Feeding broccoli and cauliflower to dairy sheep: influence on feed intake, metabolic health status and milk production and composition

The production of broccoli and cauliflower generates large amounts of vegetable by-products that often accumulate in the environment; however, these residues have nutritional value for ruminants. This study evaluated the effects of including industrial broccoli and cauliflower waste in the diet of dairy ewes on feed intake, metabolic health and milk production and composition. Thirty Assaf dairy ewes in mid-lactation were divided into three groups, with 10 animals per group. The control group (CON) received a total mixed ratio (TMR) ad libitum, the broccoli group (BRO) received the same TMR plus 1.5 kg FM/d of fresh chopped broccoli, and the cauliflower (CAU) group received the TMR plus 1.5 kg/d of fresh chopped cauliflower. The trial lasted 42 d, divided into 21 d for adaptation and 21 d of measurements, where feed intake and milk yield were recorded daily. Milk samples were taken once a week. At the end of the experiment, fresh cheese was prepared, using the milk from each feeding group. A sensory analysis was carried out, to detect eventual differences in flavour among treatments. Blood samples were taken to analyse the biochemical profile and acid-base status. The animals of the BRO and the CAU groups ate all the vegetal offered without decreasing the daily intake of TMR or affecting milk production. No differences were observed between groups in the biochemical profile or the blood acid-base status, with the exception of the urea concentration, which was higher in the BRO group compared to the control (55.2, 61.8, 57.2 mg/dL for CON, BRO and CAU; P= 0.022). Regarding milk composition, the most relevant differences were observed in protein content, being higher in the BRO group (P=0.006) than in the CON and CAU groups, and in the fatty acids profile, which showed an increase in the saturated fatty acids content (P=0.012) and a decrease in the monounsaturated fatty acids content (P=0.005) in the groups supplemented with broccoli and cauliflower. In conclusion, supplementation with 1.5 kg of broccoli or cauliflower in lactating sheep did not affect feed intake, milk production or health status of the animals and had little impact on the quality of milk.