Grass-clover Silage Research Articles

Effect of Iodoform in Maize and Clover Grass Silages: An In Vitro Study

Iodoform has been shown to be an enteric methane-reducing agent. This study aimed to investigate if iodoform differentially affected maize (MS) and clover grass silage (GS). These substrates were used in four 22 h in vitro gas production fermentations with and without 0.032 mg/g of dry matter substrate of 0.064% iodoform in zeolite (IZ). The results of organic matter degradation (dOM, g/g), volatile fatty acids (VFAs, mMol/L), partitioning factor (PF, mg/mL), total gas production (TGP, mL/g OM), and periodic hydrogen and methane yield (mL/g OM) were evaluated. The interaction between substrate and IZ for dOM was significant with significantly less in GS. The interaction between substrate and additive was continuously significant for TGP. The additive in GS numerically decreased the TGP, but significantly increased TGP in MS. The interaction between substrate and additive was sporadically significant with methane, increasing the yield when IZ was added to MS, but a consistent, non-significant, decrease in yield was found when IZ was added to GS. Total VFA production and propionate content increased in both substrates with the addition of IZ, but only significantly in GS. Iodoform significantly decreased the efficiency of microbial conversion (PF) in both substates. Differential effects of iodoform on GS and MS were evident. More research is needed to determine the modes of action of iodoform.

Feed intake in housed dairy cows: validation of a three-dimensional camera−based feed intake measurement system

Measuring feed intake accurately is crucial to determine feed efficiency and for genetic selection. A system using three-dimensional (3D) cameras and deep learning algorithms can measure the volume of feed intake in dairy cows, but for now, the system has not been validated for feed intake expressed as weight of feed. The aim of this study was to validate the weight of feed intake predicted from the 3D cameras with the actual measured weight. It was hypothesised that diet−specific coefficients are necessary for predicting changes in weight, that the relationship between weight and volume is curvilinear throughout the day, and that manually pushing the feed affects this relationship. Twenty-four lactating Danish Holstein cows were used in a cross-over design with four dietary treatments, 2 × 2 factorial arranged with either grass-clover silage or maize silage as silage factor, and barley or dried beet pulp as concentrate factor. Cows were adapted to the diets for 11 d, and for 3 d to tie-stall housing before camera measurements. Six cameras were used for recording, each mounted over an individual feeding platform equipped with a weight scale. When building the predictive models, four cameras were used for training, and the remaining two for testing the prediction of the models. The most accurate predictions were found for the average feed intake over a period when using the starting density of the feed pile, which resulted in the lowest errors, 6% when expressed as RMSE and 5% expressed as mean absolute error. A model including curvilinear effects of feed volume and the impact of manual feed pushing was used on a dataset including daily time points. When cross-validating, the inclusion of a curvilinear effect and a feed push effect did not improve the accuracy of the model for neither the feed pile nor the feed removed by the cow between consecutive time points. In conclusion, measuring daily feed intake from this 3D camera system in the present experimental setup could be accomplished with an acceptable error (below 8%), but the system should be improved for individual meal intake measurements if these measures were to be implemented.

Operation of a Pilot-Scale Biogas Plant Made of Textile Materials and Application of Its Results to a Full-Sized Demonstration Plant

In small German farms, there is a technically usable potential of cattle manure and pig manure ranging from 153 to 187 million tons of fresh matter per year. Since 2021 and 2023, new incentives under the Renewable Energy Sources Act (EEG) have been promoting biogas production in small farms. These incentives, applicable to biogas plants up to 150 kWel, include direct compensations for plants up to 100 kWel and market premiums for those up to 150 kWel. A small biogas plant made of textile materials was designed for both pilot and full-scale applications. Compared to conventional concrete biogas reactors, these textile-based reactors offer a simplified construction and operation, eliminating the need for specialized civil engineering. The primary objective of this research is to demonstrate the process engineering feasibility of biogas reactors based on textile materials for small farm biogas plants (30 to 75 kWel). Another goal is to design the construction method in such a way that this type of system can be built by farmers themselves after type testing on site. Operational insights were gathered from the laboratory plant with a 300-L digester volume, using cattle manure and clover grass silage. To adapt the system to the biogas reactor made of textile materials, the reactor was designed without a stirrer. These insights were considered in the design and approval procedure of the full-sized demonstration biogas plant made of textile materials. The full-size demonstration plant digesters underwent an approval procedure from local authorities, featuring treatment volumes of 120 m3 for the main biogas reactor and 550 m3 for the digestate reactor in an earth basin style. This new type of biogas plant could be built in small farms for self-sufficiency in electrical and thermal energy or for treating sewage sludge in small-scale communal wastewater treatment and biogas plants.

