Rumination Efficiency Research Articles

Side effects of high environmental temperature on reproductive efficiency of ruminants

Side effects of high environmental temperature on reproductive efficiency of ruminants

Intake, digestibility, water balance, ruminal dynamics, and blood parameters in sheep fed diets containing extra-fat whole corn germ

We evaluated the effects of replacing ground corn with extra-fat whole corn germ (EFCG; 0%, 25%, 50%, 75%, and 100%) on the intake and concentration of soluble nutrients of dry matter and its components, ingestive behavior, water balance, ruminal dynamics, and blood parameters in sheep. Five rumen-fistulated sheep with an average body weight of 67.56 ± 9.13 kg were assigned to a 5 × 5 Latin square experimental design. The experimental period lasted five consecutive 22-day periods divided into 14-day adaptation and 8-day sampling periods. The diets were composed of corn silage and cactus cladodes as roughage and soybean meal, ground corn, EFCG, urea, and mineral premix as concentrate. The forage: concentrate ratio was 70:30. There were no differences in nutrient intake, except for ether extract. However, the concentration of digestible crude protein (CP; P = 0.038) and ether extract (EE; P < 0.001) increased. The replacement levels did not influence ingestive behavior, nor rumination efficiencies. Water intake and excretion were unaffected, except for excretion by feces (P = 0.040), which decreased. There was no effect of treatments on the dry matter (DM), neutral detergent fiber (NDF), and indigestible neutral fiber detergent (NDF) pools; however, the pool of EE (P < 0.001) increased. The rates of passage (Kp), ingestion (Ki), and degradation (Kd) of DM and aNDF, as well as the passage rate (Kpi) of iNDF, were uninfluenced. Levels of cholesterol (P < 0.001) and triglycerides (P = 0.001) increased. It was concluded that ground corn can be fully replaced by EFCG without affecting intake and concentration of digestible dry matter and its components, water balance, ingestive behavior, rumen dynamics, and glucose and fructosamine serum concentrations. On the other hand, the replacement increased ether extract intake and consequently, cholesterol and triglyceride serum concentrations. Therefore, we recommend total replacement of ground corn by EFCG in diets for sheep. However, further investigations are needed on animal performance and sensory and biochemical characteristics of meat and milk.

Cell signalling compound improves pasture and livestock productivity and the environment

A biogenic agricultural compound enables pasture to synthesise more soluble sugars and delivers benefits attributable to bioactive molecules: phenylpropanoids. Phenylpropanoids are plant secondary compounds that help plants overcome biotic and abiotic stress to increase pasture quality and yield. When consumed by ruminants, phenylpropanoids improve the conversion efficiency of pasture protein to milk and meat. The effect of this compound, trademarked Biozest™, on pasture and ruminant efficiency was evaluated via split block trials followed by full scale, full life cycle, on-farm trials. Aspects measured include pasture resilience, quality and productivity, livestock productivity and urea excretion. Biozest™ improved pasture resilience, quality, and yield by over 75%. Soluble sugar content of the pasture increased (18%). When livestock grazed Biozest™ treated pasture, urea excretion was reduced (20–48%), and milk and meat production increased (30%). The pasture, livestock productivity and urea benefits of Biozest™ have been established. Trial results support the following inferences. First, the fermentation of the increased soluble carbohydrates in Biozest treated pasture would result in increased propionates and less acetoclastic methanogenesis. Second, the reduction in urea excretion and increase in livestock productivity would result from a reduction in the proportion of dietary protein digested to ammonia and reduced deamination of some of the ammonia to urea. Further, due to the reduced deamination, fewer carbonyls and hydride moieties would be available for methylotrophic and hydrogenotrophic methanogenesis. Future work may include quantification or modelling of increased carbon dioxide sequestration and quantification of the reduction in nitrous oxide and methane emissions.

