Lung volumes in giraffes, Giraffa camelopardalis.

We have measured lung mass and trachea dimensions in 46 giraffes of both genders ranging in body mass from 147 kg to 1441 kg, calculated static and dynamic lung volumes, and developed allometric equations that relate changes in them to growth. We found that relative lung mass is 0.6±0.2% of body mass which is significantly less than it is in other mammals (1.1±0.1%). Total lung volume is significantly smaller (46.2±5.9 mL kg⁻¹) than in similar sized mammals (75.0±2.1 mL kg⁻¹). The lung volume:body mass ratio decreases during growth rather than increase as it does in other mammals. Tracheal diameter is significantly narrower than in similar sized mammals but dead space volume (2.9±0.5 mL kg⁻¹) is larger than in similar sized mammals (2.4±0.1 mL kg⁻¹). Our calculations suggest that tidal volume (10.5±0.2 mL kg⁻¹) is increased compared to that in other mammals(10.0±0.2 mL kg⁻¹) so that the dead space:tidal volume ratio is the same as in other mammals. Calculated Functional Residual Capacity is smaller than predicted (53.4±3.5 vs 33.7±0.6 mL kg⁻¹) as is Expiratory Reserve Volume (47.4±2.6 vs 27.2±1.0 mL kg⁻¹, but Residual Volume (6.0±0.4 mL kg⁻¹) is the same as in other similar sized mammals (6.0±0.9 mL kg⁻¹. Our calculations suggest that Inspiratory Reserve Volume is significantly reduced in size (11.6±1.6 vs 3.8±2.4 mL kg⁻¹), and, if so, the capacity to increase tidal volume is limited. Calculated dynamic lung volumes were the same as in similar sized mammals. We have concluded that giraffe morphology has resulted in lung volumes that are significantly different to that of similar sized mammals, but these changes do not compromise ventilatory capacity.

An allometric analysis of the giraffe cardiovascular system.

There has been co-evolution of a long neck and high blood pressure in giraffes. How the cardiovascular system (CVS) has adapted to produce a high blood pressure, and how it compares with other similar sized mammals largely is unknown. We have measured body mass and heart structure in 56 giraffes of both genders ranging in body mass from 18 kg to 1500 kg, and developed allometric equations that relate changes in heart dimensions to growth and to cardiovascular function. Predictions made from these equations match measurements made in giraffes. We have found that heart mass increases as body mass increases but it has a relative mass of 0.51+/-0.7% of body mass which is the same as that in other mammals. The left ventricular and interventricular walls are hypertrophied and their thicknesses are linearly related to neck length. Systemic blood pressure increases as body mass and neck length increase and is twice that of mammals of the same body mass. Cardiac output is the same as, but peripheral resistance double that predicted for similar sized mammals. We have concluded that increasing hydrostatic pressure of the column of blood during neck elongation results in cardiac hypertrophy and concurrent hypertrophy of arteriole walls raising peripheral resistance, with an increase in blood pressure following.

Osteophagia provide giraffes with phosphorus and calcium?

The daily requirement for calcium and phosphorus by giraffes to sustain the growth and maintenance of their skeletons is large. The source of sufficient calcium is browse. The source of necessary phosphorus is obscure, but it could be osteophagia, a frequently observed behaviour in giraffes. We have assessed whether bone ingested as a result of osteophagia can be digested in the rumen. Bone samples from cancellous (cervical vertebrae) and dense bones (metacarpal shaft) were immersed in the rumens of five sheep, for a period of up to 30 days, and the effect compared to immersion in distilled water and in artificial saliva for 30 days. Distilled water had no effect on the bones. Dense bone samples were softened by exposure to the saliva and rumen fluid, but did not lose either calcium or phosphorus. In saliva and rumen fluid the cancellous bone samples also softened, and their mass and volume decreased as a result of exposure to saliva, but in neither fluid did they lose significant amounts of calcium and phosphorus. We conclude that although saliva and rumen fluid can soften ingested bones, there is an insignificant digestion of bones in the rumen.

Captive breeding of the white rhinoceros, Ceratotherium simum, and the Cape buffalo, Syncerus caffer.

