Measurements Of Basal Metabolic Rate Research Articles

SIZE DETERMINANTS IN TERRITORIES WITH INFLEXIBLE BOUNDARIES: MANIPULATION EXPERIMENTS ON WHITE-WINGED TRUMPETERS’ TERRITORIES

We investigated determinants of territory size in White-winged Trumpeters (Psophia leucoptera), frugivorous, cooperatively breeding birds that defend large, permanent, all-purpose territories in lowland Amazonian rain forest. During a 7-mo period, we measured changes in food density at a site in Manu National Park, Peru, and conducted full-day focal samples on individuals that allowed us to record daily food intake of territorial birds. We used data from laboratory analyses on energy content of fruit species eaten by trumpeters to calculate a phenology of energy content for food available on territories of focal groups, and to calculate daily energy intake of focal trumpeters. Additionally, we used lab measurements of basal metabolic rate of trumpeters to estimate daily energy requirements of wild trumpeters. Both census and focal sample data suggested that food availability on trumpeter territories varied widely, sometimes greatly exceeding and sometimes falling short of the amount that we calculated was necessary to meet average daily energy requirements of groups. To determine whether trumpeter territory size was related to food density, we conducted fruit removals. Every day, we removed an amount of fruit from the territory that was equivalent to the amount of fruit ingested daily by the focal group during a control period preceding the removal experiment. We conducted removal experiments during periods when food density on territories appeared to be abundant and also when food abundance appeared to be low. Trumpeter food consumption did not change when fruit was removed during periods of resource abundance; however, when experimental removals were conducted during periods of food scarcity, the total energy value of food consumed decreased significantly. These results suggest that food abundance on trumpeter territories sometimes exceeds and sometimes is close to or below the amount needed to meet energy needs of the groups. Based on our data, we propose that territory size of White-winged Trumpeter groups reflects some minimum size needed to provide the group with a baseline level of food intake during seasonal periods of decreased food abundance.

Average daily metabolic rate of rodents: habitat and dietary comparisons

1.Average daily metabolic rate (ADMR) is the metabolizable energy intake required by a caged animal to maintain constant body energy content. Linear regression of standardized, phylogenetically independent contrasts was used to describe the allometric relationship between ADMR and body mass in rodents. It was predicted that desert species would have a lower ADMR than non‐desert species and that granivores would have a lower ADMR than those of herbivores and omnivores. The efficiency of utilization of energy for maintenance was also determined in these species. Here, it was predicted that the efficiency in granivores would be higher than in both herbivores and omnivores and in desert species would be higher than in non‐desert species.2.The regression of the phylogenetic contrasts of ADMR on body mass (mb) for 53 independent data points based on 63 species of rodents was highly significant (P< 0·0001) with an allometric slope of 0·53. Independent comparisons of both basal metabolic rate (BMR) and ADMR showed significantly lower rates in desert than in non‐desert species. There was a trend for granivores to have a lower ADMR per g0.53than either omnivores or herbivores, but this trend is not significant in independent comparisons between the categories. Thus, the predictions in regard to desert and non‐desert habitats were confirmed, and there is a non‐significant trend in the predicted direction with respect to diet. Herbivores and omnivores showed no significant difference in either BMR or ADMR.3.In independent comparisons between categories, there was no evidence for trends in the efficiency of utilization of energy for maintenance (BMR:ADMR ratio orkm) with either habitat or diet categories. Thus, these results are not in agreement with our predictions. Taking simple means,kmequals 0·47±0·21, 0·37±0·12 and 0·56±0·11 for granivores, omnivores and herbivores, respectively, and 0·37±0·12 and 0·55±0·16 for desert and non‐desert mammals, respectively.4.It is recommended that conditions for ADMR measurements be standardized, as is common for basal metabolic rate measurements. This would allow more reliable comparisons among species measured in different laboratories and also provide more accurate estimates of efficiency of utilization of energy.

