The Effect of Rumination Time on Milk Performance and Methane Emission of Dairy Cows Fed Partial Mixed Ration Based on Maize Silage

The objective of this study was to determine the effect of the rumination time on milk yield and composition as well as methane emission during lactation in high-yielding dairy cows fed a partial mixed ration based on maize silage without pasture access. A total of 365 high-yielding Polish Holstein-Friesian multiparous dairy cows were included in the study covering 24 to 304 days of lactation. Methane emission, rumination time, and milk production traits were observed for the period of 12 months. Next, the data from the cows were assigned to three groups based on daily rumination time: low rumination up to 412 min/day (up to 25th rumination percentile), medium rumination from 412 to 527 min/day (between the 25th and 75th percentile), and high rumination above 527 min/day (from the 75th percentile). Rumination time had no effect on milk yield, energy-corrected milk yield, or fat and protein-corrected milk yield. High rumination time had an effect on lower fat concentration in milk compared with the medium and low rumination groups. The highest daily CH4 production was noted in low rumination cows, which emitted 1.8% more CH4 than medium rumination cows and 4.2% more than high rumination cows. Rumination time affected daily methane production per kg of milk. Cows from the high rumination group produced 2.9% less CH4 per milk unit compared to medium rumination cows and 4.6% in comparison to low rumination cows. Similar observations were noted for daily CH4 production per ECM unit. In conclusion, a longer rumination time is connected with lower methane emission as well as lower methane production per milk unit in high-yielding dairy cows fed a maize silage-based partial mixed ration without pasture access.

The Effect of Electromagnetic Microwave Radiation on Methane Fermentation of Selected Energy Crop Species

The aim of the present study was to determine how thermal stimulation via electromagnetic microwave radiation impacts the yields of biogas and methane produced by methane fermentation of five selected energy crop species in anaerobic reactors. The resultant performance was compared with that of reactors with conventional temperature control. The highest biogas production capacity was achieved for maize silage and Virginia mallow silage (i.e., 680 ± 28 dm3N/kgVS and 506 ± 16 dm3N/kgVS, respectively). Microwave radiation as a method of heating anaerobic reactors provided a statistically-significantly boost in methane production from maize silage (18% increase). Biomethane production from maize silage rose from 361 ± 12 dm3N/kgVS to 426 ± 14 dm3N/kgVS. In the other experimental variants, the differences between methane concentrations in the biogas were non-significant.

Prevalence of Mycotoxins and Endotoxins in Total Mixed Rations and Different Types of Ensiled Forages for Dairy Cows in Lithuania

In this study, 119 samples of total mixed rations and different types of ensiled forage (maize and grass silage, and haylage) collected in 2019–2020 from dairy farms in Lithuania were analyzed to evaluate the quantitative occurrence of mycotoxins and endotoxins. Samples were analyzed using high-performance liquid chromatography (HPLC) with a fluorescent (FLD) and an ultraviolet detector (UV) of mycotoxins and a detection assay based on the ELISA technology for endotoxins. The study included toxins regulated within the European Union (aflatoxin B1 (AFB1), zearalenone (ZEA), deoxynivalenol (DON) and T-2 toxin) and nonregulated toxins (endotoxins). Mycotoxin analysis showed that 49.58% of the samples out of 119 were positive for AFB1, 52.11% for ZEA and DON, 55.47% for T-2 toxin and 84.04% for endotoxins. In the contaminated samples, the highest mean values of AFB1 and T-2 toxin were determined in the grass silage samples, while ZEA and DON–were determined in the maize silage samples. Maize silage samples had the highest ZEA and DON concentrations, exceeding the EU maximum permissible concentration limits. In the haylage samples, AFB1 mycotoxin exceeded the maximum concentration limits. The highest mean value of endotoxins was determined in the total mixed rations samples. This is the first study to provide information about the concentrations of mycotoxins and endotoxins in total mixed rations and different types of ensiled forages for dairy cows in Lithuania.

