Effect of Replacing Dietary Inorganic Forms of Zinc, Manganese, and Copper with Complexed Sources on Lactation and Reproductive Performance of Dairy Cows

Abstract

ABSTRACT One hundred eighty multiparous Holstein cows (90 cows/treatment) were blocked according to calving date and randomly assigned to a study to determine the effect of trace mineral source on performance. Treatments were 1) all trace minerals supplied by inorganic sources or 2) inorganic minerals (360 mg Zn/d, 200 mg Mn/d, and 125 mg Cu/d) replaced with amino acid complexes of Zn, Mn, and Cu (CTM, Availa-4, Zinpro Corporation). Neither level nor source of Co supplementation differed between dietary treatments. Cobalt was supplemented as Co carbonate to supply 12 and 23 mg Co/d to dry and lactating cows, respectively. Cows received their respective treatments from 60 d prior to calving through 200 d oflactation. Replacing inorganic trace minerals with CTM tended to increase (P = 0.06) milk protein yield (1.09 vs. 1.05 kg/d) and tended to decrease (P = 0.15) linear SCC. There was no effect oftreatment on milk yield and yields of 3.5% fat-corrected milk and energy corrected milk. Feeding CTM increased (P = 0.005) BCS (2.97 vs. 2.86), decreased (P = 0.02) culling rate (13.3 vs. 25.6%) and tended (P = 0.07) to increase incidence of retained placentas (13.3 vs. 6.7%). Feeding CTM also tended to decrease (P = 0.15) incidence of metritis (14.4 vs. 16.7%) and to increase (P = 0.15) first service conception rate (21.9 vs. 19.1%). Replacing inorganic trace minerals with those supplied by CTM tended to improve lactation performance and reduced culling rates.