Altering Dietary Soluble Protein Levels With Decreasing Crude Protein May Be a Potential Strategy to Improve Nitrogen Efficiency in Hu Sheep Based on Rumen Microbiome and Metabolomics

Ruminants account for a relatively large share of global nitrogen (N) emissions. It has been reported that nutrition control and precise feeding can improve the N efficiency of ruminants. The objective of the study was to determine the effects of soluble protein (SP) levels in low-protein diets on growth performance, nutrient digestibility, rumen microbiota, and metabolites, as well as their associations of N metabolism in fattening Hu sheep. Approximately 6-month-old, 32 healthy fattening male Hu sheep with similar genetic merit and an initial body weight of 40.37 ± 1.18 kg were selected, and divided into four groups (n = 8) using the following completely randomized design: the control diet (CON) with a 16.7% crude protein (CP) content was prepared to meet the nutritional requirements of fattening sheep [body weight (BW): 40 kg, average daily gain (ADG): 200–250 g/d] according to the NRC recommendations; other three include low protein diets (LPA, LPB, and LPC) of CP decreased by ~10%, with SP proportion (%CP) of 21.2, 25.9, and 29.4 respectively. The feeding trial lasted for 5 weeks including the first week of adaptation. The results showed no difference in the growth performance (P > 0.05); DM and CP digestibility were higher in LPB and LPC, with maximum organic matter digestibility in LPB (P < 0.05). Low-protein diets decreased serum urea-N whereas urinary urea-N was lower in LPB and LPC (P < 0.05), while N retention and the biological value of N were higher in LPB and LPC (P < 0.05). Ruminal NH3-N concentration in LPA and LPB was low than CON (P < 0.05), while total volatile fatty acid (TVFA), acetate, propionate, and butanoate were all lowest in LPA (P < 0.05). In the rumen microbiome, LPB increased the community richness in Prevotellaceae and Prevotella_1 (P < 0.05); Metabolomics analysis revealed low-protein diets downregulated the amino acid metabolism pathways, while the biosynthesis of unsaturated fatty acids along with vitamin B6 metabolism were upregulated with increased SP. These findings could help us understand the role of different SP levels in the regulation of rumen microbial metabolism and N efficiency. Overall, low-protein diets (CP decreased by ~10%) can reduce serum urea-N and ruminal NH3-N without affecting the growth performance of fattening Hu sheep. Additionally higher N efficiency was obtained with an SP proportion of ~25–30%.

Meta-analysis of dietary chitosan effects on performance, nutrient utilization, and product characteristics of ruminants.

Chitosan (CHI) has been used as a feed additive in ruminant diets, but the effects obtained to date have been varied. This study aimed to evaluate the dietary addition of CHI on performance, nutrient utilization, and product characteristics of ruminants by using a meta-analysis approach. A total of 15 articles that composed of 21 studies and 57 data points were included in the database. Number of articles reported the effects of dietary CHI addition were six on beef cattle, seven on dairy cows, and two papers on sheep. Data analysis was based on the mixed model methodology, in which CHI addition levels were considered as fixed effects whereas different studies were treated as random effects. Results revealed that, across various studies, CHI decreased ruminal acetate proportion (p < 0.05) and increased propionate proportion (p < 0.01). Dry matter and crude protein digestibility were elevated due to CHI addition (p < 0.05). CHI decreased blood cholesterol level (p < 0.05) and increased monounsaturated fatty acid proportion in the milk (p < 0.05). However, CHI addition had no effect on dry matter intake, milk production, and milk efficiency of ruminants. In conclusion, CHI is able to modify rumen fermentation towards a favorable direction, but it limitedly affects performance of ruminants.

Sugarcane bagasse or elephant grass hay in diets for goats: Performance, feeding behavior and carcass characteristics

