Milk production, nitrogen utilization, and methane emissions of dairy cows grazing grass, forb, and legume-based pastures

Foraging preferences of dairy cows grazing on contrasted multispecies swards

Selective foraging has been reported in many wild and domesticated ruminants, yet modern livestock production systems rarely allow animals to express this natural behaviour. However, it is assumed that giving livestock the opportunity for forage selection positively influences their health and welfare. This study investigated the forage selection of individual dairy cows on pasture. Over one grazing season, a herd of 23 dairy cows was observed grazing on an experimental pasture in Switzerland, which consisted of different plant mixtures. The cows had unrestricted access to all mixtures and their individual foraging behaviour was documented by scan sampling. The four mixtures were rich in grasses (G), grasses and legumes (L), grasses and tanniferous plants (T), and grasses and herbs containing essential oils (E). The results revealed a partial preference for the L mixture at herd level across all grazing rotations (P ≤ 0.001). All mixtures were frequented, indicating that the herd utilized the array of available plants. Individual preferences varied and not all cows followed the herd's average pattern. Individual preferences shifted throughout the grazing season, but the pattern of this variability differed between animals. The findings demonstrate that dairy cows actively select from different pasture plants and that preferences vary between individuals and over time. Importantly, average herd preferences do not accurately represent the behaviour of all cows. Individual preferences should be considered when aiming to meet the foraging needs of all herd members.

Allicin enhances urea-N conversion to microbial-N by inhibiting urease activity and modulating the rumen microbiome in cattle

BACKGROUND

Urea serves as a vital nonprotein nitrogen source in ruminant nutrition, but its efficient utilization is often hampered due to rapid urease activity in the rumen. This study explores the potential of allicin, a garlic-derived compound, as a urease inhibitor to improve urea nitrogen utilization. Enzyme inhibition kinetics and molecular docking were used to identify allicin's interaction sites on urease. Additionally, metagenomic and 15N-urea metabolic flux analyses were conducted to evaluate allicin's impact on microbial populations and urea-N metabolism.

RESULTS

Allicin was identified as an inhibitor of ruminal urease, with an IC50 of 126.77 ± 1.21 μM. Molecular docking studies have shown that allicin forms hydrogen bonds with key urease residues, leading to the preemption of the urease active site and thus impeding urea binding. In a simulated rumen environment, allicin significantly reduced urea hydrolysis and ammonia production. Furthermore, allicin modified the rumen microbial community by inhibiting Prevotella species while promoting the growth of Ruminobacter species and Denitrobacterium detoxificans. A 15N-urea metabolic flux analysis revealed that allicin facilitated the incorporation of urea-derived nitrogen into microbial amino acids and nucleotides.

CONCLUSION

Allicin effectively inhibits urease activity in the rumen, enhancing the conversion of urea-N into microbial biomass. These findings suggest that allicin has significant potential to optimize urea metabolism in the rumen, offering a novel strategy for improving ruminant nitrogen nutrition. Video Abstract.

Polyphenol-Containing Feed Additive Polygain™ Reduces Methane Production and Intensity from Grazing Dairy Cows Measured Using an Inverse-Dispersion Technique

This study, conducted on a commercial dairy farm using a robotic milking system in Victoria, Australia, examined the effects of Polygain™ (The Product Makers Australia), a polyphenol-rich sugarcane feed material (PRSFM), on CH4 emissions in grazing dairy cattle using an inverse-dispersion model (IDM) combined with open-path laser techniques. Thirty lactating Holstein Friesian cows (aged 2-5 years with an average body weight of 663 kg and average daily milk production of 28.9 kg) were divided into two dietary treatment groups of fifteen cows each. Before the measurement, the PRSFM (0.25%) was supplemented for 3 weeks as an adaptation period and mixed with pellet feed for the treatment group. Over the 2-week measurement period, CH4 production (MP) was 495 ± 12 and 377 ± 12 (mean ± standard error) g CH4/animal/day for the control and treatment groups, respectively. Methane intensity (MI) was 17.04 and 13.01 g CH4/animal/kg milk/day in the control and treatment groups, respectively. On average, Polygain supplementation reduced MP and MI by 24%. This potential CH4 reduction extrapolated across Australia contributes to a 2.63% reduction in national agricultural emissions. This study underscores the potential of Polygain for CH4 mitigation in dairy cattle.

