Yongjing Zhao

The objective of this study was to determine if a commercial feed additive blend composed of quebracho, chestnut tannins, and saponins (TAN; Silvafeed BX) could reduce enteric GHG and ammonia (NH₃) emissions without negatively effecting the productive performance of dairy cows. Twenty mid lactation Holstein dairy cows were blocked by DIM and parity in a randomized complete block design, and were assigned to 1 of 2 treatments: TAN (n = 10) or control with no TAN (CON; n = 10). The treatments were administered as a top dress at each of 2 daily feedings with TAN supplemented at a rate of 0.07% of dietary DM. Cow blocks were sampled for enteric gaseous emissions in head chambers (HC) for a 12 h period on their respective treatment d 0, 16, 32, and 48. After the enteric emission sampling period concluded, collected urine and manure were combined into a manure slurry at 1:1.7 (urine wt:feces wt) per cow. Manure slurry methane (CH₄), carbon dioxide (CO₂), nitrous oxide (N₂O), and NH₃ emissions were measured for 24 h. Supplemental TAN decreased enteric production (g/HC period or mg/HC period gas) of CH₄, CO₂, and N₂O over the trial period, and tended to increase NH₃ production in TAN-supplemented cows. Gaseous emission yield (g or mg gas/kg HC DM intake) did not differ between TAN- and CON-supplemented cows for CH₄, CO_2, or N₂O, although TAN-supplemented cows had greater NH₃ yield. Methane, CO₂, N₂O, and NH₃ intensity (g or mg gas/kg PM ECM) were not affected by TAN supplementation. Supplemental TAN did not effect slurry GHG emissions, although it increased NH₃ emissions. No differences in ECM, milk fat yield, milk protein yield, and DMI in TAN-supplemented cows versus CON-supplemented cows were noted.

Manure management emits large quantities of greenhouse gases (GHG) in California. Eminex^®, a manure additive, previously demonstrated significant GHG reductions in slurry. However, it has not been tested in lagoon wastewater. The aim of the present study was to investigate the effects of Eminex^® on GHG, ammonia (NH₃), and ethanol (EtOH) emissions from fresh dairy slurry and dairy lagoon wastewater. Both manures received the following treatments: high (1.0 kg Eminex^®/m³ manure), low (0.5 kg Eminex^®/m³ manure). Experiments were conducted in four replicates with an untreated manure control. The physical characteristics of the manure were determined during the monitoring periods of emissions: 7 days for slurry and 28 days for lagoon wastewater. All slurry emissions, except for N₂O, declined over time (p < 0.05). Lagoon wastewater total N increased with treatment (p < 0.05) possibly due to the urea provided by Eminex^®. Most lagoon wastewater emissions also decreased over time (p < 0.05). However, Eminex^®, compared to control, increased lagoon wastewater NH₃ volatilization (p < 0.05). With improvements to manure composition through increasing N content, as well as reductions in emissions, Eminex^® is a promising tool to mitigate the negative environmental impacts of manure management.

The objective of the present study was to mitigate ammonia (NH₃), greenhouse gases (GHGs), and other air pollutants from lactating dairy cattle waste using different freestall management techniques. For the present study, cows were housed in an environmental chamber from which waste was removed by either flushing or scraping at two different frequencies. The four treatments used were (1) flushing three times a day (F3), (2) flushing six times a day (F6), (3) scraping three times a day (S3), and (4) scraping six times a day (S6). Flushing freestall lanes to remove manure while cows are out of the barn during milking is an industry standard in California. Gas emissions were measured with a mobile agricultural air quality lab connected to the environmental chamber. Ammonia and hydrogen sulfide (H₂S) emissions were decreased (p < 0.001 and p < 0.05) in the flushing vs. scraping treatments, respectively. Scraping increased NH₃ emissions by 175 and 152% for S3 and S6, respectively vs. F3. Ethanol (EtOH) emissions were increased (p < 0.001) when the frequency of either scraping or flushing was increased from 3 to 6 times but were similar between scraping and flushing treatments. Methane emissions for the F3 vs. other treatments, were decreased (p < 0.001). Removal of dairy manure by scraping has the potential to increase gaseous emissions such as NH₃ and GHGs.

