Body composition in lactating sheep and its indirect measurement in the live animal using tritiated water

1979 ◽  
Vol 92 (1) ◽  
pp. 69-81 ◽  
Author(s):  
J. Z. Foot ◽  
E. Skedd ◽  
D. N. McFarlane

SummaryIn two experiments with female Scottish Blackface or Border Leicester x Scottish Blackface sheep nine or ten animals were slaughtered in mid lactation and the remainder either in November at the time of the subsequent mating (Expt 1) or at weaning (Expt 2).The sheep were infused periodically, including just before slaughter, with 100 μCi tritiated water (TOH) in order to measure total body water by dilution and to estimate body fat using the inverse relationship between the proportions of fat and water in the body. The accuracy of the methods was assessed when the sheep were slaughtered. In the ton lactating Scottish Blackface sheep of Expt 1 fat made up 11.5% of the total body weight with an S.D. of 8·38% whereas the 11 sheep slaughtered at mating were twice as fat (23·2, S.D. 4·01 %). The 25 Border Leicester × Blackface sheep were all thin, whether they were slaughtered in mid lactation (4·4, S.D. 2·56%) or at weaning (3·4, S.D. 2·81%).The standard error of estimate of body water from TOH space in Expt 2 was 1·2 kg c.v. 2·8%) and lower in Expt 1.The precision with which an animal could be weighed was very important in determining the accuracy with which body fat could be predicted from live weight and TOH space. In both experiments the standard error of estimate for body fat in lactating sheep was between 600 and 700 g, compared with 1·3–2·7 kg when body fat was predicted from live weight alone. These estimates were sufficiently accurate to be of value in following changes in body composition in live animals as their nutritional and physiological state alters and for comparing animals in groups where the average fatness is greater and the range wider than in the sheep used in Expt 2.

1983 ◽  
Vol 101 (2) ◽  
pp. 257-264 ◽  
Author(s):  
P. R. N. Chigaru ◽  
D. H. Holness

SUMMARYThe body composition of 18 each of Mashona, Afrikaner and Hereford heifers was measured at the beginning and after 16 and 32 weeks of the experiment. The heifers not slaughtered at the beginning of the experiment were fed a complete diet containing 132 g crude protein and 12·0 MJ metabolizable energy/kg dry matter. Before slaughter, the animals were deprived of food and water for 24 h. Each animal was infused with 1 mCi of tritiated water (TOH) in order to measure total body water (TBW) and to estimate body fat.The growth rate of the three breeds of heifers was similar despite differences in age and initial live weight. Both TBW and fat proportions, however, differed significantly (P < 0·01) between slaughter stages for each breed and between breeds at each slaughter stage. At the first, second and final slaughter stages the proportions of TBW were: 68·0, 59·4 and 54·5% for Mashona; 70·;5, 64·3 and 58·3% for Afrikaner and 65·3, 57·6 and 46·2% for Hereford heifers respectively. The corresponding proportions of body fat were: 10·2, 18·4 and 24·2% for Mashona; 6·6, 12·0 and 20·0% for Afrikaner and 13·7, 20·8 and 25·8% for Hereford heifers respectively.There was a close relation between empty body weight and live weight at slaughter which was not influenced by breed. Both TBW and fat were estimated more accurately when TOH space and live weight were used jointly. However, the slopes of the prediction equations for each breed were significantly different (P < 0·05) in the case of both total body water and fat. It was necessary to use separate equations for each breed in order to predict either body water or fat. The significance of these findings for the estimation of body fat in live cattle is discussed.


1972 ◽  
Vol 78 (3) ◽  
pp. 505-508 ◽  
Author(s):  
D. A. Little ◽  
J. G. Morris

SUMMARYTwo methods of determining body composition in live cattle have been compared with the composition of the cattle as determined by chemical analysis. Total body water (TBW) was estimated from tritiated water (TOH) dilution, and circulating redcell volume (RCV) estimated from measurements of plasma volume and haematocrit. TBW was very closely related to fat-free weight and fat weight as a percentage of live weight (LW) in eight cattle ranging from 3 to 34% fat. TOH space was more precise than RCV in the estimation of the various chemical fractions of the live animal.TOH injected intravenously equilibrated with ruminal water in 8–10 h; one could be confident that equilibration had occurred 10 h after injection, and equilibration time was not affected by previous restriction of feed and water. The mean biological half life of TOH was 4·2 ± 0·4 days. Equations are presented for the practical determination of the various compartments.