Welfare Status in Dairy Cows during Confined and Grazing Periods in the North American Pacific Northwest using Blood Parameters and Visual Assessments

Grazing is usually associated with higher well-being in dairy cows. However, current research on the welfare of grazing cows lacks validation via blood profiling. We monitored four dairy farms that seasonally graze in the temperate North American Pacific Northwest, USA, to address this gap. We collected blood and hair samples and scored the animals for welfare-related visual evaluations during the dry period and early and late lactation stages during the confined and grazing periods. Over 20 blood parameters were analyzed, plus cortisol in the tail hair as a stress indicator. Blood profiling indicated that cows during the grazing period had a more stable metabolism across the stages of lactation, a more robust immune system, and slightly greater inflammation than during the confined period. The amount of cortisol in the hair was lower in cows during the grazing vs. confined period. Only a few direct animal measurements were affected, including a better body condition and cleanliness score compared to the confined period. Overall, our data indicate better welfare conditions in cows during the grazing period compared to the confined period.

Animal as the Solution II: Phenotyping for Low Milk Urea Nitrogen A1PF Dairy Cows

The societal pressure on intensive pastoral dairying demands the search for strategies to reduce the amount of N flowing through and excreted by dairy cows. One of the strategies that is being currently explored focuses on the animal as a solution, as there are differences in N metabolism between cows even within the same herd. This work was conducted to explore such an approach in A1PF herds in New Zealand and the possibility of identifying A1PF cows that are divergent for milk urea nitrogen (MUN) concentration through phenotyping as a potential viable strategy to reduce N leaching and emissions from temperate dairy systems. Three herd tests were conducted to select a population sample of 200 cows (exhibiting the lowest 100 and highest 100 MUN concentrations). Milk samples were collected from the 200 cows during mid and late lactation to test for milk solids content and MUN. From the 200 cows, urine for urinary N concentration (UN), blood for plasma urea N, total antioxidants (TAS), and glutathione peroxidase (GPx) were collected from the 20 extremes (the lowest 10 and highest 10 MUN concentrations). Milk urea N was greater in cows selected as high-MUN cows (16.2 vs. 14.32 ± 0.23 mg/dL) and greater during late lactation (16.9 vs. 13.0 ± 0.19 mg/dL). Milk solids and fat content were 38% and 20% greater in cows selected as low-MUN cows than in high-MUN cows during mid lactation (p < 0.001). Low-MUN cows had lower UN than high-MUN cows during mid lactation (0.64 vs. 0.88 ± 0.11%). The N concentration in the plasma (p = 0.01) and Tas (p = 0.06) were greater during late lactation. There was a positive relationship between the MUN concentration phenotype used for selection and the MUN concentration for the trial period and MUN concentration and UN concentration during mid and late lactation (p < 0.001). Our results suggest that A1PF cows within a commercial herd can be phenotyped and selected for low-MUN, which may be potentially a viable strategy to reduce N losses to the environment and create healthier systems. Following genetic tracking, those cows can be bred to further promote low-MUN A1PF herds.

Effect of dietary supplementation of plantain herb, lemongrass and their combination on milk yield, immunity, liver enzymes, serum, and milk mineral status in dairy cows

Objective

This research aimed to assess the effects of dried plantain herb, lemongrass, and their combination on milk yield, immunological, liver enzymatic, serum, and milk mineral status in dairy cows.

Materials and Methods

Twenty cows were arbitrarily assigned to 4 diets. Cows were given a basal ration considered as control diet (CL-D) having 14.93% crude protein (CP)and 10.96 MJ ME per kg dry matter (DM). Each cow was given 100 gm plantain, 100 gm lemongrass, and 50 gm plantain + 50 gm lemongrass with CL-D and taken as plantain diet (PT-D), lemongrass diet (LG-D), and plantain-lemongrass diet (PL-D), daily for 63 days, respectively. Blood and milk samples were taken four times at an interval of 14 days. Data were analyzed using a two-way repeated measures analysis of covariance.

