Effect of feeding kelp on growth and profitability of group-fed calves in an organic production system

The objective of this study was to evaluate the effect of feeding kelp on growth and economics of group-fed organic dairy calves. Heifer calves born at the University of Minnesota West Central Research and Outreach Center, Morris, organic dairy during the fall of 2012 (n = 52) and the spring of 2013 (n = 64) were used to evaluate the effect of feeding kelp on growth and profitability of group-fed calves fed once per day in an organic production system. The treatment groups were (1) control calf starter (18% CP as fed; CON = 5 groups), (2) calf starter plus 56.7 g/d of kelp per calf daily (K2 = 4 groups), or (3) calf starter plus 113.5 kg/d of kelp per calf daily (K4 = 4 groups). Calf groups were fed organically produced milk once daily at 1.5% (DM basis) of the combined birth weight of calves in the group. Body weight and hip height were recorded at birth, once per week, at weaning (60 d), and at 90 d of age. Calf group ADG to weaning and weaning BW were 0.67, 82.2; 0.62, 78.8; and 0.63, 80.7 kg for CON, K2, and K4, respectively. Hip heights at weaning were 94.2, 90.7, and 91.1 cm for CON, K2, and K4, respectively. Daily gains from d 0 to 90 d of age were 0.78, 0.73, and 0.71 kg for CON, K2, and K4, respectively. The cost per kilogram of gain from d 0 to 90 d of age was greater (P = 0.07) for the K4 ($4.13) group compared with the CON ($3.69) group. In summary, calves fed a control calf-starter ration had greater (P = 0.06) ADG than calves fed calf-starter rations with kelp. Feeding kelp in calf-starter rations for organic dairy calves may not be economically justified.