Societal pressure to reduce enteric methane emissions from cattle continues to increase. The present study evaluated the efficacy of the commercial essential oil feed additive Agolin^® Ruminant on reducing enteric gas emissions and improving milk parameters in dairy cattle. Twenty mid-lactation Holstein cows, blocked by parity and days in milk, were randomly assigned to a top dress treatment with Agolin or an un-supplemented control for a 56-day trial. Cows were group housed and individually fed twice daily. Enteric gas emissions, including methane, carbon dioxide, ammonia, and nitrous oxide, were sampled every 14 days for a 12 h period via head chambers connected to a mobile air quality laboratory. Cows supplemented with Agolin versus the control had less methane intensity (g/period/kg energy-corrected milk (ECM); p = 0.025). Ammonia was the most affected gas, with lower ammonia production (mg/period; p = 0.028), and ammonia intensity (mg/period/kg ECM; p = 0.011) in Agolin-fed versus control-fed cows. All cow performance variables, including dry matter intake, ECM, milk fat, milk protein, or feed efficiency were similar between treatments. Further research should evaluate how Agolin impacts ruminal flora, focusing on mechanistic impacts to fermentation.

Feed additives have received increasing attention as a viable means to reduce enteric emissions from ruminants, which contribute to total anthropogenic methane (CH4) emissions. The aim of this study was to investigate the efficacy of the commercial feed additive SOP STAR COW (SOP) to reduce enteric emissions from dairy cows and to assess potential impacts on milk production. Twenty cows were blocked by parity and days in milk and randomly assigned to one of two treatment groups (n = 10): supplemented with 8 g/day SOP STAR COW, and an unsupplemented control group. Enteric emissions were measured in individual head chambers over a 12-h period, every 14 days for six weeks. SOP-treated cows over time showed a reduction in CH4 of 20.4% from day 14 to day 42 (p = 0.014), while protein % of the milk was increased (+4.9% from day 0 to day 14 (p = 0.036) and +6.5% from day 0 to day 42 (p = 0.002)). However, kg of milk protein remained similar within the SOP-treated cows over the trial period. The control and SOP-treated cows showed similar results for kg of milk fat and kg of milk protein produced per day. No differences in enteric emissions or milk parameters were detected between the control and SOP-treated cows on respective test days.

Animal manure is a source of greenhouse gas (GHG) emissions and other pollutants and nuisances such as ammonia and odors. There are several technologies to reduce emissions on animal farms including manure additives; however, few have been proven effective and easy to apply to dairy lagoon systems. The present research aimed at testing the ability of the commercial additive “SOP LAGOON” to reduce emissions of GHGs (i.e., carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O)), as well as ammonia (NH₃) and odors from lagoon stored liquid manure. Emissions of GHGs, NH₃ and odors were measured in the laboratory from barrels filled with 65 L of manure treated with SOP LAGOON or left untreated as a control. Manure was collected from a commercial dairy that is located in Solano County, California. Emissions of GHGs and NH₃ were continuously measured for one week using flux chambers placed on top of the barrels and connected to a mobile air emissions laboratory. The effects of the untreated control, versus the two respective treatment additive doses of 30.8 and 61.6 g/m³ of manure were compared to each other. The low dose was selected based on the manufacturer recommendation and the high dose was selected by doubling the low dose. Results showed that SOP LAGOON applied at the high dose (61.6 g of SOP LAGOON per m³ of manure) versus the control greatly reduced (p < 0.05) emissions of CO₂, CH₄, N₂O and NH₃ by 14.7%, 22.7%, 45.4% and 45.9%, respectively. Furthermore, the high dose of SOP LAGOON treated samples versus the control samples showed less odor intensity (p < 0.05). There was no significant effect of the low dose of SOP LAGOON on the emissions of different gases. The HIGH dose of SOP LAGOON might decrease the number of methanogens and hydrolytic microorganisms and their excreted enzymes during manure storage. Further studies are needed to investigate the mechanism of emission reduction using SOP LAGOON.