Results

Better DM consumption and milk yield were observed in the PT-D and LG-D compared to the CL-D (p ≤ 0.05). LG-D improved the milk's total solids, protein, and fat compared to CL-D (p < 0.05). Substantially, herbal groups improved serum albumin and reduced globulin concentrations compared to CL-D. LG-D had the highest serum immunoglobulin G, while herbal groups effectively reduced the liver enzymes compared to CL-D. Herbal groups did not affect serum and milk's calcium and phosphorus concentrations, while LG-D and PL-D substantially improved serum and milk zinc concentrations.

Conclusions

Both plantain and lemongrass improved dairy cows' DM consumption and milk yield. Plantain and/or lemongrass enhanced the immune system and liver health, but not serum and milk calcium and phosphorus level. Lemongrass and a combination of plantain and lemongrass increased the serum and milk zinc concentrations.

How does grazing pressure affect feed intake and behavior of livestock in a meadow steppe in northern China and their coupling relationship

Livestock feeding behavior and intake play a crucial role in influencing grassland health and productivity. A comprehensive investigation into livestock feeding behavior and intake can effectively elucidate the interactions and impacts of livestock and grasslands, providing scientific evidence and technical support for the formulation and implementation of sustainable grassland development strategies. Based on a long-term controlled grazing experiment platform conducted over 13 years, the feeding behavior and forage intake of cattle under different grazing intensities were observed and analyzed. Additionally, we used GPS sensors to study cattle grazing behavior trends. Using Mantel's test, we analyzed the relationship between cattle movement distance, forage intake, and environmental factors. The results demonstrated that cattle forage intake decreased with increasing grazing intensity. Forage intake peaked at the end of July and beginning of August, with the highest efficiency observed in August. Moreover, under light grazing intensity, cattle exhibited greater fluctuations in forage intake than those under moderate and heavy grazing intensity. Cattle movement levels increased with higher grazing intensity, and during the period of lush grass growth, cattle displayed significantly higher movement levels than during grass senescence. The accuracy of the behavior determination model based on cattle velocity ranged from 60 to 80 %. Using this model, we found that under heavy grazing conditions, cattle spent significantly more time roaming than under light and moderate grazing. Conversely, under light grazing conditions, cattle spent significantly more time feeding. A negative correlation was identified between cattle forage intake and movement distance. Cattle's forage intake was significantly positively correlated with grass height and grass biomass and significantly negatively correlated with stocking rate and movement distance. Thorough research on livestock feeding behavior and intake offers scientific evidence and technical support for formulating and implementing sustainable grassland development strategies.

Sward type alters enteric methane emissions, nitrogen output and the relative abundance of the rumen microbial ecosystem in sheep

Observed improvements in animal and sward performance, coupled with a desire for more sustainable pasture-based feeding systems, has triggered a surge in the implementation of more botanically diverse pastures. However, thus far, there has been limited research investigating the effects of botanically diverse sward types on enteric methane (CH4) or nitrogen (N) excretion, alongside the ruminal microbiota and fermentation profile, in sheep. Hence, this study investigates the effect of sward type on CH4 production and N excretion, in addition to assessing the rumen microbiome, volatile fatty acid proportions, and ammonia nitrogen (NH3-N) concentration in sheep. A 5 × 5 Latin square design experiment was implemented to investigate 5 dietary treatments; perennial ryegrass (Lolium perenne L.; PRG) only or PRG plus white clover (Trifolium repens L.; PRG + WC), red clover (Trifolium pratense L.; PRG + RC), chicory (Chicorium intybus L.; PRG + Chic) or plantain (Plantago lanceolata L.; PRG + Plan). Diets were mixed at a ratio of 75% PRG and 25% of the respective companion forage and 100% PRG for the PRG treatment, on a dry matter basis. Twenty castrated male sheep were housed in metabolism crates across 5 feeding periods. Methane measurements were acquired utilizing portable accumulation chambers. Rumen fluid was harvested using a transoesophageal sampling device. Microbial rumen DNA was extracted and subjected to 16S rRNA amplicon sequencing and fermentation analysis. Data were analyzed using PROC MIXED in SAS. Results show that animals consuming PRG + WC ranked lower for CH4 production (g/d) than sheep offered PRG, PRG + Chic or PRG + Plan (P < 0.01) while the addition of any companion forage ranked CH4 yield (g/kg dry matter intake (DMI)) lower (P < 0.001) than PRG. There was a moderate positive correlation between DMI and CH4 (g/d; r = 0.51). Ruminal NH3-N was lowest in animals consuming the PRG diet (P < 0.01). There was a greater abundance of Methanobrevibacter and reduced abundance of Methanosphaera (P < 0.001) in sheep offered PRG, compared with any binary sward. On average, herb diets (PRG + Chic or PRG + Plan) reduced the urinary nitrogen concentration of sheep by 34% in comparison to legume diets (PRG + WC or PRG + RC) and 13% relative to the PRG diet (P < 0.001). Sheep offered PRG + Chic had a greater dietary nitrogen use efficiency than PRG + RC (P < 0.05). This study demonstrates the potential for sward type to influence rumen function and the microbial community, along with CH4 and N output from sheep.

