Suspected citrus pulp toxicosis in dairy cattle

Thirteen lactating dairy cows from a herd of 650 died over a 6-week period. Most animals were down in milk production at 1 milking and were found dead at the next milking. Two cows had elevated heart rate and enlarged mandibu lar lymph nodes. Two others had azotemia, elevated heart rate, hyperglycemi a, and weight loss. Necropsy of 10 cows revealed hemorrhages on the intesti nal serosa and epicardium, lymphadenopathy, interstitial nephritis, small i ntestinal hemorrhage, and interstitial pneumonia. Histopathology showed lym phocytic to lymphogranulomatous inflammation in the heart, spleen, kidney, lymph nodes, liver, lung, pancreas, and adrenal gland. Phlebitis was presen t in 2 livers. The lesions resembled those of hairy vetch toxicosis, but no vetch was being fed. Similar lesions have been reported with the feeding o f citrus pulp. Citrus pulp was being fed to the lactating cows and had been added to the diet 6 weeks before the first death. The syndrome resolved wi th elimination of citrus pulp from the diet.