Multivariate modelling of milk fatty acid profile to discriminate the forages in dairy cows’ ration

Although there are many studies on the importance of fatty acids (FA) in our diet and on the influence of dairy diets on FA metabolism, only a few investigate their predictive capacity to discriminate the type, amount and conservation method of farm forages. This research quantifies differences in milk FA concentrations and, using a supervised factorial discriminant analysis, assesses potential biomarkers when replacing maize with other silages, grass/lucerne hays or fresh grass. The statistical modelling identified three main clusters of milk FA profiles associated with silages, hays and fresh grass as dominant roughages. The main implication of a dairy cow feeding system based on poliphytic forages from permanent meadows is enhancing milk’s nutritional quality due to an increase in beneficial omega-3 polyunsaturated FA, conjugated linoleic acids and odd chain FA, compared to feeding maize silage. The study also identified a small but powerful and reliable pool of milk FA that can act as biomarkers to authenticate feeding systems: C16:1 c-9, C17:0, C18:0, C18:3 c-9, c-12, c-15, C18:1 c-9, C18:1 t-11 and C20:0.

Progress in the Production of Biogas from Maize Silage after Acid-Heat Pretreatment

One of the most effective technologies involving the use of lignocellulosic biomass is the production of biofuels, including methane-rich biogas. In order to increase the amount of gas produced, it is necessary to optimize the fermentation process, for example, by substrate pretreatment. The present study aimed to analyze the coupled effects of microwave radiation and the following acids: phosphoric(V) acid (H3PO4), hydrochloric acid (HCl), and sulfuric(VI) acid (H2SO4), on the destruction of a lignocellulosic complex of maize silage biomass and its susceptibility to anaerobic degradation in the methane fermentation process. The study compared the effects of plant biomass (maize silage) disintegration using microwave and conventional heating; the criterion differentiating experimental variants was the dose of acid used, i.e., 10% H3PO4, 10% HCl, and 10% H2SO4 in doses of 0.02, 0.05, 0.10, 0.20, and 0.40 g/gTS. Microwave heating caused a higher biogas production in the case of all acids tested (HCl, H2SO4, H3PO4). The highest biogas volume, exceeding 1800 L/kgVS, was produced in the variant with HCl used at a dose of 0.4 g/gTS.

Authenticity of Hay Milk vs. Milk from Maize or Grass Silage by Lipid Analysis

Hay milk is a traditional dairy product recently launched on the market. It is protected as “traditional specialty guaranteed” (TSG) and subjected to strict regulations. One of the most important restrictions is that the cow’s feed ration must be free from silage. There is the need for analytical methods that can discriminate milk obtained from a feeding regime including silage. This study proposes two analytical approaches to assess the authenticity of hay milk. Hay milk and milk from cows fed either with maize or grass silage were analyzed by targeted GC-MS for cyclopropane fatty acid (dihydrosterculic acid, DHSA) detection, since this fatty acid is strictly related to the bacterial strains found in silage, and by HPLC-HRMS. The presence of DHSA was correlated to the presence of maize silage in the feed, whereas it was ambiguous with grass silage. HPLC-HRMS analysis resulted in the identification of 14 triacylglycerol biomarkers in milk. With the use of these biomarkers and multivariate statistical analysis, we were able to predict the use of maize and grass silage in the cow’s diet with 100% recognition. Our findings suggest that the use of analytical approaches based on HRMS is a viable authentication method for hay milk.

Predicted milk production per hectare based on yield and chemical composition of native and hybrid maize silage varieties on temperate and tropical regions

