American journal of veterinary research
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A field trial was conducted to evaluate the use of prostaglandin F2 alpha (PGF2 alpha) (lutalyse)a in lactating dairy cattle with unobserved estrus in the presence of a functional corpus luteum (CL) and clinically normal reproductive tract. Seventy-three Holstein and 9 Jersey cows, weighing between 340.0 and 772.7 kg, were allotted to treatment and control groups. All treated cows were inseminated within 80 hours after treatment as assigned by this trial. ⋯ Pregnancy rates were 57% for treated and 47% for control cows (P = 0.5, by X2). Days from treatment to first-observed estrus, treatment to first service, and treatment to conception were significantly reduced in the treatment group compared with these criteria for the control group (P less than 0.05, 0.005, and 0.01 respectively). It was concluded that induction of luteolysis with PGF2 alpha in lactating dairy cattle with unobserved estrus and a palpable functional CL will be an effective addition to reproductive health programs.
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The precision of isoflurane delivery from 4 vaporizers designed and calibrated for halothane was studied. Isoflurane concentration in oxygen (O2) was determined for various vaporizer dial settings (0 to maximum) and O2 flow rates (0.375 to 15 L/min). The effects on vaporizer output of time (settings constant for up to 15 minutes), ambient temperature (15, 22, 30 C), and conditions simulating intermittent positive-pressure ventilation were also studied. ⋯ There was little effect of simulated positive-pressure breathing on vaporizer output at peak inspired circuit pressures less than 12 mm of Hg. Use of halothane-specific vaporizers to deliver isoflurane has advantages and disadvantages which must be evaluated individually. The delivery of isoflurane by halothane-specific vaporizers is not recommended by anesthetic and vaporizer manufacturers.