Background: Novel feeding strategies should be developed to produce high-quality meat in current goat production systems. Objective: To evaluate the effects of castration and the association of spineless cactus with sugarcane bagasse or elephant grass hay on nutrient intake, digestibility, performance, feeding behavior and carcass traits of feedlot kids. Methods: A total of 24 male kids (12 castrated and 12 intact), with an average initial weight of 18.5 ± 3.8 kg were allotted to a completely randomized 2 x 2 factorial design (sugar cane bagasse or elephant grass hay; intact or castrated), and confined for 70 days. Results: Nutrient intake and animal performance were similar between treatments. Sugarcane bagasse increased, when compared to elephant grass hay, the digestibility of dry matter (66.12 vs 62.88; p=0.005), crude protein (74.26 vs 70.95; p=0.029) and non-fibrous carbohydrates (91.94 vs 83.07; p&lt;0.001). The forage source affected the time spent resting, ruminating and total chewing time, but there was no effect of diet on feeding and rumination efficiencies. Elephant grass hay increased, when compared to sugarcane bagasse, hot carcass weight (9.87 vs 10.79; p=0.025) and hot carcass yield (43.81 vs 46.87; p=0.013). Intact kids produced heavier hot carcasses when compared with castrated kids (10.80 vs 9.86; p=0.014). Conclusion: Feeding intact or castrated kids with sugar cane bagasse or elephant grass hay do not affect nutrient intake and performance. Feedlot goats have improved carcass traits if kept intact and fed elephant grass hay.

Net protein contribution and enteric methane production of pasture and grain-finished beef cattle supply chains

Ruminant red meat production systems around the world often include a grain feeding phase. The role of red meat in the food system is therefore often discussed in terms of the food vs feed debate, as well as invoking the comparatively poor feed conversion efficiency of ruminants and climate impacts from enteric methane. The concept of net protein contribution (NPC) incorporates the quality attributes of protein produced by livestock systems into estimates of the efficiency of production systems. We applied the NPC method to two Australian beef supply chains, i) Grass-fed and ii) Grain-finished beef, using an established model of ruminant grazing systems (GrassGro®) and these are reflective of beef production systems in other countries. The beef supply chains evaluated did not compete with humans for protein. The Grain-finished beef supply chain, while positively contributing to human protein requirements (NPC value 1.96), had markedly lower NPC values than the Grass-fed system (NPC value 1 597). However, Grass-fed beef production systems have a higher methane intensity than the Grain-finished supply chain. The two examples of pasture-based beef production systems examined provide a positive net protein contribution to human food supply, even with extended periods of finishing on grain-based diets. This is achieved by ruminant grazing on pastures converting low-quality forage into high value human edible protein. The efficiency of protein production varies according to the system design, and other considerations such as land use and enteric methane production are elements that need consideration in the overall assessment of the production footprint.

Effect of dietary replacing of corn grain with the blend of residues from the candy industry and corn gluten feed on performance of growing lambs

Corn is an international commodity, which can increase the costs of livestock production, since it is part of ruminants, non-ruminants, and human diets. Thus, it is important to include alternative feedstuffs for ruminants to reduce costs with animal feeding. The objective of this study was to evaluate the intake and apparent digestibility of dry matter (DM) and nutrients, as well as voluntary water intake, ingestive behavior, performance, nitrogen (N) balance, blood serum metabolites, and hematological profiles of Santa Inês lambs fed different inclusion levels (0, 116, 233 and 353 g/kg of diet DM) of a blend of residues from the candy industry (RCI) and corn gluten feed (CGF), at the ratio of 613:387 on DM basis. Thirty-six Santa Inês lambs (approximately six months old and 19.43 ± 1.69 kg of initial body weight [BW]) were distributed in a completely randomized design. Intakes of DM, crude protein (CP), neutral detergent fiber treated with heat-stable α-amylase and corrected for ash and protein (aNDFap), water, and metabolizable energy (ME), and the apparent digestibility coefficients (DM, CP and NFCap), N balance, growth performance, feeding efficiency of DM and aNDFap, blood serum profile, erythogram and leukogram (neutrophil, lymphocytes, eosinophils and basophils) were not affected (P > 0.05) by the level of inclusion of the RCI:CGF blend in the diet. The apparent digestibility coefficient of aNDFap and monocyte tended to increase (P < 0.10), while aNDFap rumination efficiency tended to decrease (P < 0.10) with the increase in the RCI:CGF blend inclusion in the diets. Time on feeding, rumination, and total time chewing increased linearly (P < 0.001) with the inclusion of the RCI:CGF blend in the diets. The blend of the residues from the candy industry and corn gluten feed (at the ratio of 613:387 on DM basis) can totally replace ground corn in up to 353 g/kg diet DM.

