PSXII-1 Effects of copper, zinc, and manganese source and concentration during late gestation on beef cow colostrum yield and quality.

Our objective was to determine effects of Cu, Zn, and Mn metal methionine hydroxy analogue chelates (MMHAC) on beef cow colostrum. Multiparous, fall-calving, Sim-Angus cows (n = 48; BW: 649 ± 80 [SD] kg; BCS: 5.3 ± 0.5; age: 4.3 ± 1.2 yr) were individually-fed tall fescue-based hay (12.2% CP, 61.5% NDF; DM basis) and DDGS and soyhulls-based supplement daily to meet or exceed all nutrient recommendations except Cu, Zn, and Mn. Cows were allocated by BW, BCS, age, and breeding group during late gestation (91.2 ± 6.2 d pre-calving) to receive: no additional Cu, Zn, or Mn (CON); Cu, Zn, and Mn sulfates supplying 133% NASEM recommendations (ITM); Cu, Zn, and Mn as MMHAC (MINTREX®, Novus International) supplying 133% NASEM recommendations (CTM); or sulfate and MMHAC Cu, Zn, and Mn supplying 100% NASEM recommendations (reduce and replace, RR). Cows were moved to calving pens 17.5 ± 8.0 d pre-calving and pen-fed treatments. Single rear-quarter total colostrum yield was collected pre-suckling and analyzed. Treatment and breeding group were fixed effects in the model. Treatment tended to affect (P ≤ 0.10) colostrum yield, where cows fed CTM had greater weight (P ≤ 0.06) and volume (P ≤ 0.04) than ITM and RR. Cows fed CTM had greater (P ≤ 0.04) lactose (% and total g) than ITM and RR. Additionally, CON tended (P = 0.06) to have greater lactose concentrations than RR. Colostrum from ITM and CTM had greater (P ≤ 0.04) Zn concentrations than CON and RR, whereas CTM had greater (P ≤ 0.05) total Zn than other treatments. There was no treatment effect (P ≥ 0.17) on colostrum protein, urea N, Cu, Mn, IgG, IgA, and IgM (concentration and total). Chelated Cu, Zn, and Mn supplementation may increase colostrum yield, while also improving nutrient composition, in beef cows.