Evaluation of three strategic parasite control programs in captive wild ruminants.

Parasite control in wild ruminants is based mainly on anthelmintics. The objective of the present study was to evaluate three parasite control programs in seven herds of captive wild ruminants in 3 consecutive years. In the first year, a biannual spring-summer treatment regime with fenbendazole at 7.5 mg/kg body weight p.o. for 3 days was applied. The next year, an early-season treatment program with three administrations of fenbendazole at the same dosage at 3-wk intervals was used. In the third year, an early-season treatment program with ivermectin (0.2 mg/kg p.o. for 3 days), applied three times at 5-wk intervals, was evaluated. Effectiveness of these control programs was assessed by fecal egg counts and by scores of body condition and fecal consistency at weekly intervals. Involved animal species were Arabian oryx (Oryx leucoryx), scimitar-horned oryx (Oryx dammah), slender-horned gazelle (Gazella leptoceros), Soay sheep (Ovis aries soay), ibex (Capra ibex), red deer (Cervus elaphus hippelaphus), and Nelson's elk (Cervus elaphus nelsoni). With the spring-summer regime, fecal egg counts remained low during the first 5 mo, but from September onward, they slowly increased to significant levels in all seven herds. The early-season program with fenbendazole resulted in fecal egg counts near zero during the entire year in four herds but a significant egg shedding from August onward was noted in Arabian oryx, scimitar-horned oryx, and Soay sheep. The early-season program with ivermectin resulted in very low to zero egg shedding in gazelle, adult Soay sheep, ibex, red deer, and Nelson's elk during the entire grazing season, but failed to prevent high shedding in October in Arabian oryx and scimitar-horned oryx. High contamination of grassy pastures with infective larvae/eggs in the previous year or before the first treatment may explain failure of the treatment regimes in some herds.     

Rostrum abnormalities in the endangered Indian Ocean humpback dolphin (Sousa plumbea) in South Africa

Morphological abnormalities in wild animals can be indicators of the underlying health of a population and may be determined through routine photographic surveys. Here, we assess unusual rostrum conditions in Indian Ocean humpback dolphins (Sousa plumbea) inhabiting South African coastal waters to understand the rate of prevalence of abnormal rostrums and formulate hypotheses on potential causes. Photographic data were collated from systematic boat surveys and opportunistic sightings, obtained between April 1998 and March 2021 in various regions along the South African coast. Overall, 31 unique individuals were found with abnormal rostrum conditions, varying from slight misalignments to severe wounds and/or aberrant morphologies. In most cases, injuries were likely caused by natural events during the animal's life history such as interactions with sharks and/or reef-associated hunting strategies. Mark–recapture data indicated that individuals had survived with these injuries for up to 10 years. This study reports the highest incidence of rostrum abnormalities in the species. As numbers reflect only those that have survived their injuries, they are considered a minimum estimate. A better understanding of the cause(s) of these injuries is important given the endangered status of this species.     

Immune-mediated thrombocytopenia associated with angiostrongylus vasorum infection in a Jack Russell terrier

A twenty-month-old Jack Russell terrier was presented with a four-day history of thrombocytopenia, echymotic inguinal haemorrhages, coughing and reduced exercise tolerance. Clinical examination revealed several petechial haemorrhages on the gingivae and small echymotic haemorrhages in the inguinal region, along with mild bilateral epistaxis. Haematology confirmed a platelet count of 1.0 × 10/L. Thoracic radiographs revealed a wide-spread mixed alveolar-interstitial lung pattern, apparent throughout the entire lungfield, but particularly marked within the left lung lobes. A presumptive diagnosis of immune-mediated thrombocytopenia was made and the dog was treated with vincristine and immunosuppressive doses of prednisolone. Initially anaemia developed following gastrointestinal haemorrhage; however, after symptomatic treatment the dog showed a marked clinical improvement. Evaluation for an underlying cause of the disease revealed Angiostrongylus vasorum L1 larvae on faecal analysis and treatment with fenbendazole was commenced. The dog made a full clinical recovery with all treatment was withdrawn within five weeks of diagnosis. This is the second report of immune-mediated thrombocytopenia associated with Angiostrongylus vasorum infection and it is the first to be successfully managed. The report highlights that Angiostrongylus vasorum should be considered in young dogs presented with thrombocytopenia.     