Breeding records of 40 white rhinoceros and 155 Cape buffalo were analysed. Three rhinoceros cows bred in captivity, themselves conceived for the first time at 84, 87 and 95 months of age, respectively. Rhinoceros cows breed throughout the year. There is no evidence of a relationship between calving interval and month of birth. Calving intervals were normally distributed about the mean of 34 months and there were no significant differences between bulls, cows or sex of calf. There was no difference in the sex ratio of calves born to young cows nor older cows. The male:female ratio of the calves was 1:1. Younger cows did not have shorter birth intervals. Although captive Cape buffaloes breed throughout the year, there is a preponderance of births in midsummer. There was some evidence that larger cows produce heavier calves and that season of birth may influence birth weight. Male calves weighed 41.20 +/- 0.68 kg vs 39.00 +/- 0.73 kg (range 24-60 kg) for female calves but this difference was not significant. Calving intervals were normally distributed about the mean of 395 days and the male:female ratio of the calves was 1:1.2.

Helminths in sympatric populations of mountain reedbuck (Redunca fulvorufula) and gray rhebok (Pelea capreolus) in South Africa.

Helminths of mountain reedbuck (Redunca fulvorufula fulvorufula) and gray rhebok (Pelea capreolus) were investigated in South Africa between June 1999 and February 2002. Forty-one mountain reedbuck were culled at Sterkfontein Dam Nature Reserve over 8 different periods, and 25 mountain reedbuck were culled at Tussen die Riviere Nature Reserve over 3 different periods. A total of 17 kinds of helminths were found at the 2 sites, including 15 nematodes, 1 trematode, and 1 cestode. At Sterkfontein, the most prevalent and abundant species were Cooperia yoshidai, Longistrongylus schrenki, and Haemonchus contortus, with the latter 2 being more abundant during November/December than at other times of the year, probably because infective larvae increased on pasture at that time. No statistical differences were found in parasite loads between male and female mountain reedbuck. No correlation was found between fecal egg counts and adult worm counts or between parasite counts and body condition. At Tussen die Riviere, helminths in mountain reedbuck were less prevalent and abundant than at Sterkfontein. The most important species were Nematodirus spathiger, Trichostrongylus falculatus, and Cooperia rotundispiculum. Four gray rhebok died of natural causes at Sterkfontein, from which 5 kinds of helminths were recovered, including C. yoshidai and Paracooperioides peleae.

Predictors of children's body mass index: a longitudinal study of diet and growth in children aged 2-8 y.

OBJECTIVE: To identify longitudinal variables related to children's body mass index (BMI) (kg/m(2)) at age 8 y. DESIGN: A longitudinal design, with nine interviews per child from ages 2 to 8 y. SUBJECTS: In all, 70 white children (37 males, 33 females) who were continuous participants since infancy in the longitudinal study. Families were primarily middle and upper socioeconomic status. MEASUREMENTS: At each interview, children's height and weight were measured, and mothers provided 3 days of the child's intake data (a 24-h recall and 2 days of food records). ANALYSES: Analyses used were means+/-s.d., correlations, repeated measures analysis of variance, and forward stepwise regression. BMI at each interview was calculated and age of adiposity rebound was determined. RESULTS: Children's BMI at 8 y was negatively predicted by age of adiposity rebound and positively predicted by their BMI at 2 y. Additionally, each model included one longitudinal dietary variable; mean protein and fat intakes recorded between 2 and 8 y were positive predictors of BMI at 8 y; mean carbohydrate intake over the same time period was negatively related to BMI at 8 y. R(2) values indicated that these three-variable models predicted 41-43% of the variability in BMI among children. BMI of 23% of the children exceeded the 85th CDC percentile. CONCLUSIONS: The results of this study show that factors in early life are associated with children's BMI at age 8 y.

Effect of ram introduction on the oestrous cycle of springbok ewes (Antidorcas marsupialis).