Identification of Bioactive Phytochemicals from Six Plants: Mechanistic Insights into the Inhibition of Rumen Protozoa, Ammoniagenesis, and α-Glucosidase.

Simple SummaryRumen protozoa have some contribution to feed digestibility in the rumen, but Entodinium, the most predominant genus, is the main culprit of inefficient nitrogen utilization in ruminants. Using chemical drugs, many studies have attempted to inhibit the rumen protozoa, but few of the approaches are either effective or practical. In this study, we investigated the nutritional and functional properties of Adansonia digitata (baobab), Flemingia macrophylla (waras tree), Kalimeris indica (Indian aster), Brassica rapa subsp. chinensis (bok choy), Portulaca oleracea (common purslane), and Calotropis gigantea (giant milkweed) for their potential as feed additives in animal husbandry. The plants were also analyzed for their major phytochemicals using reversed phase-high performance liquid chromatography (HPLC) and then evaluated for their ability to inhibit rumen protozoa, ammoniagenesis, and microbial α-glucosidase activity in vitro. C. gigantea inhibited the rumen protozoa and reduced the wasteful ammoniagenesis, thereby indicating improved nitrogen utilization. A. digitata also reduced the microbial α-glucosidase activity that can potentially contribute to rumen acidosis. The tested plants, especially C. gigantea and A. digitata, could be used as potential alternatives to chemicals or antibiotics to ensure sustainable and green animal husbandry.Rumen protozoa prey on feed-degrading bacteria synthesizing microbial protein, lowering nitrogen utilization efficiency in ruminants. In this in vitro study, we evaluated six plants (Adansonia digitata, Flemingia macrophylla, Kalimeris indica, Brassica rapa subsp. chinensis, Portulaca oleracea, and Calotropis gigantea) for their potential to inhibit rumen protozoa and identified the phytochemicals potentially responsible for protozoa inhibition. Rumen protozoa were anaerobically cultured in vitro in the presence of each plant at four doses. All of the tested plants reduced total rumen protozoa (p ≤ 0.05), but C. gigantea and B. rapa were the most inhibitory, inhibiting rumen protozoa by 45.6 and 65.7%, respectively, at the dose of 1.1 mg/mL. Scanning electron microscopy revealed a disruption of the extracellular structure of protozoa cells. Only C. gigantea also decreased the wasteful ammoniagenesis (p ≤ 0.05). Moreover, the A. digitata extract inhibited α-glucosidase activity by about 70% at 100 µg/mL. Reversed-phase high-performance liquid chromatography analysis detected quercetin, anthraquinone, 3-hydroxybenzoic acid, astragaloside, and myricetin in the tested plant leaves. These plants may hold potential as feed additives to reduce rumen protozoa and α- glucosidase activity. Future research is needed to identify the specific anti-protozoal compound(s), the effects on the rumen microbiome, and its fermentation characteristics.

The Recent Trend in the Use of Multistrain Probiotics in Livestock Production: An Overview.

Simple SummaryProbiotics are live microorganisms that confer a health benefit to the administered animal when ingested. Their use has been an effective alternative to antimicrobial growth promoters in the livestock industry, and they could be bacteria or non-bacterial species or strains. However, there has been an increasing trend in administering multistrain probiotics in recent years. Multistrain probiotics comprise two or more species or strains of important microorganisms as a consortium beneficial to the administered animal. Several studies are being carried out to explore their potency or efficiency. They have proven to be a promising alternative to antibiotics growth promoters and were responsible for enhancing gut health, growth performance, maintaining a balance in gut microbiota, stimulating immunity against pathogenic organisms, improving digestion, and overall production efficiency in ruminants, poultry, and swine production.It has been established that introducing feed additives to livestock, either nutritional or non-nutritional, is beneficial in manipulating the microbial ecosystem to maintain a balance in the gut microbes and thereby improving nutrient utilization, productivity, and health status of animals. Probiotic use has gained popularity in the livestock industry, especially since antimicrobial growth promoter’s use has been restricted due to the challenge of antibiotic resistance in both animals and consumers of animal products. Their usage has been linked to intestinal microbial balance and improved performance in administered animals. Even though monostrain probiotics could be beneficial, multistrain probiotics containing two or more species or strains have gained considerable attention. Combining different strains has presumably achieved several health benefits over single strains due to individual isolates’ addition and positive synergistic adhesion effects on animal health and performance. However, there has been inconsistency in the effects of the probiotic complexes in literature. This review discusses multistrain probiotics, summarizes selected literature on their effects on ruminants, poultry, and swine productivity and the various modes by which they function.

