Acute febrile diarrhoea in horses: 86 cases (1986–1991)

SUMMARY: Eighty-six horses presented for examination at the Rural Veterinary Centre between January 1986 to December 1991 with acute diarrhoea. The average age of affected horses was 3.2 ± 0.2 years (mean ± SE), with 69% three years or younger. Sixty-one horses were male (36 stallions, 25 geldings) and 83 horses were Thoroughbreds (47) or Standardbreds (36). Sixty-six horses were undergoing routine training at the time of onset of diarrhoea. Eight horses were afflicted with a non-specific illness within one to five days before the onset of diarrhoea, whereas eight horses developed diarrhoea during or within 48 h of discontinuation of antimicrobial therapy. Three horses developed the diarrhoea within 24 h of road transportation. Clinically, the disorder was characterised by a fever, sudden onset of profuse diarrhoea, clinical evidence of dehydration (estimated to be 5 to 12% of body weight at the time of admission) and shock. Degenerative leucopaenia, hyponatraemia, hypochloraemia, hyperkalaemia, hyperglycaemia and azotaemia were characteristic laboratory findings. Laminitis was a sequel in about 30% of cases. The cause of diarrhoea remained undetermined in most cases. Salmonellas were isolated from faecal or tissue samples in only two cases. Similarly, there was no evidence of seroconversion to Erhlichia risticii in 17 cases. Sixty-two of the horses survived the acute phase of the disease in response to supportive care. In horses that did not survive, necropsies were performed and revealed sanguineous or turbid peritoneal fluid. The colonic and caecal walls were oedematous and thickened with serosal congestion and discolouration of these organs evident grossly. Histopathological examination of the caecum and colon revealed diffuse congestion, oedema, inflammatory reactions and submucosal vascular thrombosis with varying degrees of mucosal devitalisation. Most cases presented in this series represent a distinct syndrome of diarrhoea characterised by acute diarrhoea predominantly affecting young horses in training with concomitant signs of fever and toxaemia.     

Monitoring changes in back fat thickness and its effect on the restoration of ovarian activity and fertility in Bos indicus cows

With the objective of testing the hypothesis if animals with a stable layer of body fat (FAT) during the peripartum have a better chance of becoming pregnant after calving, fifty‐nine multiparous Brahman cows in their last trimester of pregnancy were used. Animals averaged four parturitions and were stocked at a rate of 1.25 animal units per hectare and divided into two groups depending on the time postpartum (dpp) that the intravaginal releasing device CIDR was inserted; Group 1 (<30 dpp; n = 30) received the implant at 25.2 ± 4.21 and withdrawn 9 days later. Group 2 (≥30 dpp; n = 29) received the CIDR at 38.41 ± 5.8. Animals were AI at detected oestrus until 170 dpp and calculated as pregnant at first service or requiring more than one service (1s and >1s), not pregnant but cycling (not pregnant) and those not cycling at all (anestrus). The FAT measurements were taken twice each month from the last trimester of gestation until 96 dpp. The onset of ovarian activity was monitored through blood levels of progesterone (P4) at days 14 and 9 prior to CIDR insertion and days 10, 13, 30 and 33 after CIDR withdrawal. Animals pregnant did not have any major changes in their fat thickness. In contrast, cows pregnant in the group ≥30 dpp had changes in their FAT homoeostasis, and pregnant animals in the 1s and >1s groups did not show differences in dorsal back fat in the last trimester of pregnancy and early postpartum. In contrast, animals not pregnant and in anestrus FAT values decreased considerably after parturition. Overall, fertility was 49%, but 18% of all the animals remained anestrus losing FAT. Thus, animals with adequate metabolic conditions will have a better chance of pregnancy regardless of the time postpartum when the reproductive programme starts.     

Occurrence of cutaneous infections of Myxobolus episquamalis (Myxozoa: Myxobolidae) in sea mullet, Mugil cephalus L, in Australia

Objective To report the occurrence of Myxobolus episquamalis in sea mullet, Mugil cephalus L , caught in estuaries in eastern and western Australia.
Design A prospective study of commercial catches of mullet in the Clarence River of NSW and individual cases from other areas.
Results The organism caused pale, white to pink, raised lesions on the scales and fins of sea mullet. Occurrence of infection was highest in spring and in a marine (down-river) environment compared to a brackish environment. Up to 6% of fish were affected in commercial catches.
Conclusion The infection is widespread in Australian mullet, but rarely causes significant economic loss.     

Uterine serpin (SERPINA 14) correlates negatively with cytokine production at the foetal–maternal interface but not in the corpus luteum in pregnant dairy heifers experimentally infected with Neospora caninum

This study examines gene expression patterns in dairy heifers experimentally infected with N. caninum during on Day 110 of pregnancy with live foetuses at euthanasia, 42 days later. The study population was constituted of four non‐infected controls and three infected dams. Gene expression was determined on gamma interferon (IFNγ), (Th1 pro‐inflammatory cytokine), interleukin‐4 (IL4) (Th2 pro‐gestation cytokine) or interleukin‐10 (IL10) (T regulatory cytokine) and the serine peptidase inhibitor SERPINA14 in intercaruncular, placental, uterine lymph node (UTLN) and luteal tissue samples. Intercaruncular SERPINA14 expression was negatively correlated with IFNγ expression in cotyledon samples and with IL4 expression in UTLN. No relationships were detected between cytokine gene expression at the foetal–maternal interface and SERPINA14 expression in the luteal samples. Our findings suggest that gene expression of the uterine serpin SERPINA14 correlates negatively with the expression of Th1 and Th2 cytokines at the foetal–maternal interface but not in the corpus luteum.     

