Greenhouse Gas Emissions From Two Contrasting Beef Systems from Birth to Slaughter in Eastern Nebraska

Over the last 15 years, the increase in land use for corn and soybean has come at the expense of acres of grasslands and perennial forages employed in conventional beef-production systems. Implementing alternative cow-calf production systems into existing cropping systems may be a solution for reduced land availability and reducing total greenhouse gas emissions (GHG). Therefore, GHG from a conventional (CONV) pasture-based cattle production system with cows wintered on corn residue and summer grazing of brome pasture were compared to partial-confinement system (ALT) with cows and calves in a drylot during the summer and grazing cover crops and corn residue over the fall and winter. Eddy covariance and pen chambers were used to measure emissions from grazing and confinement scenarios. Measured CH4 and modeled N2O emissions totaled 7.5 ± 0.3 and 7.4 ± 0.3 kg CO2e kg-1 HCW for CONV and ALT production, respectively. There was a measured uptake of 233 g C m-2 and 98 g C m-2 from brome pasture and cover crop, respectively. Accounting for CH4 and N2O emissions using global warming potential (GWP) of 23 and 298 resulted in a net sink of 0.7 ± 0.2 kg CO2e kg-1 HCW for CONV and a net source of 16.7 ± 1.5 kg CO2e kg-1 HCW for ALT. The same calculations using global warming potential (GWP) of 4 and 234 resulted in a net sink of 10.9 ± 1.0 kg CO2e kg-1 HCW for CONV and a net source of 7.1 ± 1.5 kg CO2e kg-1 HCW for ALT. Carbon sequestration from perennial grasslands in the CONV was enough to offset all emissions and biogenic CO2. Annual forage grazed in the ALT system offset 42 to 72% of systems emissions depending on GWP metric used. These net carbon results open new horizons to livestock carbon balance research and give evidence that grazing systems sequester carbon emissions from cattle and in some cases are a carbon sink. Advisors: Galen E. Erickson and Andy Suyke

Evaluation of Masters Choice Corn Silage on Growing Steer Performance

A growing study evaluated three corn silage hybrids on growing steer performance. Th e three hybrids were: a conventional hybrid- Farm Choice (CON) commonly grown in Eastern Nebraska which served as the control, Masters Choice hybrids MCT6365 RIB (MC1) selected to improve fi ber and starch digestion and MCT6733 GT3000 (MC2) that has been selected to improve fi ber digestion in cattle. Relative to CON, feeding hybrid MC1 resulted in similar DMI, but numerically increased ADG which significantly improved F:G compared to CON. Feeding MC2 led to greater DMI, similar ADG, and poorer (greater) F:G compared to CON. Feeding Masters Choice hybrid MCT6365 RIB (MC1) corn silage at 80% of the diet DM likely improved digestion and energy availability to the steers, which allowed greater ADG and improved F:G, while the opposite was true for MC2. Differences in hybrids exist when fed to growing cattle at 80% of the diet

Grain Adaptation and Source Impact on Eating Behavior and Performance of Feedlot Steers

A feedlot experiment was conducted to evaluate the effect of replacing steam-processed corn (SPC) with steam-flaked wheat (SFW) in feedlot rations. In experiment 1, 152 crossbred steers (321 ± 2.7 kg BW) were blocked by weight and randomly assigned to 1 of 4 treatments with 8 pens per treatment. Treatments contained varying levels of SFW (0, 20, 40, 60; CON, SFW20, SFW40, SFW60) were fed for 175d. All diets contained DDGS 20% of diet DM. In experiment 2, 6 ruminally cannulated steers (BW 395 ± 12 kg) were used to determine the in situ DM digestibility (ISDMD) of a fresh sample of: 1) dry-rolled corn (DRC); 2) SFW obtained immediately after flaking (SFW-F); 3) SFW obtained after drying through a vacuum air lift (SFW-D); 4) steam-flaked corn (SFC) obtained from a commercial feed yard (SFC); 5) composited sample of SPC fed throughout Exp. 1 (SPC). In Exp. 1 no differences in BW (P = 0.74) or ADG (P = 0.45) were observed. SFW60 had the lowest DMI (P = 0.05). A positive linear relationship in G:F (P = 0.03), YG (P = 0.01) and wheat inclusion. Cost of gain can be maintained if wheat price/27 kg is $0.18 to$0.76 greater than 25 kg of corn. In Exp. 2 there was no difference between SFW-E and and SFW-F (P = 0.99) and SFP had lower ISDMD than SFC at all time points (P 550 kg), and previous nutrition (54.8% wet corn gluten feed for 160d) may have increased caloric capacity.Animal Scienc

