Influence of feeding direct-fed microbial supplementation on growth performance and feeding behavior in naturally fed and conventionally fed finishing cattle with different dietary adaptation periods

Abstract

To determine the effects of finishing system (conventional vs. natural), dietary adaptation length (14 vs. 28 d), and direct-fed microbial (DFM) supplementation (no DFM vs. DFM) on growth performance and feeding behavior, 120 yearling steers (390 ± 2.8 kg) were used in a completely randomized design with a 2 × 2 × 2 factorial arrangement of treatments. Feed intake was monitored using the Insentec feeding system. Blood samples were collected every 28 d. After 140 d on feed, steers were slaughtered and carcass characteristics collected. Conventionally fed steers had greater (P ≤ 0.001) final BW, carcass weight, and dressing %. Dry matter intake was not influenced (P ≥ 0.31) by treatment. Length of dietary adaptation period did not influence (P ≥ 016) final BW, ADG, and G:F. There was a feeding system × DFM interaction (P ≤ 0.02) for ADG and G:F with conventionally fed steers fed DFM having the greatest (P ≤ 0.05) and naturally fed steers supplemented with DFM having the least (P ≤ 0.05) ADG and G:F. Number of visits to the feed bunk and number of meals per day did not differ (P > 0.05) among treatments. Time eating per visit and per meal was greater (P = 0.05) in steers supplemented with DFM than in steers not supplemented with DFM. On day 56 and 140, plasma glucose concentration was greater (P ≤ 0.03) in steers adapted in 14 d than in steers adapted in 28 d. On day 84, plasma glucose concentration was greater (P = 0.02) in naturally fed compared to conventionally fed steers. On day 112, there was a dietary adaptation period × DFM interaction (P = 0.004) for plasma glucose concentration with glucose concentration greatest (P ≤ 0.05) in steers adapted in 14 d supplemented with DFM and in steers adapted in 28 d not supplemented with DFM, least for steers adapted in 28 d supplemented with DFM, with steers adapted in 14 d not supplemented with DFM intermediate (P ≤ 0.05). On day 112 and 140, plasma urea N concentration was greater (P ≤ 0.05) in steers adapted in 28 d than in steers adapted in 14 d. These data indicate that conventionally fed steers generally had improved growth performance compared to naturally fed steers. Length of dietary adaptation and DFM supplementation had minimal effects on growth performance but did interact with feeding system to influence feeding behavior and blood metabolite concentrations.

Effects of feeding CLOSTAT (Bacillus subtilis PB6) on the clinical health, performance, and carcass characteristics of feedlot steers1

“…(2003) frequently reported the literature supports that direct-fed microbial supplementation is not likely to affect carcass traits. Others have also reported findings similar to those in the present experiment; Swanson et al. (2018) evaluated the effects of the finishing system, dietary adaption length, and direct-fed microbial supplementation on the growth performance and feeding behavior of feedlot steers but did not report an effect of the direct-fed microbial on carcass characteristics.…”

“…Incorporating nutraceuticals into diets of feedlot cattle, especially during the receiving period, may be advantageous, particularly as a management tool to aid in improving animal performance and decreasing morbidity ( Duff and Galyean, 2007 ; Ballou et al., 2019 ;). Research also suggests the supplementation of nutraceuticals in diets of newly received cattle may have the potential to decrease the dietary adaption period, allowing cattle to consume a more energy-dense diet earlier in the finishing period ( Swanson et al., 2018 ). Finally, some data suggest that feeding nutraceuticals may increase performance of finishing cattle ( NASEM, 2016 ).…”

Temporal Dynamics in Rumen Bacterial Community Composition of Finishing Steers during an Adaptation Period of Three Months

“…Swanson et al (2018) reported that an adaptation period of two weeks or four weeks had little effect on growth performance (e.g., final body weight and average daily gain). However, slight risks were present for feedlot steers with an adaptation period of less than four weeks, mainly for animals suffering from subacute or acute acidosis [38]. Previous methodological research has found that an adaptation period of 14 days was suitable for changeover and crossover nutritional experiments with cattle fed forage-based diets [13].…”

Effects of ractopamine hydrochloride supplementation on feeding behavior, growth performance, and carcass characteristics of finishing steers1,2

“…In this study, alterations in the rate of DMI and time eating by steers supplemented with RAC could potentially influence rumen fermentation and result in decreased ruminal pH ( Gonzalez et al, 2012 ). Although visual signs of acidosis were not observed in steers from either treatment, changes in forage source and level ( Swanson et al, 2017 ), grain source ( Rodenhuis et al, 2017 ) and processing ( Swanson et al, 2014 ), time of feeding ( Prezotto et al, 2017 ), and feed additive inclusion ( Swanson et al, 2018 ) can potentially alter effects and interactions with RAC.…”