GIL, Enrique. Comparative Evaluation of 4 acetoamido antipyrine and Specific Gravity Techniques with Determined Physical and Chemical Composition in Beef Cattle. Dissertation Abstracts. 1968

Abstract of Dissertation
Two indirect methods for determining body composition of cattle were studied: a dye dilution technique (4 acetamido antipyrine) and specific gravity (by water displacement).
The measurements obtained by both indirect techniques were evaluated against detailed body composition data determined by direct analysis of body tissues. 18 Herefords., in three age groups: 5, 12 and 18 month; with two bulls, two steers, and two heifers per group were used. The body was divided for analysis into seven large sampling units: (1) abdominal and thoracic organs and empty digestive tract; (2) head, hide ears, tail, and metacarpals and tarsals; (3) carcass, right fore quarter; (4) carcass, right hind quarter; (5) carcass, left fore quarter minus the bone; (6) carcass, left hind quarter minus the bone and (7) bones of the left side of the carcass. Analysis of variance on the chemical analysis of each anatomical unit studied was computed for sex, age, weight differences within age groups and sex-age interactions. Prediction formulas interrelating different body variables were calculated.
4-acetamido antipyrine (4-AAA) was utilised to estimate empty body water in cattle. Procedures for performing the quantitative injection of the drug were detailed; formulas for determining correct 4-AAA dosage and calculating percent body are explained stepwise. The distribution and disappearance rate of 4-AAA was determined. A linear function was found between concentration of 4-AAA and time 300 minutes after injection. Reasons are given to tentatively explain this phenomenon. Highly significant prediction equations relating 4-AAA water space to body composition were calculated.
Specific gravity measurements were determined on quarter carcasses and the values divided for analysis into six groups according to their fat content. Only samples with more than 30 percent fat showed any fat-density relationship. The influence of bone on density measurements was found to be high and superior to fat on all except those units high in fat. The importance of the water-carcass temperature relationship and the use of chilled carcasses was studied and found to be essential for accuracy of the underwater measurements.
The specific volume of the quarter carcasses were mathematically determined from the chemical composition of the samples. The correlation with carcass fat was found to increase as carcass fat levels increased. The same tendency was observed when calculated specific volume was compared to observed specific volume. The mean water content of the carcass lean (73.79%) was found to be exceptionally constant and only slightly influenced by age.
Although the density technique offers the advantage of ease in determining the fat content of large samples its reliability is seriously questioned when used on samples of low fat contents.

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