Springbok are aseasonally breeding wild ungulates that inhabit arid environments, and interest has been shown in domesticating them for agricultural purposes. The present study was conducted for husbandry purposes to determine the effect of introducing a vasectomized ram to an isolated herd of springbok ewes (n = 9). Blood was collected from ewes every third day, before and after introduction of a vasectomized ram. Ewes were subjected to the ram for 42 days. Plasma progesterone was measured by radioimmunoassay and was used to establish the stage of the oestrous cycle. After introduction of the ram, the variation in the timing of the follicular phase between ewes was clearly reduced, compressing the spread of oestrus in the springbok ewes from 11 to 3 days. In seven of the nine ewes, the ram was introduced during the luteal phase of the oestrous cycle, causing this cycle to be significantly longer in duration (P < 0.05) and to have a higher maximum concentration of progesterone (P < 0.001) than cycles before and after introduction of the ram. This finding implies that the mechanism of synchronization operates through a luteotrophic effect. These results indicate that rams may be used successfully to synchronize breeding in springbok.

Sex differences in the influence of mothers on the sociosexual preferences of their offspring.

The extent to which "nurture" as opposed to "nature" determines behavior and sociosexual preferences in mammalian species is controversial although most recent interest has focused on genetic determinants. We report here that if sheep and goats are cross-fostered at birth, but raised in mixed-species groups, their play and grooming behavior resembles that of their foster rather than genetic species. There are no sex differences in effects on these behaviors, and other species-specific behavior patterns such as aggression, browsing, climbing, and vocalizations are unaffected. In adulthood, cross-fostered males strongly prefer to socialize and mate with females of their foster mother's species, even if raised with a conspecific of their own species. Castration within 2 days of birth slightly reduces the level of this altered social preference but mating preference following short-term testosterone treatment is the same as for gonadally intact animals. Cross-fostered females also show significant preference for socializing with females and mating with males of their foster mother's species, although this effect is weaker than that in both gonadally intact and castrated males. When cross-fostered animals are placed in flocks containing members of only their genetic species for 3 years, male social and mating preferences for females of their mother's species remain virtually unaffected. Females change to display an exclusive mating preference for members of their genetic species in 1-2 years although they still retain some social interest in female members of their foster species. Thus, there are clear sex differences in the impact of the emotional bond between a mother and her offspring in these mammals. Effects on males are strongest and irreversibly maintained even after altering their social environment, whereas those on females are weaker and mating preferences are clearly adaptable in the face of altered social priorities. These sex differences are presumably caused by pre-, or early postnatal, organizational effects of sex hormones on the brain.

The role of dietary calcium and other nutrients in moderating body fat in preschool children.

OBJECTIVE: To assess preschool children's food consumption (24-60 months) and relate these findings to body composition at 70+/-2 months. DESIGN: A longitudinal study of children's dietary intakes for selected nutrients and servings of dairy products. SUBJECTS: Fifty-three white children participating in a longitudinal study (2-96 months) of children's food practices and growth. MEASUREMENTS: Using in-home interviews and trained interviewers, 18 days of dietary data and measured height and weight of each child at 6 month intervals were collected. Body composition was determined by dual energy X-ray absorptiometry. RESULTS: Dietary fat was 30-33% of energy with saturated and monounsaturated fat intakes>10% and polyunsaturated<10%. Adjusting for body mass index (BMI), GLM models to predict percent body fat (%BF) or grams of total fat (gTF) with mean longitudinal calcium intake (%BF: R2=0.51, F=7.88, P<0.0001; gTF: R2=0.51, F=9.84, P=0.0001) or total servings of dairy products (%BF: R2=0.47, F=6.93, P<0.0001; gTF: R2=0.47, F=8.31, P<0.0001) as independent variables gave significant results. Higher mean longitudinal calcium (mg/day) intakes and more servings/day of dairy products were associated with lower body fat. Males had significantly less body fat (P=0.01) than females. CONCLUSIONS: Higher longitudinal intakes of calcium, monounsaturated fat, and servings of dairy products were associated with lower body fat.

A longitudinal study of children's juice intake and growth: the juice controversy revisited.

