The intrauterine effects of a maternal winter diet of either kale or fodder beet on measures of calf stature and bone morphology at birth

ABSTRACT Fodder beet and kale are commonly used winter crops in New Zealand dairy and dairy support farm systems. Fodder beet (FB) is known to have lower crude protein, phosphorus and calcium content compared to kale. The intrauterine effects of feeding FB during late pregnancy on bone growth and development in calves requires attention. This study aimed to examine the intrauterine effects of a maternal diet of either kale or FB on measures of calf stature and bone morphology at birth. In winters 2019 and 2020, two herds of pregnant Friesian × Jersey cows were fed either kale (2019, 2020 n = 20) or FB (2019, 2020 n = 20) supplemented with pasture baleage. Calves born from these mobs were euthanised within ten days of birth and a forelimb and section of rib including the costochondral junction were harvested for peripheral quantitative computed tomography and histological analysis. Calves from the FB treatment had reduced bone density and strength compared to calves from the kale treatment ( p < .05). The effect of a nutritional deficit on bone morphology at birth emphasises the importance of sufficient nutrition in pre‐calving diets. Future research is required to examine the long‐term impact of dam undernutrition on calf growth and production.