Death of a neonatal lamb due to Clostridium perfringens type B in New Zealand

ABSTRACT

Case history and clinical findings: A flock of 20 sheep was kept within three paddocks on a single property. None of the animals in the flock had been vaccinated against any disease for at least three years. Abdominal bloating and haemorrhagic diarrhoea were observed in Lamb 1 at 24 hours-of-age. The lamb subsequently died within an hour of the onset of clinical signs. Lamb 2 was 3-days-old when observed to be recumbent with opisthotonus. The lamb was treated with dextrose, vitamins B1 and B12, and penicillin G, but died 4 hours later.

Pathological findings: Examination of Lamb 1 revealed markedly increased gas within the peritoneum and within dilated loops of intestine. The intestines were dark red and contained large quantities of haemorrhagic fluid. Histology of the intestines revealed peracute mucosal necrosis with minimal accompanying inflammation. The intestinal lumen contained cell debris, haemorrhage, and myriad large Gram-positive bacilli. The intestines of Lamb 2 did not appear bloated or reddened. However, multiple fibrin clots were visible within the pericardial sac. Histopathological examination revealed small foci of necrosis within the mucosa of the distal intestine. The necrotic foci were often associated with large numbers of large Gram-positive bacilli.

Immunohistochemsitry and molecular biology: Intestinal samples from Lamb 1 were processed for Clostridium perfringens immunohistochemistry, which revealed large numbers of intralesional, positively immunostained rods. Fragments corresponding to the expected sizes for genes encoding alpha, beta, and epsilon C. perfringens typing toxins were amplified by PCR from DNA extracted from formalin-fixed sections of intestine.

Diagnosis: Lamb dysentery due to C. perfringens type B.

Clinical relevance: C. perfringens bacteria have a worldwide distribution, but disease due to C. perfringens type B has only been diagnosed in a small number of countries and has never been reported in New Zealand or Australia. C. perfringens type B produce both beta toxin and epsilon toxins, therefore both haemorrhagic enteritis and systemic vascular damage can develop. As many animals are exposed to C. perfringens without developing disease, there must be additional unknown factors that resulted in disease in these particular sheep. Vaccines that specifically protect against C. perfringens type B are available and may be recommended for use in smaller non-commercial flocks, as in the present case.     

Assessing the effectiveness of manure export plus intensive silage cropping for lowering the Olsen‐P status of P‐enriched grassland

A substantial proportion of farmed grassland soils in Northern Ireland (NI) are overly enriched with P and pose a risk to water quality. To address this problem, manure could be exported rather than recycled to P‐enriched land and the latter intensively cropped with grass silage to deplete soil P. To assess the efficacy of such a strategy, a P‐ and K‐enriched grassland site was intensively cropped over a 6‐yr period with fertilizer N alone supplied to support silage growth. By year 6, soil P had declined from index 5 to index 3, and it was estimated that two more years of this management may bring it into the target index 2 range. Soil K, however, declined rapidly from index 4 to index 1 in just 4 yr, with the result that grass production became limited by K deficiency. It was concluded that nonrecycling of manure to P‐enriched grassland under silage management is probably the most effective strategy for lowering soil P status, but care must be taken to prevent K deficiency occurring.     

Digital analysis of ulnar trochlear notch sclerosis in Labrador retrievers

OBJECTIVES: To compare ulnar trochlear notch bone radiopacity in Labrador retrievers with and without fragmented medial coronoid process using quantitative analysis of film density on digitised radiographs. METHODS: Mediolateral view elbow radiographs from Labrador retrievers (n=34) aged between six and 18 months were obtained and digitised. Images from dogs with an arthroscopic diagnosis of fragmentation of the medial coronoid process (n=17) were compared with that of a control population (n=17), and this data subject to statistical analysis. RESULTS: A statistically significant relationship between the presence of increased trochlear notch radiopacity and a fragmented medial coronoid process was identified. Fractional analysis of this area shows the region of greatest difference in radiopacity between normal and fragmented medial coronoid process cohorts to be in the trochlear region of the medial coronoid process of the ulna. A decrease in radiopacity values in the dysplastic group versus the normal cohort was observed for the region of the proximo-caudal ulnar trochlear notch. CLINICAL SIGNIFICANCE: An increase in ulnar trochlear notch radiopacity is a finding associated with fragmentation of the medial coronoid process in Labrador retrievers.     

Measurement of aldosterone in feline, canine and human urine

BACKGROUND: Systemic hypertension is an important problem in older cats associated with kidney disease and hypokalaemia, suggesting that excessive activity of the renin-angiotensin-aldosterone system might contribute to the hypertensive state. Fluctuations in plasma renin activity and plasma aldosterone concentrations complicate the interpretation of these assays. OBJECTIVES: The aim of this study was to determine whether measurement of urinary aldosterone excretion in cats aided the investigation of hypertension. METHODS: Urine concentrations of free (ethyl acetate extract) and 18-glucuronidated aldosterone (acid hydrolysis before extraction) were measured by radioimmunoassay in normal, normotensive and hypertensive azotaemic cats (n=11 per group). Urine samples from 11 healthy human volunteers and eight normal dogs were also analysed for comparison. Urinary aldosterone concentration was corrected for the urinary creatinine concentration. RESULTS: Cats excreted 7.3 times less free aldosterone than human beings, and no free aldosterone was detected in dog urine. Acid hydrolysis led to large increases in aldosterone recovery from both human beings and dog but not feline urine. No significant effect of hypertension or azotaemia on feline urinary aldosterone concentration was found. CLINICAL SIGNIFICANCE: Measurement of aldosterone in feline urine using the available methodology has limited or no utility in investigating feline hypertension.     

