Three methods of feeding calves were compared as follows: 1) milk replacer only with restricted movement, 2) milk replacer only with freedom of movement, and 3) hay, grain, and water with freedom of movement. No significant differences were noted for variables of acid-base balance (sampled while resting). An Fe deficiency, microcytic, hypochromic anemia, developed in the calves receiving milk replacer only. Average daily gain, carcass grade, and sale price were superior for calves receiving only milk replacer with freedom of movement as compared with those with restricted movement. A fourth method (calves nursing cows), represented by calves having a different origin, was compared as a supplemental group. Absolute numbers for lymphocyte and neutrophils were significantly higher for calves nursing cows than for calves reared by the other methods.

The injection of iron-dextran into beef calves at an early age immediately increased values for erythrocyte (RBC) numbers, hemoglobin (Hb) concentration, packed cell volume (PCV), mean corpuscular hemoglobin (MCH) and mean corpuscular volume (MCV), even though the calves were not anemic. There were no significant differences in average daily gain (ADG) from birth through 15 wk between those that were injected and those that were not injected. Hereford calves had lower values for PCV, Hb, MCH and MCV than Angus and crossbred calves, and both Hereford and Angus calves had lesser body weight and slower ADG than crossbred calves. Serum iron (Fe) concentrations were higher in calves born in the spring and pastured in the summer than in calves born in late summer and fall and pastured in the fall. The serum Fe concentration of calves at first sampling (during first week of life) was positively correlated with their weight at that and subsequent times to 15 wk. Mean corpuscular volume and MCH in cows before calving were positively correlated with the MCV and MCH in their calves at first sampling. Serum Fe concentration in cows before calving was negatively correlated with the ADG of their calves through 15 wk.

The objectives of this research were to observe the effects of increased K in the diets of growing tom turkeys from 6 to 18 wk of age on body weight, feed-to-gain ratio, and leg weakness; to study the effects of time and temperature of blood storage after sampling and before centrifugation on plasma K concentration; and to evaluate plasma creatine kinase activity as an indicator of leg weakness. Male Nicholas White turkeys were fed corn-soybean meal based starter and grower diets from 1 d to 6 wk of age. At this time, each of three dietary treatments was assigned randomly to three pens of toms, 30 toms per pen. The dietary treatments consisted of 1) corn-soybean meal control (control) diets, 2) corn-soybean meal diets supplemented with 25% more K than the control diets contained (Mod K), and 3) corn-soybean meal diets supplemented with 50% more K than the control diets (High K). Potassium carbonate was used as the source of supplemental K for the Mod K and High K diets. Calculated K concentrations of the control diets fed from 6 to 9, 9 to 12, 12 to 15, and 15 to 18 wk were 0.84, 0.74, 0.57, and 0.54%, respectively. Results of laboratory analysis of the diets agreed closely with the calculated values. By 12 wk, toms fed the High K diets weighed less (P = 0.018) than toms fed the control diets, and this difference was still evident at 18 wk (P = 0.013), even though the High K groups were changed to the control diets at 12 wk. Toms fed the Mod K diets also tended to weigh less at 16 and 18 wk than those fed the control diets, however, the diet effect at the latter time was not significant (P > 0.05). There were no consistent effects of dietary K on feed efficiency. Total incidence of leg weakness at 12 wk was greater (P = 0.015) among toms fed Mod K and High K diets than for those toms fed the control diets. These results show that dietary K concentrations greater than those usually present in corn-soybean meal based diets for growing turkeys should be avoided. Increases in dietary K concentrations were associated with increases in plasma K concentration. Storage of blood after sampling and before centrifugation decreases the plasma concentration of K. The decrease is minimized when ambient temperature of storage is decreased. Accordingly, blood should be centrifuged immediately after sampling for accurate measurement of plasma K concentration. Plasma creatine kinase activity is not a good indicator of associated leg weakness unless physical activity and stress can be controlled before blood sampling.

No abstract

The objectives of this research were to evaluate the effects of thermal panting in domestic turkeys on arterial blood values for the acid-base variables, pH(a), bicarbonate concentration ([HCO(-) (3)](a)), partial pressure of carbon dioxide (P(a)CO(2)), and hemoglobin concentration [Hb]. In addition, body temperature and partial pressure of oxygen (P(a)O(2)) were measured to determine the effectiveness of panting in their control. Nine adult (23 wk) broad-breasted white turkey toms, all from the same hatch and reared contemporaneously in the same facility, were acclimated to room conditions of 19 degrees C and 65% RH. After a 1-wk control period, a 3-wk heat-stress period (32 degrees C, 65% RH) was induced, for a heat-stress group of 9 turkeys. Thermal panting began at this time and continued to its end. A 1-wk recovery period followed (19 degrees C, 65% RH) during which panting ceased. An age-matched group of 8 turkeys was similarly acclimated (19 degrees C, 65% RH) but was continued at this level to the end of the experiment. During the heat-stress period, the bicarbonate concentration increased, whereas pH(a) and P(a)CO(2) did not change significantly. Body temperature changes were not significant. Parabronchial ventilation was not compromised by panting, as noted by a significant increase in P(a)O(2). Hemoglobin concentration decreases were significant. The only significant change that occurred for the age-matched group was an increase in [Hb]. Domestic turkeys, reared in confinement, have the ability to resist changes in blood pH and prevent the development of respiratory alkalosis while panting in response to thermal stress. Normal body temperature and oxygenation of the blood are also maintained.