Search Results (161)

Feed supplementation strategies are essential for optimizing cattle productivity, and the incorporation of non-conventional feed resources may reduce both production costs and environmental impact. This study evaluated the effects of pelletized protein concentrates (including Acacia farnesiana, A. schaffneri, and Agave duranguensis bagasse) on rumen fermentation parameters, microbial communities, and gas emissions. Fistulated bullocks received the concentrate daily, and ruminal contents were collected and filtered before and after supplementation to assess in vitro gas and methane production, pH, and microbial composition using high-throughput sequencing of 16S rRNA and mcrA amplicons. In addition, in situ degradability was evaluated during and after the supplementation period. Supplementation led to a significant (p < 0.05) reduction in degradability parameters and methane production, along with a marked decrease in the abundance of Methanobrevibacter and an increase in succinate-producing taxa. These effects were attributed to the enhanced levels of non-fiber carbohydrates, hemicellulose, crude protein, and the presence of bioactive secondary metabolites and methanol. Rumen microbiota composition was consistent with previously described core communities, and mcrA-based sequencing proved to be a valuable tool for targeted methanogen detection. Overall, the inclusion of non-conventional ingredients in protein concentrates may improve ruminal fermentation efficiency and contribute to methane mitigation in ruminants, although further in vivo trials on a larger scale are recommended. Full article

The aim of this study was to determine, through meta-analysis, the effects of malic acid/malate addition on ruminal and blood parameters and diet digestibility in cattle. The literature search was conducted in Web of Science, Science Direct, and Google Scholar using the terms “organic acids”, “malic acid”, “malate”, and “bovine”. The database was composed of papers published between 1980 and 2023. The average effect of malate/malic acid inclusion was calculated using the “DerSimonian and Laird” random effects model. Meta-regression and subgroup analyses were conducted to explore sources of heterogeneity. Overall, malic acid (MAC) addition did not significantly affect rumen pH (ES = 0.310, p = 0.17), but subgroup analysis showed that malate increased pH (ES = 1.420, p < 0.01). MAC increased rumen propionate (ES = 0.560, p < 0.01) and total volatile fatty acids (VFAs; ES = 0.508, p = 0.03), while reducing the acetate-to-propionate ratio (p < 0.01). Starch and NDF intake were significant covariates affecting pH and VFA-related variables. MAC improved total-tract digestibility of dry matter (DM; ES = 0.547, p ≤ 0.05), crude protein (CP; ES = 0.422, p ≤ 0.05), and acid detergent fiber (ADF; ES = 0.635, p ≤ 0.05). It increased glucose levels (Overall ES = 0.170, p = 0.05) and reduced NEFA (Overall ES = −0.404, p = 0.03). In conclusion, the effectiveness of MAC depends on its chemical form. Improvements in rumen pH, fiber degradation, and blood parameters suggest more efficient energy use and potential metabolic benefits. The influence of diet-related covariates suggests that the response to MAC may vary depending on the nutritional composition of the diet. Full article

Against the backdrop of the green circular economy, the exploration of reliable and sustainable applications of lignocellulosic biomass (LCBM) has emerged as a critical research frontier. The utilization of LCBM as a ruminant roughage source offers a promising strategy to address two pressing issues: the “human-animal competition for food” dilemma and the environmental degradation resulting from improper LCBM disposal. However, the high degree of lignification in LCBM significantly restricts its utilization efficiency in ruminant diets. In recent years, microbial pretreatment has gained considerable attention as a viable approach to reduce lignification prior to LCBM application as ruminant feed. White-rot fungi (WRF) have emerged as particularly noteworthy among various microbial agents due to their environmentally benign characteristics and unique lignin degradation selectivity. WRF demonstrates remarkable efficacy in enzymatically breaking down the rigid lignocellulosic matrix (comprising lignin, cellulose, and hemicellulose) within LCBM cell walls, thereby reducing lignin content—a largely indigestible component for ruminants—while simultaneously enhancing the nutritional profile through increased protein availability and improved digestibility. Solid-state fermentation mediated by WRF enhances LCBM utilization rates and optimizes its nutritional value for ruminant consumption, thereby contributing to the advancement of sustainable livestock production, agroforestry systems, and global environmental conservation efforts. This review systematically examines recent technological advancements in WRF-mediated solid-state fermentation of LCBM, evaluates its outcomes of nutritional enhancement and animal utilization efficiency, and critically assesses current limitations and future prospects of this innovative approach within the framework of circular bioeconomy principles. Full article

