CHANGES IN BODY-COMPOSITION OF DAIRY GOATS CAUSED BY PHOSPHORUS DEPLETION

Just after peak of lactation, four goats were slaughtered (control) and four goats were subjected to diets low in P. After having lost, on average, 85 g P and 139 g Ca from their bodies, these goats were also slaughtered. Bodies were dissected into 11 fractions which were analysed. Proportional weights of body fractions remained unaltered with the sole exception of udders. Total lipid concentration was not affected by P depletion in any body fraction; nitrogen concentration was only significantly reduced in the liver. Ash P and Ca concentrations were significantly reduced in the head and total skeleton. P concentrations were significantly reduced in the emptied digestive tract, liver, kidneys and spleen, but remained unaffected in skin plus hair, muscles, heart, lungs and udder. Total quantities contained in the empty body differed between the two respective groups on average by 67 g P and 127 g Ca per goat, with no significant contribution of soft tisues to these losses. It is concluded that 18 g of mobilized P and 12 g of mobilized Ca, which cannot be verified from comparative analysis of the empty body, must have been contributed by lowering the concentrations of these elements in the content of the digestive tract.