil populations currently show minimal medium-term evidence of exposure to lead pollution, although samples were concentrated in peri-urban areas. The results provide a baseline level which can be used to assess the impact of any future changes in lead use in Tasmania. Furthermore, these data can be used as a comparison for lead exposure studies in other mammalian scavengers, including other carnivorous marsupial species.