Acetate is naturally produced in the rumen through feed degradation and fermentation. It serves as a primary energy source for ruminants and as a key substrate for de novo fatty acid synthesis in the mammary gland. The interaction of exogenous acetate with different animal and dietary factors is an area of growing interest, as it may have significant implications for milk fat synthesis. This study aimed to assess the effect of two diet fermentability levels on the short-term response of lactation to acetate supplementation in dairy cows. Eight ruminally cannulated multiparous European Holstein cows were randomly assigned to treatments in a crossover design that tested the effect of diet fermentability, acetate supply, and their interaction. Using corn silage as the only forage source and a constant forage-to-concentrate ratio, high-fermentability (HF) and low-fermentability (LF) diets were formulated. Acetate supply was investigated by infusing ruminally 10 moles of sodium acetate/d (ACE) or an equimolar infusion of control (CON). Therefore, the treatments were as follows: LF + CON; LF + ACE; HF + CON; and HF + ACE. No interactions between acetate and diet fermentability were found on performance variables. Acetate infusion decreased dry matter intake (DMI), milk yield, and milk protein yield and content but did not affect milk fat yield; however, it increased milk fat concentration, and this response tended to be more pronounced in the HF diet. Acetate infusions increased plasma β-hydroxybutyrate in the HF diet, but not in the LF diet, and increased plasma non-esterified fatty acid, which was likely a lipolysis response to reduced DMI and decreased energy balance. This study demonstrates that acetate availability can be a constraint on mammary lipogenesis, even with adequate dietary fiber. Full article

The aim was to investigate the suitability of Santhica 27 industrial hemp leaves as a protein source in dairy cow nutrition. Twelve Holstein dairy cows received a total mixed ration (TMR) containing 7.4% industrial hemp leaves (HEMP) and a TMR containing 3.5% soya extraction meal (CON) in a crossover design. Cows were kept in a free-stall barn for 2 weeks to measure feed intake, milk yield and sample plasma, ruminal fluid, and urine. In week 3, cows were housed in a respiration chamber to measure gas exchange, urine, and feces excretions. In the first two weeks, cows of the HEMP group rested longer but spent less time ruminating. Feeding the HEMP diet reduced dry matter intake (DMI), milk yield, and urinary N-metabolite concentrations and tended to lower total N-excretion, milk fat, and lactose concentrations. During the stay in the respiration chamber, DMI, milk yield, apparent digestibility, and crude protein degradability were similar between groups, but feeding the HEMP diet tended to reduce methane yield. In conclusion, Santhica 27 hemp leaves are a suitable protein source for dairy cows as they have no negative effects on animal health, apparent digestibility, and crude protein degradability. Nevertheless, inadequate adaptation to the diet reduces feed intake and milk yield. Full article

Ferulic acid esterase (FAE) plays an important role in plant fiber degradation by catalyzing the hydrolysis of lignocellulosic structures. FAE-producing lactic acid bacteria (LAB), as potential probiotics, can improve ruminant digestion and gut health. In this study, two LAB strains (Q2 and Q6) with FAE activity were isolated from sheep rumen. Based on 16S rDNA sequencing, they were identified as Lactobacillus mucosae and Streptococcus equinus, respectively. Compared to Q2, Q6 demonstrated higher enzyme production, lactic acid yield, broader carbohydrate utilization, and stronger antimicrobial activity. The whole genome sequencing revealed Q2 and Q6 possess genomes of 2.14 Mbp and 1.95 Mbp, with GC contents of 46.81% and 37.30%, respectively. Q2 and Q6 exhibited the highest average nucleotide identity (ANI) with L. mucosae DSM 13345 (97.30%) and S. equinus ATCC 33317 (97.92%), respectively. The strains harbored 2101 and 1928 predicted genes, including 1984 and 1837 coding sequences (CDSs), respectively. GO enrichment analysis showed the CDSs predominantly associated with membranes (or cells), catalytic activity, and metabolic processes. KEGG analysis revealed both strains enriched in metabolic pathways, with Q6 showing a notably higher number of proteins in the ABC transporters and quorum sensing than Q2. Carbohydrate-active enzymes database (CAZy) profiling identified 75 CAZymes in Q2 and 93 CAZymes in Q6, with each strain containing one novel fae gene. Safety assessment identified 1 and 33 pathogenic genes, along with 2 and 4 putative antimicrobial peptide genes, in Q2 and Q6, respectively. Notably, Q6 carried 12 virulence factor genes. These findings suggest Q2 exhibits a superior safety profile compared to Q6, indicating a higher probability of Q2 being an effective probiotic strain. In conclusion, both LAB strains produce FAE. L. mucosae Q2 demonstrates suitability as a direct-fed probiotic for livestock, while Q6 exhibits potential as a silage inoculant, though comprehensive safety evaluations are required prior to its application. Full article

