Monensin controlled-release intraruminal capsule for control of bloat in pastured dairy cows

Monensin, a polyether ionophore antibiotic, is potentially an important agent for bloat relief in dairy cows grazing temperate legume-based pasture. A series of studies was undertaken to determine the effect of monensin, when delivered continuously in the rumen of lactating dairy cows by means of controlled-release capsules (monensin CRC). Such devices release approximately 300 mg/head/day for 100 d. A short-term pilot study made at Ruakura, New Zealand, tested monensin CRC in cows selected for high susceptibility to bloat and grazing lucerne (Medicago sativa) or red clover (Trifolium pratense). Treatment significantly reduced the incidence of bloat, while milk yield and protein yield were increased. There was no effect on fat yield. Following the pilot study, 6 large-scale field experiments involving a total of 368 lactating dairy cows, were made in Australia and New Zealand to confirm the effectiveness of monensin CRC for bloat control and to measure the effect of such treatment on milk production and composition. A severe bloat problem occurred in 2 experiments, mild bloat occurred in 2 others, while no visual signs of bloat were observed in the remaining 2 experiments. Bloat was significantly (P less than 0.05) reduced by monensin CRC treatment when data was pooled over the 4 experiments in which bloat occurred. Daily milk yield was increased in all experiments from a mean of 17.7 in untreated groups to 18.8 kg/head/day (P less than 0.05) in monensin CRC-treated cows. Protein percentage was not affected by treatment, while there was a decrease from 4.29 to 4.10% fat, although total fat yield was not affected.(ABSTRACT TRUNCATED AT 250 WORDS)     

Rotavirus excretion by village pigs in Papua New Guinea

Cohort studies were conducted on 29 pigs from 3 villages in the Highlands of Papua New Guinea. Animals ranged in age from 9 d to 5 m old. Three hundred and twenty nine faecal samples were collected from individual pigs followed over 3 to 6 w periods, and were examined for group A rotavirus antigen by ELISA, and rotaviral genomic RNA by polyacrylamide gel electrophoresis (PAGE). Electron microscopy was also conducted on selected samples. Group A rotavirus was detected in the faeces of 16 pigs with infected individuals coming from all villages. Non-group A rotavirus resembling group C was found in faeces from pigs from 2 villages. All of the group A rotaviruses examined had the same electrophoretype and this was distinct from that of the common type infecting humans in the area at the time of the study. None of the group A positive samples reacted with monoclonal antisera specific for human group A rotaviruses of serotypes 1, 2, 3, 4, or 8. The non-group A rotaviruses also all had identical electrophoretypes. In contrast to previous findings in intensive piggeries, rotavirus infection did not occur in all young pigs and was not limited to young animals under 2 m of age. Infected pigs varied in age from 12 days to 20 weeks of age. This pattern of infection was attributed to the non-intensive husbandry situations in the villages, with less opportunity for transmission to occur than in intensive piggeries.     

A simplified double immunodiffusion technique for detection of Corynebacterium ovis antitoxin

A method is described for obtaining yields of Corynebacterium ovis exotoxin sufficiently high to allow use of unconcentrated supernatant and serum as the reactants in a double immunodiffusion test. C ovis supernatant with a haemolytic titre or rabbit dermal necrosis titre of 1:16,394 or greater produced readily detectable precipitation lines with specific antitoxin in the range of concentrations commonly found in sera from cases of natural C ovis infection. When used as a diagnostic screening test, sera from 32 confirmed cases of caseous lymphadenitis in sheep and goats were positive whereas sera from 16 sheep free of caseous lymphadenitis were negative. Sera from 10 out of 16 kids which had been suckled by mothers from an affected flock of goats were positive.     

Phloem transport of xenobiotics in Ricinus communis var. Gibsonii

Whole plants of Ricinus communis var. Gibsonii were used to study the mobility of some xenobiotics in the phloem. Solutions of ¹⁴C- or ³⁵S-labelled test compounds were introduced directly into the hollow petiole of a leaf that was exporting assimilates. Translocation was monitored by collecting phloem exudate from an incision in the stem bark beneath the treated leaf. Using [³H]sucrose as an internal standard, qualitative and quantitative results were obtained for a variety of model compounds, including herbicides, fungicides and a nematicide.     

Deep digital flexor tenotomy for treatment of severe laminitis in a cow

A first-calf Guernsey cow was referred for evaluation of severe udder edema, mastitis, metritis, and ketosis. During the course of treatment, the cow became recumbent and was unable to rise. Intensive treatment resulted in the cow being able to stand for short periods with the aid of a sling. However, severe pressure necrosis of the udder and ongoing mastitis made performance of a complete mastectomy necessary. After surgery, the cow's condition improved, although assistance in standing was still required. Radiography of the distal phalanges revealed severe rotation in the right lateral and left medial digits of the hind limbs. The laminitis was nonresponsive to medical management; therefore, a deep digital flexor tenotomy was performed in the affected claws. The procedure provided almost immediate relief of signs of foot pain and resulted in ability to stand without assistance. Deep digital flexor tenotomy should be considered when treating cows with severe laminitis.