Feeding spent hemp biomass to lactating dairy cows: Effects on performance, milk components and quality, blood parameters, and nitrogen metabolism

The legalization of industrial hemp by the 2018 Farm Bill in the United States has driven a sharp increase in its cultivation, including for cannabinoid extraction. Spent hemp biomass (SHB), produced from the extraction of cannabinoids, can potentially be used as feed for dairy cows; however, it is still illegal to do so in the United States, according to the US Food and Drug Administration Center for Veterinary Medicine, due to the presence of cannabinoids and the lack of data on the effect on animals. To assess the safety of this byproduct as feed for dairy cows, late-lactation Jersey cows (245 ± 37 d in milk; 483 ± 38 kg body weight; 10 multiparous and 8 primiparous) received a basal total mixed ration (TMR) diet plus 13% alfalfa pellet (CON) or 13% pelleted SHB for 4 wk (intervention period [IP]) followed by 4 wk of withdrawal period (WP), where all cows received only the basal TMR during WP. The dry matter intake (DMI), body weight, body condition score, milk yield, milk components, and fatty acid profile, blood parameters, N metabolism, methane emission, and activity were measured. Results indicated that feeding SHB decreased DMI mainly due to the low palatability of the SHB pellet, as the cows consumed only 7.4% of the total TMR with 13.0% SHB pellet offered in the ration. However, milk yield was not affected during the IP and was higher than CON during the WP, leading to higher milk yield/DMI. Milk components were not affected, except for a tendency in decreased fat percentage. Milk fat produced by cows fed SHB had a higher proportion of oleate and bacteria-derived fatty acids than CON. The activity of the cows was not affected, except for a shorter overall lying time in SHB versus CON cows during the IP. Blood parameters related to immune function were not affected. Compared with CON, cows fed SHB had a lower cholesterol concentration during the whole experiment and higher β-hydroxybutyric acid during the WP, while a likely low-grade inflammation during the IP was indicated by higher ceruloplasmin and reactive oxidative metabolites. Other parameters related to liver health and inflammatory response were unaffected, except for a tendency for higher activity of alkaline phosphatase during IP and a lower activity of gamma-glutamyl transferase during WP in the SHB group versus CON. The bilirubin concentration was increased in cows fed SHB, suggesting a possible decrease in the clearance ability of the liver. Digestibility of the dry matter and protein and methane emission were not affected by feeding SHB. The urea, purine derivatives, and creatinine concentration in urine was unaffected, but cows fed SHB had higher N use efficiency and lower urine volume. Altogether, our data revealed a relatively low palatability of SHB affecting DMI with minimal biological effects, except for a likely low-grade inflammation, a higher N use efficiency, and a possible decrease in liver clearance. Overall, the data support the use of SHB as a safe feed ingredient for lactating dairy cows.