Uterine Involution of Mares Supplemented with Dietary Algae-Derived Omega-3 Fatty Acids During the Peripartum Period

Different approaches have been used to improve conception rates at foal heat. Omega-3 fatty acids family and derivatives have improved reproductive efficiency in ruminants, but literature lacks studies evaluating these components on equines. The objective of this study was to evaluate effects of mare dietary supplementation with microalgae rich in docosahexaenoic acid (DHA) during peripartum on follicular dynamics and uterine involution in early post-partum. Eighteen pregnant mares, no particular breed, 410 ± 39.5 kg body weight (BW), and 7.83 ± 2.01 yr old were used. Mares were randomly assigned to control (CONT) or supplementation with microalgae rich in DHA at 0.06 g/kg BW (ALG). Treatments were supplied from 90 d prior to expected foaling date until 7 d after first ovulation. Reproductive evaluations were performed during early post-partum until 7 d after first ovulation through rectal palpation and ultrasonography of the following parameters: uterine and endometrium diameters, intrauterine fluid (IUF), uterine echogenicity, uterus tone, and follicular dynamics. Endometrial cells samples were collected to assess mRNA expression of CRP, IL-1β and AKR1C4, using RT-qPCR. Data were analyzed by mixed procedure of SAS. ALG mares had smaller uterine horns diameters and greater uterine echogenicity during post-partum in comparison with CONT. No treatment effects were detected for other characteristics evaluated, but a day effect was observed for uterine and endometrium diameter, IUF, uterine echogenicity, and transcript abundance of endometrial AKR1C4. Supplementation with DHA during peripartum may benefit uterine involution process and odds of early conception, but more studies should be performed regarding fertility.

Invited Review: Advances in rumen efficiency

The purpose of this review was to explain how advances in our knowledge of rumen microbial ecology provide opportunities to improve ruminal fiber degradation, decrease enteric methane production, and limit wastage of dietary protein without disrupting ruminal efficiency. Peer-reviewed literature was the primary course of information reviewed. As numbers of microbial taxa in the rumen have expanded in the past 10 yr, we have gained appreciation for why rumen efficiency is so variable among dietary situations and even among dairy cattle fed the same diets. In typical dairy rations with mixed forage and grain, the primary fibrolytics support a balanced community. However, that community can be disrupted and thus limit fiber digestibility or DMI unless forage quality and particle size along with RDP are maintained. Efforts to decrease enteric methane or improve the efficiency of dietary protein usage should appreciate the complexity of the microbial community to improve consistency of responses. Many feeding practices indirectly influence the rumen microbial structure and function, and future opportunities for feed additives will likely be adjusted for likelihood of benefit using microbial sequence data.

Plasma proteins δ15N vs plasma urea as candidate biomarkers of between-animal variations of feed efficiency in beef cattle: Phenotypic and genetic evaluation

