Kale Anaemia. III. A Survey of Kale Feeding Practices and Anaemia in Cattle on Dairy Farms in England and Scotland

On each of 83 dairy farms growing kale in 1969 (49 in southern England and34 in southwest Scotland) blood samples were taken from 10 cows about 4 weeks after the start of kale feeding. Samples were also taken from 70 cows in other herds, not given kale. The mean haemoglobin (Hb) concentration for the kale-fed cows was 10·00 g./ml., and for the control cows, 10·51 g./ml. Of the kale-fed cows 6·4% were classified as anaemic (Hb ≤ 8 g./ml), the respective proportions for England and Scotland being 5·1 and 8·1%. A much higher proportion of the cows (36·4%) showed evidence of disordered blood metabolism in having Heinz-Ehrlich bodies in more than 5% of their red cells. The blood composition of individual cows was not related to their age, milk yield or stage of lactation. The average area of kale grown per cow was 0·10 ha.; most of the kale was marrowstem. Average dry matter intake as kale was estimated to be 3·3 kg./cow per day, or 32% of total dry matter intake. Plant nutrients applied as inorganic fertilizer were 117 kg. N, 29 kg. P and 45 kg. K per ha. Less than 10% of the farmers had observed haemoglobinuria or high heart rates in cows given kale in the year of the survey or in previous years but, in Scotland, diarrhoea was commonly associated with kale feeding. There were no clear relationships between herd mean values for blood composition and cow characteristics (e.g. milk yield), the circumstances in which the kale was grown (e.g. fertilizer application) or the quantity of kale eaten. However, there was a fall in blood Hb between October and December. Ten herds were re-sampled during kale feeding in 1970. Mean blood composition was similar to that found in 1969, except that 2 herds which had had a low Hb concentration in 1969 had values about 2 g./100 m1/. higher in 1970.