409 Impact of late-gestation chromium propionate supplementation of Brangus cows on the physiology of the offspring.

Abstract Our objective was to evaluate the effects of late-gestation chromium (CR) supplementation of beef cows on the physiology of the offspring. Twenty-four multiparous Brangus cows [6.3 ± 2.45 yr of age; body condition score (BCS) = 5.5 ± 0.88; body weight (BW) = 603 ± 65.8 kg] were assigned to 1 of 2 treatments (3 cows/pasture; 4 pasture/treatment): 1) control (no CR) or 2) CR. The CR propionate (KemTRACE Chromium 0.4%, Kemin Industries) was added to the free-choice mineral supplement (mineral target intake of 113 g/head/d) at a rate of 1.6% (CR target intake of 6.3 mg/cow/d) and was offered from d -94 to calving (d 0). After calving, all animals were allocated to a single pasture and received the control mineral until weaning (d 214). On d 0, before treatment application, calves were vaccinated against infectious bovine rhinotracheitis (IBR), parainfluenza-3 (PI3) virus, bovine viral diarrhea virus type 1 (BVDV-1) and 2 (BVDV-1), bovine respiratory syncytial virus (BRSV), and Mannheimia haemolytica. Blood samples were collected from cows on d -94, -29, 81, and 214 and calves on d 0, 81 and 214. The free-choice mineral intake was similar between control and CR treatments (60.6 and 55.8 ± 8.49 g/cow/d; P = 0.71), and the CR intake was approximately 3.11 mg/cow/day. On cows, the CR supplementation tended to decrease (P = 0.09) the concentration of serum aspartate aminotransferase (AST) and reduced (P = 0.02) the concentration of alanine aminotransferase (ALT) on d 81. No other effects were detected (P ³ 0.15) for other serum biochemistry variables evaluated on cows. Maternal CR supplementation reduced (P = 0.03) the concentration of ALT and increased the serum titer concentration of BVDV-I in calves. No other effects were detected (P ³ 0.17) for other serum biochemistry variables and serum titer concentration against other viruses on offspring. Our findings suggest maternal chromium supplementation during late gestation reduces serum AST and ALT in cows and reduces serum ALT, and increases the response of vaccination of offspring.