1988 ◽  
Vol 59 (1) ◽  
pp. 109-124 ◽  
Author(s):  
R. J. Johnson ◽  
D. J. Farrell

1. Birds (n169) which varied in age, live weight, nutritional history, physiological state and genotype were slaughtered and analysed for total body water. Before slaughter, birds were injected with the water isotopes tritiated water (TOH) or deuterium oxide (D2O), or both, to determine TOH space or D2O space, or both, as estimates of total body water in vivo.2. At the mean total body water of all birds determined by desiccation, of 1096·4 (SD 424·1) g, TOH space and D2O space overestimated total body water by 10·4 and 8·5 % respectively. The difference between the isotopes was significant (P< 0·05).3. Based on recovery of isotope it was postulated that the main reason for the observed overestimation of total body water in vivo was incomplete recovery of isotope due to the vacuum sublimation technique. The mean recovery (%) of added isotope to whole blood after vacuum sublimation was 93·0 (SD 2·6) and 92·4 (SD 5·5) of the theoretical concentrations of TOH and D2O respectively.4. Nevertheless, accurate prediction of total body water was obtained from regression equations which included live weight and isotope-dilution space. Values required logarithmic (base 10) transformation before derivation of linear and multiple linear regression equations, and the precision of prediction was determined by the residual standard deviation (RSD).5. Total body water could be predicted with nearly equal accuracy from live weight or isotope-dilution space (RSD 0·025 and 0·020 respectively). Prediction of carcass protein was more accurate from live weight (RSD 0·033) than from TOH space (RSD 0·036), and inclusion of both variables resulted in only a marginal decrease in RSD to 0·031.6. The prediction of carcass fat and energy was markedly improved by the inclusion of isotope-dilution space in conjunction with live weight compared with live weight alone.7. The relations show the developmental nature of body composition of domestic fowl given diets adequate in nutrients. The prediction equations demonstrate the precision possible for studies in which estimates of body composition in poultry are required without slaughter.


1988 ◽  
Vol 47 (3) ◽  
pp. 435-445 ◽  
Author(s):  
F. R. Dunshea ◽  
A. W. Bell ◽  
K. D. Chandler ◽  
T. E. Trigg

ABSTRACTA two-pool model of tritiated water kinetics was investigated as a means of partitioning total body water into empty body water and gut water in 17 lactating goats. Empty body water, gut water and total body water were of a similar magnitude to, and highly correlated with, a rapidly equilibrating tritiated water pool, a more slowly equilibrating pool and the sum of these two pools, respectively.Empty body fat was poorly correlated with both live weight and empty body weight (R2 = 0·42 and 0·51, respectively). However, there was a strong inverse relationship between the water and fat contents of the empty body. Consequently, empty body fat was accurately predicted by a multiple regression equation which included both empty body weight and empty body water as independent variables (R2 = 0·97). Substitution of these variables with estimates derived from tritiated water kinetics still resulted in a high correlation (R2 = 0·88). Tritiated water kinetics offered little improvement over live weight alone in the prediction of empty body protein, empty body ash or fat-free empty body.


2001 ◽  
Vol 2001 ◽  
pp. 206-206 ◽  
Author(s):  
R. E. Agnew ◽  
W J McCaughey ◽  
J.D. McEvoy ◽  
D C Patterson ◽  
M G Porter ◽  
...  

San Pietro and Rittenberg (1953) reported that urea appeared to meet all the requirements of a satisfactory tracer. Urea is non toxic, not foreign to the body and it shows an even and rapid distribution throughout the total body water without any physiological effect. For these reasons in addition to its easy and accurate measurement, urea is an ideal candidate tracer to estimate empty body water in vivo. Total body water volume (urea space) can be estimated by dividing the total amount of urea infused by the increase in plasma urea concentration from prior to infusion until 12 or 30 minutes after mean infusion time. Kock and Preston (1973) reported significant relationships between urea space measurements and percentage of empty body fat and water in cattle. However, Andrew et al. (1995) using 21 Holstein cows showed that prediction of empty body water using the urea space technique only explained 31 % of the variation. The objective of this experiment was to use the urea dilution technique to estimate the body composition of lactating dairy cows and produce relationships between urea space and body fat and protein content.


1970 ◽  
Vol 27 (5) ◽  
pp. 929-942 ◽  
Author(s):  
T. D. D. Groves

The body composition of young sockeye (Oncorhynchus nerka) in the weight range of 0.5–300 g was investigated to further document changes in body composition with growth, and to develop equations that would allow the estimation of total body composition in this species, either in vitro or in vivo, based on easily measured parameters such as fork length, live weight, and total body water. The major components of the fat-free mass (protein, water, and ash) in nonstarving fish were closely related to each other and to fork length. Body fat tended to increase with size, but was not closely related to the other components of body composition. The following equations were derived, allowing the accurate estimation of total water (W), protein (P), and fat-free dry material (FFDM, consisting of protein and ash) in grams, based on the measurement of either water or fork length (L) in centimeters: W = 0.00571 L3.118, P = 0.204 W 1.038, and FFDM = 1.113 P. Body fat (F) may be estimated as the difference between wet body weight (M) and the lean mass: F = M − (W + FFDM).These equations are similar to, but not identical to, the relations derived for other species of salmon, based on other published data, and to the respective relations reported in the literature for mammals. The applications of these equations to the nutritional evaluation of wild populations and to quantitative nutritional studies on young sockeye are discussed and illustrated.