Dynamics of weed growth in an apple orchard tree strip

The aim of this work is to visualise weed growth in an apple orchard tree-strip and how it develops under three different mulch treatments using a biological age modelling approach. Field data were obtained from a weed control experiment conducted in 2021 at the Kompetenzzentrum Obstbau Bodensee in Southwest Germany. A completely randomised experimental design with three different organic mulch treatments (grass clover silage, biodegradable spray or woodchips) and nine replicates used repeated time-series assessments to determine weed growth as weed area coverage (%), maximum height (cm) and mean height (cm). Assessments were conducted four times at monthly intervals from mid-May to early August. The weed growth rates estimated by the models were distinct for each treatment but common for all the assessed variables. Woodchip mulch was the best treatment to suppress weed growth, silage and spray mulch were less effective and gave similar results with a small benefit of the spray application. Typically, growth processes are non-linear across time and fitting a non-linear model can partition the existing biological variation in such a way that it forms a very good basis upon which to further explore repeated measures data. Given the very high variation in weed growth, field studies should be designed with a large number of repetitions (∼20) per treatment.

Effects of proportion and digestibility of grass-clover silage on milk protein, mineral and fatty acid compositions in Danish Holstein cows

ABSTRACT The objective of this study was to investigate the effects of proportion and organic matter digestibility (OMD) of grass-clover silage on milk composition. Grass-clover silages with low (LD) or high (HD) OMD were mixed at low (30:70, LP) or high (70:30, HP) proportion (DM basis) with maize silage to arrange 4 total mixed rations (TMR) with a forage-to-concentrate ratio of 60:40. The TMR were fed ad libitum to 36 cows in a 4 × 4 Complete Latin Square design. The proportion × OMD interaction showed that feeding a high proportion of low-digestible grass-clover silage resulted in a higher content of milk urea nitrogen (P < .001). The diets had a minor impact on milk protein and mineral compositions. Decreasing the grass-clover to maize silage ratio from 70:30 to 30:70 improved the nutritional value of milk fat by decreasing the share of saturated and increased the share of unsaturated fatty acids (P < .001).

Effect of substituting grass-clover silage with maize silage for dairy cows on nutrient digestibility, rumen metabolism, enteric methane emission and total carbon footprint

The aim of this experiment was to determine the optimal ratio between maize silage and grass-clover silage in lactating dairy cow diets. The evaluation was based on nutrient digestibility, rumen metabolism and total carbon footprint (CF). Carbon footprint included enteric methane emission and CF from feed production, transportation, processing, and C sequestration in the soil, based on a Life Cycle Assessment (LCA) approach. Four diets varying in proportions of grass-clover silage and maize silage (100:0, 67:33, 33:67, and 0:100 on dry matter (DM) basis, respectively) were fed ad libitum to 4 lactating Holstein cows (a fifth cow was involved later in the study) fitted with ruminal, duodenal, and ileal canulae in a 4 × 4 Latin square design. Nutrient digestibility was measured using chromium oxide and titanium oxide as flow markers, and methane and CO2 emissions were measured in open-circuit respiration chambers on 5 consecutive days for each cow in each period. Data were analyzed with treatment and period as fixed effects and cow as random effect. DM intake (DMI) increased linearly (P = 0.01) with increased proportion of maize silage in the feed ration. Under the conditions in the present study, diets had only minor effects on digestibility of nutrients and there was no influence on rumen pH. Total VFA concentration decreased linearly with increased level of maize silage, but there were only minor effects on molar proportions of VFAs in the rumen. However, there was a linear increase in duodenal flow of microbial DM with increasing level of maize silage. The cows produced 30.7, 29.4. 28.4, and 26.2 L of methane/kg of DMI on diets 100:0, 66:33, 33:66, and 0:100, respectively (P = 0.02 for linear effect), which is equivalent to a 15% decrease, when all grass-clover silage was replaced by maize silage. Despite the significant reduction in enteric methane emission with increased proportion of maize silage, only a 4% decrease in total CF per kg DMI was found, when including CF from feed production, transportation, processing, manure, energy use and C sequestration in the soil, when using a LCA approach. If direct Land Use Change (LUC) or indirect LUC was included in estimation of CF, the reduction in CF when replacing all grass-clover silage was also 4–6%. However, the total CF was highly dependent on assumptions related to yield of grass-clover and maize.

