Detection of Ureaplasma diversum in the upper airways of Australian feedlot cattle

Bovine respiratory disease (BRD) exerts a major impact on the beef cattle industry nationally and worldwide, with a range of aetiological factors impacting its pathogenesis. Previous research has focussed on an increasing number of bacteria and viruses that have been shown to play a role in eliciting disease. Recently, additional agents have been emerging as potential contributors to BRD, including the opportunistic pathogen Ureaplasma diversum. To determine if U. diversum was present in Australian feedlot cattle and if that presence was linked to BRD, nasal swabs were collected from a cohort of 34 hospital pen animals and compared to 216 apparently healthy animals sampled contemporaneously at feedlot induction and again after 14 days on feed at an Australian feedlot. All samples were subjected to a de novo polymerase chain reaction (PCR) assay targeting U. diversum in combination with other BRD agents. U. diversum was detected at a low prevalence in cattle at induction (Day 0: 6.9%, Day 14: 9.7%), but in a significantly greater proportion of cattle sampled from the hospital pen (58.8%). When considering the presence of other BRD-associated agents, co-detection of U. diversum and Mycoplasma bovis was most common in hospital pen animals receiving treatment for BRD. These findings suggest that U. diversum may be an opportunistic pathogen involved in the aetiology of BRD in Australian feedlot cattle, in combination with other agents, with further studies are warranted to identify if a causal relationship exists.     

Caudal Sartorius Muscle Flap in the Dog

An anatomic study was performed on canine cadavers to define the blood supply to the caudal sartorius muscle. The vascular supply to this muscle was segmental with the saphenous artery and vein providing a distal vascular pedicle. Anastomotic channels existed between distal and proximal capillary beds within the muscle belly. This anatomic information was used to determine the feasibility of performing caudal sartorius muscle flaps in dogs. The caudal sartorius muscle was transposed to the medial tibial region in four dogs. The muscle flap was based on a singular vascular pedicle of the saphenous artery and vein. The muscle transpositions were all successful on day 14 as evidenced by gross appearance and results of histologic examination. Grossly, the muscles were well adhered to the recipient sites and were covered by connective tissue. Histologically, the specimens were characterized by viable skeletal muscle fibers, large amounts of granulation tissue, varying degrees of inflammatory response, and small foci of myocyte necrosis (2 cases). Seroma formation was a consistent postoperative complication.     

Postoperative Analgesia for Stifle Surgery: A Comparison of Intra-articular Bupivacaine, Morphine, or Saline

A prospective study was undertaken to compare the analgesic effect of intra-articular bupivacaine, morphine, or saline in the 24-hour period following cranial cruciate ligament repair in dogs. Thirty-six clinical patients with ruptured cranial cruciate ligaments were randomly assigned to one of three groups. After surgical stabilization, and before skin closure, an intra-articular injection was given; group one (n = 12) received 0.5% bupivacaine HCl at 0.5 mL/kg, group two (n = 12) received morphine at 0.1 mg/kg diluted with saline to a volume of 0.5 mL/kg, and group three (n = 12) received saline at 0.5 mL/kg. Heart rate, respiratory rate, mean arterial blood pressure, cumulative pain score, visual analog pain score, and pain threshold test on both stifles were recorded preoperatively and at 0 to 6 and 24 hours postoperatively. Surgeons and pain scoring investigators were unaware of the intra-articular medication given. Supplemental analgesia, if needed, was provided in the postoperative period according to subjective assessment of patient discomfort. Postoperative pain scores were lowest in the bupivacaine group and highest in the saline group. Pain threshold, measured by applying calibrated loads to the knee, was higher postoperatively in the bupivacaine group than in the saline group. Dogs in the morphine and bupivacaine groups required less supplemental analgesia than dogs in the saline group. The local provision of analgesia reduces the need for systemic drugs with potential side effects. Both intra-articular morphine and intra-articular bupivacaine provided better postoperative analgesia than intra-articular saline, with intra-articular bupivacaine showing the greatest effect.     

