Identifying the psychological needs of foster children.

Recent research has pointed to the increased risk of pathology for children placed in foster care. In response, the Child Welfare League of America has advocated for routine assessment of the psychological needs of children in foster care. A model for standardized psychological screening for all foster children shortly after placement is described. Interdisciplinary relationships between medical and psychological staff are stressed. Typical referral questions are outlined and suggestions for a testing battery that covers cognitive, behavioral, and emotional realms are given. Issues and problems inherent in testing this population are discussed, but the importance of psychological screening of this at-risk population is emphasized.

A mathematical integration of energy and amino acid metabolism of lactating sows.

A dynamic mathematical model of energy and protein metabolism of lactating sows is described in this article. The model is designed to contribute to a systematic and quantitative understanding of the biological connection between diet and reproduction. It traces the flow of energy-containing nutrients from absorption through intermediary metabolism, into and out of body stores, and into milk. State variables (pools) include lysine, other amino acids, glucose, fatty acids, acetate, propionate, acetyl-coenzyme A, ATP, oxygen, carbon dioxide, urea, lean-body protein, visceral protein, storage triacylglycerol, milk protein, milk triacylglycerol, and milk lactose. The rate of each transaction is a function of substrate and inhibitor concentrations, assuming saturable kinetics. Protein and fat turnover, substrate cycles, and the energy cost of membrane transport are explicitly considered. Dynamic simulation of a complete lactation is accomplished by iterating the numerical integration of 16 first-order, nonlinear differential equations, each associated with a pool. Most kinetic parameters were estimated indirectly. Preliminary tests suggest the model is sound. It promises to be useful as a research tool and, with further development, as a guide to practical feeding strategies.

Evaluation of a mathematical model of lactating sow metabolism.

A mathematical model of lactating sow metabolism was evaluated using three types of tests. First, 16 experimental treatments from four experiments reported in the literature were simulated with the model, and the simulated values for change in BW and protein and fat content were compared to reported or calculated values. Second, the model's response to level of feed intake, level of milk production, BW and composition at farrowing, and dietary lysine concentration was compared to expected responses. Third, the model's sensitivity to changes in several of its kinetic parameters was measured. There was good agreement between simulated and measured values for BW and fat loss and reasonable agreement for body protein loss. All responses to changes in external conditions were in expected directions and biologically reasonable. The model seemed rather robust with respect to changes in the kinetic parameters considered, although important changes in simulated values were found in some cases. Overall, the model seems sound. It can be useful in evaluation of feeding programs and in understanding biological relationships.

Mathematical models of sow reproduction.

Nutrition affects reproduction, but the physiological mechanisms are not known. Defining those mechanisms is a high priority for animal scientists. This paper briefly describes mathematical models developed to aid in elucidating those mechanisms and which may be applied to predict animal performance. Two types of mechanistic mathematical models of sows are described, based respectively on nutrient partitioning and on metabolic and physiological principles. The nutrient partitioning model is relatively mature but the metabolic/physiological model is still at an early stage of development. The use of such models in the design and evaluation of feeding programmes, in understanding the biological system and in improving research efficiency are outlined. These two models are now being used as described, and it is anticipated that they, and other models, will make important contributions to the marked improvements in reproductive performance in commercial pig production that is anticipated during the next few years.

The influence of transportation on the induction of estrus in gilts of different ages.

Six series of experiments, involving 72 gilts in groups of 4 were carried out to investigate the effects of transportation, vibration and noise, and proximity of sexually mature adult breeding stock on attainment of first estrus in gilts of different ages. The animals grew normally during the periods of observation. Gilts aged 120 days (n = 12) at the start of the observations did not display estrus in response to exposure to vibration and noise or a 2 hr road journey. Similarly aged groups housed near adult breeding stock, but not exposed to vibration and noise, displayed estrus during the first 30 days of observation. All gilts aged 140 days (n = 12) displayed estrus within 5 days of being housed adjacent to adult breeding stock. Others, not housed near adult stock, but exposed to vibration and noise, or a road journey, did not consistently display estrus. When the observations were repeated on gilts aged 160 days (n = 12), the observations were similar. It was concluded that proximity of adult breeding stock and not transportation per se was the critical factor in inducing estrus behavior in normally growing gilts.

