Synthesis and antimicrobial activity of ethyl N-aryl-S-(triphenylstannyl)isothiocarbamates.

Five ethyl N-aryl-S-(triphenylstannyl)isothiocarbamates were synthesized by the reaction of triphenyltin iodide with the appropriate ethyl N-arylthiocarbamate in the presence of triethylamine. The IR spectrum of each compound was obtained over the 4000--200-cm--1 range, and some bands were assigned. These new compounds were found to be generally better antifungal agents than the previously tested N-substituted N'-cyano-S-(triphenylstannyl)isothioureas. The new compounds were also investigated for antibacterial activity and were especially inhibitory toward Gram-positive species. Except for their lower activity toward Bacillus subtilis, their antibacterial activity was identical to the previously tested N-phenyl-N'-cyano-S-(triphenylstannyl)isothiourea.

Response of growing-finishing pigs to decreasing floor space allowance and(or) virginiamycin in diet.

Five hundred forty crossbred pigs were utilized in four trials (10 replications) at two stations to determine the separate and interacting effects of decreasing floor space allowance with or without the addition of virginiamycin to the diet on performance of growing-finishing pigs. Pigs were allowed .37, .33 or .28 m2/pig during the growing phase (23 to 55 kg) and .74, .66, .56 m2/pig during the finishing phase (55 to 100 kg) and fed either a corn-soybean meal control diet or the control diet plus 11 mg of virginiamycin/kg of diet. Floor space allowances were achieved by varying pen size, so the number of pigs and feeder space per pig were constant for all pens. During the growing phase, daily gain (P less than .01) daily feed intake (P less than .05) and feed conversion ratio (P less than .05) decreased as floor space allowance decreased. During the finishing phase and for the total test period, daily gain (P less than .01) and feed conversion ratio (P less than .05) were reduced but daily feed intake was not affected (P greater than .05) by restricted floor space allowance. The addition of virginiamycin to the diet had no effect on pig performance. The virginiamycin X floor space allowance interaction was not significant, suggesting that pigs fed a diet with or without virginiamycin responded similarly to restricted floor space allowance. The data suggest that the addition of virginiamycin to the diet was ineffective in overcoming the decrease in performance of growing-finishing pigs caused by crowded conditions.

Evaluation of high protein oats as a replacement for corn in diets fed to growing-finishing swine.

In a series of five trials, 680 crossbred pigs were fed isolysine diets in which high protein (13.8 to 16.0%) oats constituted 0, 20, 40 or 60% of the cereal portion. There was a linear depression in average daily gain (P less than .001) and average daily feed intake (P less than .005) with increasing level of oats, but feed/gain was unaffected (P less than .05) during the growing period from 22 to 46 kg. There were no significant differences in average daily gain during the finishing period from 46 to 102 kg; however, feed/gain increased linearly (P less than .01) with increasing level of oats in the diet. Increases in the percentage of oats in the cereal portion of the diet resulted in a linear (P less than .01) decrease in average daily gain and an increase (P less than .01) in feed/gain for the entire feeding period. We conclude that high protein-high lysine oats of the quality used in these trials can be included at up to 20% of the cereal portion of the diet without greatly affecting performance.

Effects of oral doses of corn oil and other factors on preweaning survival and growth of piglets.

Piglets were provided supplemental energy as oral doses of corn oil to find whether such treatment might improve survival or weight gains. A total of 1,840 piglets from 182 litters was used. Piglets were allotted to dosed and control treatments within litter on the basis of body weight. Dosed piglets received a total of 8 ml of corn oil in four doses during the first 48 h postpartum. The survival rate to weaning was high and not affected (P greater than .10) by the corn oil doses. Deaths of piglets low in birth weight were delayed by the fat doses, suggesting some utilization. The fat doses did not affect piglet weight gain. Factors affecting preweaning survival and growth of piglets were also evaluated using data from the same piglets. Specific factors investigated were sex, parity of dam, birth weight, litter size and the mean and standard deviation of piglet birth weights within litters. Male piglets were heavier at birth than females, but there was no sex effect on weight at 7 d or at weaning. Small males were less likely to survive to 3 d than were small females. Litters from primiparous sows were smaller at birth and weaning, but had lower percentages of stillbirths and of preweaning deaths than did those from multiparous sows. Piglets from primiparous sows were more uniform in birth weight. Piglets that were heavier at birth grew faster and were more likely to survive. Litter size affected growth but not survival of piglets. A heavier average birth weight in the litter reduced slightly the growth rate of individual piglets. An increase in variability of piglet birth weight within a litter was associated with an increase of the percentages of stillbirths and of preweaning mortality. A few litters accounted for a major portion of the mortality. Much of the variation in piglet mortality and growth was not explained by factors considered.