OBJECTIVES: To determine associations between children's longitudinal juice intake and growth parameters at age 72 months and to determine children's beverage intake patterns over time. SUBJECTS/SETTING: White children (n = 72) residing in the vicinity of a Southern US city participated in a longitudinal study. METHODS: Seven in-home interviews were conducted per child when each child was between 24 and 72 months of age. The 7 sets of 3-day dietary data were analyzed for beverage intake, categorized as juice (100% juice only), milk, carbonated beverages, and other drinks (e.g., lemonade, tea, juice drinks). The following growth parameters were determined for each child at age 72 months: height, weight, body mass index (measured as kg/m2), and ponderal index (measured as kg/m3); the 3 latter are measures of overweight. STATISTICAL ANALYSES: Associations between longitudinal juice intake and each growth parameter were tested with general linear models. Repeated measures analysis of variance tested changes in beverage intakes over time. RESULTS: There were no statistically significant associations between juice and children's height, weight, or body mass index, as tested by general linear models. Children's longitudinal juice intake was negatively related to ponderal index (beta = 0.065, P = .050). Children's juice intake decreased significantly between ages 2 and 6 years, from 6.8 to 3.6 oz/day (P = .0001); intakes of carbonated beverages and other drinks increased from 1.7 to 3.8 oz/day (P = .0016) and from 2.7 to 6.2 oz/day (P = .0001), respectively. APPLICATIONS/CONCLUSIONS: Children's longitudinal juice intake was not associated with either short stature or overweight. As juice consumption decreased, intakes of less nutritious beverages increased. Consumption of 100% juices should be encouraged by health professionals and parents/caregivers.

Annual ovarian cycles in an aseasonal breeder, the springbok (Antidorcas marsupialis).

The springbok is an arid-adapted antelope inhabiting the desert and semidesert regions of southern Africa. Because it thrives in these sparsely vegetated areas, the springbok is of potential agricultural importance and the prospect of domestication has been speculated for many years. However, apart from observational studies on its breeding in the wild, suggesting it is an aseasonal breeder, little is known about the underlying reproductive endocrinology of this species. In this study, biweekly peripheral blood samples were collected from eight captive springbok ewes from October 1995 until September 1998 and analyzed for progesterone. At the start of the study, six ewes were prepubertal and cycling commenced spontaneously between November 1995 and June 1996. Cycling had already commenced in two ewes. At the end of November 1996, estrous cycles ceased abruptly in all ewes and restarted in April 1997. Cycling ceased again between December 1997 and February 1998 and restarted in June 1998 in six ewes; there was no cessation of estrous cycles in two ewes. Thus, although some individuals cycle continuously, there is a clear endocrine anestrus of between 4 and 5 mo in springbok, the timing and duration of which is synchronized between some individuals but the time of onset and cessation is variable from year to year. To ensure that the fluctuations we observed in progesterone levels were reliable indicators of changes in the estrous cycle, blood samples were collected every 6 h for 16 days in August 1998. A surge in LH secretion was observed in all ewes 55 +/- 5 h after the fall in progesterone. Progesterone levels increased again 45 +/- 8 h after the surge. A final study showed that the pattern of melatonin release in springbok exhibits a normal day/night profile, and thus photoperiodic information is transformed into an endocrine code to springbok but does not appear to affect reproduction. Rather, our data raise the possibility that the prevailing ambient temperature may influence the onset of ovarian activity in this species.

Mothers' sources of information about feeding their children ages 2 months to 54 months.

The purpose of this study was to determine sources and types of information about child feeding practices that were received by 62 mothers with children aged 2 to 54 months. Each mother participated in 10 or 11 in-home interviews. Data analyses included chi-square testing for differences in information sources over time and content analyses to develop information themes. As sources, citations for professionals and magazines decreased, with no significant changes for relatives over time. After 24 months, newspapers, television, and friends were reported more frequently than earlier. Mothers reported multiple and concurrent information sources over time. Thus, nutrition educators have concurrent and multiple opportunities to disseminate nutrition information.

Addition of supplementary foods and infant growth (2 to 24 months).

