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In this study, we compared changes in female rape myth acceptance (RMA) between 1998 and 2018 in two separate samples of college students from the same university in the U.S. Pacific Northwest. The primary measure was the Attitudes Toward Rape Victims Scale (ARVS). First, we examined the factor structure of the ARVS with confirmatory factor analysis, finding good fit for a four-factor model comprising Assigning Blame or Responsibility to the Victim (Blame/Responsibility), Considering the Victim as Deserving of Sexual Violence (Deserving), Undermining the Victim’s Credibility (Undermine Credibility), and Trivializing the Experience or Denigrating the Victim (Trivialization/Denigration). Second, we used profile analysis, a type of multivariate repeated-measures ANOVA, to examine the main and interactive effects of Survey Year, Gender, and ARVS Subscale and Item within each subscale. At the subscale level, we found large main effects for Survey Year, Gender, and Subscale, with lower scores for the 2018 sample, women, and Deserving and Trivialization/Denigration, relative to Undermine Credibility and Blame/Responsibility. We also found interactions between Survey Year and Subscale and Gender and Subscale, indicating non-parallel profiles for the 1998 versus 2018 samples and women versus men. We found similar patterns at the item level within each subscale. These results indicate a substantial decline of female RMA in college students over a 20-year period, replicate the well-established gender difference in female RMA, and demonstrate that RMA varies by item content.

The world acreage of organic crop production systems is increasing, but the soil microbial dynamics in these systems are not fully understood. We studied the composition and functioning of soil microbial communities in 4-year organic or conventional rotations. The organic systems were tilled to control weeds, and N2-fixing legumes or compost supplied nutrients. The conventional systems were managed under no-till; herbicides controlled weeds, and compost or fertilizers supplied nutrients. Soil microbial biomass C (MBC), the diversity and composition of bacterial communities, and activities of enzymes that mediate C, N, P, and S cycling were determined. The bacterial classes Gemmatimonadetes, C0119 (phylum Chloroflexi), and Thermomicrobia (phylum Chloroflexi) were more abundant in organic than conventional cropping systems, so were some genera from the class Actinobacteria. The bacterial β-diversity showed similar cropping system differences. However, acid phosphomonoesterase activity was greater in conventional than organic cropping systems, presumably because the soil P from the large amounts of compost applied in the organic system suppressed this enzyme. MBC, bacterial α-diversity, the relative abundances of the bacterial classes δ-Proteobacteria, γ-Proteobacteria, and Bacilli (phylum Firmicutes) were all greater in compost than no-compost treatments. The relative abundances of three genera from Actinobacteria class were negatively correlated with acid phosphomonoesterase activity due to the high relative abundances of these genera, but low acid phosphomonoesterase activities, where compost was applied in the organic system. Therefore, there were soil bacterial compositional differences between organic and conventional cropping systems, but only differences in the activities of a P cycling enzyme were detected.

In cattle, proper rumen functioning and digestion are intimately linked to chewing behavior. Yet, high grain feeding impairs chewing activity, increasing the risk of subacute ruminal acidosis and dysfermentation. This study aimed to screen 9 different phytogenic compounds for their potential to modulate chewing activity, meal size, rumino-reticular short-chain fatty acids (SCFA), and pH during consumption in a first daily meal and shortly thereafter in cattle fed a grain-rich diet. Treatments were control (total mixed ration without phytogenic) or addition of a phytogenic compound at a low or high dose. Phytogenic compounds and doses (all in mg/kg) were angelica root (6.6 and 66), capsaicin (10 and 100), gentian root (6.6 and 66), garlic oil (0.3 and 3), ginger extract (40 and 400), L-menthol (6.7 and 67), mint oil (15.3 and 153), thyme oil (9.4 and 94), and thymol (5 and 50), for the low and high groups, respectively. Before the start of the screening experiment, cows were fed to reach subacute ruminal acidosis conditions, confirmed with the time of ruminal pH5.8 being 655 ± 148.2 min/d. During the screening experiment, the treatments were offered in a controlled meal (2.5 kg of DM for 4 h) as part of the daily diet with 65% concentrate. Each treatment was tested in 4 of the 9 cannulated Holstein cows using an incomplete Latin square design. Ruminal and reticular fluids were sampled before and after each treatment, and data collected before the meal were used as covariates. Chewing and ruminal pH were monitored during the treatment, followed by 2 h of complete feed restriction, and then 4 h of ad libitum feed intake without phytogenic. Data showed that supplementation of angelica root tended to linearly increase rumination time immediately after the first meal when feed was restricted (27.3, 41.9, and 42.6 ± 5.99 min for control, low and high groups, respectively). Capsaicin increased eating time (43.6, 49.4, and 66.4 ± 4.93 min) during consumption but did not affect ruminal total SCFA or mean ruminal pH. Garlic oil reduced the concentration of reticular total SCFA (75.7, 71.3, and 60.1 mM) and tended to decrease ruminal acetate-to-propionate ratio (2.50, 1.78, and 1.87 ± 0.177) with no effect on ruminal pH. The L-menthol affected reticular total SCFA quadratically (76.1, 64.9, and 81.0 ± 4.22%), and ruminal pH responded quadratically when feed was reintroduced ad libitum (6.0, 6.3, and 6.1 ± 0.07). Mint oil did not affect chewing or total SCFA during consumption, but the low dose increased ruminal pH (6.5, 6.7, and 6.5 ± 0.08). Thyme oil tended to lower the severity of ruminal acidosis. Overall, phytogenic compounds demonstrated distinct dose-dependent effects to beneficially influence chewing behavior, modulate fermentation, and mitigate ruminal acidosis in dairy cows under a high-grain challenge diet.

