Nierembergia rivularis poisoning in cattle

Nierembergia rivularis causes enzootic calcinosis (EC) in sheep. In this work, we describe EC caused by N. rivularis in cattle. For 3 years cattle grazing in 7 paddocks were evaluated. Cows with clinical signs compatible with EC were detected in only one paddock with a morbidity of 9.4%, 24.5%, and 34.5% during the summer of 2019, 2020, and 2021, respectively. Affected cows weighed 55 kg less (p < 0.01) than cows without signs of the same paddock, and 19.6% of these cows had hypercalcemia and/or hyperphosphatemia. Typical soft tissue calcification was observed in 3 autopsied cows. Additionally to the arterial calcification, 2 cows had multiple mineralized foci in several veins. In the Paddock A where EC occurred, the pasture contained 7-12% N. rivularis. In the other 6 paddocks (Paddocks B-G) where EC had not occurred, the pasture had 0.2-3.5% N. rivularis. Cows grazing in Paddock A had similar to 30% lower pregnancy rates than cows from Paddocks B-G. At the slaughterhouse, the carcasses of 45 cows from Paddock A weighed 17.6% (p < 0.01) less than 93 carcasses of cows from Paddocks BG. Furthermore, the carcasses of cows from Paddock A were classified as low quality. Eight cows with EC signs from Paddock A and 10 cows without EC signs from Paddocks B-G were removed to a Lolium multiflorum pasture. After 120 days of grazing, the cows from Paddock A gained 45.2% less (p < 0.01) live weight than cows from Paddocks B-G. Poisoning with N. rivularis may cause significant economic losses in Uruguay due to low fertility rates and weight gain of affected cattle.

Automated summary

This study found that Nierembergia rivularis can cause enzootic calcinosis in cattle, leading to weight loss and reduced pregnancy rates, resulting in significant economic losses.