Nitrogen input on organic amendments alters the pattern of soil–microbe-plant co-dependence

The challenges of nitrogen (N) management in agricultural fields include minimizing N losses while maximizing profitability and soil health. Crop residues can alter N and carbon (C) cycle processes in the soil and modulate the responses of the subsequent crop and soil– microbe-plant interactions. Here, we aim to understand how organic amendments with low and high C/N ratio, combined or not with mineral N may change soil bacterial community and their activity in the soil. Organic amendments with different C/N ratios were combined or not with N fertilization as follows: i) unamended soil (control), ii) grass clover silage (GC; low C/N ratio), and iii) wheat straw (WS; high C/N ratio). The organic amendments modulated the bacterial community assemblage and increased microbial activity. WS amendment had the strongest effects on hot water extractable carbon, microbial biomass N and soil respiration, which were linked with changes in bacterial community composition compared with GC-amended and unamended soil. By contrast, N transformation processes in the soil were more pronounced in GC-amended and unamended soil than in WS-amended soil. These responses were stronger in the presence of mineral N input. WS amendment induced greater N immobilization in the soil, even with mineral N input, impairing crop development. Interestingly, N input in unamended soil altered the co-dependence between the soil and the bacterial community to favor a new co-dependence among the soil, plant and microbial activity. In GC-amended soil, N fertilization shifted the dependence of the crop plant from the bacterial community to soil characteristics. Finally, the combined N input with WS amendment (organic carbon input) placed microbial activity at the center of the interrelationships between the bacterial community, plant, and soil. This emphasizes the crucial importance of microorganisms in the functioning of agroecosystems. To achieve higher yields in crops managed with various organic amendments, it is essential to incorporate mineral N management practices. This becomes particularly crucial when the soil amendments have a high C/N ratio.

Effects of forage and grain legume-based silages supplemented with faba bean meal or rapeseed expeller on lactational performance, nitrogen utilization, and plasma amino acids in dairy cows

The objective of this experiment was to investigate the effect of forage type [red clover (51%)-grass silage, i.e., RCG; vs. faba bean (66%)-grass silage, i.e., FBG] and concentrate type (faba bean, FB; vs. rapeseed expeller, RE) on lactational performance, milk composition and nitrogen (N) utilization in lactating dairy cows. Eight lactating multiparous Nordic Red cows were used in a replicated 4 × 4 Latin Square experiment, with 21-d periods, in a 2 × 2 factorial arrangement of treatments. The experimental treatments were as follows: (1) RCG with RE, (2) RCG with FB, (3) FBG with RE, and (4) FBG with FB. Inclusion rates of RE and FB were isonitrogenous. Crude protein contents of the experimental diets were 16.3, 15.9, 18.1, and 17.9% of dry matter, respectively. All diets included oats and barley and were fed ad libitum as total mixed rations with forage-to-concentrate ratio of 55:45. Dry matter intake and milk yield were recorded daily, and spot samples of urine, feces, and blood were collected at the end of each experimental period. Dry matter intake did not differ across diets, averaging 26.7 kg/d. Milk yield averaged 35.6 kg/d and was 1.1 kg/d greater for RCG versus FBG, and milk urea N concentration was lower for RCG compared with FBG. Milk yield was 2.2 kg/d and milk protein yield 66 g/d lower for FB versus RE. Nitrogen intake, urinary N, and urinary urea N excretions were lower, and milk N excretion tended to be lower for RCG compared with FBG. The proportion of the dietary N excreted as fecal N was larger in cows fed RCG than for those fed FBG, and the opposite was true for urinary N. We detected an interaction for milk N as percentage of N intake: it increased with RE compared with FB for RCG-based diet, but only a marginal increase was observed for FBG-based diet. Plasma concentration of His and Lys were lower for RCG than for FBG, whereas His tended to be greater and Lys lower for FB compared with RE. Further, plasma Met concentration was around 26% lower for FB than for RE. Of milk fatty acids, saturated fatty acids were decreased by RCG and increased by FB compared with FBG and RE, respectively, whereas monounsaturated fatty acids were increased by RCG versus FBG, and were lower for FB than for RE. In particular, 18:1n-9 concentration was lower for FB compared with RE. Polyunsaturated fatty acids, such as 18:2n-6 and 18:3n-3, were greater for RCG than for FBG, and 18:2n-6 was greater and 18:3n-3 was lower for FB versus RE. In addition, cis-9,trans-11 conjugated linoleic acid was lower for FB compared with RE. Faba bean whole-crop silage and faba bean meal have potential to be used as a part of dairy cow rations, but further research is needed to improve their N efficiency. Red clover-grass silage from a mixed sward, without inorganic N fertilizer input, combined with RE, resulted in the greatest N efficiency in the conditions of this experiment.