Identifying animals that are superior in terms of feed efficiency may improve the profitability and sustainability of the beef cattle sector. However, measuring feed efficiency is costly and time-consuming. Biomarkers should thus be explored and validated to predict between-animal variation of feed efficiency for both genetic selection and precision feeding. In this work, we aimed to assess and validate two previously identified biomarkers of nitrogen (N) use efficiency in ruminants, plasma urea concentrations and the 15N natural abundance in plasma proteins (plasma δ15N), to predict the between-animal variation in feed efficiency when animals were fed two contrasted diets (high-starch vs high-fibre diets). We used an experimental network design with a total of 588 young bulls tested for feed efficiency through two different traits (feed conversion efficiency [FCE] and residual feed intake [RFI]) during at least 6 months in 12 cohorts (farm × period combination). Animals reared in the same cohort, receiving the same diet and housed in the same pen, were considered as a contemporary group (CG). To analyse between-animal variations and explore relationships between biomarkers and feed efficiency, two statistical approaches, based either on mixed-effect models or regressions from residuals, were conducted to remove the between-CG variability. Between-animal variation of plasma δ15N was significantly correlated with feed efficiency measured through the two criteria traits and regardless of the statistical approach. Conversely, plasma urea was not correlated to FCE and showed only a weak, although significant, correlation with RFI. The response of plasma δ15N to FCE variations was higher when animals were fed a high-starch compared to a high-fibre diet. In addition, we identified two dietary factors, the metabolisable protein to net energy ratio and the rumen protein balance that influenced the relation between plasma δ15N and FCE variations. Concerning the genetic evaluation, and despite the moderate heritability of the two biomarkers (0.28), the size of our experimental setup was insufficient to detect significant genetic correlations between feed efficiency and the biomarkers. However, we validated the potential of plasma δ15N to phenotypically discriminate two animals reared in identical conditions in terms of feed efficiency as long as they differ by at least 0.049 g/g for FCE and 1.67 kg/d for RFI. Altogether, the study showed phenotypic, but non-genetic, relationships between plasma proteins δ15N and feed efficiency that varied according to the efficiency index and the diet utilised.

Assessing the relationship between the rumen microbiota and feed efficiency in Nellore steers

BackgroundRuminants rely upon a complex community of microbes in their rumen to convert host-indigestible feed into nutrients. However, little is known about the association between the rumen microbiota and feed efficiency traits in Nellore (Bos indicus) cattle, a breed of major economic importance to the global beef market. Here, we compare the composition of the bacterial, archaeal and fungal communities in the rumen of Nellore steers with high and low feed efficiency (FE) phenotypes, as measured by residual feed intake (RFI).ResultsThe Firmicutes to Bacteroidetes ratio was significantly higher (P < 0.05) in positive-RFI steers (p-RFI, low feed efficiency) than in negative-RFI (n-RFI, high feed efficiency) steers. The differences in bacterial composition from steers with high and low FE were mainly associated with members of the families Lachnospiraceae, Ruminococcaceae and Christensenellaceae, as well as the genus Prevotella. Archaeal community richness was lower (P < 0.05) in p-RFI than in n-RFI steers and the genus Methanobrevibacter was either increased or exclusive of p-RFI steers. The fungal genus Buwchfawromyces was more abundant in the rumen solid fraction of n-RFI steers (P < 0.05) and a highly abundant OTU belonging to the genus Piromyces was also increased in the rumen microbiota of high-efficiency steers. However, analysis of rumen fermentation variables and functional predictions indicated similar metabolic outputs for the microbiota of distinct FE groups.ConclusionsOur results demonstrate that differences in the ruminal microbiota of high and low FE Nellore steers comprise specific taxa from the bacterial, archaeal and fungal communities. Biomarker OTUs belonging to the genus Piromyces were identified in animals showing high feed efficiency, whereas among archaea, Methanobrevibacter was associated with steers classified as p-RFI. The identification of specific RFI-associated microorganisms in Nellore steers could guide further studies targeting the isolation and functional characterization of rumen microbes potentially important for the energy-harvesting efficiency of ruminants.

In situ rumen degradation characteristics and bacterial colonization of whole cottonseed, cottonseed hull and cottonseed meal with different gossypol content

