Performance, health, and physiological responses of newly received feedlot cattle supplemented with pre- and probiotic ingredients

Nutritional strategies that optimize immunity of feedlot cattle are warranted due to increasing regulations with the use of feed-grade antimicrobials. This study evaluated physiological, health, and performance responses of cattle receiving a synbiotic supplement (yeast-derived prebiotic + Bacillus subtilis probiotic), which replaced feed-grade antimicrobials or were fed in conjunction with monensin during the initial 45 days in the feedlot. Angus-influenced steers (n = 256) were acquired from an auction facility on day -2, and transported (800 km) to the feedlot. Shrunk BW was recorded upon arrival (day -1). Steers were allocated to 1 of 18 pens (day 0), and pens were assigned to receive (n = 6/treatment) a free-choice diet containing: (1) monensin and tylosin (RT; 360 mg/steer daily from Rumensin and 90 mg/steer daily from Tylan; Elanco Animal Health, Greenfield, IN, USA), (2) yeast-derived ingredient and B. subtilis probiotic (CC; 18 g/steer daily of Celmanax and 28 g/steer daily of Certillus; Church and Dwight Co., Inc., Princeton, NJ, USA), or (3) monensin in addition to yeast-derived and B. subtilis ingredients (RCC) as in RT and CC. Steers were assessed for bovine respiratory disease (BRD) and DMI daily. Steer BW was recorded on days 45 and 46, and averaged for final BW. Blood samples were collected on days 0, 7, 17, 31, and 45. Feed intake was greater (P ≤ 0.05) in CC vs. RCC and RT during the initial 3 weeks upon feedlot arrival. No treatment differences were noted (P ≥ 0.41) for average daily gain, BW, and feed efficiency. Incidence of BRD did not differ (P = 0.77) between treatments (average 80.1%). A greater proportion (P ≤ 0.03) of RT steers diagnosed with BRD required a second antimicrobial treatment compared with CC and RCC (57.3, 37.3, and 38.6%, respectively). Removal of steers from the trial due to severe morbidity + mortality was greater (P = 0.02) in RT vs. CC (22.4 and 7.0%), and did not differ (P ≥ 0.16) among RCC (12.9%) vs. RT and CC. Plasma glucose concentrations were greater (P ≤ 0.02) in CC vs. RCC and RT on day 7. Plasma concentrations of nonesterified fatty acids were greater (P ≤ 0.02) in RT and RCC vs. CC on day 7, and in RT vs. CC on day 17. Steers receiving the synbiotic supplement had improved response to BRD treatment, suggesting heightened immunocompetence from partially enhanced metabolism and the nutraceutical effects of B. subtilis and yeast compounds.

Effect of Pluronic-F68 fog solution on performance and morbidity of newly received heifer calves

Morbidity and mortality from bovine respiratory disease (BRD) of newly received feedlot cattle continue to be problems for the feedlot industry. The objective of this study was to evaluate the effects of utilizing a novel breathing treatment containing a nonionic surfactant (Pluronic-F68) on performance and morbidity of high-risk calves during a 45-d receiving period. Angus/Angus-cross heifer calves (n = 240) were acquired in Delhi, LA, and transported (14 h) to the research facility. Heifers were allowed 21-h rest with access to water and RAMP prior to processing. Heifers were sorted into 16 pens by processing order and randomized by pen into one of two treatments: novel breathing treatment containing 6.25% Pluronic-F68 solution, 28.13% glycerin, and 65.62% water (FOG; n = 8 pens per treat and 15 heifers per pen) and control (CON; n = 8 pens per treat and 15 heifers per pen). Control heifers were held in an enclosed stock trailer for 10 min and followed by FOG heifers, during which time treatment was administered. The person responsible for identifying signs of morbidity was blinded to treatment assignments. Data were analyzed as a completely randomized design using MIXED (continuous) or GLIMIX (binomial) models of SAS 9.4. Average daily gain was similar between treatments (P = 0.91). No differences were found in dry matter intake (P = 0.14) nor in gain efficiency (P = 0.58). There were no differences (P = 0.74) in final body weights. Morbidity was similar at first, second, and third antimicrobial administration regardless of treatment (P ≥ 0.34). The number of antimicrobial treatments required or the management of BRD was similar between treatments (P = 0.72). There was no difference (P = 0.44) in mortality between FOG and CON groups. The Pluronic-F68 solution did not improve performance or reduce morbidity of newly received heifer calves; however, further research with a different concentration and/or duration of fogging may be warranted.