D. F. Cox

Social dominance in swine

Summary Data on social dominance value (DV) of 1629 Duroc and Hampshire pigs were obtained from Iowa State Universitys swine irradiation project. Two measures of DV were analysed within subclasses differentiated by irradiation treatment of sires, and breeds. The analysis of DV was done on a within-litter basis as pigs were raised in litter groups. Angular dominance value (the proportion of animals dominated, transformed to angles) and least-squares dominance value (the result of least-squares minimization of dij — (DVi — DVj) where dij is the observed difference in DV between animals i and j) were highly correlated within sex, within litters. Evaluation of pigs was practically identical by the two methods. Barrows were more dominant than gilts. The sex difference was larger in Hampshires than in Durocs. Scrotal irradiation of sires increased the variance component for interaction of sire by sex and increased variance within litters. Within sex, within litter, DV was most significantly correlated with weight at all ages. It was not correlated with backfat thickness if weight was held constant.

Incidence of molds and mycotoxins in commercial animal feed mills in seven midwestern states, 1988-1989

A total of 82 feed manufacturers located within seven midwestern states (Iowa, Nebraska, Minnesota, Illinois, Indiana, Ohio, Michigan) participated in a survey of mold and mycotoxin contamination of corn. Samples were submitted from a composite of the grading samples taken from each incoming load of corn. The survey was initiated in July 1988. During the 12-mo period, moisture content of the corn samples upon receipt at the laboratory ranged from 10.5 to 13.3%. The greatest variation occurred in the springtime. Iowas corn samples were driest (11.2%), and samples submitted from Ohio were wettest (12.8%). Mold counts averaged 2.63 x 10(4) per gram during the year. The predominant mold found was Fusarium sp. Samples were checked by black light and averaged 25.4% positive during the period. When assayed for mycotoxins, 19.5% of the samples were positive for at least one of the following: aflatoxin, zearalenone, T2 toxin and deoxynivalenol (vomitoxin). Aflatoxin and T2 toxin made up the majority of these samples containing toxin. The highest incidence of mycotoxin-contaminated corn (48%) occurred in samples submitted in July of 1988. Over the 12-mo period, the highest mycotoxin contamination occurred in Iowa, Illinois and Michigan. When samples were subjected to 90% relative humidity and 32 degrees C, an average of 3.9 d was required for mold growth to appear. After incubation, 24.7% of the samples contained one of the four toxins. The data indicate that mold and mycotoxin contamination of mixed samples of corn is widespread, even in the midwestern corn belt of the U.S.

AVOIDANCE LEARNING IN SWINE

The purpose of the present study was to develop a measure of learning in swine that could be mzde rapidly and would be sensitive to individual differences, so that the genetic effects of irradiation on this measure of learning could be investigated. Pxevious learning studies with swine (Hafez, et al., 1962) used procedures not amenable to testing the large numbers of Ss necessary for genetic analysis. Therefore, avoidance learning, typified by the work of Solomon (1953) with dogs and Mowrer (1946) with rats, was chosen since a response indicative of learning could be obtained in a relatively few trials of a short, near constant length. The performance of swine was tested in 40 trials under three different spacings: consecutively (40 X 1 ), 20 per day (20 X 2 ) , and 10 per day (10 X 4 ) . Although spacing would be expected to increase performance, more Ss could be tested under massed training. If the latter approached spaced training in sensitivity to individual differences, it would be preferable. Sensitivity to individual differences was defined as maximum when the average percentage of avoidances for a set of trials was 50%, since the variance of binomial data is maximum when p = q = 1/2.

Sperm production in swine after exposure to x-irradiation.

The number of sperm per collection was followed for one year in swine exposed to 0, 300, 600, and 900 r of radiation directed to the testicles. The general response pattern in swine conforms to that outlined for other mammals. About 60 days has been estimated as the interval from primary spermatocyte to sperm in the ejaculate. These data indicate that the general recovery pattern, as measured by sperm number per collection between 70 and 300 days, is linearly related to dose on a logarithmic plot. This suggests that recovery is a function of the number of surviving spermatogonia. The length of time required for recovery to fertility appears to be longer in swine than in mice.

RANDOMIZATION TESTS FOR COMPARING SURVIVAL CURVES

SUMMARY The paper deals with a study of data from work in swine concerning the genetic effects of paternal irradiation on survival in the first generation. The randomization test procedure was taken as the basis for evaluation of the results because of the inherently complex correlational structure of the data. Three ways in which this procedure can be applied are described and related to the actual conduct of the experiment. A brief statement of the actual results is given.

Effect of Cream of Tartar Level and Egg White Temperature on Angel Food Cake Quality

The effects of amount of cream of tartar, time of cream of tartar addition, and egg white temperature were evaluated with angel food cakes. Two replications of each of 12 treatments were used: factorial combinations of three levels of cream of tartar (representing 1/12, 1/8, or 1/4 tsp per egg white), two times of cream of tartar addition (before beating or at foamy stage), and two egg white temperatures (2° or 22°C). Increased cream of tartar decreased pH; increased specific gravity, cake slice area, and tenderness; and caused whiter interior crumb and darker exterior crust. Cakes made with 22°C (vs. 2°C) egg whites had increased exterior yellow color, decreased specific gravity after flour addition, and decreased preference. Cold egg whites did not decrease cake quality, eliminating the need to warm eggs with attending bacterial risk and decreasing preproduction time.

Birth weight in pigs descended from irradiated spermatogonia

Abstract Birth weights of individual descending from irradiated spermatogonia were studied in 2 breeds of domestic pigs. The data included measurement on 30965 pigs born between 1960 and 1966 on a single farm. The average birth weight was 1.3 kg. The weights were adjusted for season of birth, litter size, parity and sex, and the adjusted weights were analyzed for the effect of paternal exposure to 300 R X-irradiation. Pigs from irradiated sires were 0.003 kg lighter than the contemporary controls, a difference of approximately half of the standard error and representing only 0.2% of the total variance. The absence of any important changes in the average birth weight ascribable to radiation was accompanied by a lack of detechable differences in the range or variance. Genetic control of the birth weight was evidenced by distinct breed differences, but no additive genetic variance was detected within the breeds. A correlation of +0.3 among the birth weights of litter mates was probably the result of common uterine environment, with possible contributions from nonadditive genetic variance. The mutations induced in the spermatogonia by the radiation treatment either had no influence on birth weight or were largely recessive.