Influence of Megasphaera elsdenii and feeding strategies on feedlot performance, compositional growth, and carcass parameters of early weaned, beef calves

Abstract

Simmental–Angus calves [n = 135; 72 steers and 63 heifers; body weight (BW) = 212.4 kg ± 36.1] were early weaned (~5 mo) to evaluate multiple feeding regimens (conventional vs. aggressive energy diets ± Megasphaera elsdenii NCIMB 41125 (M. elsdenii culture (MEC); Lactipro Advance; MS Biotec Inc., Wamego, KS) in order to elucidate the optimal development strategy. Objectives were measured by tracking the effects of caloric density and oral drenching of growing phase performance and subsequent carcass traits. The 72-d experiment featured three groups: 1) control (CON), fed exclusively a 35% roughage diet; 2) aggressive (AGR), fed a blend of a 10% and 35% roughage diets; 3) MEC, fed the same diet as AGR and drenched with 50 mL of M. elsdenii NCIMB 41125 on day 1. A subset of calves (n = 45) was equipped with wireless rumination tags (Allflex Flex Tag; SCR Engineers, Ltd; Netanya, Israel), which logged daily rumination and general activity. Skeletal growth variables were assessed by measuring wither and hip height pretrial and posttrial. Ultrasonography provided additional resolution concerning growing phase compositional gain, which was later verified by carcass data collection. Data were analyzed as a nested analysis of variance with BW and gender serving as blocking factors. The increased caloric density of the diets administered to MEC and AGR calves resulted in greater average daily gain and gain:feed values compared with CON even during the first 21 d of diet acclimation (P ≤ 0.05). Additional fiber concentration of CON diets led to increased rumination times in 9 of the 10 wk of trial (P ≤ 0.10). No differences amongst treatments were detected for skeletal variables or ultrasound 12th rib fat. Cattle fed CON diets posted 3.4% inferior BW at the end of the growing period trial and a 3.8% reduction in hot carcass weight (HCW), reinforcing the theory that intensifying caloric intake during the growing phase does not compromise future feedlot performance. Ultrasound marbling scores for MEC-treated cattle were 19° greater than AGR treated cattle (P ≤ 0.05) at the end of the growing phase trial. Nearly the exact same advantage (22°) was observed in the cooler 5 mo later (P = 0.42). Implying MEC metabolically imprinted cattle to favor marbling development. It appears that maximizing dietary caloric density in light-weight calves does not adversely affect the growth curve, while oral dosing of MEC during the growing period may be a precursor for enhanced quality grade.

Effects of Megasphaera elsdenii administration on performance and carcass traits of finishing Bos indicus feedlot cattle

“…The lack of statistical significance on mean DMI for animals dosed with MEG corroborate with other studies in beef ( Drouillard et al, 2012 ; DeClerck et al, 2020a ; DeClerck et al, 2020b ; DeClerck et al, 2020c ) and dairy cattle ( Aikman et al, 2011 ; Henning et al, 2011 ). Evaluating a subacute ruminal acidosis ( SARA ) model, Mazon et al (2020) demonstrated that MEG administration 4 d prior to the challenge reduced the time-period and area at which rumen pH remained below 5.8 and 5.6, as well as improved DMI and milk production of mid-lactation dairy animals.…”

“…Conversely, the lack of ruminal disorders in MEG-0 and MEG-6 supports the efficacy of MEG in alleviating the occurrence of digestive disorders in beef cattle offered a high-concentrate diet without a step-up adaptation period ( Kettunen et al, 2008 ; Horn et al, 2009 ; McDaniel et al, 2009 ; DeClerck et al, 2020b ). DeClerk et al (2020c) also did not report any case of clinical acidosis in beef calves abruptly transitioned from a grower to a finishing diet over a short period of time, supporting the efficacy and success of ruminal colonization after exogenous MEG drench. Removing the adaptation diet from the feedlot might benefit the entire operation, given the elevated cost per unit of energy and that the use of forage and consequent the space required to store this bulky material will consequently decrease ( Buttrey et al, 2012 ; Schneider et al, 2017 ).…”

“…Megasphaera elsdenii is a gram-negative bacterium that consumes a major fraction of lactic acid produced in the rumen ( Counotte et al, 1981 ) and, therefore, reduces the occurrence of rumen acidosis ( Kung and Hession, 1995 ). The utilization of a commercial patented strain (Lactipro NXT; M. elsdenii NCIMB 41125) has demonstrated positive results in controlling acidosis under in vitro ( Horn et al, 2009 ; McDaniel et al, 2009 ) and in vivo ( Drouillard et al, 2012 ; DeClerck et al, 2020a ; DeClerck et al, 2020b ; DeClerk et al, 2020c ) experimental settings.…”

“…Similar results were observed when MEG administration was evaluated in beef cows receiving a low- and high-roughage diet (10% and 25% diet DM, respectively) for 42 d ( DeClerck et al, 2020a ). Conversely, the same group of researchers reported improvements in performance over a 72-d period of newly-weaned beef calves receiving MEG and offered a high-concentrate diet containing 22.7% and 38.7% starch from steam-flaked corn during the growing and finishing diets, respectively ( DeClerck et al, 2020c ). In the present study, animals were offered high-starch diets containing 31.2% to 42.9% starch from ground flint corn for 119 (MEG-0), 112 (MEG-6), and 105 (MEG-14 and CONT) d, which is a significantly longer feeding period than the aforementioned studies and others reported in the literature.…”

“…Inoculation of MEG in animals assigned to reduced number of step-up diets during the adaptation period (3 vs. 5 diets) resulted in a maintenance of live feedlot performance (final BW, ADG, and feed conversion rate) and DMI over a 95-d period, whereas carcass ADG and HCW were positively impacted by MEG orally drenched to cattle ( Drouillard et al, 2012 ). Subsequently, DeClerck et al (2020c) demonstrated that MEG inoculation in beef calves abruptly transitioned to a finishing diet improved ADG and FE when compared to cohorts fed a growing diet during the initial feedlot period. To the best of our knowledge, no other research trial evaluated the effects of MEG in feedlot animals without any type of adaptation/transition diet management protocol.…”