Dairy Cows Grazing Plantain-Based Pastures Have Increased Urine Patches and Reduced Urine N Concentration That Potentially Decreases N Leaching from a Pastoral System

The objective of this study was to determine the effect of grazing plantain-based pastures on urine volume, urination frequency, and urinary nitrogen (UN) concentration of dairy cows under a typical pastoral dairy practice offering approximately 25% supplemented feeds. The experiment was a completely randomised design with three pasture treatments (perennial ryegrass-white clover (RGWC); RGWC + low plantain rate (PLL); and RGWC + high plantain rate (PLH)), five replicate plots, and repeated in two sequential grazing periods. Forty-five lactating Friesian × Jersey cows were randomly assigned into three groups of 15 animals each to graze over six days in adaptation paddocks and three days in experimental plots. Urine flow sensors were used to measure urine volume and urinary frequency, while spot urine sampling was conducted to determine nitrogen (N) concentration in cow urine. The results showed that including 25% plantain in the diet (PLH) increased daily urine volume by 44% and the daily number of urinations by 28%, compared to grazing the RGWC pasture. In addition, N concentration in cow urine was decreased by 18 and 29% when the diet contained 18% and 25% plantain, respectively. In conclusion, under a typical dairy farm practice, incorporating plantain into the RGWC pasture with the proportion of 25% plantain in the diet can increase the number of urine patches and reduce the concentration of N in the urine, thereby providing the opportunity to decrease N leaching from pastoral systems.

Effects of incremental increases in grass silage proportions from different harvest years on methane emissions, urinary nitrogen losses, and protein and energy utilisation in dairy cows

Dairy cows, methane and global warming have become publicly related terms. However, appropriate dairy cow management may in fact be part of the climate solution when viewed as part of the biogenic carbon cycle. Accordingly, governments and consumers are encouraging more sustainable, locally produced, climate friendly dairy production that often includes grassland-based feeding. However, this system is presumed to result in greater methane emissions compared to corn silage- or concentrate-based diets. An increase in urine nitrogen, associated with increased ammonia and nitrous oxide emission potential, questions the environmental usefulness of this strategy pertaining to global warming. This study is the first to compare the effects of incremental increases of grass silage proportion on enteric methane production as well as N and energy losses in dairy cows. Twenty-four mid- to end-lactation dairy cows were each fed one of 24 different diets, from two different harvest years, gradually increasing in grassland-based feeds (grass silage and hay) from about 500 to 1000 g/kg and concomitantly decreasing in corn silage. Each cow underwent a 7-day total collection period and was housed for 48 h in respiration chambers. Incremental data were subjected to an approved parametric regression analysis approach. The dietary increase in grassland-based feeds did not impair milk yield, N and energy utilisation. Simplified regression equations revealed that, contrary to current assumptions, there was a decline in methane production from 373 to 303 g/day when increasing grassland-based feeds from 500 to 1000 g/kg diet, and there was a trend for a decline in emission intensity from 20.6 to 17.6 g/kg of energy-corrected milk. However, urine nitrogen emissions clearly increased even when related to nitrogen intake; the latter from 260 to 364 g/kg when increasing grassland-based feeds from 500 to 1000 g/kg. Methane and urine nitrogen emissions were not affected by year of harvest.

Enteric methane research and mitigation strategies for pastoral-based beef cattle production systems

Ruminant livestock play a key role in global society through the conversion of lignocellulolytic plant matter into high-quality sources of protein for human consumption. However, as a consequence of the digestive physiology of ruminant species, methane (CH₄), which originates as a byproduct of enteric fermentation, is accountable for 40% of global agriculture's carbon footprint and ~6% of global greenhouse gas (GHG) emissions. Therefore, meeting the increasing demand for animal protein associated with a growing global population while reducing the GHG intensity of ruminant production will be a challenge for both the livestock industry and the research community. In recent decades, numerous strategies have been identified as having the potential to reduce the methanogenic output of livestock. Dietary supplementation with antimethanogenic compounds, targeting members of the rumen methanogen community and/or suppressing the availability of methanogenesis substrates (mainly H₂ and CO₂), may have the potential to reduce the methanogenic output of housed livestock. However, reducing the environmental impact of pasture-based beef cattle may be a challenge, but it can be achieved by enhancing the nutritional quality of grazed forage in an effort to improve animal growth rates and ultimately reduce lifetime emissions. In addition, the genetic selection of low-CH₄-emitting and/or faster-growing animals will likely benefit all beef cattle production systems by reducing the methanogenic potential of future generations of livestock. Similarly, the development of other mitigation technologies requiring minimal intervention and labor for their application, such as anti-methanogen vaccines, would likely appeal to livestock producers, with high uptake among farmers if proven effective. Therefore, the objective of this review is to give a detailed overview of the CH₄ mitigation solutions, both currently available and under development, for temperate pasture-based beef cattle production systems. A description of ruminal methanogenesis and the technologies used to estimate enteric emissions at pastures are also presented.

