Effects of nonadherent dressing materials on the healing of open wounds in dogs

Four types of nonadherent dressing materials (rayon/polyethylene dressing, cotton nonadherent film dressings, fine mesh gauze petrolatum dressings, and commercial petrolatum emulsion dressings) were applied on small full-thickness skin defects on the backs of 12 Beagles. At 7 days, the wounds treated with the petrolatum-containing dressings had more contraction than wounds dressed with cotton nonadherent film dressings and wounds dressed with rayon/polyethylene dressings. However, by days 14 and 21, there was little difference in the amount of contraction of any of the wounds. At 7, 14, and 21 days, the wounds dressed with petrolatum-containing dressings had less epithelialization than wounds dressed with cotton nonadherent film dressings and rayon/polyethylene dressings. The uniform open mesh of the commercial petrolatum emulsion dressings allowed the best absorption of exudate and bacteria into the secondary overlying bandage.     

Passive transfer of colostral immunoglobulins from ewe to lamb and its influence on neonatal lamb mortality

The transfer of immunoglobulin G (IgG) and immunoglobulin M (IgM) from ewe to lamb was quantitated to determine the occurrence of failure in passive transfer. Concentrations of IgG and IgM in ewe serum did not correlate with those in the colostrum. Colostrum from all ewes contained abundant amounts of immunoglobulins when compared with serum values, with IgG being selectively concentrated over IgM. Absorption through the intestinal tract of the lamb appeared to be a nonselective process, lacking predilection for IgG and IgM. All lambs tested 24 hours after birth absorbed colostral immunoglobulins to some extent; however, 13 (14%) of 91 clinically normal lambs demonstrated some failure of passive transfer. In contrast, failure of passive transfer was found in 27 (46%) of 59 lambs dying of natural causes between 24 hours and 5 weeks of age. Evidence presented emphasizes the importance of absorption of adequate amounts of immunoglobulins to enable the newborn lamb to survive the first few weeks of life.     

Energetic and kinematic consequences of weighting the distal limb

REASON FOR PERFORMING STUDY: It is well known that adding a load to a horse's back increases its energetic costs of locomotion, but the magnitude of increase obtained by loading the most distal portion of limb has not been measured. OBJECTIVES: To measure oxygen consumption in horses with mass added to the back and hooves. Because such mass distribution alters inertial parameters of the limbs, kinematic measurements were made to quantify the magnitude of change in limb movement. METHODS: Steady-state oxygen consumption was measured in 6 horses with a load of 2.4 kg. The load was either carried on the back or distributed equally between the 4 limbs. Modified bell boots kept the mass at the level of P3. Horses trotted on a treadmill at speeds ranging from 2 to 5 m/sec (in 0.5 m/sec increments). High-speed (250 Hz) digital images were recorded in a sagittal plane and the positions of retroreflective markers located on standard positions on the limbs were digitised for kinematic analysis. RESULTS: Loading of the distal limbs produced a 6.7% increase in metabolic rate, an order of magnitude higher than when the mass was added over the back. Although the stride period was 2% longer in horses with loads on the distal limbs, time of contact and duty factor were not different. Distal limb loading increased the range of motion in hind- but not forelimbs. CONCLUSIONS: The costs of swinging the limbs in the horse are considerable and the addition of weights to the distal limb can have a profound effect on not only the energetics of locomotion but also the kinematics, at least in the hindlimb. POTENTIAL RELEVANCE: The use of weighted shoes, intended to increase animation of the gait, increases the metabolic effort of performance horses a disproportionate amount. The additional mass also increases the joint range of motion and, potentially, the likelihood of injury.     

Hearing with the third ear: dichotic perception of a melody without monaural familiarity cues

Julesz has shown that cross-correlations between two patterns that appear random to either eye alone can give rise to the perception of form and depth when viewed stereoscopically. We produced auditory analogs by presenting eight simultaneous and continuous sine waves to both ears and by either phaseshifting or frequency-shifting one of them relative to its counterpart in the opposite ear. Particular tones were shifted in sequence such that a melody was heard which was undetectable by either ear alone.