The nutrient and food intakes of British male dieters aged 16–17 years

Background: There is little information available about the dieting habits of teenage boys. This study aimed to examine the food and nutrient intake of male teenage dieters and compare these with the patterns reported among female dieters.Method: Male dieters aged 16–17 years were isolated from the 1970 Longitudinal Birth Cohort study group. Five hundred and one males who provided a 4‐day unweighed dietary diary, height and weight measurements and appropriate background information.Results: Thirty‐nine subjects (7.8%) both reported dieting and had a ratio of reported energy intakes to estimated basal metabolic rate measurements of less than 1.35. Dieters were taller and heavier than non‐dieters, with mean BMIs of 24.6 and 20.0, respectively, for the two groups. Dieters reported average energy intakes of 9.16 MJ/day compared to intakes of 12.83 MJ/day among non‐dieters, and the percentage of energy provided by protein was higher and that provided by NMES lower among dieters. Reported micronutrient intakes were lower among dieters, with calcium, magnesium, zinc, selenium, iodine, vitamin B6, vitamin C and retinol equivalents the nutrients most vulnerable to reduction in energy intakes. Dieters reported lower intakes of most food groups, but reported intakes of alcohol and meat and meat products were not reduced among dieters.Conclusion: Dieters clearly reported energy intakes which were unlikely to represent levels of intake sufficient to maintain existing weight. The nutrient and food intakes reported by the dieters were likely to reflect either true dieting behaviour during the study period, under‐reporting or a combination of these effects.

Total Energy Expenditure and Physical Activity in Young Chinese Gymnasts

The energy expenditure and hence energy requirements of 12 young Chinese gymnasts attending a specialized school in Beijing were assessed. Total energy expenditure was measured using the doubly labeled water technique and this, in conjunction with measures of basal metabolic rate (BMR), allows the calculation of a physical activity level (PAL). Mean PAL value for the gymnasts was 1.98, which is significantly different from published mean values found in nongymnast children of a similar age. This mean value is equivalent to very heavy levels of physical activity during the periods of training being undertaken. This is the first time that energy expenditure has been noninvasively measured in free-living young gymnasts. The data will be of use to sports scientists and nutritionists alike.

Basal metabolic rate and dietary seasonality among Tibetan nomads.

The results of 51 overnight measurements of basal metabolic rate (BMR) in a sample of pastoral nomads resident permanently in Phala, Tibet Autonomous Region, China, are reported. Past studies demonstrated a culturally driven seasonality of diet, with very low summer and very high winter caloric intake. The study was designed to test the hypothesis that the ability of Phala nomads to subsist on low caloric intake for several summer months without signs of malnutrition is explained by lower summer BMR. However, BMR measurements of 40 nomads 13-69 years of age during the summer and remeasurement of 11 nomads during the winter of 1993 provide no evidence for low summer BMR to compensate for the low summer caloric intake. BMR in both seasons is within the normal range predicted by international equations. The BMR of males does not differ from that of females, and the BMR of females averages 7% higher than predicted. Anthropometric evidence reveals that the Phala nomads accumulate body fat during the winter. It is inferred that this may buffer the summer period of low intake. The pattern of subcutaneous fat accumulation in winter, moreover, may afford slight improvement in physiological cold insulation during the severe winters as a consequence of depositing winter fat on the trunk rather than on the periphery. Thus, the dietary seasonality in Phala is a stress that elicits fluctuation in fat energy stores but not BMR. © 1996 Wiley-Liss, Inc.

Summer acclimatization in the short-tailed field vole, Microtus agrestis.

We investigated the changes that occurred in basal and noradrenaline-induced metabolic rate, body temperature and body mass in short-tailed field voles, Microtus agrestis, during exposure to naturally increasing photoperiod and ambient temperature. These parameters were first measured in winter-acclimatized voles (n = 8) and then in the same voles which had been allowed to seasonally acclimatize to photoperiod and ambient temperature (6 months later). Noradrenaline induced metabolic rate, basal metabolic rate and non-shivering thermogenesis were significantly higher in winter-acclimatized compared to summer-acclimatized voles. There was a significant positive relationship between basal metabolic rate and noradrenaline-induced metabolic rate. Body mass was significantly higher in summer-acclimatized compared to winter-acclimatized voles. There was a significant positive relationship between body mass and noradrenaline-induced metabolic rate in both winter-acclimatized and summer-acclimatized voles; however, there was no relationship between basal metabolic rate and body mass in either seasonal group of voles. Body temperature after measurements of basal metabolic rate was not significantly different in the seasonal cohorts of voles. However, body temperature was significantly higher in winter-acclimatized compared to summer-acclimatized voles after injection of noradrenaline. Previously we have found that a long photoperiod was not a sufficient stimulus to reduce thermogenic capacity in winter-acclimatized voles during cold exposure, since basal metabolic rate increased to compensate for a reduction in regulatory non-shivering thermogenesis. Here we found that a combination of increased ambient temperature and photoperiod did significantly reduce thermogenic capacity in winter-acclimatized voles. This provided evidence that the two aspects of non-shivering thermogenesis, obligatory and regulatory, are stimulated by different exogenous cues. Summer acclimatization in the short-tailed field vole is manifest as a significant decrease in both basal and noradrenaline-induced metabolic rate, combined with a significant increase in body mass.