Studies on the energy metabolism of the pregnant sow. 1. Uterus and mammary tissue development.

Twenty-six gilts were used in an experiment to study the effects of level of feed intake on the growth and chemical composition of the gravid uterus and mammary tissue at several stages of gestation. The animals were given either 1.8 or 2.5 kg feed/d (20 or 30 MJ metabolizable energy (ME) respectively) and were slaughtered at intervals between days 40 and 110 of gestation. The gravid uterus was dissected into fetal, placental, fluid and empty uterus components. From day 70 of gestation the mammary tissue was also dissected. The fresh weight and dry matter (DM), energy and nitrogen contents of the various tissues were determined. With the exception of the fluid component, there was a significant increase (P less than 0.01) in the fresh weight of each tissue with both stage of gestation and level of feeding. At comparable litter sizes the total weight of the fetuses in late gestation was 16% higher with the higher feed intake. The DM content of the individual uterine tissues increased significantly (P less than 0.01) with increase in stage of gestation so that the mean DM content of the gravid uterus increased from 74.6 g/kg at day 50 to 103.1 and 159.0 g/kg at days 90 and 110 of gestation respectively. Neither stage of gestation nor feeding level influenced the respective energy contents of the individual uterine tissues, when expressed per g DM. The mean energy content of the total gravid uterus was 19.5 kJ/g DM. The N content (g/g fresh weight) of the tissues increased with stage of gestation and was generally higher at the higher feeding level. The mean N contents (g/g DM) of the fetal, placental, fluid and empty uterine tissues were 0.090, 0.101, 0.098 and 0.128 respectively. The mammary tissue was the most variable of all the tissues investigated. Whereas the fresh weight and N content increased with stage of gestation, both the DM and energy content decreased. Gompertz equations were fitted to describe the effects of stage of gestation, level of feed intake and liter size on the fresh weight and chemical content of the individual uterine tissues, total gravid uterus and mammary tissue. The use of these equations for calculating the nutrient requirements of pregnancy is demonstrated. It was calculated that between days 50 and 110 of gestation the ME requirement for reproduction increased from 3 to 12% of maternal energy intake. The calculated requirement for protein was from 7 to 41% of maternal dietary protein intake respectively.

Studies on the energy metabolism of the pregnant sow. 2. The partition and utilization of metabolizable energy intake in pregnant and non-pregnant animals.

The heat losses and energy and nitrogen balances of pregnant gilts, and of their non-pregnant litter sisters (controls), were measured for periods of 7 d at feed intakes of 1.8 or 2.5 kg/d (20 or 30 MJ metabolizable energy (ME) respectively) at an environmental temperature of 20 degrees. The measurements were made within three separate periods of gestation; 40-60 d (early), 60-80 d (mid) and 90-110 d (late). Values for ME intake, heat loss, energy retention (ER), protein deposition and fat deposition were determined for both the pregnant and control animals on each treatment. When expressed per kg body-weight0.75 per d, there was little difference in heat loss between pregnant and non-pregnant animals and between pregnant animals at the different stages of gestation at any given ME intake. However, heat loss was higher at the higher ME intake. ER varied inversely with heat loss. The decrease in ME intake (kJ/kg body-weight0.75 per d) during pregnancy resulted in a decrease in ER so that the pregnant animals were in negative energy balance at the low feed intake during late gestation. From the relation between ER and ME intake, estimates of the maintenance energy requirement (MEm) of 411 and 401 kJ/kg body-weight0.75 per d were calculated, with corresponding partial efficiencies of energy utilization (k) of 0.74 and 0.68 for the pregnant and non-pregnant animals respectively. For the pregnant animals, protein deposition was highest during mid-pregnancy and was relatively independent of level of feeding during mid- and late pregnancy. There was little difference in protein deposition between pregnant and non-pregnant animals at the high feed intake. At the low feed intake, the pregnant animals generally had a higher protein deposition than their non-pregnant litter sisters and this was entirely associated with the accretion in reproductive tissue. Fat deposition depended on the level of feeding, and at any given ME intake was similar for pregnant and control animals. In late gestation the low level of feeding was insufficient to prevent the pregnant animals losing fat. It was calculated that at term these animals lost 140 g fat/d from maternal stores. From the relation between ME intake and protein and fat deposition, estimates of MEm and the energetic efficiencies of protein (kp) and fat (kf) deposition were determined. There was little difference in MEm (422 and 420 kJ/kg body-weight 0.75 per d) and kf (0.88 and 0.90) between pregnant and non-pregnant animals respectively.(ABSTRACT TRUNCATED AT 400 WORDS)

Influence of environmental temperature on glucose tolerance and insulin response in the new-born piglet.

