Kale anaemia

Abstract
The two main types of kale grown in Britain, marrowstem and thousandhead, both belong to the species Brassica oleracea L. Marrowstem is a thick-stemmed plant, 1–1·5 m tall, whereas thousandhead has a higher ratio of leaf to stem and is a shorter plant. Kale is sown in late spring and normally harvested from October to February, thousandhead being the more resistant to frost. The crop yields about 50 000 kg green matter per hectare (7000 kg dry matter) and is either consumed in situ or cut and carried to housed animals. Cattle are rarely fed on kale alone, but sheep may be; when kale is grazed its consumption is not closely controlled. Kale is grown widely in Britain and north Europe generally, and also in New Zealand.