Environmental consequences of pig production scenarios using biomass from rotational grass-clover leys as feed

Production of pork based on monoculture cereal-based cropping systems causes substantial environmental pressures and feed-food competition. This study evaluated the environmental consequences of five different scenarios involving inclusion of rotational grass-clover leys and incorporation of grass-clover biomass in pig diets: (1) a conventional reference scenario without grass-clover biomass; (2) a conventional scenario with replacement of feed with grass-clover silage in a total mixed ration, i.e., with grass-clover biomass replacing other feed; (3) an organic scenario using grass-clover silage for enrichment purposes only; (4) an organic scenario using grass-clover silage for enrichment purposes and additional grass-clover leys for green manuring; and (5) an organic scenario using grass-clover silage and pasture to replace feed. The functional unit was 1 kg of pork slaughter weight and the system boundary was from cradle to farm gate. We used life cycle assessment, the introductory carbon balance method and human edible feed conversion efficiency to assess the performance of the pig production system. Introducing grass-clover biomass as a total mixed ration in conventional pig diets, reduced the climate impact (-17%), eutrophication (-7.1%), marine eutrophication (-15%), energy use (-13%), and feed-food competition (-20%) per kg of pork meat, while acidification (+2.7%) and land use (+1.5%) were slightly increased compared with the reference. The lower climate impact (without considering soil carbon change) was attributable to reduced fertilizer and diesel needs due to pre-crop effects. Overall, feeding grass-clover biomass decreased several environmental impact categories, feed-food competition and improved cereal-based cropping systems by the introduction of grass-clover leys.

Anaerobic Digestion of Solid Agricultural Biomass in Leach-Bed Reactors.

This study focuses on the feasibility of the dry anaerobic digestion of solid agricultural biomass for efficient renewable-energy production and nutrient recycling. Methane production and the amount of nitrogen in the digestates were measured in pilot- and farm-scale leach-bed reactors. In the pilot scale, with a digestion time of 133 days, the methane production of a mixture of whole crop fava bean and horse manure corresponded to 94% and 116%, respectively, of the methane potentials of the solid substrates. The mono-digestion of fava beans resulted in relatively low methane production (production/potential ratios of 59% and 57%). In two full-scale experiments, the methane production of mixtures of clover-grass silage, chicken manure, and horse manure corresponded to 108% and 100% of their respective methane potentials with digestion times of 117 and 185 days. In co-digestion, the production/potential ratios were similar in the pilot and farm experiments. High nitrogen loss was observed in the farm scale when the digestate was stored in a stack covered with a tarpaulin during summertime. Thus, although the technology seems promising, attention needs to be paid to management practices to minimise nitrogen losses and greenhouse gas emissions.

Effects of particle size and toasting of fava beans and forage source on nutrient digestibility, ruminal fermentation, and metabolizable protein supply in dairy cows.

The objective of this study was to investigate the effects of heat treatment (toasting) and particle size alterations (grinding; rolling) on nutrient utilization, ruminal fermentation, and supply of metabolizable protein (MP), and to study the interaction between processing conditions of fava beans and forage type. Six Danish Holstein dairy cows fitted with ruminal, duodenal, and ileal cannulas were used in a 6 × 4 incomplete Latin square design with 4 periods of 21-d duration. Cows were fed ad libitum with 6 experimental diets: diets high in either grass-clover silage or corn silage were combined with ground untoasted, ground toasted, or rolled untoasted fava beans. Samples of ruminal fluid, digesta from duodenum and ileum, and feces were collected, and nutrient digestibility was estimated using Cr2O3 and TiO2 as flow markers. Diets high in corn silage resulted in higher ruminal pH and higher proportion of propionate in ruminal volatile fatty acids compared with diets high in grass-clover silage. Diets high in corn silage resulted in higher apparent total-tract digestibility of crude protein and starch but lower apparent ruminal and total-tract digestibility of neutral detergent fiber compared with diets high in grass-clover silage. Rolling of fava beans decreased the in situ small intestinal disappearance of rumen-undegradable protein corrected for particle losses. Compared with grinding, rolling of fava beans reduced apparent ruminal digestibility of starch, true ruminal digestibility of organic matter, crude protein, and AA, and small intestinal digestibility of AA and starch. Grinding of fava beans increased apparent ruminal digestibility of neutral detergent fiber and reduced the proportion of propionate in ruminal volatile fatty acids compared with rolling of fava beans. In addition, rolling of fava beans had no effect on MP supply. Toasting of fava beans had no effect on in vivo nutrient digestibility except for an interaction with forage source on apparent ruminal dry matter and organic matter digestibility. Toasting of fava beans did not affect small intestinal digestion of individual and total AA, and therefore failed to increase MP supply. In conclusion, neither replacing grass-clover silage with corn silage, nor toasting nor rolling of fava beans had an effect on supply of MP.

