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

  • J. Z. Foot (a1), E. Skedd (a1) and D. N. McFarlane (a1)


In 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.



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Cabneoie, A. B. & Tulloh, N. M. (1968). The in vivo determination of body water space in cattle using the tritium dilution technique. Proceedings of the Australian Society of Animal Production 7, 308313.
Cowan, B. T., Robinson, J. J. & Greenhalgh, J. F. D. (1978). Body composition changes in lactating ewes. British Society of Animal Production, Winter Meeting 1978. Animal Production 26, 392393.
Donnelly, J. R. & Freer, M. (1974). Prediction of body composition in live sheep. Australian Journal of Agricultural Research 25, 825834.
Farrell, D. J. & Reardon, T. F. (1972). Undernutrition in grazing sheep. III. Body composition and its estimation in vivo. Australian Journal of Agricultural Research 23, 511517.
Foot, J. Z. (1969). Body water in ovine pregnancy. Journal of Reproduction and Fertility, supplement 9 (Water metabolism in pregnancy), 916.
Kumar, I. & Bergek, E. Y. (1968). Preparation of samples for liquid scintillation analysis of tritiated water. International Journal of Applied Radiation and Isotopes 19, 805807.
Robelin, J. (1973). Estimation de la composition corporelle des animaux à partir des espaces de diffusion de l'eau marquée. Annales de Biologie animale, Biochimie, Biophysique 13, 285305.
Robelin, J. (1975). Estimation of body composition in vivo by dilution techniques. EEC Seminar on Criteria and Methods for Assessment of Carcass and Meat Characteristics in Beef Production Experiments, Zeist, 1975.
Robelin, J. (1977). Estimation in vivo de la composition corporelle des agneaux a partir de l'espace de diffusion de l'eau lourde. Annales de Biologie animale, Biochimie, Biophysique 17, 95—105.
Russel, A. J. F., Gunn, R. G. & Doney, J. M. (1968). Components of weight loss in pregnant hill ewes during winter. Animal Production 10, 4351.
Searle, T. W. (1970). Body composition in lambs and young sheep and its prediction in vivo from tritiated water space and body weight. Journal of Agricultural Science, Cambridge 82, 269275.
Smith, B. S. W. & Sykes, A. R. (1974). The effect of route of dosing and method of estimation of tritiated water space on the determination of total body water and the prediction of body fat in sheep. Journal of Agricultural Science, Cambridge 82, 105112.
Sykes, A. R. (1974). The prediction of the body composition of hill sheep from body weight, red cell volume and tritiated water space. Journal of Agricultural Science, Cambridge 82, 269275.


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