This may explain why pigs appear to be most susceptible at weaning because they have likely consumed very little drinking water before this time. The major effect of poor quality drinking water on pigs is diarrhea, especially in the case of the weanling pig. Adult swine are more tolerant but also exhibit diarrhea in severe cases. Diarrhea, at varying levels of severity, is almost always present when pigs consume poor quality water. The impact of water quality on animal performance is not always clear.
Clinical reports suggest a major impact of poor quality water on animal performance on some farms.
Yet, controlled research has consistently concluded that pigs have considerable ability to handle water of widely varying quality with no effect on performance. The observation on increased diarrhea has never been questioned. The results of experiments summarized in Tables 4 to 6 provide useful information. The pigs actually grew better on the poor quality water, apparently due primarily to increased feed intake. From these studies, and research conducted elsewhere, it is clear that pigs can perform well on water containing high levels of sulphate.