Three alfalfa biotypes were chosen based on the presumption that they would be sources of alfalfa herbage that differed in lignin concentration and therefore cell wall digestibility. The hypothesis was that a lesser lignin concentration would result in greater alfalfa neutral detergent fiber (NDF) digestibility and greater beef steer growth performance. The three alfalfa biotypes were HarvXtra (Forage Genetics International), Hi-Gest 360 (Alforex Seeds), and a control alfalfa, and LegenDairy XHD (Winfield Solutions LLC). High-moisture wrapped bales were prepared from second-harvest, d 30 crops. Digestibility of NDF was determined using in vitro incubations and a steer digestibility trial. Alfalfa baleage and trace mineral salt were fed to Angus steers (300 kg initial body weight, 4 pens/treatment) in an 83-day growing-phase trial. Alfalfa acid detergent lignin concentrations were 75.6, 71.8, and 63.0 g/kg dry matter (P = 0.34) for LegenDairy, Hi-Gest and HarvXtra, respectively. Based on in vitro total-tract NDF digestibility coefficients, HarvXtra tended (P ≥ 0.09) to have the highest NDF digestibility. Alfalfa biotype affected in vivo apparent total tract digestibility of NDF (P < 0.001) and there was a trend for an effect on acid detergent fiber digestibility (P = 0.051). Hi-Gest and HarvXtra had similar in vivo apparent NDF digestibilities, which were greater than for LegenDairy (P < 0.05). There was no alfalfa biotype effect on daily alfalfa dry matter intake (DMI; P = 0.51) or average daily gain (P = 0.25) by growing steers. The absence of an effect by the novel alfalfa biotypes on DMI by growing steers suggests that the compositional and digestibility differences of the novel alfalfa biotypes compared to LegenDairy were not sufficient to alleviate the limitation of physical fill (if evident) on DMI. If more disparity in cell wall composition and NDF digestibility were to exist between control and reduced-lignin biotypes, then perhaps an advantage in cattle growth performance for a reduced-lignin alfalfa biotype would be detectable.

Weather conditions often dictate the quality of corn, corn silage, and corn stover harvested for livestock feed. When growing and/or harvest conditions are wet, mycotoxin producing fungi can flourish. Mycotoxin levels were determined to be elevated in the fall 2018 corn crop (Table 1). A 3 x 2 factorial experiment was initiated to observe effects of a mycotoxin binder, hydrated sodium calcium aluminosilicate (Engage-M, United Animal Health, Sheridan, IN), on cattle performance. Three treatment diets with elevated mycotoxin levels were amended with Engage-M fed at 0 or 14 g hd-1 d-1. Steers (n = 72, 12 pens total) were fed during Grow (21 d) and Finish (51 d) phases. During the Grow phase a 52% corn silage, 20% DDGS, and 8% supplement basal diet was fed and treatments were an additional 20% diet DM included as corn silage (CSIL), conventional corn stover (CST), or single-pass bale stover (SPB). Cattle fed Engage-M during Grow phase had numerically higher daily gains, 1.35 kg d-1, compared to no binder, 1.26 kg d-1 (P = 0.17). During the Finish phase, all cattle were fed similarly (72.1% rolled corn, 12% corn silage, 8.9% DDGS, 7% supplement diet DM). Cattle fed Engage-M tended (P = 0.09) to have increased daily gains, 2.07 kg d-1, compared to no binder, 1.9 kg d-1. Dry matter intake was similar for both treatments during the Finish trial, 12.9 kg hd-1 d-1 (P = 0.83), suggesting the increase in cattle performance was due to improved utilization of feed and not feed intake. The Finish phase feed to gain ratio was 6.25 vs. 6.83 (P = 0.06) with and without Engage-M, respectively. The trend was for cattle fed Engage-M to be 9.2% more efficient. The present study suggests that feeding Engage-M may increase cattle performance when diets have elevated levels of zearalenone and vomitoxin.

Novel alfalfa varieties have been developed to have less lignin by genetic modification, (HarvXtra, Forage Genetics International) and by conventional breeding, (HiGest 360, Alforex Seeds). Second crop (d 29) of these alfalfas and a control, LegenDairy XHD (Winfield Solutions LLC), were harvested as high moisture wrapped bales (45.9–51.6 % DM) at the Arlington Agricultural Research Station (AARS) located near Arlington, WI, on July 5, 2017. The objectives of these experiments were to characterize novel reduced-lignin alfalfa varieties, assess their effects on growth of beef steers, and determine digestibilities using a total fecal collection trial. Treatments were fed ad libitum as alfalfa baleage to 300 kg (initial weight) black-hided beef steers, (n = 72, 4 pens/treatment, 83 d). Steers were fed solely alfalfa baleage and offered a trace mineral salt block by way of fence line feed bunks. Alfalfa lignin values were 7.56, 7.18, and 6.3% DM (P = 0.34) for LegenDairy, HiGest and HarvXtra, respectively. Steers gained 0.94, 1.00, and 1.07 kg hd-1 d-1 (P = 0.25) for LegenDairy, HiGest and HarvXtra, respectively. The same harvested alfalfa was used in a total collection fecal trial with fecal collection bags (Table 1). Numerical differences between alfalfa digestibilities were observed but no significant treatment effects were detected. Total tract NDF digestibilities (TTNDFD) for harvested alfalfas were 33.9, 35.0 and 40.3 % NDF (P = 0.079) for LegenDairy, HiGest and HarvXtra, respectively. Alfalfa lignin concentration differences were not detected through acid detergent-lignin analysis of harvested bales. While the ranking of lignin concentrations, digestibilities, and growth rates followed prevailing logic, alfalfa variety treatment effects were not detected. Experimental designs with greater sensitivity should be implemented in the future.