The objective of the present study was to characterize maize silage according to chemical composition, maize silage yield, as well as their predicted milk production. A search was made on studies related to maize silage yield, density, chemical composition (DM, CP, NDF, starch), and dry matter digestibility (DMD). In this study, 41 maize varieties from temperate regions and 101 maize varieties from tropical origin were analyzed. The net energy of lactation (NEL Mcal/kg DM), kilograms of milk per t of silage (kg of milk/t DM), and kilograms of milk per hectare of silage (kg of milk/ha) were determined. A cluster (CL) analysis was performed, and six CL of maize silage were obtained. The CL1 included digestibility for dry matter, crude protein, neutral detergent fiber, NEL, and kg of milk/t DM. CL2 was characterized by maize silage with the highest number of plants per hectare and NDF. CL3 included the highest ash content. CL4 consisted of intermediate values for all variables. CL5 included the highest forage yield (t DM/ha) and kg of milk/ha whereas CL6 included the highest kg of milk/t. Overall, CL1 resulted in the highest DMD and NEL, producing more milk per t DM. Results suggested that the ideal option is maize silage with a higher forage yield and more than 35 % DM (CL5) since this produces more kg of milk per hectare.

Effect of Different Regions and Ensiling Periods on Fermentation Quality and the Bacterial Community of Whole-Plant Maize Silage

This study aimed to explore the changes in the microbial community on the silage material surface and during the ensiling process of whole-plant maize in different regions. Whole-plant maize silages were sampled in Ziyun, Guanling, and Weinning counties within warm and humid climate areas in southern China. Silages were sampled at 0, 2, 5, 10, 20, and 45 days during ensiling. The nutritional components, fermentation properties, and microbiomes were examined to evaluate the influence of sampling area and fermentation time on the quality of silage. The results showed that the pH values of all silages significantly decreased (<4.2 at ensiling day 2) during fermentation and all silages achieved satisfactory fermentation at 45 days. Butyric acid was not detected during ensiling, and the contents of acetic acid and ammonia nitrogen in the final silages were below 6 g/kg DM and 50 g/kg total nitrogen, respectively. Weissella was the dominant epiphytic bacteria of raw material in Ziyun and Weinning, while Lactobacillus was prevalent in Guanling. Lactobacillus dominated the ensiling process, and its abundance significantly increased with increasing fermentation time in the three groups. Lactobacillus was negatively correlated with pH of all silages (p < 0.05) and positively correlated with lactic acid, propionic acid and acetic acid (p < 0.05). Furthermore, the bacterial community was significantly correlated with environmental factors. Altitude had a highly positive correlation with the abundance of Stenotrophomonas, Chryseobacterium, and Massilia (p < 0.01), while precipitation was negatively correlated with these bacteria. The humidity and average temperature significantly influenced the Lactobacillus and Weissella abundances of fresh whole-plant maize. During the ensiling process, the silages from three regions had similar bacterial dynamic changes, and the Lactobacillus formed and maintained good fermentation characteristics in whole-plant maize silage.

Evaluating the effects of cellulolytic enzymes and Lactobacillus bulgaricus on mycotoxins production and the quality of maize silage

Fungal spoilage and mycotoxin contamination are two of the greatest hazards of silage. The present work was carried out to evaluate the impact of Lactobacillus bulgaricus and cellulolytic enzymes on the maize silage (MS) quality. Fungal analysis of different MS samples showed different mycotoxigenic fungi. The highest frequency (62.8%) was associated with Fusarium spp. Four species with different relative densities were found: F. graminearum (71.1%), F. culmorum (15.2%), F. proliferatum (11.2%), and F. oxysporum (2.50 %). High-performance liquid chromatography analysis showed the presence of trichothecene, nivalenol, zearalenone, and fumonisins mycotoxins in MS inoculated by F. graminearum. The inhibition % of trichothecene, nivalenol, and zearalenone synthesis was 50.2%, 47.5%, and 23.5%, respectively, in MS inoculated by Lactobacillus bulgaricus after a 30 d incubation period. Trichoderma harzianum succeeded in producing cellulolytic enzymes, i.e., carboxymethyl cellulase, manganase peroxidase, and laccase, with a maximum production of 350 µg/mL, 5.47 µg/mL, and 16.0 µg/mL, respectively, after 21 d using MS as the substrate. Treatment by the extracted cellulolytic enzyme with L. bulgaricus enhanced unfavorable conditions for MS fungal contamination, i.e., the production of lactic acid, a lowered pH, and increased L. bulgaricus colony-forming units, compared to the addition of enzyme extract or L. bulgaricus alone.