Intraindividual variation in the basal metabolic rate of women: Effect of the menstrual cycle.

The validity of using the basal metabolic rate (BMR) to calculate an individual's energy requirements is based upon the assumption that the intraindividual variation in BMR is small. Early studies (pre-1940) on BMR in women had shown that the menstrual cycle may have a profound effect, contributing to high levels of intraindividual variation. To investigate this issue further, and to explore whether BMR is indeed a biological constant in women, sequential measurements of BMR were made in women over one menstrual cycle. Two independent studies were undertaken in which the BMR of 12 weight-stable women (not taking the contraceptive pill) was measured every day (excluding weekends) for a period of 5 weeks. The six women participating in the first study were measured using a Douglas bag, while the six subjects in the second study were measured with a Deltatrac (Datex, Helsinki). Nine of the 12 subjects demonstrated a peak in BMR during the late luteal phase of the menstrual cycle, while 8 of the 12 subjects exhibited a fall in BMR after the onset of menstruation. Group analysis of the results indicated that the BMR during the early follicular phase was significantly lower than the BMR during the late luteal phase (Wilcoxon's signed rank test: P < 0.01). The level of intraindividual variation was assessed by calculating the coefficient of variation (CV) for the measurement period. The CV in six of the women exhibited a level of variation comparable to men (2-4%). However, intraindividual variation in the BMR of the other six women was considerably higher (up to 12%). In these six women, therefore, BMR may not be considered a biological constant. All available data on sequential measurements of BMR in fertile women were collated from the literature for the first time, and statistically analyzed. BMR during the early follicular phase was found to be significantly lower (P < 0.05) than during the late luteal phase. Further work on the biological constancy of BMR in women and the impact of the menstrual cycle on BMR is required. This area is of particular importance given the fact that the energy requirements of both individuals and populations are now calculated using the BMR. © 1996 Wiley-Liss, Inc.

Basal metabolic rate of Colombian children 2–16 y of age: ethnicity and nutritional status

Measurements of basal metabolic rate (BMR) were made in 528 children 2-16 y of age living in underprivileged areas of the city of Cali, Colombia (153 control and 186 undernourished boys, 93 control and 96 undernourished girls). The data are related to BMR calculated from the equations of Schofield and to estimates of the lean body mass (LBM). The ethnic composition of the subjects was 80% mestizo (mixed European and South Amerindian ancestry), 15% black, and 5% white. The data do not show any variations due to race in these subjects. The Schofield equations overestimate the BMR of boys by approximately 6% whereas the estimation of BMR in girls is not significantly different from measured values. More than 65% of the variation in BMR of both nutritionally normal and undernourished boys and girls is explained by variation in body size as estimated by the LBM.

Estimates of metabolic adaptation in women living in developing countries: technical limitations

The measurement of food intake has long been used to describe 'adaptation' to low energy intakes in certain tropical peoples. However, the methods available to quantify food intake are unlikely to reflect accurately real energy intakes in free living peoples. Alternatively, estimating energy expenditure shows some promise--particularly the measurement of basal metabolic rate (BMR). The BMR may be measured effectively in males, but females show wide intra-individual variation in BMR during their menstrual cycle, which makes BMR measurements more difficult to interpret in the context of adaptation. The use of double-labelled water may be the only method suitable to quantify and define 'adaptation' to low intakes in women.

