Silage Fermentation, Bacterial Community, and Aerobic Stability of Total Mixed Ration Containing Wet Corn Gluten Feed and Corn Stover Prepared with Different Additives

The objective of this study was to investigate the effects of different additives on the fermentation quality, bacterial community, and aerobic stability of total mixed ration (TMR) silage containing wet corn gluten feed (WCGF) and corn stover. The TMR was ensiled with four treatments: (1) no additive (control); (2) lactic acid bacteria (LAB); (3) fibrolytic enzyme (EN); (4) LAB + EN. The EN and LAB + EN decreased the neutral detergent fiber and acid detergent fiber contents. Additives led to a higher lactic acid (LA) content (p < 0.0001) compared to control at all ensiling times. Silages inoculated with LAB and LAB + EN had higher dry matter (p = 0.0007), LA (p < 0.0001) and acetic acid (AA) contents (p < 0.0001) compared to control. The LAB and LAB + EN had significantly lowest ammonia nitrogen among the treatments, while no significant difference occurred after days 7 of ensiling. Silages treated with LAB and LAB + EN had a higher LAB count (p < 0.0001) and a lower pH, yeast, and mold counts compared to other silages. The LAB and LAB + EN greatly increased the portions of Firmicutes and Lactobacillus (p < 0.0001, and p < 0.0001, respectively) and reduced undesirable bacteria. Inoculation with LAB + EN and LAB improved aerobic stability of TMR silages indicated by higher and more stable LA and AA contents, smaller rise in pH, and yeast count than other silages. The LAB + EN and LAB reduced microbial diversity and improved the fermentation quality and aerobic stability of TMR silage containing WCGF and corn stover.

Diurnal and dietary impacts on estimating microbial protein flow from urinary purine derivative excretion in beef cattle1

Two experiments were conducted to determine the effects of diet composition and time of urine spot sampling on estimates of urinary purine derivative (PD) excretion. In Exp. 1, 116 individually fed crossbred heifers (407 ± 32 kg) were arranged in a randomized block design (82 d). Treatments were arranged in a 2 × 3 factorial design, with two urine spot sample collection times (0700 and 1700 hours; AM and PM) and three diets: 85% steam-flaked corn (SFC); 85% SFC + 1.5% urea (UREA); or 25% SFC, 30% wet corn gluten feed, and 30% corn bran (BYPROD). In Exp. 2, six ruminally and duodenally fistulated steers (474 ± 37 kg) were arranged in a replicated 3 × 3 Latin square design, with dietary treatments identical to Exp. 1 (63 d). Treatment diets were selected to result in varied amounts of microbial crude protein (MCP) in order to evaluate the accuracy of using estimates of urinary PD excretion to predict MCP. Urine spot samples were collected at 0700, 1200, 1700, and 2200 hours. No urine collection time × diet interactions occurred (P &gt; 0.20) for any variable in either experiment. In Exp. 1, dry matter intake (DMI) was greatest with BYRPOD (10.40 kg/d) and lowest with SFC (7.90 kg/d; P &lt; 0.05). Feed efficiencies were greatest for UREA (0.182) and least for SFC (0.141; P &lt; 0.05). Urinary PD:creatinine (PD:C) ratio was greatest for BYPROD (1.25) and least for SFC (0.94; P &lt; 0.05). Urine spot sampling time had a significant (P &lt; 0.05) impact on PD:C, 1.03 for AM and 1.22 for PM samples. In Exp. 2, DMI was greater (P &lt; 0.05) with BYPROD than with SFC and tended (P = 0.07) to be greater with BYPROD than with UREA. Ruminal pH was greatest for BYPROD (5.94; P &lt; 0.05). Flow of MCP was 636, 829, and 1,056 g/d for SFC, UREA, and BYPROD, with BYPROD being greater (P &lt; 0.05) than SFC and tending (P = 0.06) to be greater than UREA. Urinary PD:C was greater (P &lt; 0.05) for BYPROD than SFC and tended (P = 0.09) to be greater for UREA than SFC. Urinary PD:C increased linearly (P &lt; 0.05) with sampling time. Diets formulated to affect DMI and MCP flow resulted in differences in urinary PD excretion, and these results related well with MCP flow estimated from duodenal purines. Collecting spot samples of urine later in the day resulted in greater estimates of urinary PD excretion; purine and PD flows appear to increase with time after one morning feeding per day. This method is well suited to evaluating relative differences between treatments but should not be extrapolated to assume absolute values.

