A study was conducted to evaluate the impact that level of intake has on methane and carbon dioxide production by growing steers. Two treatments were evaluated that included ad-libitum intake compared to limit-fed steers. The ad-libitum fed cattle had greater gains, similar feed efficiency and produced more methane and carbon dioxide per day, while the limit fed cattle produced more methane and carbon dioxide per pound of intake than the ad-libitum fed cattle

Boyd, Bradley M.

Erickson, Galen E.

Fernando, Samodha C.

Hilscher, F. Henry, Hilscher

Stowell, Richard

Winders, Tom M.

English

DigitalCommons@University of Nebraska

University of Nebraska - LincolnDigitalCommons@University of Nebraska - LincolnNebraska Beef Cattle Reports Animal Science Department2018Impact of Intake on Methane Production inGrowing SteersTom M. WindersUniversity of Nebraska - LincolnBradley M. BoydUniversity of Nebraska-Lincoln, bboyd4@unl.eduF. Henry Hilscher HilscherUniversity of Nebraska-Lincoln, henry.hilscher@unl.eduSamodha C. FernandoUniversity of Nebraska - Lincoln, samodha@unl.eduRichard StowellUniversity of Nebraska - Lincoln, rstowell2@unl.eduSee next page for additional authorsFollow this and additional works at: http://digitalcommons.unl.edu/animalscinbcrPart of the Large or Food Animal and Equine Medicine Commons, Meat Science Commons, andthe Veterinary Preventive Medicine, Epidemiology, and Public Health CommonsThis Article is brought to you for free and open access by the Animal Science Department at DigitalCommons@University of Nebraska - Lincoln. It hasbeen accepted for inclusion in Nebraska Beef Cattle Reports by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln.Winders, Tom M.; Boyd, Bradley M.; Hilscher, F. Henry Hilscher; Fernando, Samodha C.; Stowell, Richard; and Erickson, Galen E.,"Impact of Intake on Methane Production in Growing Steers" (2018). Nebraska Beef Cattle Reports. 950.http://digitalcommons.unl.edu/animalscinbcr/950AuthorsTom M. Winders, Bradley M. Boyd, F. Henry Hilscher Hilscher, Samodha C. Fernando, Richard Stowell, andGalen E. EricksonThis article is available at DigitalCommons@University of Nebraska - Lincoln: http://digitalcommons.unl.edu/animalscinbcr/9502018 Nebraska Beef Cattle Report · 55 ©  The Board Regents of the University of  Nebraska. All rights reserved.or of their paired pen (pen in their block). Steers were implanted with Synovex®- Choice on day 1. Methane and carbon dioxide were monitored in the methane barn through a negative pressure system. The methane barns are a completely en-closed facility using two fans per pen to pull air through at a rate of 79 m3 /min. Near the fan outlets are the sampling ports with pumps that pull air into a sampling line. The air is analyzed using a LI- COR® 7500 for carbon dioxide and a LI- COR® 7700 for methane analyzing The air sampling system cycles between 3 sampling lines; one line in each methane pen (east and west), and one line on the south side of the methane barn to get an ambient supply. Each cycle lasts 20 minutes with 2 minutes in the ambient line, 6 minutes in the west line, 6 minutes in the ambient line, 6 minutes in the east line. This cycles continues non- stop on this 20- minute loop. The ambient line is used in part to flush the system between pen measurements as well as to gather baseline environmental gas measurements.The 8 pens of steers are rotated through the barn on a weekly basis by block, with two pens in the barn at a time, with both treatments being present in the barn at all times. The steers entered the barn on Thursdays, and were removed on Tuesdays, yielding 5 days of measurements. The barn then sits empty on Tuesday just reading manure gas production without cattle pres-ent. On Wednesday am, pens were scraped level of intake, which is what was done in this growing trial. The amount of feed consumed is well documented as being highly correlated with amount of methane produced. Most previous methane work has been done in head boxes or calorimetry chambers on individual animals. This study was done in the methane barn, which is two enclosed dry lot pens that hold 10 head per pen. The methane barn is monitored for methane and carbon dioxide production every second that the cattle are in the pens. Therefore this method is closer to a produc-tion level setting whereas other methods commonly used are small- scale methods.The objective of this study was verify if the newly constructed methane barn was correctly measuring methane production and if the measurements were realistic using steers fed at two levels of intake to create differences in methane production.ProcedureA 105- day growing study was conduct-ed using 80 steers (initial BW = 603 ± 97 lb.) fed on a rotation between their feedlot pens and the methane monitoring barns. Five days before the trial began, cattle were limit- fed a common diet of 50% alfalfa and 50% Sweet Bran® at 2% of BW. They were weighed 2 consecutive days and the weights were averaged to get an accurate initial BW. Steers were blocked by body weight and assigned to one of two treatments (Table 1), with 40 steers per treatment. There were 4 blocks with 2 pens per block and 2 treat-ments, thus the study design is a random-ized complete block design (RCBD). The two treatments were ad- libitum intake or limit fed steers fed the same diet. Treatment effects were evaluated for methane produc-tion and growth performance. Performance and emissions data were analyzed using the MIXED procedure of SAS (SAS Institute, Inc., Cary, N.C.) with pen being the exper-imental unit.The limit fed steers were fed 75% of the ad- libitum cattle’s intake from the week pri-Tom M. WindersBrad M. BoydHenry F. HilscherSamodha C. FernandoRick R. StowellGalen E. EricksonSummaryA study was conducted to evaluate the impact that level of intake has on methane and carbon dioxide production by growing