A pathological and microbiological evaluation of omphalophlebitis in very young calves slaughtered in New Zealand

Omphalophlebitis, generally referred to as navel ill, is a common post-mortem meat inspection finding in very young calves slaughtered in New Zealand, and a gross pathological, histopathological and bacteriological evaluation of 147 carcasses condemned for this condition at routine post-mortem meat inspection was undertaken. Localised lesions restricted to the umbilicus alone were present in 29.9% of cases. The majority of cases included gross pathological change in the umbilical vessels and other tissue sites beyond the umbilicus. Most hepatic nodes were grossly normal but histological examination revealed that 61.5% of nodes from other than localised cases of navel ill were hyperplastic. However, there was little difference in the prevalence of hyperplastic hepatic nodes from cases of localised navel ill (21.4%) compared with normal calves (15.9%). Despite the wide range of bacteria isolated from umbilical lesions, Salmonella typhimurium recovered from the navel, liver and hepatic nodes of a single extended case of navel ill was the only isolation of known public health importance. Given the separation of cases of navel ill into different gross pathological, histopathological and microbiological categories, current meat inspection judgments whereby all calves with navel ill are condemned should be revised. In particular, routine condemnation of the carcass and viscera in all cases of localised navel ill (lesions restricted to the umbilicus alone) should be reassessed.     

The pharmacokinetics of thiamphenicol in lactating cows

The pharmacokinetics of thiamphenicol were studied after intravenous and intramuscular administration of 25 mg/kg body weight in lactating cows. Distribution (t _1/2) and elimination (t _1/2) half-lives of 6.10±1.39 min and 1.60±0.30 h, respectively, were obtained after intravenous administration. The body clearance was 3.9±0.077 ml/kg per min and the apparent volume of distribution was 1220.79±256.67 ml/kg. The rate at which thiamphenicol appeared in the milk, as indicated by the penetration half-life (t _1/2P) (serum to quarters), was found to be 36.89±11.14 min. The equivalent elimination half-life (t _1/2E) (quarters to serum) from the milk was 3.62±1.06 h and the peak thiamphenicol concentration in the milk was 23.09±3.42 µg/ml at 2.5±0.32 h.After intramuscular injection, the elimination half-life was 2.2±0.40 h, the absorption half-life was 4.02±1.72 min and the peak concentration in the serum was 30.90±5.24 µg/ml at 23±8.4 min. The bioavailability after intramuscular administration approached 100%. The penetration half-life was 50.59±6.87 min, the elimination half-life was 5.91±4.97 h and the mean peak concentration in the milk was 17.37±2.20 µg/ml at 3.4±0.22 h.Abbreviations AUC area under the concentration-time curve - CAP chloramphenicol - C _max peak concentration - IM intramuscular - IV intravenous - TAP thiamphenicol - t _1/2 distribution half-life - t _1/2 elimination half-life - V _c volume of central compartment - V _d volume of distribution     

Chemical modification of the photoluminescence quenching of porous silicon

The photoluminescence of porous silicon can be quenched by adsorbates, and the degree of quenching can be tuned by chemical derivatization of the porous silicon surface. Thus, as-prepared porous silicon has a hydrophobic, hydrogen-terminated surface, and the photoluminescence is strongly quenched by ethanol and weakly quenched by water. Mild chemical oxidation (iodine followed by hydrolysis) produces a hydrophilic porous silicon surface. Photoluminescence from this hydrophilic material is quenched to a lesser extent by ethanol and to a greater extent by water, relative to the original surface. This demonstrates that the visible luminescence from porous silicon is highly surface-sensitive, and the surface interactions can be tuned by specific chemical transformations.     

Genotypic differences in speed and magnitude of response to ahemeral lighting

1. The paper compares between three genetically different lines in their egg weight and shell thickness response to a 28‐h cycle.

2. The response in shell thickness to ahemeral lighting was more rapid (2.2 d) than for egg weight (4.2 d).

3. Differences between genotypes were evident in both the speed and magnitude of response.

4. Overall, egg weight and shell thickness on the 28‐h cycle were 7% and 8% greater than on 24 h.

5. The allometric increase indicates that the increase in shell weight was on average 14% more than the increase in egg weight.