431 Late-Breaking: The effects of including cotton byproducts in a finishing ration on the performance, carcass characteristics, and fecal characteristics of crossbred beef steers

Increased cotton production in the Southwest U.S. has increased the availability of cotton byproducts for use in cattle diets. The objective of this experiment was to evaluate the inclusion of cotton byproducts in feedlot finishing rations on the performance, carcass characteristics, and fecal characteristics of steers. Crossbred beef steers (n = 64; BW = 318 ± 12.3 kg) were assigned to 1 of 2 experimental treatments in a randomized complete block design (8 pens/treatment; 4 steers/pen). Treatments included a control (CON) diet (7% hay, 15% wet corn gluten feed, 67% rolled corn, 5% liquid supplement) and a cotton byproduct (CTN) diet (7% gin trash, 15% whole cottonseed, 72% rolled corn, 5% water). Both diets included 0.75% urea and 5% dry supplement. The CTN steers tended to have a heavier final BW (P = 0.09) and greater ADG (P = 0.08). Over the entire feeding period, DMI was greater for CTN steers than CON steers (P = 0.04) with no difference in G:F between treatments (P = 0.89). The CTN steers had heavier HCW (P = 0.02) and greater fat thickness (P = 0.03) than CON steers, but marbling score and REA were not different between treatments (P ≥ 0.64). Steers fed the CON diet tended to have a lower YG (P = 0.07), less KPH fat (P = 0.09), and lower dressing percentage (P = 0.10) than CTN steers. Liver scores did not differ between treatments (P ≥ 0.17). Fecal scores were lower for CTN steers on d 56 (P = 0.03) and fecal pH tended to be higher for the CTN steers on d 28 (P = 0.09), but neither differed during other periods (P ≥ 0.18). These results suggest that cotton byproducts can be used in feedlot rations without adverse effects on performance or carcass characteristics.

Effect of harvest method and ammoniation of baled corn residue on intake and digestibility in lambs

To determine the effect of harvest method and ammoniation on both in vivo and in vitro digestibility of corn residue, six corn residue treatments consisting of three different harvest methods either with or without anhydrous ammonia chemical treatment (5.5% of dry matter [DM]) were evaluated. The harvest methods included conventional rake-and-bale (CONV) and New Holland Cornrower with eight rows (8ROW) or two rows (2ROW) of corn stalks chopped into the windrow containing the tailings (leaf, husk, and upper stem) from eight rows of harvested corn (ammoniated bales of each harvest method resulted in treatments COVAM, 8RAM, and 2RAM). Nine crossbred wether lambs (49.2 ± 0.5 kg BW) were fed 64.2% corn residue, 29.8% wet corn gluten feed, 3.3% smooth-bromegrass hay, and 2.8% mineral mix (DM basis) in a 9 × 6 Latin rectangle metabolism study with a 3 × 2 factorial treatment to measure total tract disappearance. Six 21-d periods consisted of 14-d adaptation and 7-d total fecal collection, and lambs were fed ad libitum (110% of the previous day’s DM intake [DMI]) during days 1 to 12 and reduced to 95% of ad libitum intake for days 13 to 21. There was a harvest method by ammoniation interaction (P &lt; 0.01) for ad libitum DMI (days 7 to 11). Ammoniation increased (P &lt; 0.01) intake across all harvest methods, where 2RAM DMI was 4.1%, COVAM was 3.6%, and 8RAM was 3.1%, which were all different (P &lt; 0.01) from each other, but all untreated residues were consumed at 2.6% of BW (P ≥ 0.92) regardless of harvest method. There were no interactions (P &gt; 0.34) between harvest method and ammoniation for any total tract or in vitro digestibility estimate. Harvest method affected (P &lt; 0.04) DM, neutral detergent fiber (NDF), and acid detergent fiber (ADF) digestibility, where 2ROW was greater than both CONV and 8ROW, which did not differ. The organic matter (OM) digestibility (P = 0.12) and digestible energy (DE; P = 0.30) followed the same numerical trend. Both in vitro DM digestibility (IVDMD) and in vitro OM digestibility (IVOMD) of the residue were affected (P &lt; 0.01) by harvest method, with 2ROW being greater (P &lt; 0.01) than both CONV and 8ROW. For IVDMD, 8ROW was not (P = 0.77) different from CONV, but 8ROW IVOMD was lower (P = 0.03) than CONV. Ammoniation improved (P &lt; 0.01) DM, OM, NDF, and ADF digestibility of all harvest methods, resulting in a 26% increase (P &lt; 0.01) in DE due to ammoniation. Similar digestibility improvements were observed in vitro with ammoniation improving IVDMD and IVOMD by 23% and 20%, respectively. Both selective harvest methods and ammoniation can improve the feeding value of baled corn residue.