Non-starch polysaccharide-degrading enzymes are widely used as feed additives in monogastric and ruminant species, with positive effects reported. In this study, the commercial, fiber-degrading enzyme complex Hostazym^® X, derived from Trichoderma citrinoviride (DSM34663), was included in the total mixed rations of 17 mid-lactating (135 ± 61 days in milk) Holstein cows for 10 weeks. A control group (n = 17) was included. Dry matter intake (DMI), milk yield, 4% fat-corrected milk, solid yield, and milk fatty acid profile were assessed. The structure and composition of fecal bacterial communities, as well as PICRUSt2-based functional prediction of bacterial communities, were also evaluated. Higher DMI and milk yield scores were observed in the supplemented group (27.20 vs. 26.59 kgDM/cow/d; and 39.01 vs. 36.70 L/cow/d, respectively). No effects were observed in fat yield, contrary to lactose and protein, which were greater in the supplemented group compared to the control group (1.18 vs. 1.13 and 1.83 vs. 1.75 kg/cow/d, respectively; p < 0.05). Palmitic and oleic acids, in addition to monounsaturated fat in milk, were increased in the supplemented group (p > 0.05). Enzyme supplementation increased the Patescibacteria (p < 0.5) and Actinobacteriota (p > 0.05) in feces, but slightly reduced the Bacteroidota and Firmicutes. The Turicibacter genus remained at a lower relative abundance after supplementation but Candidatus_Saccharimonas, Clostridioides, Prevotellaceae UCG 003, Corynebacterium, Akkermansia, Syntrophococcus, Erysipelotrichaceae UCG 008, other Lachnospiraceae, other members of the Eubacterium_coprostanoligenes_group, Bifidobacterium, Rumminococcus, Akkermansia, and other Spirochaetaceae increased, modifying the functional predicted profile of bacterial communities. In conclusion, a positive effect on performance and milk composition were observed through modulation of microbiota induced by enzyme supplementation. The enzyme complex could be a viable supplement alternative in the feeding of dairy cows in semi-intensive productive systems, mainly when an ad libitum feeding scheme is used. Full article

The purpose of this research was to investigate the impact of chestnut tannins (CHTs) on nutrient digestibility, nitrogen balance, in situ crude protein (CP) digestibility, protease enzymes, and microbial community composition in sheep. Eighteen 1.5-year-old sheep (43.0 ± 2.0 kg initial BW) fitted with permanent ruminal cannula were selected and randomly divided into three groups, which were fed with CHTs added at 0, 2, and 6%/kg DM. The pre-feeding period lasted for 12 days, and the actual trial period was 18 days. Rumen fluid was collected to assess in situ crude protein (CP) degradability, while rumen digesta was analyzed for total and ruminal proteolytic bacterial populations. Using one-way ANOVA in SAS to analyze data, the results indicated that 2% CHT reduced in situ degradability by 26.23%, while 6% reduced it by 58.01% in the rumen of the sheep. The CP apparent digestibility, nitrogen metabolism, and population of proteolytic bacteria of sheep were decreased in the 6% CHT group (p < 0.05), while the above indices of the 2% CHT group were not affected. Furthermore, CHT supplementation significantly altered the ruminal microbial community structure. Particularly in the 2% CHT group, the relative abundances of Bacteroidota and Prevotella increased. LEfSe analysis revealed that Bacteroidale replaced U29-B03 as the dominant microbiota at 2% CHT. Doses of 2% CHT can be incorporated into sheep diets without impairing digestion. These findings support the inclusion of CHT doses of less than 2% for enhancing protein digestion and increasing the types of beneficial bacteria in the rumen, while doses above 6% should be avoided. Full article