Effect of proportion and digestibility of grass-clover silage on feed intake, milk yield, and nitrogen excretion in lactating dairy cows

The aim of the current study was to examine the effect of proportion and digestibility of grass-clover silage on dry matter intake (DMI), milk yield and nitrogen (N) excretion in lactating dairy cows. In total, 36 Danish Holstein dairy cows, 12 primiparous and 24 multiparous, were included in the study. At the beginning of the experiment the cows were on average (mean ± SD) 122 ± 81 days in milk (DIM). The cows were divided into 9 groups (4 cows in each group) based on parity and DIM, and were randomly assigned to one of four dietary treatments in a 4 x 4 Latin square design with 9 replications. The four dietary treatments differed in forage source as follows: 1) low proportion of low digestible grass-clover silage; 2) low proportion of high digestible grass-clover silage; 3) high proportion of low digestible grass-clover silage; 4) high proportion of high digestible grass-clover silage. Different proportions were obtained by exchanging grass-clover silage with maize silage (30:70 or 70:30 on DM basis). Different digestibilities of grass-clover silages were obtained by using two grass-clover silages differing in harvest time, spring growth and first re-growth, with these expected to have a high and low digestibility, respectively. The experiment was divided into 4 periods, all lasting for 3 weeks of which the first 17 d were used as adaption and the last 4 d were used for sampling and recording. Feed and water intake as well as milk yield were recorded daily, and milk samples were collected for determination of milk composition. In addition, faeces and blood samples were collected for chemical analyses. Replacing grass-clover silage with maize silage increased DMI and milk protein but reduced milk fat, whereas increased digestibility of grass-clover silage decreased DMI but increased milk protein. Milk yields (kg and kg of energy-corrected milk (ECM)) were not affected by diet, probably due to the increase in DMI observed in cows offered low digestible grass-clover. Excretion of N in urine increased with high proportion and low digestibility of grass-clover silage, probably a result of the greater crude protein (CP) concentration in grass-clover silages than in maize silage, and in low compared to high digestible grass-clover silage, respectively. Thus, proportion and digestibility of grass-clover silage surprisingly seemed to have only minor effect on milk production and composition. However, digestibility was confounded with the harvest used, and the different cuts of grass-clover silage likely differed in clover proportion, which could have affected the results. Finally, urinary N excretion increased with increased dietary CP concentration.

Importance of Feedstock in a Small-Scale Agricultural Biogas Plant

Although no legal sustainability criteria have been formulated for electricity and heat production from biogas, the sustainability and profitability of large-scale biogas plants which use mainly energy crops is now questioned. Small (farm-size) biogas plants characterized by CHP electrical output in the range between 15 kWel and 99 kWel, operating on agricultural wastes and by-products, seem more suitable; however, the variety of feedstock may be crucial in the proper design and operation of such family biogas plants. This paper aims to present the problems that occurred in small agricultural biogas plants fed with sheep manure (SM), horse manure (HM), and grass-clover silage (GCS). This paper also focuses on analyzing the energy balance and carbon dioxide (CO2) emissions related to four technological solutions (Scenarios 1–4) based on various feedstocks, grinding and feeding systems, and wet/dry fermentation. The biogas plant was originally based on dry fermentation with an organic loading rate ~10.4 kgVS·m−3·d−1, a hydraulic retention time of 16 days, and temperature of 45 °C in the fermentation chamber. The material was shredded and mixed in a mixing device, then the mixture of manures and silage was introduced to the horizontal fermentation chamber through a system of screw feeders. The biogas and the digestate were collected in a reinforced concrete tank. The biogas was sent to the CHP unit of an installed electrical power of 37 kWel, used to produce electricity and recover the heat generated in this process. Scenario 1 is based on the design assumptions used for the biogas plant construction and start-up phase. Scenario 2 includes a new feeding and grinding system, in Scenario 3 the feedstock is limited to SM and HM and wet fermentation is introduced. In Scenario 4, a dry fermentation of SM, HM, and maize silage (MS) is assumed. Avoided CO2 emissions through electricity and heat production from biogas were the highest in the case of Scenarios 1 and 4 (262,764 kg CO2·y−1 and 240,992 kg CO2·y−1) due to high biogas production, and were the lowest in Scenario 3 (7,481,977 kg CO2·y−1) because of the low specific methane yield (SMY) of SM and HM. Nevertheless, in all scenarios, except Scenario 3, CO2 emissions from feedstock preparation and biogas plant operation are much lower than that which can be avoided by replacing the fossil fuel energy for the electricity and heat produced from biogas. Our observations show that a small agricultural biogas plant can be an effective energy source, and can contribute to reducing CO2 emissions only if the appropriate technological assumptions are adopted, and the entire installation is designed correctly.

