Assessment of the role of manganese in congenital joint laxity and dwarfism in calves.

Pregnant beef cows were winter-fed (November 15 to calving) hay (24 cows), red clover silage (21 cows) or grass silage (52 cows). Blood samples were taken from each cow in December and February. A condition of congenital joint laxity and dwarfism was observed in 38% and 28% of calves born to cows fed red clover silage and grass silage, respectively. None of the calves born to hay-fed cows were affected by the condition. The congenital joint laxity and dwarfism was associated with a lower serum manganese concentration in silage-fed cows than in hay-fed cows. However, manganese concentrations were similar in red clover silage, grass silage and in hay. A lower bioavailability of manganese in silages other than in hay, resulting in an apparent manganese deficiency in silage-fed cows, is suggested as a possible factor contributing to the etiology of congenital joint laxity and dwarfism in calves.