Accidental sodium chloride poisoning in sheep – a case study

In April 2015, a farmer in the Silesia Region, Czech Republic, suffered a massive loss of 51 sheep. Two days before the incident, the flock of approximately 300 sheep were transferred from their wintering stable to pastureland. The pasture had a brook as a source of drinking water and in addition, a water cistern with drinking water was provided as well as mineral salt licks; otherwise the animals were left to graze with no supplementary feed. During the night of 28/29 April it rained heavily. The salt blocks were damaged and softened, showing signs of intensive nibbling. In the morning of 29 April, dead animals were found all over the pastureland. Four of the sheep were sent for post mortem examination and toxicological analyses. Evidence of extremely high concentrations of NaCl in the liver samples and characteristic pathologicalanatomical findings confirmed the suspicion that the sheep had died of fodder salt poisoning. The rapid and extreme change in the weather conditions, soaking of the otherwise solid salt lick, and the short period of acclimatisation of the sheep to the pasture were at fault. The main preventative measure is to respect the transitory period for the animals to get accustomed to a different kind of roughage and local conditions. This case is noteworthy because of the number of animals affected, the speed of the poisoning progress, and the detailed pathological examination of the dead animals. As there is a limited number of articles describing salt poisoning in sheep, this case study may contribute to the broadening of the knowledge on this issue.