1969 ◽  
Vol 72 (1) ◽  
pp. 139-147 ◽  
Author(s):  
D. M. Keenan ◽  
W. R. McManus ◽  
M. Freer

SUMMARYThe body composition of eight Merino wethers was estimated from the tritiated water (TOH) space and live weight at intervals during a cross-over experiment in which they were fed to either maintain a uniform live weight (about 34 kg) or to lose and, later, recover live weight over a 17-week period. The diet was a pelleted mixture of lucerne and wheat.The multiple regression equations used for these estimates were established from the chemical analysis of 24 sheep, including six from the cross-over experiment, which were killed at intervals during these two feeding regimens. The inclusion of TOH space in addition to live weight in the regression equations decreased the standard error of the estimates of body water, fat and energy by two-thirds. Correction of TOH space and live weight for gut water did not increase the precision of the equations.Shoop which ate, during the first 4 weeks of the experiment, one-third of the amount of food required to maintain their original live weight, lost 16% of their weight and 30% of their total body energy. This weight loss consisted of 45% water, 39% fat and 13% protein. It appeared that tissue was mobilized inefficiently to meet a sudden energy deficit.When food was offered ad lib. to these sheep after they had maintained a liveweight deficit of about 11 kg for 8 weeks, they regained their weight in 5 weeks but only 75% of their energy deficit. This was due to the high content of water (60%) and low content of fat (23%) in the regained tissue.The sheep that lost weight and then recovered it were, over-all, about 86% as efficient in their use of food to maintain body energy and produce wool as the sheep that maintained their original weight.


1968 ◽  
Vol 19 (2) ◽  
pp. 267 ◽  
Author(s):  
BA Panaretto

Correlations are described between tritiated water space, total body water, fat, and protein in sheep subjected to 18–21 hr of fasting. These provide a system for estimating the body composition of living ruminants.


1979 ◽  
Vol 29 (1) ◽  
pp. 81-90 ◽  
Author(s):  
R. T. Cowan ◽  
J. J. Robinson ◽  
J. F. D. Greenhalgh ◽  
I. McHattie

ABSTRACTChanges in body composition during lactation were measured in 12 Border Leicester × Scottish Blackface ewes by serial slaughter at 12, 41 and 111 days of lactation. Ewes suckled twin lambs and were given daily 1·6 kg dry matter of a complete diet containing 151 g crude protein and 10·2 MJ metabolizable energy/kg dry matter.Live weights of ewes averaged 60·2, 58·9 and 55·8 kg at 12, 41 and 111 days of lactation respectively. There were no significant changes in weights of stomach, small and large intestine and liver.The weight of body fat averaged 9·19, 2·28 and 1·19 kg at 12, 41 and 111 days respectively (P < 0·001) and weight of ash increased from 1·72 kg at 12 days to 2·30 kg at 111 days (P < 0·001). Water to protein ratios at the three stages of lactation were 2·94, 3·36 and 3·18 (P < 0·10). The energy value of weight loss varied from 68 to 17 MJ/kg, depending on the relative changes in total body water and fat. Live-weight change was therefore a poor indicator of change in body energy during early lactation.Body fat could be predicted from its combined relationships with live weight and total body water (residual s.d. ±0·70 kg), but when deuterium oxide space was used to estimate body water separate equations were necessary for early and later stages of lactation. This was apparently due to differences between stages of lactation in the time required for deuterium oxide to equilibrate with water in the reticulo-rumen.


1999 ◽  
Vol 1999 ◽  
pp. 50-50
Author(s):  
S. De Campeneere ◽  
L.O. Fiems ◽  
J.M. Vanacker ◽  
B.G. Cottyn ◽  
Ch.V. Boucqué

Urea is non-toxic, not foreign to the body and it shows an even and rapid distribution throughout the total body water without any physiological effect or toxic manifestation. For these reasons and for its easy and accurate measurement, urea is an ideal tracer to estimate body composition in vivo. Total body water volume (urea space) can be estimated by dividing the total amount of urea infused by the increase in plasma urea concentration between prior to infusion and 12, 18 or 24 min after mean infusion time (Preston and Kock, 1973). In this experiment the urea infusion technique was evaluated to estimate body composition of Belgian Blue double-muscled bulls.


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