Ultrahigh-performance liquid chromatographic-tandem mass spectrometric multimycotoxin method for quantitating 26 mycotoxins in maize silage

A multianalyte method was developed to identify and quantitate 26 mycotoxins simultaneously in maize silage by means of ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The extraction and cleanup procedure consists of two extraction steps followed by purification on a Waters Oasis HLB column. The method developed was validated with the requirements of Commission Decision 2002/657/EC taken into account. The limit of detection and quantitation ranges were 5-348 and 11-695 ng/g, respectively. Apparent recovery varied between 61 and 116%, whereas repeatability and reproducibility were within the ranges of 3-45 and 5-49%, respectively. The method developed was successfully applied for maize silage samples taken at the cutting surface and 1 m behind that surface. Mainly Fusarium toxins (beauvericin, deoxynivalenol, enniatins, fumonisins, fusaric acid, and zearalenone) were detected, but postharvest toxins such as mycophenolic acid and roquefortine C were identified as well.     

Fecundity in adult Haemonchus contortus parasites is correlated with abomasal tissue eosinophils and γδ T cells in resistant Canaria Hair Breed sheep

Canaria Hair Breed (CHB) sheep are more resistant than Canaria sheep (CS) to experimental Haemonchus contortus infection. Protective responses appear effective against the adult stage of the parasite, not as commonly reported in other breeds against the larval stages. In this study we have quantified several abomasal immune cells and correlated these with parasitological variables for each breed. A significant negative correlation between CD4+ T cell numbers and worm burden or length at 28 dpi was seen only in CS sheep. Significant negative correlations for both abomasal eosinophils and γδ/WC1+ T cells, and fecundity of the adult worms were observed only in the resistant CHB sheep breed. Tissue eosinophils and γδ/WC1+ T cells were positively correlated in CHB sheep. We suggest that the two sheep breeds have disparate immune responses following infection with the parasite and that γδ+ T cells in association with eosinophils may play a hitherto unrecognised role in modulating fecundity in H. contortus adult female parasites.     

Broiler chicken health, welfare and fluctuating asymmetry in organic versus conventional production systems

The aim of this study was to test three predictions: (1) that a combination of animal-based parameters indicates better health and welfare in broilers from organic versus conventional farms, (2) that broilers from organic farms show less fluctuating asymmetry (FA) than broilers from conventional farms, and (3) that, at the level of the individual bird, the relationship between FA and welfare is negative and strongest in conventional broilers. On 140 slaughter-age birds randomly selected from seven organic and seven conventional flocks in Belgium we measured standardised FA and five conventional animal-based welfare indicators (tonic immobility duration, latency-to-lie, and condition of the foot pad, hock, and breast). The caeca from the birds from four organic and four conventional flocks were removed for assessing the presence of two bacterial pathogens (Salmonella and Campylobacter) and the concentration of the health-promoting lactic acid bacteria. Finally, the blood serum concentration of the acute phase protein alpha-1-acid glycoprotein (AGP), a non-specific indicator of immunological stress, was determined. Salmonella was found in the caeca content of two (2.5%) birds only (both from the same conventional farm), whereas 44 (55.7%) birds were infected with Campylobacter. The prevalence of Campylobacter, the concentration of lactic acid bacteria, the duration of tonic immobility, and the condition of the breast and foot pad did not differ between both production systems. Apart from a higher concentration of AGP, organic birds had better scores for hock condition and a longer latency-to-lie indicating better leg health. In addition, organic birds scored better on the aggregated welfare index (i.e. the average of the five standardised welfare indicators). As both production systems differed in many aspects (e.g. slower-growing genotypes, slaughter age, feed, stocking density, group size) it is impossible to assign differences in welfare/health indicators to a single factor. Whatever the causes may be our findings suggest that, despite the potentially elevated risk of immunological challenge, broiler chicken welfare is generally superior in organic farms as compared with conventional farms in Belgium. Regarding the validity of FA as welfare indicator, the prediction of lower FA in the population with highest aggregated welfare score was confirmed but, at the level of the individual, no associations between FA and the aggregated welfare index were found irrespective of whether data from organic and conventional broilers were analysed separately or combined.