Animal board invited review: Grassland-based livestock farming and biodiversity

Grasslands dominate land cover nationally and globally, and their composition, structure and habitat value are strongly influenced by the actions of domestic and wild grazing animals that feed on them. Different pastures are characterised by varying opportunities for selective feeding by livestock; agronomically improved, sown swards generally consist of a limited range of plant species whereas longer-term leys and semi-natural grasslands are characterised by a more diverse mixture of plants. In the case of botanically diverse permanent pastures/grazing lands, the dietary preferences of different grazers have a more pronounced effect on the botanical composition of the sward in the longer term. Selection of a dominant species within the sward can give less abundant components a chance to compete, increasing community evenness and species richness. Conversely, the selection of minor components reduces sward compositional heterogeneity and hence plant species richness and evenness. Body size, gut type (foregut vs hindgut fermentation), physiological status (growing, pregnant, lactating), metabolic status (extent of body reserves) and environmental conditions all influence the nutrient requirements of a given animal and related foraging priorities. The diet selected is also strongly influenced by the availability of preferred food items, and their vertical and horizontal distribution within the sward. In general, larger animals, such as cattle and horses, are less selective grazers than smaller animals, such as sheep and goats. They are quicker to switch to consuming less-preferred sward components as the availability of preferred resources declines due to their greater forage demands, and as a result can be very effective in controlling competitive plant species consistently avoided by more selective grazers. As a result, low-intensity mixed grazing of cattle and sheep has been shown to improve the diversity and abundance of a range of taxa within grazed ecosystems. Mixed/co-species grazing with different animals exploiting different grassland resources is also associated with increased pasture use efficiency in terms of the use of different sward components and related improvements in nutritional value. In situations where cattle are not available, for example if they are not considered commercially viable, alternative species such as goats, ponies or South American camelids may offer an opportunity to diversify income streams and maintain productive and biodiverse pastures/grazing lands. Stocking rate and timing of grazing also have a considerable role in determining the impact of grazing. Regardless of the species grazing or the pasture grazed, grazing systems are dynamic since selective grazing impacts the future availability of sward components and subsequently dietary choices. New technologies under development provide opportunities to monitor plant/animal interactions more closely and in real time, which will in future support active management to deliver targeted biodiversity gains from specific sites.

Feeding Strategies to Mitigate Enteric Methane Emission from Ruminants in Grassland Systems

Ruminants produce approximately 30% of total anthropogenic methane emissions globally. The objective of this manuscript was to review nutritional enteric methane abatement practices for ruminants that are applicable under grazing conditions. A total of 1548 peer-reviewed research articles related to the abatement of enteric methane emissions were retrieved and classified into four categories: non-experimental, in vitro, in vivo confined, and in vivo grazing. The methane abatement strategies for grazing systems were arranged into grazing management and supplementation practices. Only 9% of the retrieved papers have been conducted under grazing conditions. Eight grazing management practices have been evaluated to reduce methane emissions. Decreasing the pre-grazing herbage mass reduced the methane emission per unit of product. Other grazing management practices such as increased stocking rate, decreased forage maturity, rotational stocking, and incorporating tannin-containing or non-tannin-containing feeds showed contradictory results. Nitrogen fertilization or silvopastoral systems did not modify methane emissions. Conversely, supplementation practices in grazing conditions showed contradictory responses on methane emissions. Lipid supplementation showed promising results and suggests applicability under grazing conditions. Identifying and implementing grazing strategies and supplementation practices under grazing conditions is required to increase efficiency and reduce the environmental impact of these systems.