Maize (Zea mays L.) silage in the irrigated and flat areas of Italy represents the most important large ruminant feed crop due to the high dry matter yield and nutritive value per hectare. The aim of the investigation was to evaluate the chemical composition and the in vitro fermentation patterns of five maize varieties (Tiesto, R700 1, MAS 78.T, DKC 7074 and KWS Kantico) freshly chopped and preserved via ensiling. The results indicated that the chemical composition was not significantly different among varieties. The substrates were incubated for 72 h with buffered rumen fluid collected from cow. The ensiling process slightly reduced gas production and fermentation kinetics, likely due to the consumption of soluble sugars during fermentation. Organic matter loss (OM loss) differed significantly (p < 0.01) among varieties in ensiled maize, correlating with their neutral detergent fiber (NDF) content. While total volatile fatty acid (VFA) production showed no significant differences between varieties, the buffer capacity ratio (BCR), an indicator of protein degradation, varied significantly. Ammonia production (NH₃) was significantly higher in ensiled samples, supporting previous findings that ensiling increases non-protein nitrogen (NPN) due to microbial proteolysis and plant enzyme activity. The gas production profiles and fermentation rates over time showed minor differences between fresh and ensiled samples, with fresh material exhibiting faster fermentation kinetics due to the presence of soluble sugars. These findings highlight the importance of evaluating maize silage quality to optimize ruminant nutrition and feed efficiency. Full article

Pectin is a dynamic and complex polysaccharide that forms a substantial proportion of the primary plant cell wall and middle lamella of forage ingested by grazing ruminants. Pectin methylesterases (PMEs) are enzymes that belongs to the carbohydrate esterase family 8 (CE8) and catalyze the demethylesterification of pectin, a key polysaccharide in cell walls. Here we present the crystal structure of the catalytic domain of PmeC5 that is associated with a gene from Butyrivibrio fibrisolvens D1^T that encodes a large secreted pectinesterase family protein (2089 aa) determined to a resolution of 1.33 Å. Protein in silico modelling of the secreted pectinesterase confirmed the presence of an additional pectate lyase (PL9) and adhesin-like domains. The structure of PmeC5 was the characteristic right-handed parallel β-helical topology and active site residues of Asp231, Asp253, and Arg326 typical of the enzyme class. PmeC5 is a large modular enzyme that is characteristic of rumen B. fibrisolvens megaplasmids and plays a central role in degrading plant cell wall components and releasing methanol in the rumen environment. Such secreted PMEs are significant contributors to plant fiber digestion and methane production, making them attractive targets for both methane mitigation strategies and livestock productivity enhancement. Full article

For cattle raised on tropical grass pastures, it is essential to explore strategies that circumvent climatic seasonality that affect forage availability and quality. We hypothesize that the intensification of grazing systems, with rotational and deferred methods, combined with ammonium nitrate or urea supplementation, are excellent strategies to increase ruminal efficiency and animal productivity. For this purpose, 8 cattle with cannulas were distributed in rotational and deferred grazing systems, supplemented with urea or ammonium nitrate, and evaluated throughout the four seasons of the year over a period of two years. Dry matter intake and digestibility were measured using indigestible neutral detergent fiber, titanium dioxide and chromium oxide markers. Ruminal kinetics and degradability of DM and nutrients were measured using the nylon bag technique. Urine parameters were used to estimate microbial nitrogen compounds synthesis and efficiency of microbial protein synthesis. The rotational grazing improves NPN intake, NDF and ADF digestibility, and gross energy. Ammonium nitrate supplementation showed improved efficiency in microbial protein synthesis without negatively affecting feed intake, positioning it as a valuable nitrogen source for grazing cattle. Full article

In recent years, the rapid development of the ruminant feeding industry and the limited availability and rising prices of traditional protein feed ingredients have renewed the focus on protein feeds in ruminant diets. Plant protein feeds are a core component of protein feeds for ruminants; however, the utilisation of both conventional and non-conventional plant protein feeds is limited by the presence of anti-nutritional factors (ANFs). In order to maximise the use of plant protein feeds and to promote their application in ruminant production, it is important to have a comprehensive understanding of the types and nature of their ANFs, their anti-nutritional mechanisms, and current effective methods of eliminating ANFs. Therefore, the types, anti-nutritional mechanisms, and elimination methods of ANFs in major plant protein feeds for ruminants are initially summarised in this review, which provides a reference for anti-nutritional factor elimination and the production of full-price compound feeds for ruminants. Full article