Pain-related cerebral potentials in response to acute painful electrical stimulation in sheep

Objective To examine associations between late event-related cerebral potential amplitudes and behavioural responses to noxious electrical stimulation as an indicator of acute pain in sheep.
Design Analysis of variance for the effects of stimulus intensity on the behaviour and event-related cerebral potential variables.
Procedure Ninety-six brief constant current electrical pulse trains were presented to the front left leg of eight sheep at four intensities (2.5 to 10 mA) in a randomised order. An event-related cerebral potential and a graded flinch response were recorded for each stimulus and the 24 event-related cerebral potentials at each intensity were averaged to produce a mean waveform. Various components of this waveform were analysed and changes in these measures and the sheep's flinch response, as stimulus intensity increased, were determined.
Results Both the flinch response and some event-related cerebral potential components, that is, peak amplitudes 114 {N1}, 187 {P1}, 318 {P2} and 230 {Pm} ms after stimulus onset, were significantly affected as stimulus intensity increased.
Conclusion These corresponding behavioural and event-related cerebral potential changes indicate the usefulness of using changes in the event-related cerebral potential to measure acute pain in sheep.     

An update on Reproductive Technologies with Potential Short-Term Application in Pig Production

Over the past decade, there has been an increase in the development and/or in the improvement of emerging reproductive technologies in pigs. Among emerging reproductive technologies with potential short-term application in pig production are: artificial insemination with low number of spermatozoa, cryopreservation of spermatozoa and embryos, sperm sexing, and non-surgical embryo transfer. The following review will give emphasis to recent advancements in these reproductive technologies that are starting to show possibilities of serious applications under field conditions.     

Low-Dose Insemination in Pigs: Problems and Possibilities

Low-dose AI procedures are required by the pig industry to efficiently utilize emerging sperm technologies, such as cryopreservation and sex-sorting. Currently, several different procedures for inseminating with a low or very low number of spermatozoa have been described. Deep intrauterine insemination allows the deposition of the spermatozoa in the depth of the uterine horn, allowing a significant reduction in the number of spermatozoa inseminated with maintenance of optimal reproductive performance. Intra-oviductal laparoscopic insemination has been recently applied in pigs. This technique has proved to be applicable with diluted and sex-sorted spermatozoa. This review discusses several problems encountered during the development of deep intrauterine insemination and intra-oviductal laparoscopic insemination of pigs and provides potential solutions for the practical application of both the technologies.     

Comparison of the TBARS Assay and BODIPY C11 Probes for Assessing Lipid Peroxidation in Red Deer Spermatozoa

Several methods are used to measure lipid peroxidation (LPO) in spermatozoa. The objective of this study was comparing the thiobarbituric acid reactive species (TBARS) method and the BODIPY 581/591 C₁₁ (B581) and BODIPY 665/676 C₁₁ (B665) fluorescent probes to measure induced peroxidative damage in thawed epididymal spermatozoa from Iberian red deer. Samples from three males were thawed, pooled, diluted in PBS, incubated at room temperature and assessed at 0, 3, 6 and 24 h under different experimental conditions: Control, hydrogen peroxide (H₂O₂) 0.1 mm or 1 mm , or tert‐butyl hydroperoxide (TBH) 0.1 mm or 1 mm . LPO was assessed by the TBARS assay [malondialdehyde (MDA) detection] and by the fluorescence probes B581 and B665 (microplate fluorimeter and flow cytometry). Increasing MDA levels were only detectable at 1 mm of TBH or H₂O₂. Both fluorescence probes, measured with fluorometer, detected significant increases of LPO with time in all treatments, except Control. Flow cytometry allowed for higher sensitivity, with both probes showing a significant linear relationship of increasing LPO with time for all oxidizing treatments (p < 0.001). All methods showed a good agreement, except TBARS, and flow cytometry showed the highest repeatability. Our results show that both B581 and B665 might be used for LPO analysis in Iberian red deer epididymal spermatozoa, together with fluorometry or flow cytometry. Yet, the TBARS method offered comparatively limited sensitivity, and further research must determine the source of that limitation.     

First evidence of Kunjin strain of West Nile virus associated with saltwater crocodile (Crocodylus porosus) skin lesions

Recently, the Kunjin strain of West Nile virus (WNV_KUN) has been detected using qRT‐PCR in belly skin lesions of farmed juvenile saltwater crocodiles. This follows an established association between similar lesions and West Nile virus in American alligators. The lesions present as cutaneous lymphohistiocytic aggregates in the dermal layers of both species. While these lesion do not create an obvious defect on the live crocodile, upon tanning the lesion area collapses and does not uptake the dye evenly, thus reducing its aesthetic appeal. As a result, skins are being rejected jeopardising the economic viability of the Australian crocodile industry. Over 50 skin lesions have since been confirmed as WNV_KUN‐positive and preliminary evidence of lesion restructuring is presented. Horizontal transmission of WNV_KUN by mosquitoes is well‐established but other transmission routes, such as ingestion and cloacal shedding, need further evaluation. An infection trial is currently underway to ensure WNV_KUN is the causative agent of these skin lesions.