OBJECTIVE: To determine the effect of adding supplementary foods on infant growth 2 to 8 and 12 to 24 months. METHODS: Length (cm/month) and weight (kg/month) of white infants (n = 94) were measured five to nine times from 2 to 24 months of age. Mothers reported birth weights, infants' ages at first introduction of supplementary food, illnesses and information sources about infant feeding. Simple linear regression equations were used to compute slopes for each child (unit changes in length and in weight by age). Stepwise linear regression was used to determine the effect on weight and length slopes by the introduction of supplementary foods (e.g., an infant's age when cereal, fruit, juice, vegetables and a meat cluster were first added) to the diet. Breast feeding (months duration or ever fed), illness scores and gender were covariates in the regression models. RESULTS: A significant model (F = 10.09, p = .002) for weight gain (2 to 8 months) showed that gender explained 10% of the variance; for length slope, the model was non-significant and gender explained 3% of the variance. Females had a slower weight gain compared to that of males. None of the covariates or supplementary foods were retained in the models. Weight prior to 12 months was the best predictor (p = .0001, 54% of the variance) of weight gain 12 to 24 months. CONCLUSIONS: Unit changes in weight or length for an infant's age were not statistically associated with the timing of when supplementary foods were first added to the diet 2 to 8 or 12 to 24 months. Weight prior to 12 months was a significant predictor of weight gain 12 to 24 months.

Bone mineral status in adolescent girls: effects of eating disorders and exercise.

PURPOSE: To compare whole-body, lumbar, total spine, and pelvis bone mineral density (BMD), body mass index (BMI), body composition, energy expenditure for physical activity, and dietary intake of adolescents, aged 16-22 years. METHODS: Three study groups included 25 girls with histories of eating disorderd, 25 girls with no histories of eating diso rders who exercised < or = 7 hours/week, and 15 girls with no history of eating disorders who exercised > 7 hours/week. Bone mineral density was measured by dual-energy x-ray absorptiometry (DEXA), body composition by bioelectric impedance and DEXA, energy expenditure by Personal Activity Computer, nutrient intake by 4-day dietary recalls/records, and BMI by measures of height/weight. General linear models, LSM +/- SEM, Student's t-tests, and correlation analyses were used to determine group differences. RESULTS: No significant differences in whole-body, spinal, and pelvis BMD were found among the three groups. Mean body fat (percent) was significantly higher (p =.0001) for the group with histories of eating disorders than other groups. Dietary intakes of adolescents with histories of eating disorders were significantly lower for energy (p =.0001), fat (p =.0001), calcium (p =.0007), vitamin D (p =.0180), and zinc (p =.0057) than those without eating disorder histories who exercised

Revisiting the picky eater phenomenon: neophobic behaviors of young children.

OBJECTIVES: To compare picky eater behaviors (food neophobia) of children as toddlers and at 42 to 84 months of age and to assess their mothers' neophobic behaviors. METHODS: In a follow-up study of toddlers' picky eater behaviors, trained interviewers conducted four in-home interviews with mothers (n = 71) when their children were 42, 60, 72 and 84 months of age. Mothers reported children's diets (1 weekend day and 2 week days, 12 days total) and their behaviors; weight and height were measured. An additional interview at 48 months involved only mothers' behaviors. Nutritionist IV software, correlations, t tests and repeated measures ANOVA were used to determine nutrient intake, behavioral relationships and differences by picky eater status. Mothers' descriptions of the children's food neophobia and bothersome behaviors were analyzed by qualitative methods. RESULTS: Mothers reported children's neophobic behaviors at all ages. Mothers' and children's behaviors were significantly and consistently correlated for number of attempts before deciding an unfamiliar food was disliked (p < 0.01) and trying unfamiliar foods away from home (p < 0.01). Other behavioral associations were significantly related for some ages but not for all the children's ages. There were no significant differences by picky eater status for nutrient intake or height and weight at any age. Mothers most frequently attempted unfamiliar entrees away from home because of social setting/relationships. About 20% of mothers attempted unfamiliar foods or new recipes just because they were different. CONCLUSIONS: Findings suggest that some neophobic behaviors of children did not improve with maturity. Mothers' perceptions about their children's picky eater status were inconsistent over time.

Longitudinal study of nutrient and food intakes of white preschool children aged 24 to 60 months.