Regarding whole cottonseed (WCS), cottonseed meal (CSM), and cottonseed hull (CSH), in situ rumen incubation was applied to determine their nutrient and gossypol degradation characteristics and bacterial colonization profile in lactating Holstein cows. Nylon bags containing the cotton by-products were incubated for 0, 6, 12, 24, 36, 48 and 72 h in the rumen, respectively. The relationship between nutrient degradability and free gossypol (FG) content were examined, and the differences in the composition and inferred gene function of the colonized microbiota were studied. As a result, CSM presented highest effective degradability of dry matter, neutral detergent fibre and acid detergent fibre, but the highest effective degradability of crude protein was found in WCS. Free gossypol disappearance rate increased significantly in the first 6 h, and it reached approximately 94% at 72 h of incubation among all samples. The level of FG did not affect nutrient degradability of cotton by-products. Significant differences were noted in attached bacterial community structure among cotton by-products after 24 h rumen incubation. Among the most abundant taxa at genus level, a greater abundance of Cercis gigantea and Succiniclasticum was observed in WCS samples, whereas the CSH and CSM samples contained a greater proportion of Prevotella 1 and Rikenellaceae RC9 gut group. The redundancy analysis revealed that the level of neutral detergent fibre, ether extract, and FG in cotton by-products were significantly positive related with the composition of the attached bacteria. Collectively, our results revealed the dynamics of degradation characteristics, and the difference in the composition of bacterial colonization. These findings are of importance for the targeted improvement of cotton by-products nutrient use efficiency in ruminants and further understanding of the gossypol degradation mechanism in the rumen.

An integrated gene catalog and over 10,000 metagenome-assembled genomes from the gastrointestinal microbiome of ruminants

BackgroundGastrointestinal tract (GIT) microbiomes in ruminants play major roles in host health and thus animal production. However, we lack an integrated understanding of microbial community structure and function as prior studies are predominantly biased towards the rumen. In this study, we used shotgun metagenomics to profile the microbiota of 370 samples that represent 10 GIT regions of seven ruminant species.ResultsOur analyses reconstructed a GIT microbial reference catalog with > 154 million nonredundant genes and identified 8745 uncultured candidate species from over 10,000 metagenome-assembled genomes. The integrated gene catalog across the GIT regions demonstrates spatial associations between the microbiome and physiological adaptations, and 8745 newly characterized genomes substantially expand the genomic landscape of ruminant microbiota, particularly those from the lower gut. This substantially expands the previously known set of endogenous microbial diversity and the taxonomic classification rate of the GIT microbiome. These candidate species encode hundreds of enzymes and novel biosynthetic gene clusters that improve our understanding concerning methane production and feed efficiency in ruminants. Overall, this study expands the characterization of the ruminant GIT microbiota at unprecedented spatial resolution and offers clues for improving ruminant livestock production in the future.ConclusionsHaving access to a comprehensive gene catalog and collections of microbial genomes provides the ability to perform efficiently genome-based analysis to achieve a detailed classification of GIT microbial composition and function. Our study will bring unprecedented power in future association studies to investigate the impact of the GIT microbiota in ruminant health and production.4XTAn6fj9egk7xEPDHXbzgVideo abstract

Different Non-Structural Carbohydrates/Crude Proteins (NCS/CP) Ratios in Diet Shape the Gastrointestinal Microbiota of Water Buffalo.

The microbiota of the gastrointestinal tract (GIT) are crucial for host health and production efficiency in ruminants. Its microbial composition can be influenced by several endogenous and exogenous factors. In the beef and dairy industry, the possibility to manipulate gut microbiota by diet and management can have important health and economic implications. The aims of this study were to characterize the different GIT site microbiota in water buffalo and evaluate the influence of diet on GIT microbiota in this animal species. We characterized and compared the microbiota of the rumen, large intestine and feces of water buffaloes fed two different diets with different non-structural carbohydrates/crude proteins (NSC/CP) ratios. Our results indicated that Bacteroidetes, Firmicutes and Proteobacteria were the most abundant phyla in all the GIT sites, with significant differences in microbiota composition between body sites both within and between groups. This result was particularly evident in the large intestine, where beta diversity analysis displayed clear clustering of samples depending on the diet. Moreover, we found a difference in diet digestibility linked to microbiota modification at the GIT level conditioned by NSC/CP levels. Diet strongly influences GIT microbiota and can therefore modulate specific GIT microorganisms able to affect the health status and performance efficiency of adult animals.

