Isolation of avian influenza virus (subtype H5N2) from chicken eggs during a natural outbreak

Avian influenza virus (A/Chicken/Pennsylvania/83; H5N2) was recovered from the yolk, albumen, and shell surface of eggs obtained from naturally infected chicken flocks in Pennsylvania and Virginia. These findings represent the first reported isolation of avian influenza virus from the internal contents of eggs from naturally infected flocks. The need for adequate safeguards to prevent spread of the virus during commercial movement of table and hatching eggs, cracked and "checked" eggs, and egg flats and other materials is emphasized.     

Ocular absorption and toxicity of methotrexate in the dog

The ocular absorption, elimination and toxicity of 12.5 mg of methotrexate in 0.5 cc administered subconjunctivally was studied in the dog. The purpose of this study was to establish ocular pharmacokinetics for treatment of intraocular tumours in dogs. Drug levels were measured in ocular compartments, and serum at 1,2,4,6,8 and 12 hours respectively. Tumoricidal concentrations of the drug were attained in the anterior chambers of the injected eyes up to and including six hours postinjection. Consistent signs of toxicity were anorexia, vomiting, weight loss and leukopenia. Local ocular toxicity following subconjunctival injection was minimal conjunctival hyperemia lasting up to 48 hours.     

A nutritional myopathy enzootic in a group of yearling beef cattle

Steers and bulls under feedlot conditions and on an apparently adequate ration developed transitory signs of diarrhea and unthriftiness. One animal became recumbent. Sick and clinically normal animals in the group had elevated serum creatine kinase and aspartate aminotransferase enzyme values and degenerative changes in muscle fibers on biopsy. Feed analysis was carried out and the animals were monitored over several weeks by means of muscle biopsy and serum enzyme analysis as well as by postmortem examination at slaughter. Subclinical myopathy was found in several animals and was thought to be related to low vitamin E content in the high moisture corn ration.     

Radial-intermediate Carpal Bone Fusion in a Horse

The radial carpal and intermediate carpal bones were found to be fused in a four year old Quarterhorse stallion having a subtle forelimb lameness. Clinical examination, diagnostic local anesthesia, radiography and arthroscopy were used to arrive at the diagnosis. A cause could not be established, although perinatal deformation of cartilagenous carpal bone templates is suspected. A similar case of carpal bone fusion was found among carpi collected for an anatomical study, indicating this condition may be more common than expected. Clinicians should carefully evaluate the flexed lateral view of the carpus for proximal movement of the intermediate and ulnar carpal bones in young horses presented for carpal lameness. The significance of this condition will remain uncertain until its incidence and relationship to lameness are better defined.     

Herniation of small intestine through the right lateral ligament of the bladder in a bull

A three year old Charolais bull was examined because of anorexia and depression of five days duration and progressive abdominal distention. Intestinal obstruction was diagnosed. A right flank celiotomy allowed diagnosis and correction of a herniated jejunoileal loop through the right lateral ligament of the bladder. An annular constriction located in mid-ileum was by-passed by ileocecal side-to-side anastomosis. The bull's appetite and fecal production returned to normal within 72 hours of surgery. Ten months following discharge the bull was reported to be well.     

Antibiotic residue release at the beginning of lactation following dry cow therapy

In response to farmer complaints about unfair penalties, for the presence of inhibitory substances in early lactation following the use of dry-cow antibiotic therapy, a two-part study was carried out to try and establish why these unexplained grades occur. A survey of instructions supplied with each of 13 registered dry-cow products suggested that the directions for drug use were in some cases inappropriate for long-acting antibiotics. A residue release study was conducted at the beginning of lactation following antibiotic therapy at various times during the dry period. The results showed, for the-three dry-cow preparations studied, that treatment during the dry period, especially within six weeks of calving, could lead to detectable residues in milk from treated quarters.     

Age and the ability of calves to respond to a leptospiral vaccine

The serological responses of calves at two different ages to a commercial hardjo/pomona vaccine were examined. Microscopic agglutination test (MAT) titres of a group of ten three-month-old calves and three groups of 11,12 and 12 six-month-old calves were monitored over a period of 28 weeks. The calves vaccinated at three months of age had a poorer serological response rate to vaccination (30% responded to pomona and 40% responded to hardjo) compared with those vaccinated at six months of age (91-100% responded to pomona and 83-91% responded to hardjo). Those three-month-old calves which did respond also produced a lower level of-antibody than six-month-old calves. It was concluded that in order to achieve adequate protection using commercially available leptospiral bacterins at the recommended dose, vaccination should not be undertaken routinely with animals less than six months of age. Where circumstances arise in which earlier vaccination is necessary, repeat vaccination for continued protection at six months or older is suggested.