OBJECTIVE: To determine nutrient and food intakes of 72 white preschool children primarily from families of middle and upper socioeconomic status and to compare children's nutrient intakes with current recommendations. DESIGN: Six in-home interviews were conducted with mothers when children were 24 to 60 months old; at each time mothers provided 3 days of dietary information on the child. Children and mothers independently provided information on the child's favorite and least favorite foods at 42 and 54 months. SUBJECTS: Preschool children (24 to 60 months old) participating in a longitudinal study. STATISTICAL ANALYSES: Mean nutrient intakes were compared with the most recent Recommended Dietary Allowances/Adequate Intakes. Differences over time were tested with repeated-measures analysis of variance; gender differences were determined with t tests. Food frequencies (i.e., percentage of children consuming specific foods) were determined from dietary recalls and food records. Dietary variety was assessed with the Variety Index for Toddlers or the Variety Index for Children. RESULTS: Means were consistently less than the RDA/AI for energy, zinc, folate, and vitamins D and E. Energy, carbohydrate, and fat intakes were highest (P < or = .01) at 60 months. Boys consumed more (P < or = .05) protein (10 g), calcium (197 mg), magnesium (35 mg), and pantothenic acid (0.8 mg) at 60 months than did girls. Foods most commonly eaten were fruit drink, carbonated beverages, 2% milk, and french fries. The vegetable group consistently had the lowest variety scores; vegetables also dominated least favorite foods lists. APPLICATIONS: Parents need to be encouraged to include more sources of zinc, folate, vitamin E, and vitamin D in children's diets. Parents should also encourage their children to eat more vegetables, zinc- and folate-fortified cereals, lean red meats, seafood, vegetable oils, and low-fat milk.

Brain, abdominal and arterial blood temperatures of free-ranging eland in their natural habitat.

Using implanted miniature data loggers we measured brain, arterial blood and abdominal temperatures at 5-min intervals in two free-ranging eland (Tragelaphus oryx) in their natural habitat. The animals were subjected to a nychthemeral range of globe temperature which exceeded 40 degrees C. Arterial blood exhibited a moderate amplitude (2.3 degrees C) nychthemeral rhythm, with a temperature peak at 1600-1800 hours, and a trough in the early morning at 0600-0800 hours. Mean abdominal temperature was 0.2-0.3 degrees C lower than the corresponding blood temperature, and had a peak-to-trough amplitude of 2.6 degrees C. Brain temperature closely paralleled changes in blood temperature but usually exceeded blood temperature by about 0.5 degrees C. Sporadic episodes of selective brain cooling occurred in one animal, but the duration and magnitude of such cooling was small (less than 0.4 degrees C), and took place only well above the mode of blood temperature. Our results do not support the concept that eland routinely employ adaptive heterothermy and selective brain cooling to survive in their natural environment.

Fruit juice intake is not related to children's growth.

BACKGROUND: Excessive fruit juice intake (>12 ounces/day) has been reported to be associated with short stature and obesity in preschool children. OBJECTIVE: To confirm whether excess fruit juice intake was associated with short stature and obesity in preschool children, we assessed growth parameters and fruit juice intake in 105 white children, ages 24 to 36 months. METHODOLOGY: Mothers were interviewed twice by a registered dietitian when children were age 24, 28, or 32 months (interview 1) and when children were age 28, 32, or 36 months (interview 2); interviews were assigned randomly. At each interview mothers provided 3 days of dietary data (one 24-hour recall and a 2-day food record) and the registered dietitian weighed the child and measured his/her height. Dietary data were analyzed using Nutritionist IV software. Each child's body mass index (wt/ht2) and ponderal index (wt/ht3) were calculated for each interview. Growth parameters of children consuming <12 ounces/day 100% fruit juice were compared with those consuming >/=12 ounces/day using the Student's t test, chi2, Fisher's exact test, and mixed model repeated measures analyses (PROC MIXED). RESULTS: Results consistently indicated no statistically significant differences in children's height, body mass index, or ponderal index related to fruit juice intake. Intakes of soda pop were negatively related to intakes of milk and fruit juice although intakes of milk and fruit juice were not related. CONCLUSIONS: The consistent lack of relationship between children's fruit juice intake and growth parameters in our study does not support previous recommendations to limit the intake of 100% fruit juice to <12 ounces/day.