A 2 X 2 factorial experiment (protein 12.5 and 15.5; methionine hydroxy analog 0 and .125% dry matter) included 144 cows for one complete lactation, distributed over seven locations. Rations were formulated to the desired protein, methionine analog, and constant amounts of fiber 17%, sulfur .225%, calcium .6%, phosphorus .4%, and salt .5%. Treatment effects were not apparent for dry matter intake, daily milk and fat-corrected milk production, conversion of energy, and body weight changes. Conversion of dietary crude protein into milk protein was 34.5% for the low and 25.8% for the high protein ration. Methionine analon (0% = 2.54; .125% = 1.90). Effect of methionine analog was most apparent at low protein as 0 analog cows produced 247 kg fat, required 2.9 services/contraception, and had 156 days open whereas cows on other treatments (.125% analog and/or high protein) produced 264 kg fat, required 1.8 to 2.2 services/conception, and had 124 to 134 days open. Methionine analog response is discussed in relation to tuminal and postruminal effects as well as the interrelation with protein and energy.

Animals↗

PubMed1975

Comparative hemodynamic consequences of inflation hold, PEEP, and interrupted PEEP: an experimental study in normal dogs.

Cardiac output and airway, intrathoracic, arterial, pulmonary artery, left atrial, and central venous pressures were studied in 8 mongrel dogs. They were anesthetized and ventilated with (1) inflation hold of various duration, (2) continuous positive end-expiratory pressure and one breath off). The results indicate a minimal decrease in cardiac output (of approximately 5 per cent) with inflation hold. Diminished cardiac output was noted with increasing levels of continuous PEEP. The severity of the decrease in cardiac output wasproportional to the airway pressure. The higher levels (20 cm H2O) OF PEEP were associated with profound decreases. Utilization of a technique of interrupted PEEP substantially reduced the adverse hemodynamic effects in the dog.

Animals↗

PubMed1975

Differential pulmonary residual volume determinations with radioactive xenon.

A radioactive xenon inhalation procedure was used to determine differential residual volumes (right lung vs. left lung) in 28 normal subjects (6 of whom smoked approximately 1 package of cigarettes per day). The average right lung residual volume represented 54% of the total residual volume, whereas the average left lung residual volumerepresented 46% of the total. In addition, all of the subjects were studied by a standard helium dilution technique and found to have total lung residual comparable to the total lung residual volume as determined by the xenon technique. There was no statistical difference between the data obtained from cigarette smokers vs. nonsmokers. The noninvasive nature of the xenon technique makes this a useful procedure in determining differential residual volumes.

Adolescent↗

PubMed1974