Abstract
Measures of manganese (Mn) status in cattle vary among studies, and no single criterion accurately predicts or diagnoses Mn deficiency and pathologic outcomes. Mn deficiency causes congenital joint laxity and dwarfism (CJLD) when total dietary intake is <20 ppm Mn dry matter (DM) for most of the pregnancy. However, the recommended dietary intake of 40 ppm DM can also result in clinical Mn deficiency. Some studies have found that CJLD occurs in calves from cows fed red clover or silage but not in calves from cows fed hay. The concentration of Mn in the liver is the best indicator of Mn status in neonates and adults but cannot be interpreted in fetuses. Serum, plasma, and whole blood concentrations of Mn are unreliable indicators of bovine Mn status. The primary objective of our report is to present evidence linking CJLD to a primary or secondary Mn deficiency. To predict and diagnose Mn deficiency in cattle, we propose using a combination of clinical signs, dietary Mn, liver Mn at birth and beyond, positive response to Mn supplementation or the replacement of silage with other forages, and ruling out other causes of malformations. By following these recommendations, we expect that CJLD and gestational death will decrease as hepatic Mn concentrations increase at birth. Many publications we reviewed are not statistically sound, and future research should include a statistician from the initial discussions of the study through the final publication.