A comparison of the effects of carbon dioxide and medical air for abdominal insufflation on respiratory parameters in xylazine-sedated sheep undergoing laparoscopic artificial insemination

AIMS: To determine if abdominal insufflation with medical air will improve oxygenation and ventilation parameters when compared to insufflation with CO₂ in xylazine-sedated sheep undergoing laparoscopic artificial insemination (AI).

METHODS: Forty-seven sheep underwent oestrus synchronisation and were fasted for 24 hours prior to laparoscopic AI. Each animal was randomised to receive either CO₂ or medical air for abdominal insufflation. An auricular arterial catheter was placed and utilised for serial blood sampling. Respiratory rates (RR) and arterial blood samples were collected at baseline, after xylazine (0.1?mg/kg I/V) sedation, 2 minutes after Trendelenburg positioning, 5 minutes after abdominal insufflation, and 10 minutes after being returned to a standing position. Blood samples were collected in heparinised syringes, stored on ice, and analysed for arterial pH, partial pressure of arterial O₂ (PaO₂), and CO₂ (PaCO₂). The number of ewes conceiving to AI was also determined.

RESULTS: Repeated measures ANOVA demonstrated temporal effects on RR, PaO₂, PaCO₂ and arterial pH during the laparoscopic AI procedure (p<0.001), but no difference between insufflation groups (p>0.01). No sheep experienced hypercapnia (PaCO₂>50?mmHg) or acidaemia (pH<7.35). Hypoxaemia (PaO₂<70?mmHg) was diagnosed during the procedure in 14/22 (64%) ewes in the CO₂ group compared with 8/23 (35%) ewes in the medical air group (p=0.053). Overall, 15/20 (75%) ewes in the CO₂ group conceived to AI compared with 16/22 (72.7%) in the medical air group (p=0.867).

CONCLUSIONS AND CLINICAL RELEVANCE: There were no statistical or clinical differences in RR, PaO₂, PaCO₂, pH, or conception to AI when comparing the effects of CO₂ and medical air as abdominal insufflation gases. None of the sheep experienced hypercapnia or acidaemic, yet 42% (19/45) of sheep developed clinical hypoxaemia, with a higher percentage of ewes in the CO₂ group developing hypoxaemia than in the medical air group. Based on the overall analysis, medical air could be utilised as a comparable alternative for abdominal insufflation during laparoscopic AI procedures.     

Ergovaline does not alter the severity of ryegrass staggers induced by lolitrem B

AIM: To investigate a possible interaction between lolitrem B and ergovaline by comparing the incidence and severity of ryegrass staggers in sheep grazing ryegrass (Lolium perenne) containing lolitrem B or ryegrass containing both lolitrem B and ergovaline.

METHODS: Ninety lambs, aged approximately 6 months, were grazed on plots of perennial ryegrass infected with either AR98 endophyte (containing lolitrem B), standard endophyte (containing lolitrem B and ergovaline) or no endophyte, for up to 42 days from 2 February 2010. Ten lambs were grazed on three replicate plots per cultivar. Herbage samples were collected for alkaloid analysis and lambs were scored for ryegrass staggers (scores from 0–5) weekly during the study. Any animal which was scored ≥4 was removed from the study.

RESULTS: Concentrations of lolitrem B did not differ between AR98 and standard endophyte-infected pastures during the study period (p=0.26), and ergovaline was present only in standard endophyte pastures. Ryegrass staggers was observed in sheep grazing both the AR98 and standard endophyte plots, with median scores increasing in the third week of the study. Prior to the end of the 42-day grazing period, 22 and 17 animals were removed from the standard endophyte and AR98 plots, respectively, because their staggers scores were ≥4. The cumulative probability of lambs having scores ≥4 did not differ between animals grazing the two pasture types (p=0.41).

CONCLUSIONS AND CLINICAL RELEVANCE: There was no evidence for ergovaline increasing the severity of ryegrass staggers induced by lolitrem B. In situations where the severity of ryegrass staggers appears to be greater than that predicted on the basis of concentrations of lolitrem B, the presence of other tremorgenic alkaloids should be investigated.     

Recovery of microorganisms from synovial and pleural fluids of animals using hyperosmolar media

L-phase (CWD) broth and plate media were used in parallel with conventional microbiological media during a 3-year period for culturing synovial and pleural fluids of animals. Two kinds of recoveries were obtained where parallel conventional methods were negative: (1) parent or normal bacteria, in very low numbers; and (2) Type B CWD variants in equally low numbers. Organisms in group 1 were: Streptococcus zooepidemicus from horses (2X); β-hemolytic streptococci, Lancefield Gp. G (2X); Staphylococcus aureus; Actinobacillus, and Actinomyces viscosus. Group 2 consisted of Bacteroides sp., Propionibacterium acnes, and three “Nocardia-like” sp. Catalase + Actinomyces was not recovered equally well on CWD plates as on conventional media with fluids obtained during ampicillin treatment. This occurred in spite of the fact that the CWD media was shown to support growth and reversion of laboratory induced L-phase variants of Nocardia caviae and N. asteroides, and had facilitated recovery of a Bacteroides L-phase variant from a pleural fluid. The nature of this fault in the media is under investigation in this laboratory.     