Methane mitigating options with forages fed to ruminants

AbstractNutritional strategies, including feed management measures, are promising methods for CH4 and overall GHG reduction. Evidence from literature is reviewed in this article in relation to the effects of forage quality (digestible organic matter, DOM) and forage type (grasses vs. legumes, and maize). The major determinants of forage quality are botanical composition and phenological stage, i.e., at advanced growth stages of plants, the fibre content increases while DOM decreases. Methane yield (g/kg DMI) decreases with increased digestibility of forages in both dairy cattle and sheep, and also CH4 intensity (g/kg milk) decreases with increased digestibility of forages for dairy cattle. Using forage legumes in ruminant feeding systems can reduce overall GHG emissions due to decreased N fertilizer use and related emissions. Recommended dietary mitigation measures are often related to a reduction in N excretion such as better matching of dietary protein to animal needs, shifting N excretion from urine to faeces (by tannin inclusion at low levels) and reducing the amount of excreted fermentable organic matter. Methane decreases with increasing intake of forage legumes rich in tannins and there is a shift of N partition from urinary N towards faecal N. Reduced CH4 emissions from ruminants fed on forage‐based diets will decrease the carbon footprint of livestock and agriculture and improve the efficiency of productive ruminants in both developing and developed countries. Likewise, estimations of net CH4 output should account for enteric CH4 emissions and soil carbon (C) sequestration of land used for feed production (i.e., grasslands and croplands).

Intake salinity water by creole goats in a controlled environment: ingestive behavior and physiological variables.

The study aimed to verify the effect of water salinity and environmental temperature on the physiological variables (respiratory rate, heart rate, rectal temperature, and surface temperature) and ingestive behavior (rumination, feeding, drinking, and idle) of creole goats. Thirty-six males with an average age of 5.0 ± 0.6 months and an average weight of 20.0 ± 2.3 kg were housed in metabolic cages. The experimental design was a 2 × 3 type crossover (two temperatures and three levels of salinity). The two temperatures were: T1 = 26 ± 0.6 °C (thermoneutral) and T2 = 32 ± 1.2 °C (stress) and three levels salinity (1.0, 6.0, and 12.0 dS m-1). Between the temperatures, the respiratory rate (RR) and surface temperature (ST) present a difference (P < 0,05), being higher in the high temperature. Between temperatures, respiratory rate and surface temperature show a difference (P < 0.05), being higher at high temperature, keeping heart rate and rectal temperature similar at both temperatures. Among the different salinity levels in the behavioral activities, the feeding and urination activity presented a significant difference (P < 0.05), increasing with the water's salinity level. Between temperatures, the rumination efficiency dray matter and neutral detergent fiber showed a significant difference (P < 0.05). With increasing air temperature, they decreased the rumination time-water salinity levels influence (P < 0.05) the feeding efficiency of dry matter. Therefore, water with up to 9.600 mg TDS L-1 can be used strategically in the desedentation of goats in semi-arid regions.

Increasing feed intake in domestic goats (Capra hircus): Measured effects on chewing intensity are probably driven by escape of few, large particles from the forestomach

On the one hand, oral processing – mastication – is considered a relatively inflexible component of mammalian feed acquisition that constrains instantaneous intake rates. On the other hand, experimental data shows that the level of feed intake affects faecal particle size and hence net chewing efficiency in ruminants, with larger particles occurring in the faeces at higher intakes. Here, we report the effect of an increased feed intake during maintenance (L1), late (200% of L1) and peak lactation (300% of L1) of a consistent diet (hay:concentrates 50:50) in eight domestic goats on various measures of digestive physiology including faecal mean particle size (MPS). Increasing intake led to an increased gut fill, a reduction in digesta retention times, and an increase in faecal MPS (from 0.57 to 0.72 mm). However, this was an effect of the large particle fraction (>2 mm) being disproportionately excreted at higher intakes; if MPS was assessed on the basis of particles below the typical escape threshold (≤1 mm), there was no difference between intake levels. These findings suggest that the effect of intake on the calculated net chewing efficiency in ruminants may rather be an effect of increased large particle escape from the forestomach than a reduced chewing intensity per bolus during ingestion or rumination.