H. Everts et al., CALCIUM, MAGNESIUM AND PHOSPHORUS BALANCE OF SOWS DURING LACTATION FOR 3 PARITIES, Livestock production science, 55(2), 1998, pp. 109-115
The effects of two diets, differing by total phosphorus and calcium co
ntents, on retention and excretion of Ca, P and Mg were studied in lac
tating sows. Mineral balances (n = 60) were measured during lactation
(day 4 to 25) for three successive parities. Mineral retention in the
litter was measured by chemical analysis of weaned piglets. The contro
l diet (C) contained 7.2 g P, 9.4 g Ca and 2.6 g Mg kg(-1) DM and the
experimental diet (R) 6.5, 8.1, 2.5, respectively. Calculated digestib
le phosphorus level was 3.5 g kg(-1) DM in both diets. Mean litter siz
e was 10.4 piglets and mean litter gain was 2.7 kg d(-1). Calcium, mag
nesium and phosphorus retentions in the piglets were not affected by d
ietary treatments. Mean retention in the sows was slightly negative fo
r calcium and phosphorus, but positive for magnesium. Daily recommende
d allowances for lactating sows were 23.5 g digestible calcium and 16.
5 g digestible phosphorus (both including a safety margin of 25%). Exc
retion of phosphorus in urine and faeces on diet R was 0.53 kg and on
diet C 0.61 kg during a 25-day lactation. The possibilities for reduci
ng phosphorus excretion during lactation are limited compared to those
during pregnancy. Some reduction during lactation can be achieved by
increasing phosphorus digestibility in the diet. (C) 1998 Elsevier Sci
ence B.V.