Unrecognized diversity in New Guinean crayfish species (Decapoda,Parastacidae): The evidence from molecular data

The phylogenetic relationships among imported ornamental crayfish belonging to the genus Cherax were inferred from a combined dataset of 3 mitochondrial genes (COI, 16S and 12S) and by comparison with available GenBank sequences of 14 Cherax species. Furthermore, the concordance of previously described species obtained from a wholesaler (Cherax boesemani, C. holthuisi and C. peknyi) with available GenBank sequences was verified based on COI with special respect to comparison with sequences assigned as Cherax species. Recently described species C. gherardiae, C. pulcher and C. subterigneus belong to the northern group of Cherax species. Comparison and analysis with other GenBank COI sequences show previously unreported diversity of New Guinean species, suggesting 5 putative new species. Surprisingly, species assigned to the subgenus Astaconephrops do not form a monophyletic clade; this subgenus should be reappraised relative to the purported typical morphological characteristic of the uncalcified patch on male chelae. Increasing importation of crayfish underscores the importance of accurate species identification. Use of basic molecular methods is a necessary requisite for documenting occurrence, abundance and population trends of target species. Consequently, it helps to support eventual conservation decision‐making by stakeholders.     

Major compositional units of the moon: lunar prospector thermal and fast neutrons

Global maps of thermal and fast neutron fluxes from the moon suggest three end-member compositional units. A high thermal and low fast neutron flux unit correlates with the lunar highlands and is consistent with feldspathic rocks. The South Pole-Aitken basin and a strip that surrounds the nearside maria have intermediate thermal and fast neutron flux levels, consistent with more mafic rocks. There appears to be a smooth transition between the most mafic and feldspathic compositions, which correspond to low and high surface altitudes, respectively. The maria show low thermal and high fast neutron fluxes, consistent with basaltic rocks.     

Lunar Fe and Ti abundances: comparison of lunar prospector and clementine data

The Lunar Prospector neutron spectrometer data correlate well with iron and titanium abundances obtained through analysis of Clementine spectral reflectance data. With the iron and titanium dependence removed, the neutron spectrometer data also reveal regions with enhanced amounts of gadolinium and samarium, incompatible rare earth elements that are enriched in the final phases of magma crystallization. These regions are found mainly around the ramparts of the Imbrium impact basin but not around the other basins, including the much larger and deeper South Pole-Aitken basin. This result confirms the compositional uniqueness of the surface and interior of the Imbrium region.     

Evaluating protection against Loma salmonae generated from primary exposure of rainbow trout, Oncorhynchus mykiss (Walbaum), outside of the xenoma-expression temperature boundaries

A series of challenge and re-challenge studies was conducted in which juvenile rainbow trout were exposed to the pathogen Loma salmonae , a microsporidian which typically causes xenoma formation during sporogony and inflammation in the gills as the xenomas undergo dissolution. The specific goal was to determine if a primary exposure, conducted at a water temperature outside of the range which permits the parasite to undergo sporogony and form branchial xenomas, would stimulate a protective response in the fish to a later challenge conducted under temperature conditions optimal for the parasite. Primary challenge of fish to L. salmonae at 7 °C or 21 °C blocked or limited xenoma formation, as discussed in a previous study. However, these fish had a relative percentage protection (RPP) against a second optimized exposure which matched, or was not significantly less than, the degree of protection (100%) that developed in other groups of fish that received a primary exposure throughout the range of water temperatures which permits xenoma formation. When the primary exposure was conducted at 5 °C, the RPP against the second exposure was adversely affected and declined to 61%. These findings have application to the control of L. salmonae within aquaculture, in that it may be possible to expose hatchery stocks of susceptible salmonid species to spores of L. salmonae when hatchery water temperature is at 7 °C. At this temperature, the risks of disease stemming from this primary exposure appear minimal, since xenomas fail to form. However, the degree of protection appears promising, and may be sufficient to protect fish from spore exposure occurring at netpen marine sites where the parasite may be endemic.     

Prevalence of Toxoplasma gondii antibody in wild macropods

An enzyme-linked immunosorbent assay (ELISA) was developed to measure total antibody to Toxoplasma gondii in serum samples from macropods. The validity of the assay was established by comparing parasite isolation in mice for 17 Tasmanian pademelons (Thylogale billardierii) and 17 Bennett's wallabies (Macropus rufogriseus rufogriseus). The ELISA was then used to detect antibody against T. gondii in serum from 236 macropods, collected from 21 locations in Tasmania, including Flinders Island. Antibody against T. gondii was detected in 20 animals (15 T. billardierii and 5 M. rufogriseus). There was a significant (p less than 0.01) difference in possession of T. gondii antibodies between adult (greater than or equal to 1 year of age) Tasmanian pademelons and Bennett's wallabies.