Further investigation of equine fescue oedema induced by Mediterranean tall fescue (Lolium arundinaceum) infected with selected fungal endophytes (Epichloë coenophiala)

Abstract

AIMS

To determine if equine fescue oedema (EFO) induced by grazing Mediterranean-type tall fescue (Lolium arundinaceum) infected with selected endophytes (Epichloë coenophiala) could be prevented by treatment with the corticosteroid, methylprednisolone, and anti-histamine, cetirizine, and to determine concentrations of lolines, specifically N-acetyl norloline (NANL), in grasses grazed by horses that did and did not develop EFO.     

Blood calcium,glucose and haematology profiles of parturient bitches diagnosed with uterine inertia or obstructive dystocia

Bitches with dystocia most often present with clinical signs of uterine inertia (UI). The aetiology of myometrial dysfunction in most of these cases is still not elucidated. We compared blood ionized calcium (iCa) and glucose concentrations in bitches diagnosed with primary UI (PUI, n = 14), secondary UI (SUI, n = 6) or obstructive dystocia (OD, n = 6), and we described their haematology profiles. Bitches diagnosed with UI had a patent birth canal and delivered no puppies yet (PUI) or only part of the whole litter (SUI). The OD group had no UI and showed strong abdominal contractions. Blood iCa did not differ between the PUI, SUI and OD groups and was not influenced by litter size. There was a significant positive relationship (R² = .241, p = .013) between iCa concentrations and the dam's body weight. Glucose concentrations were also not significantly different between dystocia groups or influenced by body weight and litter size. Hypocalcaemia was detected in 11 bitches, and hypoglycaemia in two bitches. Pregnancy‐associated anaemia was seen in about one‐third of the bitches. Eight of 12 dogs had increased platelet counts, and ten had leukocytosis with mature neutrophilia. Although iCa did not differ between dystocia groups, low concentrations may have contributed to the development of UI in some of the small size bitches. Hypoglycaemia was uncommon, and therefore, we consider low glucose concentrations not to have played an important role in the pathogenesis of UI in our study population. Pregnancy‐associated anaemia, thrombocytosis, leukocytosis and mature neutrophilia were common findings in otherwise healthy bitches diagnosed with different forms of dystocia.     

Associations between Theileria orientalis Ikeda type infection and the growth rates and haematocrit of suckled beef calves in the North Island of New Zealand

AIMS: The principle aim of this study was to examine the association between infection with Theileria orientalis Ikeda type and growth rates of suckled beef calves on four beef farms. In addition, associations between calf sex, sampling time, and individual farm and T. orientalis Ikeda type infection intensity and haematocrit (HCT) were investigated.

METHODS: The study was a prospective longitudinal study in which 240 calves from four purposively selected beef farms in the North Island of New Zealand were blood sampled and weighed in late spring, mid-summer and early autumn. Two farms were from high-risk (A and B) and two from low-risk (C and D) tick areas. Blood samples were analysed to determine HCT, and the number of T. orientalis Ikeda type organisms/µL of blood (infection intensity) using a quantitative PCR assay. A calf was defined as infected if >415 organisms/µL were detected in a blood sample. Linear mixed models were used to examine associations between infection intensity, mean daily liveweight gain (MDG), HCT, calf sex and time of sampling on the four farms.

RESULTS: On Farms A and B nearly all calves were infected at each sampling time, on Farm C <30% were infected at any sampling and on Farm D infection prevalence increased from 32 to 79% between late spring and early autumn. On Farms C and D, from mid-summer to early autumn, mean MDG was 0.127 (95% CI=0.072–0.183) kg/day less for infected than uninfected calves (p<0.001). On all farms MDG was negatively associated with infection intensity for mid-summer and early autumn sampling times (p=0.037). The relationship between time of sampling and infection intensity varied between farms (p<0.001), and between male and female calves (p=0.018). Females had a higher infection intensity than males at the mid-summer and early autumn samplings. The association between HCT and infection intensity varied with sampling time and farm (p=0.018). There was a strong negative association between infection intensity and HCT at the late spring sampling, but in mid-summer there was no association, and in early autumn only a weak association.

CONCLUSIONS AND CLINICAL RELEVANCE: This study has shown that beef farmers in the North Island of New Zealand should be concerned about the welfare effects and economic impacts of T. orientalis Ikeda type infection in suckled beef calves.     

Clinical haematology and biochemistry profiles of cattle naturally infected with Theileria orientalis Ikeda type in New Zealand

AIMS: To present the haematology and biochemistry profiles for cattle in New Zealand naturally infected with Theileria orientalis Ikeda type and investigate if the results differed between adult dairy cattle and calves aged <6 months.

METHODS: Haematology and biochemistry results were obtained from blood samples from cattle which tested positive for T. orientalis Ikeda type by PCR, that were submitted to veterinary laboratories in New Zealand between October 2012 and November 2014. Data sets for haematology and biochemistry results were prepared for adult dairy cattle (n=62 and 28, respectively) and calves aged <6 months (n=62 and 28, respectively), which were matched on the basis of individual haematocrit (HCT). Results were compared between age groups when categorised by HCT. Selected variables were plotted against individual HCT, and locally weighted scatterplot smoothing (Loess) curves were fitted to the data for adult dairy cattle and calves <6 months old.

RESULTS: When categorised by HCT, the proportion of samples with HCT <0.15 L/L (severe anaemia) was greater for adult dairy cattle than for beef or dairy calves, for both haematology (p<0.002) and biochemistry (p<0.001) submissions. There were differences (p<0.05) between adult dairy cattle and calves aged <6 months in the relationships between HCT and red blood cell counts, mean corpuscular volume, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentrations, lymphocyte and eosinophil counts, and activities of glutamate dehydrogenase and aspartate aminotransferase. In both age groups anisocytosis was frequently recorded. The proportion of blood smears showing mild and moderate macrocytosis was greater in adults than calves (p=0.01), and mild and moderate poikilocytosis was greater in calves than adults (p=0.005).