Evaluation of Masters Choice Corn Silage on Growing Steer Performance

A growing study evaluated three corn silage hybrids on growing steer performance. Th e three hybrids were: a conventional hybrid- Farm Choice (CON) commonly grown in Eastern Nebraska which served as the control, Masters Choice hybrids MCT6365 RIB (MC1) selected to improve fi ber and starch digestion and MCT6733 GT3000 (MC2) that has been selected to improve fi ber digestion in cattle. Relative to CON, feeding hybrid MC1 resulted in similar DMI, but numerically increased ADG which significantly improved F:G compared to CON. Feeding MC2 led to greater DMI, similar ADG, and poorer (greater) F:G compared to CON. Feeding Masters Choice hybrid MCT6365 RIB (MC1) corn silage at 80% of the diet DM likely improved digestion and energy availability to the steers, which allowed greater ADG and improved F:G, while the opposite was true for MC2. Differences in hybrids exist when fed to growing cattle at 80% of the diet

Impact of Feeding Aspergillus Subspecies Blend and Di! erent Corn Processing Methods on Finishing Beef Cattle Performance and Carcass Characteristics

A feedlot study utilizing 320 crossbred calf- fed steers (initial body weight 588 lb) compared the effect of feeding an Aspergillus additive in either dry- rolled corn or high- moisture corn finishing diets on cattle performance and carcass characteristics. Steers were fed 0 g/steer daily or 10 g/steer daily Aspergillus for both corn processing methods. # ere were no significant interactions between corn processing method and Aspergillus. Feeding finishing cattle Aspergillus did not impact performance compared to feeding none. Cattle fed dry- rolled corn had greater final body weight, dry matter intake, and gain compared to high- moisture corn diets. But cattle fed high- moisture corn had a 6.25% decrease in feed- to- gain compared to dry- rolled corn. These data suggest that feeding Aspergillus does not affect performance. The lower dry matter intake and average daily gain observed would suggest a potential acidosis problem for high- moisture corn compared to dry- rolled corn- based finishing diets

Evaluation of Condensed Algal Residue Solubles as an Ingredient in Cattle Finishing Diets

A study was conducted to evaluate feeding 0, 2.5, or 5.0% of a novel liquid feed, Condensed Algal Residue Solubles (CARS), in one of two base diets with CARS replacing corn. ! e two base diets were fed to mimic Northern Great Plains (high moisture and dry rolled corn blend fed with wet distillers grains plus solubles) and Southern Great Plains (steam- flaked corn and dry distillers grains plus solubles) feedlot diets. ! ere were no interactions between base diet and CARS inclusion. Feed intake and longissimus muscle area decreased as CARS inclusion increased in the diet. A quadratic effect was shown for average daily gain, feed efficiency, final adjusted body weight, hot carcass weight, 12th rib fat, and yield grade, increasing as CARS was included up to 2.5% of diet dry matter, then decreased at 5% inclusion. Marbling score improved with increased inclusion of CARS, with the highest score at 5% CARS inclusion. Including CARS at 2.5% of diet dry matter improved feed efficiency in both Northern and Southern Great Plains diets

Production cow-calf responses from perennial forage-based and integrated beef-cropping systems

An experiment was conducted to measure production responses of an alternative cow-calf production system integrated into a cropping system without access to perennial forage compared to a traditional cow-calf system utilizing perennial forage. Multiparous, cross-bred beef cows (n = 160; average age = 6.2 ± 2.8 yr) were utilized in a randomized complete block experimental design and unstructured treatment design. Upon initiation, cows were blocked by age and stratified by source, assigned randomly to one of two production systems, each with four replicates (n = 20 cows/replicate). Once allotted to their treatment groups, cows remained in their experimental units for the duration of the experiment. Treatments were: 1) a traditional system consisting of April to May calving with smooth bromegrass pasture and grazed corn residue as forage resources (TRAD); 2) an alternative system consisting of July to August calving utilizing partial-drylot feeding, summer-planted oats, and corn residue grazing (ALT). There were no differences (P ≥ 0.27) in calving rates (91.8 vs. 86.7 ± 2.92%), pregnancy rates (89.3 vs. 89.9 ± 2.66%), and weaning rates (87.2 vs. 82.3 ± 3.29%) for TRAD vs. ALT, respectively. However, there was an increase (P = 0.04) in the rate of twin offspring in ALT (2.9 vs. 9.4 ± 2.36% for TRAD vs. ALT, respectively). One calf from the set of twins was selected randomly at birth to be removed from the experiment, so the production data are only from single calves. There was no difference (P = 0.47) in calf body weight at birth (40 vs. 39 ± 0.7 kg for TRAD vs. ALT, respectively). At weaning, calves in the ALT system were lighter (P \u3c 0.01) at the same day of age (184 vs. 229 ± 5.5 kg) compared to TRAD calves. Cows from the ALT system had fewer (P \u3c 0.01) kg weaned per cow exposed to bull (150 vs. 199 ± 7.2 kg) compared to TRAD cows. Apart from the twinning rate, no differences in reproductive performance were observed among systems. However, reduced weaning weights and kilogram of weaned calf per cow exposed may negatively impact revenue to the cow-calf enterprise of the ALT system