Variation in Time and Energy Budgets of Breeding Wheatears

Abstract We examined the sources of variation in time allocation of males and females of the wheatear (Oenanthe oenanthe) on the island of Öland, South Sweden, throughout the breeding season. We quantified rates of prey capture attempts and specified foraging methods used. From respirometric measurements of basal metabolic rate and temperature-dependent metabolism on captive wheatears, and after having made certain assumptions abour the costs of different activities, we estimated the energy budgets of both sexes during the different reproductive phases. Males and females differed in their time allocation and foraging rates during prelaying, laying, and incubation, but not while feeding grown nestlings. During prelaying and laying, females foraged at higher rates than males; they also perched less often, gleaned more on the ground, and flew less. Although incubation was the least costly phase for females because of their low activity, high foraging rates yet indicated that this phase may represent an energetic bottleneck as a result of restrictions on foraging time. After incubation, females switched from foraging mostly on the ground during early breeding phases to hunting from elevated perches during later breeding phases. The shift in foraging behavior corresponds to the drastic changes in time allocation. Relatively high daily energy expenditures (DEE) by brooding females coupled with low foraging rates may explain the observed posthatching body mass losses. In both sexes, high required energy acquisition rates when feeding large nestlings indicate that parent wheatears then may encounter another energetic bottleneck. Postfledging was the least costly phase because, compared with the period of feeding nestlings, there were reduced thermostatic costs and a marked drop in flight time. Males and females had similar DEEs during prelaying, laying and nestling feeding, but females had lower needs during incubation. The elective components of energy budgets during nestling feeding, as well as the estimated sum of the elective components throughout the season, were 12% higher for males than for females. The elective components of the energy budgets varied more than the obligatory components (basal + thermoregulation), especially in females, and were more important in determining the variation of DEE throughout the breeding season. A validation study with doubly labeled water indicated that the energy budget model used was accurate enough for comparisons between sexes or breeding phases, but not for measuring individual variation.

Energy Requirements of Pregnancy

The energy requirements of pregnancy is a topic of considerable uncertainty because the apparent energy costs--to supply the energy required for the changes in maternal and fetal tissues and to cover the increase in basal metabolic rate (BMR), amounting to the equivalent of an extra 250-300 kcal/day--are rarely paralleled by actual findings. However, few studies have investigated this problem in a controlled longitudinal and statistically acceptable fashion. In this study, measurements of energy intake, BMR, body weight and fatness, physical activity, and mechanical efficiency of movement were made on 162 women in Scotland at 2- to 4-wk intervals throughout pregnancy, and data from 98 of these women were also obtained in the prepregnant state. Data from a parallel study in the Netherlands are also given. The gains in body weight, fatness, the fetal and placental weights, and the increase in BMR were all at the normal expected values. However, increases in energy intake were on the order of only 100 kcal/day during the second and third trimesters. Comparatively small reductions in physical activity, which would be difficult to measure precisely, are described that could account for the difference between actual energy intake and the energy costs of pregnancy.

Energy Requirements of Pregnancy

The energy requirements of pregnancy is a topic of considerable uncertainty because the apparent energy costs--to supply the energy required for the changes in maternal and fetal tissues and to cover the increase in BMR (basal metabolic rate), amounting to the equivalent of an extra 250-300 kcal/d--are rarely paralleled by actual findings. However few studies have investigated this problem in a controlled, longitudinal, and statistically acceptable fashion. In the present study, measurements of energy intake, BMR, body weight and fatness, physical activity, and mechanical efficiency of movement, were made on 162 women in Scotland at 2 to 4 weekly intervals throughout pregnancy and data from 98 of these women were also obtained in the pre-pregnant state. Data from a parallel study in Holland are also given. The gains in body weight, fatness, the fetal and placental weights, and the increase in BMR were all at the normal expected values. However, increases in energy intake were of the order of only 100 kcal/d during the second and third trimesters. Comparatively small reductions in physical activity, which would be very difficult to measure precisely, are described which could account for the difference between actual energy intakes and the energy costs of pregnancy.

Basal metabolic rate and physique of Gurkha and British soldiers stationed in Britain

Measurements of basal metabolic rate (BMR) and physique were made on Gurkha soldiers stationed in Britain, and on British controls matched by body weight and occupational background. Gurkhas were significantly shorter, with greater body mass index, calf circumference and subscapular skinfold thickness than the European controls, although there was no difference in BMR between the two groups. For the Gurkhas, linear regression analysis incorporating factors which may influence BMR showed a positive relationship between the length of time since leaving Nepal and BMR, supporting the view that Asians living in temperate regions have higher BMR than those living in the tropics.

