Sequential Unrelated Livestock Fatalities at a Farm: A Case Study
Volume 15, Issue 1 - June 2022
Editor: Linda Chalker-Scott
Accidental ingestion of toxic plant materials and contact with microbes are important causes of livestock fatality. In 2020, four fatalities of beef calves, that had grazed at two separate pastures (Pasture A and Pasture B, respectively, separated by a mile), were reported to have occurred within two months of each other. Two independent necropsies, first on one of the three animals that grazed on Pasture A and the second, on the animal that grazed on Pasture B, and site-visits to both pastures were carried out to determine the cause. Foamy discharge from the mouth of distressed calves indicating agonal death was reported in all animals. Two to three cupful of plant seed material were also recovered from the gut of the animal that grazed on Pasture B. Visits to Pasture A revealed two groves that contained approximately 20 black cherry (Prunus serotina) trees along the periphery of pasture where the animals had grazed, with branches brought down by storms on the ground at one location. We alluded to the possibility that the three animals died of cyanosis caused by accidental ingestion of wilted cherry leaves. Pasture B was a contained by fencing and had indicated signs of overgrazing revealed by poor forage stand and bare spots exposing soil. Seed material recovered from the gut was identified as that of smooth crabgrass (Digitaria ischaemum). We alluded to the possibility that the fourth animal died of clostridial infection. The producer had indicated that the vaccination program of this animal did not include protection against clostridial infection. The veterinarian who performed necropsy on this animal also speculated clostridial infection as a likely cause, however, the presence of large quantities of seed material was confusing. We hypothesized that the acidic environment created by excessive grains promoted rapid multiplication of clostridial bacteria resulting in quick animal mortality.
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