CONCLUSIONS AND CLINICAL RELEVANCE: The haematology and biochemistry changes observed in cattle infected with T. orientalis Ikeda type were consistent with extravascular haemolytic anaemia. Adult dairy cattle were more likely to be severely anaemic than calves. There were differences in haematology and biochemistry profiles between adult dairy cattle and calves, but most of these differences likely had a physiological rather than pathological basis. Overall, the haematological changes in calves aged <6 months appeared less severe than in adult dairy cattle.     

Variation in ptaquiloside content in bracken (Pteridium esculentum (Forst. f) Cockayne) in New Zealand

AIM: To examine stands of bracken fern (Pteridium esculentum) from throughout New Zealand for the presence and concentration of ptaquiloside (Pta), and to compare the presence and/or concentrations of Pta in areas where bovine enzootic haematuria (BEH) and/or acute haemorrhagic syndrome (AHS) has been known to occur with those where BEH/AHS has not been recorded.

METHODS: Stands of bracken fern were sampled from 275 sites throughout New Zealand. Sixty-two stands were from a regional survey predominantly from the Waikato and Coromandel regions, 27 were from a farm in the King Country where BEH/AHS had been investigated previously, and 186 were from a national survey of the North and South Islands. Sampling sites were from a mixture of grazed paddocks, roadsides, and forest and bush areas. Samples comprised whole young fronds, the tops of unfurling young fronds, or, for the Regional Survey, mature green fronds from the previous season. Pta was extracted from the samples, and measured using high-performance liquid chromatography. Information on the occurrence of BEH/AHS at specific locations was obtained from published information and records from animal health laboratories in New Zealand.

RESULTS: The 275 samples contained widely varying concentrations of Pta. In the Farm Survey, concentrations ranged from 280–13,300 (mean 3,800) µg/g (on a dry-weight basis) in the 63% of samples that contained Pta. A high proportion of samples from the Regional and National Surveys covering large areas of the country contained no detectable levels of Pta. The majority (61%) of samples from these two surveys which contained Pta were from areas where BEH/AHS was reported to occur. Combining data from all surveys, in areas with reported BEH/AHS, 42% of samples collected contained Pta, compared with 6% where BEH/AHS was not known to occur.

CONCLUSIONS: Concentrations of Pta in bracken in New Zealand vary greatly, and in a high proportion of stands Pta is not found. A higher incidence of Pta, and some very high concentrations, are found in areas where BEH/AHS was known to occur.     

Clinicopathological features of 11 suspected outbreaks of bovine adenovirus infection and development of a real-time quantitative PCR to detect bovine adenovirus type 10

CASE HISTORY: A retrospective study was conducted to investigate 11 outbreaks of presumptive fatal adenovirus infection diagnosed through two New Zealand diagnostic laboratories during 2014 and 2015. Outbreaks occurred in 6–12-month-old Friesian or Friesian cross cattle during autumn, winter and spring. Individual outbreaks were short in duration, with mortality rates ranging from 3/250 to 20/600 (1.2 to 3.3%).

CLINICAL AND PATHOLOGICAL FINDINGS: Clinical signs included severe diarrhoea, depression, recumbency, and death. Post-mortem examination revealed congestion and oedema of the alimentary tract and fluid to haemorrhagic intestinal contents. Histopathological lesions were characterised by congestion and haemorrhage of the alimentary tract mucosa, oedema of the submucosa, and mild interstitial inflammation in the kidneys. Large basophilic intranuclear inclusion bodies were identified in vascular endothelial cells of the alimentary tract in 11/11 cases and of the kidney in 8/9 cases.

MOLECULAR TESTING: A real-time quantitative PCR (qPCR) assay was designed to detect bovine adenovirus type 10 (BAdV-10) using hexon gene sequences available in GenBank. DNA extracted from a field case and confirmed by sequencing was used as a positive control. The qPCR had a reaction efficiency of 101% (R²=0.99) and the limit of detection was <10 DNA copies/reaction. The qPCR detected BAdV-10 in formalin-fixed paraffin-embedded (FFPE) tissue from 10/11 cases. DNA sequencing of PCR products from nine of these cases showed them to be identical to BAdV-10 sequences in GenBank. For the PCR-negative case, the PCR product had a hexon sequence 99% similar to bovine adenovirus Wic isolate Ma20-1, a close relative of BadV-10.

DIAGNOSIS: Bovine adenovirus type 10 was identified in FFPE tissues from cattle with histopathological evidence of adenovirus infection.

CLINICAL RELEVANCE: Bovine adenoviruses, and especially BAdV-10, should be considered in the differential diagnosis for acute enteric disease and death in young cattle. The qPCR detected BAdV-10 from FFPE tissue of cattle with suspected adenoviral infection diagnosed by histopathology. However results should be interpreted in light of clinical and pathological findings due to the possibility of adenovirus shedding by healthy cattle and the presence of pathogenic adenoviruses other than BAdV-10.     

波尔山羊耳成纤维细胞的分离培养与保存

本文研究了波尔山羊耳成纤维细胞的体外培养,包括分离纯化和生长特征,同时还研究了成纤维细胞的冷藏和冷冻保存.结果表明,波尔山羊耳成纤维细胞贴壁生长,一般经历潜伏期、指数增生期和平台期;4℃体外冷藏时间为5 d;冷冻保存时4℃平衡1 h、-80℃过夜,然后直接投入液氮中,解冻后培养得到61.6%的贴壁率.