170 Bakery Waste Supplementation to Late Gestating Bos Indicus-Influenced Beef Cows Successfully Impacted Offspring Postnatal Performance

Abstract

Abstract This study evaluated the growth and immune function of Bos indicus-influenced offspring born to cows offered prepartum supplementation of bakery waste containing 2 concentrations of crude fat. On day 0 (~90 d before calving), 108 Brangus crossbred cows were stratified by body weight (BW; 551 ± 65 kg) and body condition score (BCS, 5.5 ± 0.9) and were randomly allocated into 1 of 18 bahiagrass pastures (6 cows and 4.3 ha/pasture). Treatments were randomly assigned to pastures (6 pastures/treatment) and consisted of no prepartum supplementation (NOSUP) and 1 kg/d of low-fat (LFAT; 6.4% crude fat) or high-fat (HFAT; 10.7% crude fat) bakery waste-based supplement from day 0 to 70. Calves were weaned on day 292. Then, 15 heifers/treatment were randomly selected, acclimated for 7 d, and assigned to drylot pens from day 300 to 345. Heifers were vaccinated against respiratory pathogens on days 300 and 315. Cow BCS on day 70 was the least (P ≤ 0.05) for NOSUP cows and did not differ (P ≥ 0.12) between LFAT and HFAT cows. Cow BCS on day 140 (start of breeding season) was greater (P = 0.05) for HFAT vs. NOSUP cows and intermediate (P ≥ 0.35) for LFAT cows. Plasma concentrations of total polyunsaturated fatty acids (PUFA) in HFAT cows did not differ (P ≥ 0.76) compared with LFAT cows on day 70, were greater (P ≤ 0.05) compared with NOSUP cows on day 70 and were the greatest on day 140 (P ≤ 0.05). Percentage of cows pregnant on day 292 did not differ (P ≥ 0.26) among treatments but more HFAT cows calved (P ≤ 0.05) their second offspring from day 429 to 450 compared with NOSUP and LFAT cows. First offspring BW on day 292 were greatest (P ≤ 0.05) for LFAT calves and least for NOSUP calves. Maternal treatments did not impact (P ≥ 0.11) post-weaning average daily gain (ADG) and total DM intake. Average plasma cortisol concentrations were greater (P = 0.03) for NOSUP vs. HFAT heifers and intermediate for LFAT heifers (P ≥ 0.26). Final serum titers against infectious bovine rhinotracheitis (IBR) and bovine respiratory syncytial virus (BRSV) were greater (P ≤ 0.08) for LFAT vs. HFAT heifers and intermediate (P ≥ 0.27) for NOSUP heifers. Therefore, crude fat concentration in bakery waste offered to late-gestating beef cows had variable effects on offspring performance. Low-fat bakery waste led to greatest offspring preweaning growth whereas high-fat bakery waste enhanced maternal reproductive success and offspring post-weaning humoral immune response.