Impact of winter fodder beet or kale allocation on body condition score gain and early lactation performance of dairy cows

Forage crops such as fodder beet (FB) and kale are an important feature of dairy farming in Southland and Otago where winter pasture growth is negligible. However, farmers are concerned about poor performance of cows following winter FB feeding. In winter 2017, cows were offered FB or kale both with pasture baleage at two allocation rates: target (crop allocated to achieve a winter body condition score (BCS) gain of 0.7) or high (ad libitum crop). Diets with FB were lower in fibre, phosphorus, sulphur and calcium, but had a higher metabolizable energy, compared with kale diets. Body condition change and early lactation performance were monitored to compare effects of winter FB and kale diets. Average daily BCS gain before calving was similar for FB and kale cows. Crop type had a greater impact on cow performance than allocation rate. Cows wintered on FB had better reproductive performance (3-week pregnancy rate), and greater average milk solids, fat and protein yield (kg/d) than cows wintered on kale. Therefore, winter FB did not reduce cow performance compared with kale. However, the cumulative effects of a FB diet long term are yet to be determined and future research should monitor the impact on animal health.