steers. Two treatments were evaluated that included ad- libitum intake compared to limit- fed steers. The ad- libitum fed cattle had greater gains, similar feed efficiency and produced more methane and carbon dioxide per day, while the limit fed cattle produced more methane and carbon dioxide per pound of intake than the ad- libitum fed cattle.IntroductionMethane production through enteric fermentation in the rumen by cattle has received a lot of attention as an envi-ronmental concern. Methane is a potent greenhouse gas with negative impacts on the environment and is an energetic loss to the animal. Methane and carbon dioxide (CO2) are by- products of volatile fatty acid (acetate, butyrate, and propionate) produc-tion created by the microbes in the rumen. Acetate and butyrate formation promotes methane and carbon dioxide production because they produce net H2 in the rumen that needs to be eructated as CH4 or CO2, while propionate, an electron acceptor, does not net any hydrogens during formation and therefore does not contribute to methane production. Favoring propionate production by feeding more concentrates in the diet has been shown to decrease meth-ane production in cattle.Another way to manipulate meth-ane production is by reducing the steers’ Impact of Intake on Methane Production in Growing SteersTable 1. Dietary treatment for steers that were either ad- libitum or limit fed (DM basis)TreatmentAd- Libitum Limit Fed3Alfalfa 45 45Sorghum Silage 30 30MDGS1 22 22Supplement2 3 31MDGS = modified distillers grains plus solubes2 Formulated to contain 200 mg/d monensin3Fed 75% of Ad- libitum intake from previous week56 · 2018 Nebraska Beef Cattle Reportdioxide production was significantly higher (P< 0.01) and methane tended to be higher (P = 0.08) for empty pens with manure than empty pens without manure (Table 3). This occurs because cattle manure, although in small amounts, produces methane and car-bon dioxide due to fermentation of organic matter in the manure. All data reported in tables 2 and 3 have ambient levels of methane and carbon dioxide removed from the levels measured in each pen to get true animal production of gas. Carbon dioxide and methane production are thought to be highly correlated, and therefore one can be determined based on a ratio if the other is known. Many studies have been done using carbon dioxide numbers to estimate methane numbers, but in this study it was found that the ratio was significantly differ-ent between treatments (P = 0.02), implying that intake level can alter the ratio.All of the gas production results shown in tables 2 and 3 are pen totals divided by ten to get individual totals. Results are presented in grams to be consistent with how other work presents gas production in cattle. This trial accomplished its two goals: verify if ad- libitum cattle produce more carbon dioxide and methane, as well as confirm that the methane barn is robust enough to pick up differing amounts of methane and carbon dioxide produced in each pen. Ad- libitum cattle produced more methane and carbon dioxide per day than limit fed cattle, however the limit fed cattle produced more methane and carbon diox-ide per unit of intake than the Ad- libitum cattle. Producers should feed Ad- libitum rather than restrict intakes to get better growth performance, but will be producing more total methane and carbon dioxide in the process.Tom M. Winders, graduate studentBrad M. Boyd, research technicianHenry F. Hilscher, feedlot managerSamodha C. Fernando, assistant professorRick R. Stowell, associate professorGalen E. Erickson, professor, University of Nebraska– Lincoln, Department of Animal Sciencegain ratio was not different between treat-ments (P ≥ 0.36).EmissionsGas production results (Table 2) show that the ad- libitum cattle produced more grams of carbon dioxide (P= 0.04) and methane (P< 0.01) per head per day than the limit fed cattle. Gas production per pound of DMI was statistically different for carbon dioxide (P = 0.01) and tended to be different for methane (P = 0.06) with the limit fed calves producing more carbon dioxide and methane than the ad- libitum cattle when corrected for DMI amounts. When analyzed as an amount per lb. of gain, no differences for carbon dioxide (P ≥ 0.12) or methane (P ≥ 0.46) production were observed between treatments. Carbon clean and sit empty, taking measurements on no cattle and no manure. Based on this rotation, 4 weeks are required to monitor all 8 pens through the barn (one turn) to determine emissions. This study lasted 105 days (3 turns) but just one turn of gas mea-surements were usable due to monitoring errors for methane in the first two turns.ResultsPerformancePerformance results (Table 2) from this growing period show that the ad- libitum cattle had greater feed intakes and gains (P< 0.01) compared to limit fed cattle. Although not statistically significant, the ad- libitum cattle had numerically heavier ending BW compared to limit fed cattle. The feed to Table 2. The effect of level of intake in growing steers on performance and methane productionTreatmentsAd- Libitum Limit SEM P- valuePerformance Initial BW, lb 603 602 24.7 0.99 Ending BW, lb 842 786 23.8 0.15 DMI, lb 18.4 13.6 0.32 <0.01 ADG, lb 2.28 1.75 0.04 <0.01 F:G 8.10 7.83 0.18 0.36Gas Production C02 g/d 6831 6032 163 0.04 CH4 g/d 156.2 125.6 2.29 <0.01 CO2 g/lb/DMI 370.8 441.9 10.2 0.02 CH4 g/lb/DMI 8.48 9.19 0.17 0.06 CO2 g/lb/ADG 3004 3465 151 0.12 CH4 g/lb/ADG 68.7 72.1 0.06 0.46 CH4:CO2 0.023 0.021 .0003 0.02Table 3. Gas production from manure vs. no manureManure vs. No ManureManure No Manure SEM P- valueCO2 g/d 555 456 16.7 <0.01CH4 g/d 0.34 0.20 0.05  0.08

Impact of Intake on Methane Production in Growing Steers

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Impact of Intake on Methane Production in Growing Steers

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