Effect of Aldrin, Urea and DES on the Physiology of Beef Heifers Fed a Concentrate or Roughage Diet

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Abstract
THIRTY-TWO Angus heifer calves were used in a 24 factorial experiment to study the effects of aldrin, urea, DES and a roughage vs. a concentrate diet on EKG patterns, heart and respiratory rates, and blood lactic acid, minerals, proteins and PCV. Calves were placed on experiment at 14 days of age. Comparisons were: urea vs. soybean meal from the start of the experiment; aldrin fed daily at 1.0 mg/kg body weight vs. no aldrin from 28 days; all-concentrate diet vs. an 88% roughage diet from 84 days; and 12 mg DES implanted at 168 and again at 336 days vs. no implant. The last samples were collected at 476 days on experiment. A short-term toxicological effect of aldrin was indicated by a fluctuation of the T amplitude during the first few months following the initial feeding of aldrin. Continuous feeding of aldrin increased the QRS interval, suggesting a prolonged transmission of electrical response through the ventricals. Concurrently, the concentration of lactic acid in jugular blood was greater in the aldrin fed heifers. Prolonged P and P-R intervals were noted in heifers fed urea. DES implant increased heart rate, the greatest increase occurring 1 month after the initial implant. During the latter part of the study, serum albumin was significantly lower and serum gamma globulin higher in concentrate fed heifers than in the roughage fed heifers. There appeared to be little interaction among the four main effects of the study. A positive relationship existed between seasonal temperature and respiratory rate and to a lesser degree between seasonal temperature and blood lactic acid. The latter relationship appeared greater in the aldrin fed heifers. The study indicated that continuous feeding of both urea and aldrin caused small changes in the activity of the heart muscle and that aldrin caused an elevation of blood lactic acid. These changes may be indicative of a chronic toxicity; however, the biological significance of these observed changes is unknown at the present time. Copyright © 1972. American Society of Animal Science . Copyright 1972 by American Society of Animal Science.