Effect of auxin,cytokinin, and glutamine on mycelial growth of Phaeolus schweinitzii

The effect of naphthaleneacetic acid (NAA), benzylaminopurine (BAP), L-glutamine (L-gln), and combinations of these substances on mycelial growth of Phaeolus schweinitzii was studied in vitro. NAA (1 mg × 1^?1), L-gln (500 mg × 1^?1) and a combination of NAA with L-gln inhibited the growth of fungal mycelium. BAP (1 mg × 1^?1) enhanced the inhibitory effect of NAA while in combination with L-gln it reduced the inhibitory effect of L-gln.     

Cranial Sartorius Muscle Flap in the Dog

An anatomic study was performed on canine cadavers to define the blood supply to the cranial sartorius muscle. The vascular supply to this muscle was found to be a single dominant pedicle branching from the femoral artery at the proximal portion of the muscle. This anatomic information was applied in designing a study to determine the feasibility of performing a cranial sartorius muscle flap in the dog. The cranial sartorius muscle was transposed to the caudal abdominal region in four dogs. The muscle flap was based on the singular vascular pedicle defined in the anatomic study. All muscle transpositions were successful on day 19 as evidenced by gross appearance and histologic examination. Grossly, the muscles were well adhered to the recipient sites and were covered by connective tissue. Histologically, the specimens were characterized by viable skeletal muscle fibers, proliferative and maturing granulation and fibrous connective tissue, and mild to moderate mononuclear inflammation. Seroma formation and infection were the two postoperative complications noted. The cranial sartorius muscle flap has potential clinical application for repair of traumatic caudal abdominal hernias and large inguinal hernias in the dog.     

Effect of freezing bull semen in two non‐egg yolk extenders on post‐thaw sperm quality

Traditionally, extenders for bull semen included egg yolk or milk, but recently there has been a move to avoid material of animal origin. The aim of this study was to evaluate the effects of two commercial extenders (based on soya lecithin and liposomes) on bull sperm quality after cryopreservation. Post‐thaw sperm quality was evaluated by computer‐assisted sperm analysis and flow cytometric assessment of membrane integrity, chromatin integrity, mitochondrial membrane potential, production of reactive oxygen species and tyrosine phosphorylation. Furthermore, an artificial insemination (AI) trial was conducted, and 56‐day non‐return rates were evaluated. Semen frozen in the liposome‐based extender showed similar membrane integrity and higher mitochondrial membrane potential compared to those in the soya lecithin‐based extender. Chromatin integrity and production of live H₂O₂+ reactive oxygen species were similar in both extenders. Less superoxide was produced in the samples extended with liposome‐based extender, with or without menadione stimulation. Chromatin integrity and tyrosine phosphorylation were not affected by either type of extender. No differences in 56‐day non‐return rate between extenders containing soya lecithin and liposomes were observed in the AI trial (66% ± 0.8 and 65% ± 0.8, respectively). In conclusion, the sperm quality of bull semen frozen in the two extenders that do not contain material of animal origin was similar, although the semen frozen in the liposome‐based extender had higher mitochondrial membrane potential. Either extender could be used in situations where extenders containing material of animal origin are to be avoided.     

Food safety and residues in Australian agricultural produce

SUMMARY A brief history of food safety in Australia in the context of the development of scientific knowledge is presented. Australia's food and food commodity residue and contamination surveillance and monitoring programs are outlined. Although chemical residues are perceived as a major health risk by the general community, the risk of food causing illness or death because of chemical residues is low. The major threat to human health from food is microbiological contamination, in terms of deaths, sickness and economic loss. The emerging influences in food safety are scientific and technical developments, deregulation, social and demographic factors, and the media. The risk of disruption of domestic and export markets by food safety issues is considerable. The emergence of international standards for food production and processing will enable commercial contractual arrangements to minimise the frequency of disruptive food safety incidents.     

Programs for surveillance and monitoring of antibacterial residues in Australia, 1989 to 1993

SUMMARY The development of a State-based confirmatory testing capability for antibiotic residues in meat in Australia has allowed the rapid feedback to producers failing to comply with antibiotic maximum residue limits. The identification of problem areas in various categories of livestock, and subsequent focused surveillance programs, has reduced the prevalence of antibacterial residues in both domestic and export meat products. Failure to observe withholding periods of antibacterial drugs after treatment is the most significant cause of non-compliance. In the period July 1991 to June 1993 the compliance rate for antibacterial residues for all species was 99.9%.