Boar culling in swine breeding herds in Minnesota

This investigation was conducted to study boar culling patterns in swine breeding herds. Data were obtained from 84 swine breeding herds and included 440 boars that were culled. Each producer was involved for 12 consecutive months, and recorded every boar that was removed from the herd, the date, and the reason for culling. The annual culling rate for the 84 farms averaged 59.4% ± 6.4 (SEM). The correlation coefficient between boar and sow culling was 0.52 (p <0.0001). Removal was the result of being overweight (47%), reproductive problems (18%), leg problems (12%), death (7%), and other diseases (4%). From the annual culling rate, the average breeding life of boars was estimated at 20 months. From this study, we concluded that the annual culling rate for boars in commercial herds was high and related to several different factors.     

Nephrotoxicity in dogs associated with methoxyflurane anesthesia and flunixin meglumine analgesia

Uremia unexpectedly developed in five dogs 24 hours after undergoing thoracotomy in a student laboratory. In all dogs general anesthesia had been maintained with methoxyflurane, muscle relaxation had been induced with gallamine, and each dog received a single intravenous dose of 1.0 mg/kg flunixin meglumine for analgesia upon termination of anesthesia. In a subsequent group of dogs undergoing an orthopedic procedure, we assessed the effects on renal function of methoxyflurane anesthesia plus oxymorphone, or of methoxyflurane or halothane anesthesia in combination with a single IM 1.0 mg/kg dose of flunixin meglumine. Significant elevations in serum urea and creatinine values, and necrosis of collecting ducts and loops of Henle, were noted only in the dogs receiving methoxyflurane and flunixin meglumine.

We conclude that the use of combination of methoxyflurane and flunixin meglumine is contraindicated in dogs.

     

An assessment of the copper status of dairy herds in the Waikato, Taranaki and Northland in spring and the effects of daily supplementation with copper sulphate

The copper status of dairy herds in the Waikato, Taranaki and Northland regions between 1 August and 30 September was assessed by copper determinations made on composite sera from ten cows in each herd. Comparisons were made between two major groups categorised as as received and supplemented. In the latter, the cows received 2.0-6.0 g/day of copper sulphate orally from late gestation to the end of lactation. Mean copper values were determined from pastures in Taranaki and Northland and from pastures from three soil types in the Waikato. The lowest were in Northland (134.3 micromol/kg) and the highest in Taranaki (173.3 micromol/kg). Calculated dietary available copper levels showed the lowest were from pastures grown on organic soils in the Waikato. These soils also had high molybdenum levels. Serum copper values as received were lowest in Northland (7.30 micromol/l), and were marginal for both Taranaki (9.91 micromol/l) and the Waikato (9.93 micromol/l). The levels in supplemented herds were considerably higher, i.e. from the Waikato 11.7 micromol/l and from Taranaki 11.5 micromol/l. When liver and serum copper levels from paired samples were compared there was a reasonable correlation (r = 0.64) but the standard deviation approximated the mean liver copper level, i.e. 155 +/- 141 micromol/l.     

Surfactant and water migration in unsaturated sand

• 1 In unsaturated coarse disperse materials such as sand, the water on the surface is continous and ‘deep’ enough to be an adequate medium for the migration of surface active substances (SAS).
• 2 The influence of the tangential force on water migration in unsaturated coarse disperse material is studied by compensating the capillary pressure difference caused by the surface tension gradient.
• 3 The influence on water migration in unsaturated disperse materials exerted by the additional pressure difference, originating from SAS migration, is comparable to that exerted by capillary pressure difference.