Effects of Plant Secondary Compounds on Nutritional Carrying Capacity Estimates of a Browsing Ungulate

Carrying capacity estimates based on digestible protein (DP) and energy (DE) are useful in comparing effects of land management practices or the ability of different vegetation communities to support herbivores. Plant secondary compounds that negatively affect forage quality would be expected to change nutritionally based estimates of carrying capacity. We evaluated the effect of plant secondary compounds on nutritionally based carrying capacity estimates of white-tailed deer (Odocoileus virginianus Zimmerman) in Tamaulipan thorn scrub of northern Mexico. Forage biomass, nutrient concentration, and tannin concentration (protein-precipitating capacity) were measured for 23 forage items during spring and summer in three replicate pastures. Nitrogen in phenolic amines was estimated for the two principal woody browse species in deer diets and was assumed to be unavailable for amino acid synthesis. Carrying capacity estimates were calculated based on three dietary concentrations of DP and DE. Nutritional carrying capacity estimates that accounted for antinutritional compounds were reduced 50 ± 6%, 28 ± 8%, and 0 ± 0% (mean ± SE) for diets of high, medium, and low DE concentration, respectively, compared to estimates from models that ignored the effects of these compounds. Accounting for effects of plant secondary compounds reduced DP-derived carrying capacity estimates 4 ± 3%, 47 ± 9%, and 9 ± 8% for diets with high, medium, and low concentrations of DP, respectively. High variation in percent reduction in carrying capacity estimates occurred because of site and seasonal variation in plant species composition and biomass, making application of a single correction factor to account for plant secondary compound effects on carrying capacity infeasible. Protein-precipitating capacity of tannins accounted for > 98% of the reductions in carrying capacity estimates based on DP. Our results clearly demonstrate the need to consider effects of tannins on ungulate carrying capacity estimates based on DP and DE. Estimates can be further refined by accounting for nonprotein nitrogen and other antinutritional compounds in all forage items.     

Seroprevalence of psittacine beak and feather disease in wild psittacine birds in New South Wales

SUMMARY A haemagglutination inhibition assay was used to detect antibody to psittacine beak and feather disease virus in sera from wild sulphur crested cockatoos (Cacatua galerita), galahs (Eolophus roseicapillus), short-billed corellas (Cacatua sanguinea), eastern long-billed corellas (Cacatua tenuirostris) and other psittacine birds in New South Wales. The seroprevalence of psittacine beak and feather disease ranged from 41% to 94% in different flocks, indicating infection with the virus is widespread in wild populations.     

Plasma indicators of muscle damage in a model of nutritional myopathy in weaner sheep

SUMMARY Subclinical nutritional myopathy was induced in 5-month-old sheep by feeding them a diet low in vitamin E and selenium. Subsequently clinical myopathy was induced by dosing with protected polyunsaturated fatty acids. Plasma activities of creatine kinase (CK), pyruvate kinase, aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase and aldolase, enzymes of muscle origin, all remained above their reference ranges in clinically affected sheep, but fluctuated widely. Similar fluctuations occurred in subclinically affected animals, resulting in some activities being within the reference ranges and some above, at different times. Plasma malondialdehyde, an indicator of lipid peroxidation, proved of no diagnostic value. Terminal plasma CK activities were significantly correlated with microscopic damage in the vastus lateralis (VL), but not the vastus intermedius (VI) or the tensor fascia lata (TFL) muscles. AST was the most highly correlated with damage in VI and VL. In two clinically affected sheep successfully treated with an oral dose of α-tocopherol actetate all enzymes decreased steadily to within their reference ranges, at rates probably related to their plasma half-lives. These results suggest that measurement of plasma CK activity would be useful in monitoring recovery of treated sheep.     

The confidential enquiry into perioperative equine fatalities (CEPEF): mortality results of Phases 1 and 2

Objectives To document the equine perioperative mortality rate and to highlight any factor associated with an increased risk of death up to 7 days after anaesthesia. Study design A prospective observational epidemiological multicentre study. Methods Data were recorded from all equidae undergoing general anaesthesia in 62 clinics. Power calculations indicated that 45 000 cases were required to detect the significance of important variables. Details of each horse, operation, anaesthetic agents and clinic personnel were recorded. Outcome at 7 days was recorded as: alive, put to sleep (PTS) or dead. Data were analysed by a standard multilevel logistic regression approach, considering the effects of clustering at the level of clinic. Results Data were collected from 41 824 cases over 6 years. A total of 39 025 (93.3%) were alive on day 7 and 785 were dead giving an overall death rate of 1.9% (95% CI: 1.8–2.0) and 2014 (4.8%) were PTS. About 5846 horses undergoing emergency abdominal surgeries (‘colics’) were excluded from subsequent analyses. A total of 35 107 ‘noncolic’ horses were alive at 7 days and 328 dead giving a death rate for noncolics of 0.9% (95% CI: 0.8–1.0). Five hundred and forty‐three (1.5%) noncolic horses classified PTS were excluded from further analyses. There were 109 (33%) deaths from cardiac arrest or post‐operative cardiovascular collapse, with 107 (32%) from fractures and myopathies. Fracture repair, out of hours surgery, and age below 1 month was associated with increased risk of dying whereas the use of acepromazine and intravenous anaesthetic agent maintenance of anaesthesia was associated with reduced risk. Conclusions A number of potential contributors to the high risk of anaesthetic‐related mortality have been identified. Further investigation of the underlying mechanism for their apparent harmful effects and development of alternative techniques is merited.     

Studies in Iron Deficiency of Crops: II. The Interrelationships of Iron and Potassium in the Potato Plant

Attempts to reduce the growth of Lord Lambourne apple trees without adversely affecting cropping by using mild strains of single viruses or mycoplasmas were not successful. Of the five different infections used only rubbery wood significantly reduced tree size, but two infections (spy epinasty and decline and rubbery wood) reduced crop weight over an eight-year period. None of the treatments affected the skin colour, time of ripening or the seed number of the fruit.     

Cellular and extracellular vesicular origins of miRNAs within the bovine ovarian follicle

The ovarian follicle components must provide an ideal environment to ensure the success of reproductive processes, and communication between follicular cells is crucial to support proper oocyte growth. Recently, it has been demonstrated that the presence of extracellular vesicles (EVs) carrying microRNAs (miRNAs) in follicular fluid represents an important autocrine and paracrine communication mechanism inside the ovarian follicle. In this study, we tested the hypothesis that the miRNA content of EVs isolated from ovarian follicular (granulosa and cumulus–oocyte complexes) cell‐conditioned culture media is dependent upon cell type. We initially screened bovine granulosa cells (GCs) and cumulus–oocyte complexes (COCs), as well as their derived EVs for 348 miRNAs using real‐time PCR, and detected 326 miRNAs in GCs and COCs cells and 62 miRNAs in GCs and COCs EVs. A bioinformatics analysis of the identified cell‐specific and differentially expressed miRNAs predicted that they likely modulate important cellular processes, including signalling pathways such as the PI3K‐Akt, MAPK and Wnt pathways. By investigating the origins of miRNAs within the follicular fluid, the results of this study provide novel insights into follicular miRNA content and intercellular communication that may be of invaluable use in the context of reproductive technologies, diagnostic of ovarian‐related diseases and/or the identification of biomarkers for oocyte and embryo quality.