Enteric Methane Emissions and Animal Performance in Dairy and Beef Cattle Production: Strategies, Opportunities, and Impact of Reducing Emissions

Enteric methane (CH4) emissions produced by microbial fermentation in the rumen resulting in the emission of greenhouse gases (GHG) into the atmosphere. The GHG emissions reduction from the livestock industry can be attained by increasing production efficiency and improving feed efficiency, by lowering the emission intensity of production, or by combining the two. In this work, information was compiled from peer-reviewed studies to analyze CH4 emissions calculated per unit of milk production, energy-corrected milk (ECM), average daily gain (ADG), dry matter intake (DMI), and gross energy intake (GEI), and related emissions to rumen fermentation profiles (volatile fatty acids [VFA], hydrogen [H2]) and microflora activities in the rumen of beef and dairy cattle. For dairy cattle, there was a positive correlation (p < 0.001) between CH4 emissions and DMI (R2 = 0.44), milk production (R2 = 0.37; p < 0.001), ECM (R2 = 0.46), GEI (R2 = 0.50), and acetate/propionate (A/P) ratio (R2 = 0.45). For beef cattle, CH4 emissions were positively correlated (p < 0.05−0.001) with DMI (R2 = 0.37) and GEI (R2 = 0.74). Additionally, the ADG (R2 = 0.19; p < 0.01) and A/P ratio (R2 = 0.15; p < 0.05) were significantly associated with CH4 emission in beef steers. This information may lead to cost-effective methods to reduce enteric CH4 production from cattle. We conclude that enteric CH4 emissions per unit of ECM, GEI, and ADG, as well as rumen fermentation profiles, show great potential for estimating enteric CH4 emissions.

Can Grassland Chemical Quality Be Quantified Using Transform Near-Infrared Spectroscopy?

Simple Summary

Near-infrared spectroscopy (NIRS) has been applied to analyse the quality of forage and animal feed. However, grasslands more than other raw materials are linked to many variability factors (e.g., site, year, occurring species, etc.) that can represent strong points as well as weak points in NIRS estimation. This research is aimed at testing NIRS application for the determination of chemical characteristics of fresh, undried and unground samples of meadows and grasslands located in north-central Apennine. The interest lies in the possibility of monitoring grassland resources, supporting the decision in terms of the need of supplementation and identifying the critical periods for cutting grassland intended for animal feeding. The results indicated that FT-NIRS models could be used in the real-time quantification of crude protein, fibrous fraction and dry matter, while for lignin only a screening test could be considered. Minor components of grassland such as ash and lipids need improvement. As a practical point, a key factor of FT-NIRS in grassland chemical quality estimation is the absence of samples preparation and the importance of the parameters that have obtained the best results in animal diet formulation.

Abstract

Near-infrared spectroscopy (NIRS) and closed spectroscopy methods have been applied to analyse the quality of forage and animal feed. However, grasslands are linked to variability factors (e.g., site, year, occurring species, etc.) which restrict the prediction capacity of the NIRS. The aim of this study is to test the Fourier transform NIRS application in order to determine the chemical characteristics of fresh, undried and unground samples of grassland located in north-central Apennine. The results indicated the success of FT-NIRS models for dry matter (DM), crude protein (CP), acid detergent fibre (ADF), neutral detergent fibre (NDF) and acid detergent lignin (ADL) on fresh grassland samples (R2 > 0.90, in validation). The model can be used to quantitatively determine CP and ADF (residual prediction deviation-RPD > 3 and range error ratio- RER > 10), followed by DM and NDF that maintain a RER > 10, and are sufficient for screening for the lignin fraction (RPD = 2.4 and RER = 8.8). On the contrary, models for both lipid and ash seem not to be usable at a practical level. The success of FT-NIRS quantification for the main chemical parameters is promising from the practical point of view considering both the absence of samples preparation and the importance of these parameters for diet formulation.

Examining the Environmental Impacts of the Dairy and Baby Food Industries: Are First-Food Systems a Crucial Missing Part of the Healthy and Sustainable Food Systems Agenda Now Underway?

