Feeding wash water solids to sows during gestation and lactation: sow productivity, pig performance, and tissue compositions.

Diets containing 0, 10, or 20% dried wash water solids (WWS) from a milk processing plant were fed to 54 Yorkshire gilts (160 to 270 kg) for five parities. Feed intake, weight changes, and morbidity of sows were measured; number of pigs per litter, birth weight, and weight gain of pigs were also determined. Blood, tissue, and milk samples were taken from sows for hematological and mineral analyses, and tissue samples were taken from newborn pigs from each treatment per parity. Overall, initial sow weight, sow weight at weaning, and weight losses were not affected (P greater than .05) by treatment. At 107 d of gestation, overall weights decreased (P less than .05) linearly with level of WWS in the diet. The number of pigs per litter and weight of pigs were not affected (P greater than .10) by diet. Concentrations of NA (P less than .10) and Cd (P less than .05) were lower in kidney of sows fed 20% WWS, and concentrations of Zn were lower in bone and in kidney of sows fed the 20% WWS diet. The Sr and Ba concentrations increased (P less than .05, P less than .10) linearly in bone from sows with level of WWS in the diet. In pigs, concentrations of Mn in kidney and Zn in liver were lower for the 20% WWS treatment. In conclusion, feeding WWS to sows over five parities had minimal adverse effects on sow productivity and pig performance; the reduction in Zn concentrations in tissues of sows and pigs seemed to be related to the Ca content of WWS.