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D F Holleman

Publications and source records attributed to D F Holleman.

17 recordsLinked to original sources
PubMed1988

Analytical procedures for estimating milk intake and yield in steady-state and nonsteady-state systems.

A tracer method for determining milk intake, introduced earlier, was based on the transfer of tritiated water from a lactating female to a nuring offspring via milk. The analysis of the tracer data assumed a steady state system, i.e., the total body water of the offspring was assumed to be constant over the measurement period. This paper discusses the potential errors in the milk intake estimates in applications where steady-state does not exist. Three analytical procedures are considered and include the application of 1) steady state equations for a nonsteady-state system, 2) analytical solutions to nonsteady-state equations, and 3) a computer modeling program, SAAM-27. The application of steady-state equations is the simplest procedure and may yield acceptable estimates if the growth rate of the nuring offspring is low. The analytical solution procedure yields acceptable estimates at high growth rates of the nursing offspring but becomes unacceptable at low growth rates. The SAAM program requires sophisticated computer hardware and programming; however, the procedure yields the best estimates of milk intake in applications ranging from steady-state to high growth rates.

Animals↗
PubMed1986

Validation of doubly labeled water method using a ruminant.

CO2 production (CDP, ml CO2 . g-1 . h-1) by captive caribou and reindeer (Rangifer tarandus) was measured using the doubly labeled water method (3H2O and H2(18)O) and compared with CO2 expiration rates (VCO2), adjusted for CO2 losses in CH4 and urine, as determined by open-circuit respirometry. CDP calculated from samples of blood or urine from a reindeer in winter was 1-3% higher than the adjusted VCO2. Differences between values derived by the two methods of 5-20% were found in summer trials with caribou. None of these differences were statistically significant (P greater than 0.05). Differences in summer could in part be explained by the net deposition of 3H, 18O, and unlabeled CO2 in antlers and other growing tissues. Total body water volumes calculated from 3H2O dilution were up to 15% higher than those calculated from H2(18)O dilution. The doubly labeled water method appears to be a reasonably accurate method for measuring CDP by caribou and reindeer in winter when growth rates are low, but the method may overestimate CDP by rapidly growing and/or fattening animals.

Animals↗
PubMed1978

Postnatal changes in body composition of laboratory maintained brown lemmings, Lemmus sibiricus.

Postnatal changes in the body composition components, namely, body water, fat-free dry solids, and fat, were determined for laboratory-maintained brown lemmings, Lemmus sibiricus. The proportion of body water decreased while the proportion of fat-free dry solids and fat increased from birth to approximately 15 weeks of age. From 20 through 80 weeks of age, the proportions of all body composition components as well as total body weight remained relatively constant. Body composition components were more closely correlated with body weight than with chronologic age. As a function of body weight, body water decreased while fat-free dry solids and fat increased. Body fat was the most variable body composition component as related both to body weight and chronologic age. The von Bertalanffy growth equation and the differential growth equation were used to describe the body composition component data as related to chronologic age and body weight, respectively.

Animals↗