Food systems are increasingly being understood as driving various health and ecological crises and their transformation is recognised as a key opportunity for planetary health. First-food systems represent an underexplored aspect of this transformation. Despite breastfeeding representing the optimal source of infant nutrition, use of commercial milk formula (CMF) is high and growing rapidly. In this review, we examine the impact of CMF use on planetary health, considering in particular its effects on climate change, water use and pollution and the consequences of these effects for human health. Milk is the main ingredient in the production of CMF, making the role of the dairy sector a key area of attention. We find that CMF use has twice the carbon footprint of breastfeeding, while 1 kg of CMF has a blue water footprint of 699 L; CMF has a significant and harmful environmental impact. Facilitation and protection of breastfeeding represents a key part of developing sustainable first-food systems and has huge potential benefits for maternal and child health.

Effects of Pasture Type on Metabolism, Liver and Kidney Function, Antioxidant Status, and Plant Secondary Compounds in Plasma of Grazing, Jersey Dairy Cattle During Mid-lactation

Some pasture species are rich in phytochemicals, able to improve milk yield and quality and to reduce the environmental impacts of livestock farming. The phytochemicals interact with the different gene networks within the animal, such as nuclear factor erythroid 2-related factor 2 (NRF2), but their overall impact on animal health remains to be fully understood. The objective of this study was to identify the effects of pasture Legumes and non-leguminous Forbs containing high bioactive compounds on metabolism and activity of the liver, antioxidant response, kidney function, and inflammation of dairy cows using a large array of blood parameters associated with metabolism and the innate immune system. For this purpose, 26 parameters and the concentration of certain bioactive compounds were assessed in blood plasma, collected from the Jersey cows grazing either Grass, Legume, or Forb-based pastures. In addition, serum collected from all the cows was utilized to detect the changes in NRF2 activation in bovine mammary alveolar cells (MACT) and hepatocytes. Compared with Grass, the cows that grazed both Forb and Legume pastures had lower β-hydroxybutyric acid (BHB) and creatinine and larger vitamin E and the ferric reducing ability of the plasma, supporting an improved antioxidative status for these animals. Compared with both Grass and Legume, the cows that graze Forb pasture had lower urea and urea to creatinine ratio, and lower creatinine, indicating a better kidney function. The cows grazing Legume pasture had greater hematocrit, bilirubin, cholesterol, albumin, β-carotene, retinol, and thiol groups but lower ceruloplasmin, paraoxonase, and myeloperoxidase (MPO) than those grazed Grass and Forb pastures, indicating a positive effect of Legume pasture on the liver, oxidative stress, and red blood cells. The plasma of cows in the various pastures was enriched with various isoflavonoids, especially the cows grazed on Forb and Legume pastures, which likely contributed to improving the antioxidative status of those cows. However, this effect was likely not due to the higher activation of NRF2. Overall, these results indicate that Forb and Legume pastures rich in secondary metabolites do not strongly affect the metabolism but can improve the status of the liver and the kidney and improve the efficiency of N utilization and antioxidant response, compared with the Grass pasture.

Non-fiber Carbohydrates in Forages and Their Influence on Beef Production Systems

Forages can provide a complete diet for ruminant animals, increasing the sustainability of beef production systems worldwide while reducing competition with humans for agricultural land or grain crops. Much of the emphasis on the nutritional characteristics of forages has been on the fiber, sugars, starch, and protein they supply to the rumen, despite the fact that other less-explored constituents, i.e., neutral detergent soluble fiber (NDSF) and other non-structural or non-fiber carbohydrates (NFC) also play a key role in the nutrition of ruminants. This paper explores the less investigated potential of temperate legumes to accumulate levels of NFC comparable to corn silage or beet pulp in cool, dry environments under irrigation, and its implications for forage-based beef production systems. We conclude that genetic or managerial interventions (i.e., breeding programs, defoliation frequency) or ecological conditions (i.e., climate, elevation) that increase concentrations of NFC in legumes can enhance beef production, meat quality, and the efficiency of nitrogen utilization by ruminants while reducing environmental impacts.