Effects on feed intake, milk production, and methane emission in dairy cows fed silage or fresh grass with concentrate or fresh grass harvested at early or late maturity stage without concentrate.

The objective of the study was to quantify the effects on dry matter intake (DMI), nutrient digestibility, gas exchange, milk production, and milk quality in dairy cows fed fresh grass harvested at different maturity stages. Sixteen Danish Holstein cows in mid-lactation were divided into 4 blocks and used in 4 incomplete 4 × 2 Latin squares with 2 periods of 21 d. The cows received 1 of 4 treatments in each period, resulting in 8 cows per treatment, as follows: grass-clover silage supplemented with 6 kg/d concentrate pellets (SILc), fresh grass harvested at late maturity stage supplemented with 6 kg/d concentrate pellets (LATc), fresh grass harvested at late maturity stage (LAT), and fresh grass harvested at early maturity stage (ERL). The cows were housed in tiestalls and milked twice daily. The cows had ad libitum access to the forage, and concentrate pellets were divided into equal amounts and fed separately in the morning and afternoon. Fecal samples were collected to determine apparent total-tract digestibility, and samples of rumen fluid were collected for determination of short chain fatty acid composition. Halters were used for measuring eating and rumination time. Gas exchange was measured in open-circuit respiration chambers. Total DMI was higher in LATc and ERL (16.9 ± 0.45 and 15.5 ± 0.39 kg/d, respectively) compared with LAT (14.1 ± 0.42 kg/d). Relative to SILc, cows fed fresh grass experienced a convex pattern in DMI during the experiment. The changes in DMI were related to changes in leaf to stem ratio, fiber concentration, and organic matter digestibility determined in vitro in samples of the fresh grass harvested throughout the experiment. The apparent total-tract digestibility of organic matter was higher in SILc and LAT compared with LATc. Methane yield was lower for LATc compared with LAT (19.5 ± 0.61 vs. 22.6 ± 0.55 g of CH4/kg of DMI), and was not different between LAT and ERL. Compared with LAT, milk yield was higher for ERL (21.1 ± 1.14 vs. 23.4 ± 1.11 kg/d) and energy-corrected milk (ECM) yield was higher for LATc (21.5 ± 0.99 vs. 25.3 ± 1.03 kg/d). We detected no differences in milk or ECM yield between SILc and LATc. Milk protein yield was higher and milk fat concentration was lower in LATc compared with LAT. The fatty acid percentages of ∑C4-C14:1 and ∑C16 in milk were higher for SILc compared with LATc, signifying pronounced de novo synthesis. The n-6:n-3 ratio in milk fatty acids was lower for SILc and LAT compared with LATc, indicating improved nutritional quality for SILc and LAT. However, retinol concentration in milk was lower in SILc compared with all other treatments. The study implies that feeding silage instead of fresh grass has no effect on DMI, ECM yield, or CH4 yield, and that concentrate supplementation can increase milk production, affects milk quality, and reduces the effect on climate, whereas feeding less mature grass increases DMI and milk yield, but has no effect on CH4 yield.