Avian basal metabolic rates: their association with body composition and energy expenditure in nature

Measurements of basal metabolic rate (BMR), body water, fat, and lean dry mass of different organs were obtained in 22 bird species, ranging from 10.8 to 1,253 g body mass. Residuals of BMR (after subtracting BMR allometrically predicted from body mass) were positively correlated with residuals of lean dry heart and kidney mass. Measurements of both BMR and the daily energy expenditure of parent birds (DEEpar) during the period of nestling care as assessed by labeled-water turnover were collected from the literature for 26 altricial bird species. The allometric relationships with body mass in this data set were: log BMR (W) = -1.385 + 0.684 log mass (g) [fraction of variance (r2) = 0.973] and log DEEpar (W) = -0.797 + 0.659 log mass (g) (r2 = 0.967). Residuals of log BMR and log DEEpar were positively correlated with each other. The parallel regressions and correlation of residuals lead to reduced variance in the ratio of BMR/DEEpar (mean 0.301; SD 0.086). We suggest that natural selection has led to an adjustment of the size of organs (such as heart and kidney) involved in sustaining energy metabolism at the DEE maximized during parental care and that size-independent variation in BMR reflects the relative size of this highly metabolically active machinery. These relationships of BMR lead to new interpretations of the decline in mass-specific BMR with increasing body size and decreasing latitude and of the difference in mass-specific BMR between birds and mammals.

Energetic cost of standard activities in Gurkha and British soldiers

Measurements of basal metabolic rate and energy expenditure at lying, sitting, standing, and performing a step test at four levels of exercise, were made on Gurkha soldiers stationed in Britain and on British controls matched by body weight and occupational background. There was no significant difference in basal metabolic rate (BMR), nor in the energy cost of lying, sitting and standing between the two groups. Gurhas showed significantly lower gross and net energy expenditure, and so significantly greater net mechanical efficiency, at the lower levels of step exercise. The ratio of gross energy expenditure to BMR was lower in Gurkhas at the lowest rates of stepping compared with the British controls. These results suggest that the energy cost of some physical activities expressed as multiples of BMR may not be constant across populations.

The influence of different methods on basal metabolic rate measurements in human subjects

While collating basal metabolic rate (BMR) measurements made worldwide it becomes important to know how different instruments compare with each other and whether errors in methodology could account for the differences in BMRs measured. BMRs of 34 healthy individuals were measured by using five different instruments in various combinations. Results show that energy outputs were comparable between the oxylog. Hartmann and Braun Metabolator, ventilated tent and hood, and whole-body indirect calorimeter: small differences, if any, were not statistically significant. However, significant interactions existed between subjects with the ventilated tent and hood and calorimeter when measurements were taken in subjects who were unaccustomed to the apparatus. When converting O2-consumption measurements to energy output, some instruments make assumptions that introduce a variable error in the final result, which may lead to systematic errors during the compilation of large databases of human BMRs.

Basal metabolic rate in healthy Down's syndrome adults

Basal metabolic rate (BMR) was measured on 2 consecutive days with an open-circuit, indirect calorimeter in 16 healthy subjects with trisomy 21 Down's syndrome (DS) aged 22-35 years and 11 healthy control volunteers aged 20-31 years. BMR measurements did not differ on consecutive days in either the DS or control groups. Absolute BMR, BMR corrected for surface area, and BMR corrected for lean body mass did not differ between the DS subjects and the volunteers. The per cent of predicted BMR also did not differ between the two groups. These results suggest that systems controlling basal metabolism are not affected by extra genomic material from chromosome 21.

