Bovine ephemeral fever

Ephemeral fever remains a viral disease of considerable importance to many countries including Australia. The virus has been only partly characterised and still awaits final classification. Although BEF virus was first thought to contain 6 structural proteins there is increasing evidence to suggest that it contains the 5 proteins characteristic of the Rhabdoviridae. Although BEF is thought to be arthropod borne, the vector has yet to be identified but it is clear from the distribution of BEF that more than one vector is capable of transmitting the disease. Despite rigorous investigation of the clinical signs and the pathology of ephemeral fever, little progress has been made on the pathogenesis of the disease. This has been partly due to the difficulty of propagating BEF virus in vitro and the inability to define the site of replication. However, there is mounting evidence to suggest that BEF is immunopathologic in nature and that the clinical expression of the disease is influenced by the release of one or more mediators of inflammation. The disease is characterised by a number of haematological and biochemical changes and early and prolonged treatment with phenylbutazone is capable of reversing a number of these changes. The intravenous administration of calcium can now be considered a justifiable addition to the treatment regimen together with prolonged phenylbutazone therapy. The vaccines currently available are prepared from either live attenuated or killed virus and may be less than reliable. There appears to be a need for a reliable, inexpensive, cold-chain independent alternative vaccine.     

Ovine rumen papillae biopsy via oral endoscopy; a rapid and repeatable method for serial sampling

AIMS: To explore and validate the utility of rumen endoscopy for collection of rumen papillae for gene expression measurement.

METHODS: Four adult Coopworth ewes were fasted for either 4 or 24 hours. Animals were sedated, placed in a dorsally recumbent position at 45 degrees with the head upright, and an endoscope inserted via a tube inserted into the mouth. Biopsies of rumen papillae were taken from the ventral surface of the rumen atrium under visual guidance. Two biopsies were collected from one of the animals that had been fasted for 4 hours, and three from one of the animals that had been fasted for 24 hours. Video of the rumen atrium and reticulum was also collected. The animals recovered uneventfully. Biopsies were subsequently used for extraction and sequencing of mRNA.

RESULTS: The ventral surface of the rumen atrium was accessible after 4 hours off pasture, but a larger region was accessible after 24 hours of fasting. Sedation allowed access for endoscope use for around 5 to 10 minutes after which increased saliva flow was noted. Rumen papillae biopsies were easily collected, with samples from a variety of sites collected in the ～10 minute time window. High quality RNA was obtained for stranded mRNA sequencing. Of the resulting reads, 69–70% mapped uniquely to version 3.1 of the ovine genome, and 48–49% to a known gene. The rumen mRNA profiles were consistent with a previously reported study.

CONCLUSIONS: This method for obtaining rumenal tissue was found to be rapid and resulted in no apparent short or long term effects on the animal. High quality RNA was successfully extracted and amplified from the rumen papillae biopsies, indicating that this technique could be used for future gene expression studies. The use of rumen endoscopy could be extended to collection of a variety of rumen and reticulum anatomical measurements and deposition and retrieval of small sensors from the rumen. Rumen endoscopy offers an attractive and cost effective approach to repeated rumen biopsies compared with serial slaughter or use of cannulated animals.     

Interactions Among Different Devices and Electrical Stimulus on the Electroejaculation of Captive Agoutis (Dasyprocta leporina)

The interactions among different electroejaculation devices associated with serial or continuous stimuli were investigated to improve the efficiency of the electroejaculation for semen collection in agoutis. Ten sexually matured male Dasyprocta leporina were restrained by the intramuscular administration of xylazine–ketamine association. Each individual was randomly subjected to four electroejaculation protocols, by combining two devices (one presenting longitudinal electrodes emitting square waves and other presenting ring electrodes emitting sine waves) and two electrical stimuli protocols (serial or continuous). A total of 40 attempts for electroejaculation were conducted in agoutis, being 10 per treatment. The most efficient treatment in providing ejaculates containing sperm (p < 0.05) was that using and electroejaculator connected to a probe with ring electrodes and associated with serial stimuli (4/7; 57%). In spite of semen parameters obtained by sine waves were adequate for using the samples for assisted reproduction, higher values for sperm motility and functional membrane integrity were obtained in the use of the square wave, independently of the electric stimulation protocol used (p < 0.05). In conclusion, we verified that the use of a device presenting a probe with ring electrodes and emitting sine waves, associated with a serial stimuli protocol, improves the efficiency for semen obtaining by electroejaculation in adults D. leporina.