Corn stover supports feedlot operations in intensive corn producing regions. A single-pass corn grain and stover harvest system was developed to increase efficiency of field operations and capture different anatomical fractions than are typically harvested with conventional corn stover. The objectives were to feed beef steers diets that included a roughage component consisting of harvested corn residue in chopped form from conventional corn stover bales (CST) or single-pass bales (SPB). Whole-plant corn silage (WPCS) served as a control. Steers (n = 90, 5 pens/treatment) were fed during Grow (84 d) and Finish (66 d) phases to assess consumption of corn plant botanical fractions and calculate net energy values of the stover feeds. Cattle consumed a larger proportion of stover as cob (P < 0.001) and less as stalk (P = 0.001) when stover was offered as SPB rather than CST. These differences are consistent with the fractional distribution of botanical components offered. During the Grow phase, cattle fed WPCS had greater (P = 0.018) daily gains (1.27 kg d-1) than cattle fed the SPB (1.14 kg d-1) and CST (1.08 kg d-1), and were more efficient than CST cattle. Steers sorted corn stover during both phases and consumed 52.5% of corn stover offered. SPB cob intake was 70% greater than CST cob intake (P < 0.01) indicating if more cob fraction is available, cattle will consume more. There was no treatment effect on final body weight (P = 0.37) or growth rate (P = 0.12) during the Finish phase. Stover NEm and NEg were calculated using Dairy NRC (2001) methods for SPB (1.04 and 0.49 Mcal kg-1) and CST (0.98 and 0.44 Mcal kg-1), respectively. In conclusion, there is evidence that CST and SPB can substitute for WPCS in beef feedlot diets without adverse effects on overall steer performance.

Single-pass corn stover harvest is a method whereby combine harvester tailings consisting of cob, stalk, leaf, husk and tassel fractions are collected and baled without coming into contact with soil. The objective was to feed beef steers diets that included a roughage component consisting of harvested corn residue in chopped form from conventional corn stover bales (CST) or single-pass bales (SPB) to assess intake selectivity of corn stover fractions and estimate net energy values of these corn stovers. Whole plant corn silage served as the control roughage in the control diet (CSIL). Steers (n = 90, 5 pens/treatment) were fed during Grow (84 d) and Finish (66 d) trials. Steers sorted through corn stover during both trials and consumed 52.5% of corn stover offered and 40% of Cob offered. Intake of SPB Cob was 2.6-fold and 3.3-fold greater than CST Cob intake (P < 0.01) in Grow and Finish trials, respectively, indicating that when more Cob was available, cattle consumed more. During the Grow trial, stover intake tended (P = 0.07) to be lower for SPB and diet dry matter intake (DMI) was less (P< 0.05) for SPB, which may be due to the elevated Cob intake by SPB steers. Across treatments, stover DMI was similar in the Grow (1.10 kg steer -1 d -1) and Finish (1.11 kg steer -1 d -1) trials. The proportion (65%) of Fines (< 8 mm) consumed from the Grow diet (40% neutral detergent fiber, aNDF) was greater than for the Finish diet (25% aNDF; 18 to 31%) and gleaning of concentrate feeds from orts seemed to be more extensive in the Grow diet. Steers consuming Finish diets containing SPB and CST had DMI that were 17% and 18%, respectively, greater (P< 0.05) than CSIL, an indication of compensatory intake. The physical effectiveness factors for stovers fed in the Grow and Finish diets were 0.85 and 0.95, respectively. Estimates for net energy maintenance (NEm) and net energy gain (NEg), respectively, using National Research Council (2001) methods were as follows for consumed stovers: SPB (1.09 and 0.54 Mcal/kg) and CST (0.98 and 0.44 Mcal/kg) in the Grow trial, and SPB (0.96 and 0.42 Mcal/kg) and CST (0.95 and 0.40 Mcal/kg) in the Finish trial. Although SPB and CST differ in botanical fraction composition and net intakes of botanical fractions, their energetic contributions to steer performance were very similar. Steers fed the Finish diet (1.25 Mcal performance-adjusted NEg kg -1) selected stover botanical components to achieve a diet composition of 25% aNDF.