Plasma glucose and insulin concentrations were measured in 45 new-born piglets both before and at regular intervals throughout a 2-hour period following an intravenous administration of glucose (1 g/kg body weight), at environmental temperatures of 17, 24 and 33 degrees C. As anticipated, rectal temperature (TR was dependent upon the environmental temperature. During the glucose tolerance test (GTT), TR remained constant at both 24 and 33 degrees C, 37.0 +/- 0.2 compared with 38.0 +/- 0.1 degrees C. However at 17 degrees C, 12 piglets were able to maintain a constant TR (35.8 +/- 0.2 degrees C), whereas the remaining 6 piglets became hypothermic (32.8 +/- 0.4 degrees C), with TR decreasing continuously throughout the GTT. Their body weight was 210 g below that of the other piglets (p less than 0.05). Those piglets at 17 and 24 degrees C which maintained homeothermy had a higher glucose disappearance rate (KG; 2.00 and 2.31%/min, respectively) than those kept within thermal neutrality (1.66%/min). The insulin response to glucose was similar. During hypothermia, on the other hand, both KG (0.76 +/- 0.12%/min) and the insulin response were significantly less (p less than 0.05) than in all other piglets. These results indicate that the glucose uptake by the skeletal muscle is increased in cold-exposed, normothermic piglets and results in an increased metabolic rate. Failure to maintain homeothermy diminishes glucose uptake and inhibits insulin release.

The influence of transportation, proximity of adults and other stimuli on the age of onset of first puberty in the gilt.

Four series of experiments involving 44 animals were carried out to investigate the influence of transportation, proximity of sexually mature adults and other stimuli on the onset of puberty in the gilt. Transportation per se, either real or simulated, did not induce early puberty in the gilt. In contrast, the most effective stimulus was provided by accommodating the gilts in pens adjacent to mature breeding stock. Gilts housed in a sow yard exhibited oestrus when aged between 153 and 184 days, i.e. 4-6 weeks after the beginning of the experiment. This compares with 189 to 227 days, i.e. 9-12 weeks after the start of the experiment for those gilts not housed adjacent to adult stock.

The influence of protein:energy value of the ration and level of feed intake on the energy and nitrogen metabolism of the growing pig. 1. Energy metabolism.

1. The heat losses and energy and nitrogen balances of thirty-six individually-housed, entire male pigs (initial body-weight 18-30 kg) were measured over 7 d periods, when they were fed on rations containing 153, 201 and 258 g crude protein (nitrogen x 6.25; CP)/kg dry matter (DM). The rations also contained 16.29, 16.96 and 17.24 mJ metabolizable energy (ME)/kg DM so that the CP:ME values were 9.4, 11.8 and 15.0 g CP/MJ ME respectively. Each ration was given at three levels, 20, 35 and 50 g feed/kg body weight per d, thus giving nine dietary treatments. The experiments were carried out at an environmental temperature of 22 (+/- 1) degree. 2. Heat loss (H) increased significantly (P less than 0.01) with increase in ME intake. The rate of increase in H was not, however, influenced by the protein content of the ration. Thus, energy retention (ER) at any given level of ME intake was independent of the ration offered. From the relationship between ER and ME, estimates of the maintenance energy requirement (MEm) and the partial efficiency of energy utilization (k) were determined. MEm varied within the range 494-568 kJ/kg body-weight 0.75 pe d, while k varied from 0.70 to 0.76. 3. Both energy and protein intakes had a significant influence upon the rates of protein (P) and fat (F) deposition, and hence body-weight gain. At any given level of feed intake P was higher and F lower the higher the protein content of the ration. However, when compared at similar levels of protein intake, both P and F were reduced the higher the protein control of the ration. 4. From the multiple regression equations relating P and F to ME, individual estimates of MEm and the energetic efficiencies of protein (kP) and fat (kF) depositions were determined. Using an overall mean kF value of 0.86, it was calculated that MEm ranged from 462 to 525 kJ/kg body-weight 0.75 per d while kP varied from 0.48 to 0.55. The significance of these estimates of kP are discussed in the light of their derivations and in relation to theoretical values.