The increasing frequency of extreme weather events, exacerbated by climate change, has caused significant physical damage to crops worldwide. This study explores the potential of repurposing crop plants that exhibit structural breakage due to hailstorms and strong winds and were originally cultivated for seed production (amaranth, borage, camelina, flax, quinoa, soybean, and white lupin) as alternative forages for ruminants. Their nutritional value was assessed by analyzing chemical composition, in vitro dry matter degradability (DMD), in vitro neutral detergent fiber degradability (NDFD), estimated dry matter intake (DMI), and relative feed value (RFV) compared to conventional forages (alfalfa and ryegrass hay from undamaged plant). Results revealed significant variability among the damaged crops. Borage, amaranth, and white lupin exhibited superior DMD, NDFD, estimated DMI, and RFV, positioning them as promising forage alternatives. Soybean and quinoa showed protein content, DMD, NDFD, estimated DMI, and RFV comparable to alfalfa hay, suggesting their suitability as substitutes. However, camelina exhibited limited NDFD, while flax had low DMD, NDFD, estimated DMI, and RFV, indicating the need for pre-treatment strategies to optimize their nutritional value. Overall, repurposing weather-damaged borage, amaranth, white lupin, soybean, and quinoa as alternative forages for ruminants provides a promising approach to mitigating feed shortages, improving feed resource utilization, and optimizing resource utilization in livestock production. Full article

Pea (Pisum sativum L.) seeds are valuable feed ingredients due to their high-quality protein and starch digestibility, making them a viable alternative to soybean meal and corn grain. This study evaluated the nutritional value of three commercial pea varieties (Ganster, Peps, and Poseidon) through in vitro trials. Each variety was incorporated into an experimental diet (GNS, PES, and PNS) for dairy cows, partially replacing soybean and corn meals. These diets were compared to a control diet containing only soybean and corn meals. All diets were incubated anaerobically for 120 h with dairy cow rumen liquor. Results showed that GNS and PES diets enhanced protein degradability (p < 0.05) and fermentation kinetics (p < 0.001). Additionally, all experimental diets reduced ammonia production (p < 0.001), while the PES diet increased (p < 0.001) volatile fatty acid production. Among the tested varieties, Peps demonstrated the greatest potential by improving protein metabolism and volatile fatty acid production. These findings suggest that pea grains can be a suitable alternative in dairy cow diets, supporting efficient ruminal fermentation and nutrient utilization. Full article

Total mixed ration silage has been used as a strategy to optimize the use of dry and wet feed in ruminant feeding. Another promising technique is silage reallocation, which allows producers to divide the ensiled material in large silos into smaller units that can be easily transported and marketed. Thus, this study aimed to improve food preservation through the development of total mixed rations (TMRs) based on relocated sorghum silage (RSS) and cactus pear for sheep diets. A completely randomized design was used with five treatments (0, 15, 25, 30, and 35% RSS inclusion on a dry matter basis) and five replicates. Ninety days after ensiling, the silos were opened. The fermentation characteristics, nutritional aspects, aerobic stability, and microbial populations of TMR silages were evaluated. The inclusion of RSS showed a quadratic effect on pH, density, permeability, lactic acid bacteria and yeast counts, and total carbohydrates (p < 0.05). It reduced gas and effluent losses, porosity, ammonia nitrogen, buffer capacity, ash, crude protein, ether extract, and non-fibrous carbohydrates (p < 0.05) while increasing dry matter, neutral and acid detergent fiber, hemicellulose, and cellulose contents (p < 0.05). There was an interaction effect between the levels of RSS inclusion and exposure times to air on CO₂ and dry matter content (p < 0.05). Regarding carbohydrate fractionation, there was a reduction in fraction A + B1 (non-fibrous carbohydrates) and an increase in fractions B2 (fibrous carbohydrates from the cell wall and of slow ruminal availability, susceptible to the effects of the passage rate) and C (indigestible neutral detergent fiber) (p < 0.05). For protein fractionation, a quadratic effect was observed for fractions A (non-protein nitrogen) and C (insoluble protein, indigestible in the rumen and intestine), an increase in fraction B1 (soluble protein rapidly degraded in the rumen) + B2 (insoluble protein with intermediate degradation rate in the rumen), and a reduction in fraction B3 (insoluble protein with slow degradation rate in the rumen) (p < 0.05) as RSS levels increased. Under the experimental conditions, it is recommended to include up to 30% RSS in the total mixed ration silage to improve microbiological characteristics, reduce gas and effluent losses, and increase dry matter recovery and nutritional aspects of silage when associated with cactus pear. Full article