O99 Effect on carbon footprint when substituting grass-clover silage with maize silage for dairy cows

O99 Effect on carbon footprint when substituting grass-clover silage with maize silage for dairy cows

Associations among nutrient concentration, silage fermentation products, in vivo organic matter digestibility, rumen fermentation and in vitro methane yield in 78 grass silages

Grass-clover silage constitutes a large part of ruminant diets in Northern and Western Europe, but the impact of silage quality on methane (CH4) production is largely unknown. This study was conducted to identify the quality attributes of grass silage associated with variation in CH4 yield. We expected that silage nutrient concentrations and silage fermentation products would affect CH4 yield, and that these factors could be used to predict the methanogenic potential of the silages. Round bales (n = 78) of grass and grass-clover silage from 37 farms in Norway were sampled, incubated, and screened for in vitro CH4 yield, i.e. CH4 production expressed on the basis of incubated organic matter (CH4-OM) and digestible OM (CH4-dOM) using sheep. Concentration of indigestible neutral detergent fiber (iNDF) was quantified using the in situ technique. The data were subjected to correlation and principal component analyses. Stepwise multiple regression was used to model methanogenic potential of silages. Among all investigated silage composition variables, neutral detergent fiber (aNDFom) and water-soluble carbohydrate (WSC) concentrations obtained the greatest correlations to CH4-OM (r = −0.63 and r = 0.57, respectively, P < 0.001), while concentration of iNDF negatively correlated with CH4-OM (r = −0.48, P < 0.001). In vivo organic matter digestibility (OMD) and concentration of ammonia-N (NH3-N) in silages were also correlated to CH4-OM (r = 0.44 and r = −0.32, P < 0.001 and P < 0.01, respectively). The stepwise regression using CH4-OM as response variable included aNDFom, WSC, iNDF, silage propionic acid and pH in descending order. The stepwise regression using CH4-dOM as response variable included WSC, aNDFom and iNDF in descending order. Among in vitro rumen short chain fatty acids (SCFA), molar proportion of butyrate was the most prominent in increasing CH4-OM and CH4-dOM (r = 0.23 and r = 0.36, P < 0.05 and P < 0.01, respectively), while molar proportion of propionate was the most prominent SCFA in reducing CH4-OM and CH4-dOM (r = −0.23 and r = −0.26, respectively, P < 0.05). Regression models that account for silage quality attributes can be used to predict CH4 yield from silages with a coefficient of determination (R2) between 0.33 (CH4-dOM) and 0.65 (CH4-OM). In conclusion, concentration of WSC increased in vitro CH4-OM and CH4-dOM, while concentration of aNDFom and iNDF decreased CH4-OM and CH4-dOM in grass silages.

Milk Production of Dairy Cows Fed Grass-Clover Silage Pulp

Silage pulp (SP) is a byproduct from biorefinary of silage that can be used as forage source for ruminants. However, there is a lack of information regarding the complete replacement of dietary silage for SP on performance of dairy cows. The purpose of this study was to evaluate the complete substitution of dietary grass-clover silage for SP on milk production of dairy cows. Grass-clover mixture was harvested, wilted, and ensiled in bunker silos. The silage was screw pressed in a biorefinery for solid (SP) and liquid (protein-rich juice) separation. Seventy-two lactating cows were used in a completely randomized block design, receiving either the original silage- or SP-based diets. The SP-based diet had lower concentrations of water-soluble carbohydrates and crude protein but greater fibre concentration compared to the silage-based diet. Milk yield and energy corrected milk were generally greater for cows receiving the silage-based diet compared to the SP-based diet. Cows receiving the silage-based diet had a greater yields of milk protein and milk fat, and tended to have a greater yield of milk lactose than cows receiving the SP-based diet. Milk composition, body condition score and body weight were not affected by diets. The complete substitution of silage for SP reduced the lactation performance of dairy cows over time.

Can lignin and monomer composition of fibre describe the variation in iNDF in forages?

Indigestible NDF (iNDF) is an entity in feed evaluation systems. In this study, iNDF is defined as the portion of NDF not digested after 288 h of rumen incubation in Dacron bags with 12 µm pore size. However, the method is resource demanding. The objective of this study was to elucidate the effect of lignin and hemicellulose monomers on iNDF variation within and among forage types and their ability to predict iNDF variation in linear and multiple regression models. The hypotheses were 1) lignin is expected to have high ability in describing the iNDF variation and 2) the inclusion of hemicellulose monomers will increase this ability. iNDF was determined on 50 grass-clover silages and 50 whole crop maize silages as well as 40 maize stem and 10 maize ear samples. All samples were analysed for neutral detergent fibre (NDF), Klason lignin (KL), cellulose and non-cellulose polysaccharides (NCP). Grass-clover and whole crop maize silages were analysed for acid detergent lignin (ADL). Lignin variables had the most consistent correlation to the iNDF variation throughout both correlation and regression analyses. Arabinose also showed high correlations and relationships in linear regression to iNDF and almost at same level as lignin variables. Multiple linear regression increased the accuracy for grass-clover silage and combined analysis with all forage types, with KL and/or ADL as first explanatory variables. However, the increase in accuracy is not consistent between forage types.

