Productive and physiological responses of feeder cattle supplemented withYucca schidigeraextract during feedlot receiving1

Abstract

This experiment evaluated the effects of supplementing a saponin-containing feed ingredient, manufactured from purified extract of Yucca schidigera [Micro-Aid (MA); DPI Global; Porterville, CA], on performance, health, and physiological responses of receiving cattle. A total of 105 recently weaned Angus x Hereford calves (75 steers and 30 heifers), originating from eight cow-calf operations, were obtained from an auction facility on day −2 and road transported (800 km; 12 h) to the experimental facility. Immediately after arrival on day −1, shrunk BW was recorded and calves were grouped with freechoice access to grass hay, mineral supplement, and water. On day 0, calves were ranked by sex, source, and shrunk BW, and allocated to one of 21 pens (5 calves/pen; being one or two heifers within each pen). Pens were assigned to receive a total mixed ration (TMR) and one of three treatments (as-fed basis): (1) 1 g/calf daily of MA (M1; n = 7), (2) 2 g/ calf daily of MA (M2; n = 7), or (3) no MA supplementation (CON; n = 7). Calves received the TMR to yield 15% (as-fed basis) orts, and treatments were top-dressed from days 0 to 59. Calves were assessed for bovine respiratory disease (BRD) signs and TMR intake was recorded for each pen daily. Calves were vaccinated against BRD pathogens on days 0 and 21. Final shrunk BW was recorded on day 60, and blood samples were collected on days 0, 2, 6, 10, 14, 21, 28, 34, 45, and 59. ADG was greater (P = 0.03) in M2 vs. M1 and CON (1.53, 1.42, and 1.42 kg/day, respectively), and similar (P = 0.95) between M1 and CON calves. No treatment effects were detected for TMR intake (P = 0.52), whereas feed efficiency was greater (P ≤ 0.05) in M2 vs. M1 and CON calves (213, 200, and 204 g/kg, respectively) and similar (P = 0.40) between M1 and CON calves. No treatment effects were detected (P = 0.39) for diagnosis of BRD signs. The number of antimicrobial treatments required upon BRD diagnosis was greater (P ≤ 0.01) in CON vs. M1 and M2 (1.40, 1.05, and 1.10 treatments, respectively), and similar (P = 0.60) between M1 and M2 calves. No other treatment effects were detected (P ≥ 0.23), including circulating concentrations of hormones and metabolites, serum antibody titers to BRD pathogens, and mRNA expression of innate immunity genes in whole blood. Collectively, results from this experiment suggest that MA supplementation at 2 g/animal daily enhances performance and response to BRD treatment in high-risk cattle during feedlot receiving.

Impacts of commingling cattle from different sources on their physiological, health, and performance responses during feedlot receiving

“… Cumulative incidence of bovine respiratory disease (BRD) symptoms beef heifers commingled (2SRC = two sources; n = 8; 4SRC = four sources, n = 8) or not (1SRC = single source, n = 8) with cohorts from different cow-calf sources during a 56-d feedlot receiving period. Heifers were observed daily for symptoms of BRD according to the DART system (Zoetis, Florham Park, NJ) and Sousa et al (2019) , and received antimicrobial treatment as described in Lopez et al (2018) . No treatment differences nor the treatment × day interaction were detected ( P ≥ 0.24).…”

“…The heifers used in this experiment were considered high-risk as their management and health history were not fully known ( Wilson et al, 2017 ; Sousa et al, 2019 ). All heifers were exposed to the stress of transport, initial processing, and exposure to a new environment within a 48-h period, whereas the combination of these stressors impact physiological and immune responses in cattle ( Duff and Galyean, 2007 ; Cooke, 2017 ).…”

“…Heifers were observed daily for symptoms of BRD according to the DART system (Zoetis) and Sousa et al (2019) , using rectal temperature ≥40.0 °C (GLM-500, GLA Agricultural Electronics, San Luis Obispo, CA) as clinical criterion, and received antimicrobial treatment similar to Lopez et al (2018) . More specifically, heifers diagnosed with BRD received florfenicol with flunixin meglumine (Resflor Gold, Merck Animal Health) at 1 mL/7.6 kg of BW subcutaneously as the first antimicrobial administered, followed by a 5-d moratorium.…”

Supplementing Yucca schidigera extract to mitigate frothy bloat in beef cattle receiving a high-concentrate diet

“…Supplementing the Y. schidigera extract at 2 g/d (as-fed basis) improved in situ ruminal forage digestibility and microbial N flow in forage-fed steers (McMurphy et al, 2014a), as well as feed efficiency and average daily gain (ADG) in feedlot receiving cattle (Sousa et al, 2019). These latter authors did not report bloat incidence in their study, and the impacts of Y. schidigera extract on bloat in cattle fed high-concentrate diets remain unknown.…”

“…With increased public pressure and restrictions regarding the use of feed-grade antimicrobials in livestock systems (US Food and Drug Administration, 2015), alternative feeding strategies to prevent health and digestive disorders in grain-fed cattle are warranted. One example is the use of plant-derived feed additives such as Yucca schidigera extract (Sousa et al, 2019). This additive has been shown to improve rumen fermentation by decreasing population of protozoa and bacteria such as Streptococcus bovis (Wallace et al, 1994), which are associated with the etiology of bloat in grain-fed cattle (Cheng et al, 1998).…”