ABSTRACT
A routine method to determine the presence of partly environmentally relevant trace elements Al, Be, Cd, Co, Cr, Cu, Fe, Mn, Ni and Pb in lung tissue is described. The stages of process are preparation of samples conforming to the analysis material, decomposition, and subsequent trace determination by atomic absorption spectrometry. The results obtained from 125 samples show that chemical analysis is an effective aid in identifying and substantiating occupational risks.
Subject(s)
Lung/analysis , Metals/analysis , Aluminum/analysis , Cadmium/analysis , Chromium/analysis , Dust , Environmental Exposure , Humans , Iron/analysis , Manganese/analysis , Occupational Diseases/diagnosis , Siderosis/diagnosis , SmokingABSTRACT
Feeding behavior of five Holstein steers fed a complete mixed ration was studied by use of individual, electronically controlled feeding behavior units. Both individual meal and daily behavioral parameters were measured. Number of meals, size of each individual meal, time spent eating, and intervals between meals were measured. Eating rates were then calculated. Diurnal feeding patterns were observed with 60.9% of the meals occurring between 0600 and 1800 h. For individual meals, body weight accounted for less than 30% of the variation in meal size. Average meal size was 414.5 g. Respective means for overall meal duration, actual meal duration, overall eating rate, and actual eating rate were 20.3 min, 13.7 min, 23.1 g/min, and 30.0 g/min. Meal size per body weight (g/kg or g/kg.75) was relatively constant during observation. Both increased eating rate and increased meal length were associated with larger meals. However, eating rate tended to plateau while meal length continued to increase with larger meals. Steers consumed 10.01 meals per day while total daily overall meal duration and actual meal duration were 220.9 and 156.4 min.
Subject(s)
Animal Feed , Cattle/physiology , Feeding Behavior/physiology , Animals , Circadian Rhythm , Diet , Male , Time FactorsABSTRACT
Twenty-four Holstein cows were fed mixed diets of alfalfa hay and concentrate in a series of periods to determine the relationship between caloric density (mcal digestible energy/liter) of the diet and energy intake. Five diets with caloric densities of .58, .63, .68, .84, and 1.17 (as-fed form) were used. Steers were fed the diets in digestion trials to determine maintenance digestibility. Intake of digestible energy was adjusted for intake. Means of digestible energy intakes (kcal/day per kg. 75) were: 291.7, 324.0, 370.0, 371.4, and 369.1 for diets with caloric densities of .58, .63, .68, .68, .84, and 1.17. Physical fill was limiting for the two most dilute diets. The diet with caloric density of .68 represented the point above which physiological regulation was employed by the animals. The relationship between digestible energy intake (kcal/day per kg-75) body weight (Y) and caloric density (mcal/liter dry matter, as fed form) (X) was Y = 759.2X-148.4, simple correlation .99, for diets with caloric densities of .58, .63, and .68. Potential uses of this relationship in maximizing forage utilization and formulating diets to meet specific energy requirements are cited.