Evaluation of production parameters, feed sorting behaviour and social interactions in dairy cows: Comparison of two total mixed rations with different particle size and water content

Dairy cow performance is affected by both the nutritional composition and the physical structure of the diet. The structure of total mixed rations (TMR) largely depends on the ingredient composition and structure of forage, dry matter (DM) content, mixing time and type of mixer used. This study investigated feed intake, eating time, milk production, DM digestibility, ruminal pH, time budget, and sorting and antagonistic behaviours in lactating dairy cows fed grass/clover silage and concentrate, either in a TMR or in a compact total mixed ration (CTMR) with decreased particle size and DM content due to addition of water. Two cross-over experiments (3-week periods), each involving 40 lactating dairy cows of the Swedish Red and Holstein breeds, were run simultaneously. Experiment 1 was designed to measure production parameters, feed digestibility and ruminal pH, while Experiment 2 was designed to measure time budget, feed sorting behaviours and antagonistic behaviours at the feed bunk. Diets were fed ad libitum, with the same ingredient composition and a forage:concentrate ratio of 60:40 (DM basis). Decreased particle size in the CTMR diet was achieved by mixing the grass-clover silage in a feed mixer with a vertical auger with knives, before mixing with concentrate in a feed mixer without knives. Decreased DM content in CTMR was achieved by adding water to the mix. Mean DM content of the diet was 51% DM for TMR and 37% DM for CTMR. The results showed lower daily DM intake (26.7 kg DM) and shorter eating time (242 min) in cows fed CTMR than in cows fed TMR (28.5 kg DM and 278 min). Feed digestibility, ruminal pH, daily milk yield (35.1 kg and 35.8 kg for CTMR and TMR, respectively) and milk composition did not differ between the diets. Cows fed CTMR showed less sorting and fewer antagonistic behaviours at feeding than cows fed TMR. The daily time budget of the cows also differed, with cows fed CTMR spending more time resting (+45 min) than cows fed TMR.

Fava beans can substitute soybean meal and rapeseed meal as protein source in diets for lactating dairy cows

The effect of replacing mixtures of wheat and soybean meal and wheat and rapeseed meal by toasted fava beans, and the effect of toasting fava beans on feed intake, milk yield, and composition of milk and feces were investigated using 40 Holstein cows in each of two 4 × 4 Latin square design trials conducted simultaneously. In trial 1, the 4 treatment concentrates were untreated fava beans, toasted fava beans, 42% soybean meal + 58% rolled wheat, and a 21, 29, and 50% mix of soybean meal, rolled wheat, and toasted fava beans, respectively [on dry matter (DM) basis]. In trial 2, the 4 experimental treatments were untreated fava beans, toasted fava beans, 64% rapeseed meal + 36% rolled wheat, and a 32, 18, and 50% mix of rapeseed meal, rolled wheat, and toasted fava beans, respectively (on DM basis). In each trial, 16 primiparous and 24 multiparous cows were fed the treatment concentrates as part of a partial mixed ration, of which the forage consisted of 50% corn silage and 50% grass-clover silage. Substitution of soybean meal and wheat or rapeseed meal and wheat with toasted fava beans did not affect total DM intake, and no linear effects were observed on milk yield or energy-corrected milk (ECM) yield. However, in trial 2, a quadratic effect was observed on milk yield when substituting rapeseed meal and wheat with toasted fava beans. In both trials, substitution of soybean meal and wheat or rapeseed meal and wheat with toasted fava beans increased milk lactose concentration and decreased milk protein yield and concentration of protein in milk. In both trials, fecal concentration of starch increased linearly when substituting soybean meal and wheat or rapeseed meal and wheat with toasted fava beans. In trial 2, fecal concentration of P decreased when substituting rapeseed meal and wheat with toasted fava beans. In situ investigations showed increased rumen undegradable protein concentration and thereby increased estimated metabolizable protein supply when toasting fava beans. However, in both trials, milk protein yield and concentration decreased when cows were fed toasted compared with untreated fava beans. Furthermore, when cows were fed toasted compared with untreated fava beans in trial 1, milk yield, ECM yield, and nitrogen efficiency decreased. We conclude that toasted fava beans could substitute soybean meal and wheat or rapeseed meal and wheat with regard to ECM yield. However, milk protein yield decreased when substituting soybean meal and wheat or rapeseed meal and wheat with toasted fava beans. Compared with untreated fava beans, toasting had no positive effect on milk production and nitrogen efficiency.