Retrospective assessment of tolerability and efficacy of zoledronate in the palliative treatment of cancer-bearing dogs

Zoledronate is a bisphosphonate frequently used for the treatment of hypercalcaemia of malignancy and tumour-associated bone pain in dogs, however, there is a paucity of information regarding its use in veterinary medicine. The aim of this retrospective study was to report the tolerability of zoledronate in the palliative treatment of cancer-bearing dogs and secondarily to to assess the efficacy of zoledronate for the treatment of hypercalcaemia of malignancy. Thirty-seven dogs (22 with tumour-associated bone pain and 15 with hypercalcaemia of malignancy) that received 114 zoledronate infusions were included. Tolerability was assessed by the absence of post-zoledronate hypocalcaemia or other adverse events as defined by Veterinary Cooperative Oncology Group-Common Terminology Criteria for Adverse Events criteria. Efficacy was assessed by comparison of available ionized calcium levels before and after zoledronate administration in hypercalcaemic dogs. In 79% of zoledronate infusions, no adverse events were reported. The majority of adverse events which occurred in the other 21% of infusions could be attributed to concurrent chemotherapy or the underlying neoplastic disease. There was a small but significant increase in creatinine following treatment with zoledronate, however, none of the dogs developed clinically significant renal disease. In eight hypercalcaemic dogs with available ionized calcium following zoledronate administration, ionized calcium decreased rapidly within 7 days following treatment with zoledronate. Zoledronate is well-tolerated with few recorded adverse events, however, monitoring of serum creatinine is advised. Zoledronate seems to be effective in the treatment of hypercalcaemia of malignancy.     

Habitat quality,not habitat amount,drives mammalian habitat use in the Brazilian Pantanal

Landscape Ecology - An understanding of species-habitat relationships is required to assess the impacts of habitat fragmentation and degradation. To date, habitat modeling in fragmented landscapes...     

Does returning sites of historic peri‐urban waste disposal to vegetable production pose a risk to human health? – A case study near Manchester,UK

Urban waste disposal occurred on fenland to the west of Manchester, England, between 1900 and 1964. The reclaimed fenland, Chat Moss, is now used for mixed arable farming. A total of 1.92 Mt of waste including privy midden, street sweepings, clinkers and slaughterhouse refuse was incorporated into the moss resulting in a modified topsoil with raised pH and reduced organic matter content compared with the subsoil. Elevated levels of potentially toxic elements (PTEs) are observed in the topsoil beyond the typical depth of atmospheric contamination; Cd and As concentrations exceed soil guideline values (SGVs) at 1.8 and 43 mg/kg, respectively. Sequential extraction indicates that waste‐derived Pb, Zn and Ni remain predominantly in the residual fraction, whereas Cu was mainly organically bound. Arsenic was predominately found in oxide and organic matter fractions with Cd in carbonate, oxide, organic matter and residual fractions. Pot trials indicated limited uptake of PTEs by vegetables grown on the waste‐amended soil, with the exception of Cd uptake by lettuce (0.22 mg/kg FW) and Pb uptake by radish (0.16 mg/kg FW), which exceeded current EU limits of 0.2 and 0.1 mg/kg FW, respectively. Hazard quotients (HQs) identified no risks to adults from consumption of vegetables grown in these soils with the exception of lettuce consumption with a HQ of 1.4. Risks to children were slightly greater with HQs >1 for Cd in lettuce, spinach, carrots and onion, As in lettuce, parsley and onion and for Zn in spinach.     

Relationship between terrain use and performance of beef cows grazing foothill rangeland

A study was conducted on foothills rangeland to determine whether grazing patterns differed among cow breeds and to determine whether there was a relationship between individual grazing patterns and performance of beef cows. Hereford (HH), Tarentaise (TT), 3/4 Hereford x 1/4 Tarentaise (3H1T), 1/2 Hereford x 1/2 Tarentaise (HT), and 1/4 Hereford x 3/4 Tarentaise (1H3T) cows were observed during the summers of 1997 (n = 183) and 1998 (n = 159). Locations of individual cows were recorded two to three times per week during 1.5- to 2.5-h periods in the morning by observers on horseback. Statistical models included cow breed, age, and nursing status. Data from each year were analyzed separately. During 1997 and 1998, nonlactating cows were located at greater (P < 0.05) vertical distances from water than lactating cows. In 1998, nonlactating cows used steeper (P < 0.05) slopes than lactating cows. However, nonlactating cows did not travel as far horizontally from water (P < 0.05) as lactating cows in 1997. Younger cows (3 yr) traveled further (P < 0.05) from water both vertically and horizontally than older cows (5+ yr) in 1997, but not during 1998. Tarentaise and 1H3T cows were observed at greater (P < 0.05) vertical distances from water than HH cows during both years of the study. During 1998, TT and 1H3T cows used steeper (P < 0.05) slopes than HH cows. Using residual correlations, there were no consistent relationships between topographic aspects of individual grazing locations and cow weight, height, and body condition score. In 1997, cows with earlier calving dates and correspondingly heavier calf weaning weights used areas that had greater vertical distances to water; however, in 1998 there were no relationships (P > 0.05) of calving date and weaning weight with cow location. During both years, pregnant and nonpregnant cows used terrain similarly (P > 0.05), which suggests that cow reproductive performance was not related to terrain use. Grazing patterns in foothills rangeland varied among cow breeds. Performance of cows that used more rugged topography was similar to cows using gentler terrain.