Heat loss from humans measured with a direct calorimeter and heat-flow meters.

1. Heat loss from three men and three women was measured in a direct calorimeter over 2 or 3 h periods and compared with that determined simultaneously from heat-flow meters attached to the skin surface at the waist. The comparisons were made at each of four ambient temperatures, 15, 20, 25 and 30 degrees. Each subject wore a cotton boiler-suit and minimal underwear. 2. Oral temperatures and skin and clothing temperatures on both trunk and forearm were determined, thus enabling the subjects' internal and external insulation to be calculated. 3. Heat loss determined by the meters was lower than that determined by the calorimeter. The difference increased with increase in ambient temperature. 'Meter' heat loss decreased linearly as ambient temperature was raised. 4. It was concluded that heat-flow meters could provide a useful estimate of total heat loss when the evaporative component is low. The estimate might be improved if the subject is calibrated while wearing the meters in a calorimeter over several short periods. Heat-flow meters could therefore be of particular value in sedentary individuals, when the heart-rate method for estimating energy expenditure can be inappropriate.

The effects of plane of nutrition and environmental temperature on the energy metabolism of the growing pig. 1. Heat loss and critical temperature.

1. The heat losses and energy balances of thirty-eight individually housed pigs (initial body-weights 21--38 kg) were measured continuously for periods of 14 d when they were maintained at environmental temperatures of 10, 15, 20, 25 or 30 degrees. At each temperature four levels of feeding were given approximating to once, twice and three times the maintenance energy intake and the ad lib. level. The minimal maintenance energy requirement (M) was calculated to be 440 kJ metabolizable energy (ME)/kg0.75 per d at 25 degrees. 2. ME intake at the ad lib. level decreased from 1965 kJ/kg0.75 per d at 10 degrees to 1202 at 30 degrees. 3. Heat loss calculated from multiple regression analysis decreased to minimum levels between 20 and 25 degrees; 30 degrees was within the hyperthermic zone at each plane of nutrition. 4. The partition of heat loss into its sensible and evaporative components showed that evaporation increased from 25% at 10 degrees to 78% at 30 degrees. 5. Critical temperature was dependent upon food intake and decreased from 23.1 degrees at M to 20.7 degrees at 2M, 18.0 degrees at 3M and 16.7 degrees at 4M. 6. The extra food required to meet extra thermoregulatory heat production per 1 degrees below the effective critical temperature was 0.65 g/kg body-weight per d.

The effects of plane of nutrition and environmental temperature on the energy metabolism of the growing pig. 3. The efficiency of energy utilization for maintenance and growth.

1. From the relation between metabolizable energy (ME) intake and heat loss (H), energy retention (ER), protein (P) and fat (F) deposition the energy costs of maintenance (MEm) and the partial efficiencies of energy retention (k) and protein (kP) and fat (kF) retention were determined in growing pigs at environmental temperatures of 10, 15, 20, 25 or 30 degrees. 2. k decreased with increase in environmental temperature from 0.79 at 10 degrees to 0.63 at 30 degrees with 0.67 at the thermally-neutral temperature of 25 degrees. Each 0.04 decrease in k was associated with a 100 kJ/kg0.75 per d decrease in MEm. Analysis, within several ranges of environmental temperature, suggested a curvilinear relation between ER and ME intake indicating a decrease in k with increase in level of feeding, particularly at thermally-neutral temperatures. 3. Both kP and kF were similar at each environmental temperature and decreased from 0.78 at 10 degrees to 0.63 at 30 degrees. These values are discussed in relation to those predicted from experimentation and it is suggested that the wide range of predicted estimates of kF could be attributed to differences in the rate of protein turnover.