Evaluation of Processing Technique for High- Moisture and Dry Corn Fed to Finishing Cattle

A 134- day finishing trial was conducted to evaluate the effect of milling method and corn type on finishing cattle performance and carcass characteristics. Treatments were applied in a 2 × 3 factorial arrangement, with the first factor as milling method (Automatic Ag roller mill or hammer mill) and the second factor as corn type, either 100% dry corn, 50:50 blend of dry and high moisture corn, or 100% high moisture corn. $ere was no interaction between milling method and corn type for carcass- adjusted final body weight, average daily gain, or dry matter intake but there was an interaction between milling method and corn type for feed conversion. Cattle fed the diet containing 100$ ere was no effect on carcass characteristics based on milling method or corn type. Processing high- moisture corn using Automatic Ag’s roller mill improved feed conversion compared to processing with a hammer mill, but processing method had little effect on dry corn or blended diets

Evaluation of growth performance, carcass characteristics, and methane and CO\u3csub\u3e2\u3c/sub\u3e emissions of growing and finishing cattle raised in extensive or partial-intensive cow-calf production systems

An experiment was conducted over 2 yr to measure performance and greenhouse gas (GHG) emissions of weaned calves from two cow-calf production systems. Crossbred steers and heifers (n = 270, initial body weight (BW) = 207 kg, SD = 35) were used in a randomized complete block design, with treatments applied to the cow-calf system. Treatments were: 1) a traditional system consisting of April to June calving with smooth bromegrass pasture and grazed corn residue as forage resources (TRAD); 2) an alternative system consisting of July to September calving utilizing partial-drylot feeding, summer-planted oats, and corn residue grazing (ALT). Calves from both production systems were weaned at the same age and grown (diet NEg = 1.05 Mcal kg–1) for approximately 117 d. The calves then transitioned to a high-grain finishing diet (year 1: NEg = 1.32 Mcal kg–1; year 2: NEg = 1.39 Mcal kg–1) and fed to a targeted 1.52 cm backfat. Growth performance in the grower phase resulted in greater (P \u3c 0.01) average daily gain (1.39 vs. 1.22 ± 0.02 kg), greater gain:feed (P \u3c 0.01; 0.157 vs. 0.137 ± 0.003) for ALT calves compared to TRAD calves, However, a lower initial BW (P \u3c 0.01; 185 vs. 229 ± 4.9 kg) resulted in a lower ending BW (P \u3c 0.01; 347 vs. 371 ± 2.9 kg) for ALT calves compared to TRAD calves in spite of improved growth performance. In the finisher phase, ALT calves gained less (1.52 vs. 1.81 ± 0.218 kg; P = 0.02), were less efficient (0.139 vs. 173 ± 0.0151; P = 0.01) but exhibited similar hot carcass weights (HCW) (388 vs. 381 ± 3.8 kg; P = 0.14) compared to TRAD calves. Each pen of calves was put into a large pen-scale chamber that continuously measured carbon dioxide (CO2 ) and methane (CH4 ) for 5 d during the grower and finisher phases. The average CH4 and CO2 production per unit of feed intake was used to calculate total GHG emissions over the entire grower and finisher phase. Overall, there were no differences (P ≥ 0.17) between treatments for CH4 per day and per kilogram dry matter intake (DMI). However, ALT calves tended to produce less (P ≤ 0.10) CO2 per day and per kilogram DMI than TRAD calves. Overall, methane emissions were greater in ALT calves (110.7 vs. 92.2 ± 8.3 g CH4 kg–1 HCW; P = 0.04) than TRAD calves. The ALT calves required 27 additional days on feed to market, which resulted in more total CH4 per animal across the entire feeding period (P = 0.02) than TRAD calves. Production systems that reduce days to market to achieve similar HCW may reduce GHG emissions

Effect of Corn Residue Harvest Method on In Vivo and In Vitro Digestibility

A digestion study was conducted using 18 crossbred wether lambs to evaluate the effects of corn residue harvesting method and ensiling on the digestibility of corn residue. Husks had the greatest digestibility compared to any of the harvesting methods. No differences were observed for the digestibility of husklage, ensiled husklage, or stalklage. None of the harvest methods resulted in residue digestibilities similar to husks