Nonreturn rates to professional technician service of 7240 first AI Holstein cows were calculated to evaluate differences between once daily and a.m.-p.m. AI. To determine whether management practices affected nonreturn rates, participating herd owners were surveyed for methods used for detection of estrus. Nonreturn rates for once daily and a.m.-p.m. AI were 64.6 and 65.6% for 60-d, 60.1 and 60.6% for 75-d, and 58.4 and 57.8% for 90-d nonreturn periods. Signs of estrus for AI and interval from detection of estrus to AI were related to nonreturn rates. Nonreturn rate was highest, 63.4%, when cows were in standing estrus. Nonreturn rates were lowest, 36%, when cows were bred after treatment with PGF2 alpha without being detected in estrus or bred strictly on veterinary advice based on palpation. Nonreturn rates were similar for different times of the day when once daily AI was practiced. However, AI in the midmorning may have some advantages. The highest nonreturn rate for a 3-h period was 68.2% for 0800 and 1100 h; the lowest was 54.7% for 1300 to 1600 h. Movement before observation for estrus and an observation period > 15 min improved nonreturn rates for once daily AI. Once daily AI can be used effectively with no difference from the traditional a.m.-p.m. system; results are best when AI is based on standing estrus and performed between 0800 and 1100 h.

After a lapse of some years, surgeons and anesthesiologists alike are re-exploring the use of high spinal anesthesia, which is designed to produce a "useful" hypotension coupled with maximal relaxation. In the present study the hemodynamic changes induced by low and high spinal anesthesia, the latter arbitrarily defined as ablation of sympathetic, sensory and somatic nerves fibers above the fourth dermatomic segment, have been investigated in a series of waking patients not undergoing surgery.

An electronic probe with parallel stainless steel electrodes was designed to measure changes in electrical resistance in the anterior vagina associated with increased cervical mucus secretion at estrus. Three groups of Holsteins were probed, and a sample of residual milk after milking was taken for progesterone assay every 2nd day for 28 to 40 days. Group I consisted of 29 cycling virgin heifers, Group II consisted of 24 lactating cows in the Cornell herd, and Group III consisted of 62 lactating cows in three commercial herds. Lactating cows were 26 or more days postpartum when sampling began. In Group I, 77% of the measurements at the ventral surface of the anterior vagina were lowest on the day of estrus and correlated well with days KaMaR Heatmount Detectors were triggered or chalk was erased. In Groups II and III, average electrical resistance also was minimal at estrus and was correlated .92 to .99 with average milk progesterone during the 4 days preceding and including estrus. The electronic probe appears to enable one to detect which cows are cycling normally and to aid in determining when to expect estrus.

Low and high spinal anesthesia were administered to a group of 10 waking patients without the use of vasopressor drugs. Preliminary evidence does not support the view that the induced hypotension is accompanied by significant splanchnic vasoconstriction or by homeostatic diversion of blood from the splanchnic bed to maintain the circulation in "more vital" areas. IN PREVIOUS communications we havepresented the data on the general hemodynamic and blood oxygen changes induced in humans by the administration of low and high spinal anesthesia."' 1' This paper deals with the changes observed in the splanchnic vascular bed in two groups of patients receiving low and high spinal anesthesia, but in whom no surgical procedure was performed. The general technic and methods have been previously described' and mention will be made of the technic only as it applies to the problem at hand. MATERIAL AND METHODSTen patients, nine men and one woman, with various medical diseases, were selected at random from the medical wards. Their ages ranged from 31 to 77 years; the average age was 52.4 years. Although none had active infections or temperature elevations at the time of the study, it must be emphasized that only one of these patients was entirely free of disease, and that most of them could not be considered normal control subjects. In three there was a history of chronic alcoholism, one had a fatty liver which was thought to be healed, and another This investigation was supported in part by a grant from the Cleveland Area Heart Society, Cleveland, Ohio. 894 was found to have mild congestive failure, conditions which are all known to derange the normal liver function and splanchnic blood flow. For the purpose of this study, however, the selection of completely normal individuals was not deemed necessary.After an overnight fast, 0.1 to 0.2 Gm. of pentobarbital sodium was administered and the patients were transported to the cardiovascular laboratory where the air temperature was maintained at 24 C., and the humidity was kept fairly constant. The right hepatic vein was uniformly catheterized employing a 6 to SF Goodale birdseye catheter, introduced into a medial arm vein, and the position of the tip checked repeatedly by fluoroscopic observation. An indwelling round tip no. 16 venous needle was introduced into a lateral arm vein for delivery of the bromsulfalein drip.