Masters Theses

Date of Award

8-1982

Degree Type

Thesis

Degree Name

Master of Science

Major

Animal Science

Major Professor

Robert R. Shrode

Committee Members

James B. McLaren, E. R. Lidvall

Abstract

Over a ten-year period (l970), blood types, weaning and postweaning weights and gains and body measurements have been recorded from animals in the Angus herd at the University of Tennessee Plateau Experiment Station. Analyses of blood group frequencies revealed that either random genetic drift or changes and/or additions in blood typing procedures could be an important consideration in assessing trends in the herd. The herd became infected with brucellosis in 1976, and eradication was accomplished in I98O. Impressively low probabilities (.12 to .16) of chance occurrence of greater chi-square values were obtained in the B, C, and S blood group systems and in the blood serum transferrin system when chi-square was calculated using the observed frequency of reactors to the brucellosis test in the entire herd as a basis for calculating expected numbers of reactors in each blood group within a system. Even though these probabilities are greater than the traditional .05 significance level, they constitute reasonably strong evidence for sane association of frequency of brucellosis reactors with blood type. Analyses of variance were performed on adjusted weaning and postweaning weights, average daily gains and body measurements to determine if any associations existed with blood types within a system. The effects of sire within year were removed from all analyses and, where applicable, data were adjusted to remove variation due to differences in age of dam, sex of calf, and age of calf. Significant (P< .05 or P< .01) differences were found among least-squares means of average daily gains of cattle of different types within the S system and within the blood serum transferrin system, among least-squares means of adjusted weaning weights in the Z system and transferrins and among least-squares means of adjusted postweaning weights in the S system. Significant (P< .05 or P< .01) differences were found among least-squares means of various body measurements of cattle of different types within the F-V, J and S blood group systems. Observations were divided within blood group systems into two large classes of heterozygous and homozygous blood types and analyses of variance were performed with the same quantitative variables mentioned above as dependent variables. Significant (P< .05 or P< .01) differences between homozygotes and heterozygotes were found in the S and Z systems with respect to average daily gains and adjusted weaning and postweaning weights, and, within the M and S systems, differences were found with respect to various body measurements. In a comparison of observed and expected heterozygosis within the F-V and R'-S' systems. no significant differences were found in any year with respect to the F-V system. Significant differences were found in years 1975 to 1979 within the R'-S' system, but due to unreliability of the blood typing procedures in this system, no definite conclusion can be drawn.

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