Basal Metabolic Rate in the Gray Wolf in Poland

Basal metabolic rate (BMR) was measured in 12 gray wolves (Canis lupus) (t body wt = 33.0 kg) in winter. The BMR averaged 8.08 liters O,/hour; resting metabolic rate after feeding was about 45% higher. It is suggested that the factorial metabolic scope value (Vo2max/BMR) in the wolf is at least 3 x higher than an average for various mammals and may constitute an adaptation to the predatory way of life. J. WILDL. MANAGE. 51(4):800-801 Measurements of BMR provide a baseline to estimate energy requirements of free-living animals. These measurements are fundamental to a quantitative analysis of predator-prey interactions. BMR values are available for several species of canids (Hennemann et al. 1983). However, BMR has not been measured in the gray wolf, the largest and most widely distributed species of its family. Only very rough estimates of energy requirements of wolves have been made (Mech and Frenzel 1971, Kolenosky 1972, Mech 1977). We thank J. Weiner for useful comments on the manuscript, R. Tertil for his contribution to the final condition of the manuscript, and T. Kapuicinski for assistance in handling wolves. This study was supported by Grant MR-II-19. MATERIALS AND METHODS Twelve captive-born wolves were used in the metabolic measurements conducted in southeastern Poland in January 1986. The wolves, aged 1-12 years, represented both sexes and a wide range of body weights (Table 1). The animals were kept outdoors in large (100-400 m2) enclosures under quasi-natural conditions and fed a diet of raw venison. Wolves were fasted for 48-72 hours before BMR measurements. Animals were confined in metal cages (120 x 40 x 80 cm), weighed, and pl ced in a darkened room. The cages were covered by a plastic respiratory chamber. Atmospheric air was pumped through the respiratory chamber at flow rates between 37 and 39 liters/min (STPD). Calcium chloride was used to absorb water vapor from the excurrent airflow and the fractional concentration of 02 was measured with a Spirolyt II paramagnetic oxygen analyzer. The analyzer was calibrated against gas mixtures supplied by the manufacturer. The rate of 02 consumption was calculated using appropriate formulas (Fedak et al. 1981), assuming the respiratory quotient values of fasted and fed wolves are 0.7 and 1.0, respectively (Kleiber 1961). Each experiment lasted 24 or 48 hours, and O2-consumption measurements were performed at 2-4-hour intervals and lasted 0.5-2 hours. The measurements were carried out at temperatures between 3 and 25 C. After 12 or 24 hours from the start of an experiment, wolves were given about 1.5 kg of venison and the recordings of 02 consumption were continued. The results obtained were converted to standard conditions (STPD) and expressed in liters O2/hour. The statistical significance (P = 0.05) of differences between BMR's of males and females, and between adult and young, was calculated by analysis of covariance. Table 1. Mean (.R + SD) body weight (BW), basal metabolic rate (BMR), and the after-feeding resting metabolic rate (RMR) in captive-born gray wolves in southeastern Poland, 1986. BW BMR RMR (kg) (10,/hour) (10,/hour)

The nutritional and metabolic effects of a carbohydrate-rich diet in a glycogen supercompensation training regimen

It has been suggested that glycogen depletion followed by a protein-fat diet and a carbohydrate-rich diet improves performance. This study was designed to determine the nutritional and metabolic effects of a carbohydrate-rich diet in a glycogen supercompensation training regimen. Four male subjects participated in a 5-week protocol of which the first 3 weeks were devoted to a control period and the last 2 weeks to the experimental phase of the study. The variables measured before, during, and following the experimental phase included anthropometric and basal metabolic rate measurements, urinary and serum analysis for vitamins, SMA 12/60 blood profile and aerobic performance (VO2max). Results indicated an appreciable modification of the metabolic and nutritional profile of the subjects as a result of the diets. During the protein-fat diet there was a decrease in serum glucose and resting respiratory quotient and an increase in cholesterol, blood urea nitrogen, riboflavin, and N1-methylnicotinamide excretion. Subsequent to the carbohydrate-rich diet there was an increase in triglycerides and vitamin C, riboflavin, and thiamin excretion while there was a decrease in serum blood urea nitrogen, and N1-methylnicotinamide excretion. Aerobic performance was slightly decreased and the mean postexercise lactate levels were slightly higher after the carbohydrate-rich diet. It was hypothesized that the reduced niacin intake during the carbohydrate-rich diet may hamper the aerobic oxidative pathways.

Basal Metabolic Rate, Pulse Rate, Respiration Rate, and Certain Organ Weights in Relation to Neonatal Iron Deficiency Anemia in Dairy Calves

Summary An effort was made to determine how and to what extent calves born with iron-deficiency anemia were able to compensate physiologically for their low oxyhemoglobin content. Pulse rate was significantly elevated in nine anemic calves (oxyhemoglobin 9 g/100ml) throughout the 3-wk period of observation following birth. No differences in respiration rate were noted between the two groups of calves. Measurements of basal metabolic rate (BMR) soon after birth and before feeding were significantly higher in the anemic calves. Thereafter, differences in BMR were not significantly different to 3 wk of age. No difference was found in the spleen weight of 22 normal male calves compared with nine male anemic calves slaughtered at birth. Average liver weight of the anemic calves was significantly higher. Heart weights obtained on four of the anemic calves were not different from eight normal calves with which they were compared. Apparently sufficient physiological compensation resulted through increased pulse rate and perhaps other unmeasured effects to allow the normal development of the anemic newborn calves, under the environmental conditions that existed.