Posttraumatic stress disorder (PTSD) is commonly assessed with self-rated or clinician-rated measures. Although scores from these assessment modalities are strongly associated, they are often discrepant for individual symptoms, total symptom severity, and diagnostic status. To date, no known studies have empirically identified the sources of these discrepancies. In the present study, we had three aims: (a) replicate previously identified discrepancies; (b) examine contribution of possible objective predictors of discrepancies, including negative response bias, random responding, conscientiousness, neuroticism, and verbal IQ; and (c) identify subjective sources of discrepancies through analysis of participant feedback. Trauma-exposed undergraduates (

Glyphosate (N-(phosphonomethyl)glycine) is broad-spectrum herbicide that is extensively used worldwide, but its effects on the soil microbiome are inconsistent. To provide a sound scientific basis for herbicide re-review and registration decisions, we conducted a four-year (2013-2016) study in which we consecutively applied glyphosate to a wheat (Triticum aestivum L.)-field pea (Pisum sativum L.)-canola (Brassica napus L.)-wheat crop rotation at five sites in the Canadian prairies. The glyphosate rates were 0, 1, 2, 4 and 8 kg ae ha

Due to widespread adoption of no-till management and use of glyphosate-resistant transgenic crops, glyphosate is the most widely used herbicide worldwide. However, its effect on soil microbial communities is inconsistent. We studied the effects of glyphosate, tillage, and crop rotation on the diversity and composition of soil bacterial communities in wheat (Triticum turgidum var. durum Desf.) rhizosphere after 6 and 7 yr of glyphosate applications. In a 2 × 2 × 2 factorial design, there were two crop rotation treatments: continuous wheat (W–W) and wheat in rotation with field pea (Pisum sativum L.) (P–W); two tillage treatments: minimum tillage (MT) and no-till (NT); and two glyphosate treatments: no application or pre-seeding application at the recommended rate. None of the treatments affected wheat rhizobacterial α-diversity or the relative abundances of most bacterial groups. The most abundant phyla were Proteobacteria (25.1% relative abundance), Actinobacteria (21.7%), Acidobacteria (8.7%), Bacteroidetes (5.9%), Firmicutes (1.4%), Armatimonadetes (1.3%), and Verrucomicrobia (1.2%). Glyphosate reduced the relative abundance of Alphaproteobacteria in W–W rotation but increased it in P–W rotation, and it reduced the relative abundance of Opitutus spp. The W–W rotation had greater relative abundances of the classes Bacilli (Firmicutes) and Gammaproteobacteria, and genera Bacillus and Opitutus (Verrucomicrobia), than the P–W rotation. Compared with MT, NT increased the relative abundance of the phylum candidate division WPS-1, but it reduced that of Phenylobacterium spp. in W–W rotation. These treatment effects probably had implications for soil functioning, including nutrient cycling and biological disease/pest control.

Microbial composition and activity in the gastrointestinal tract (GIT) of cattle has important implications for animal health and welfare, driving the focus of research toward ways to modify their function and abundance. However, our understanding of microbial adaption to nutritional changes remains limited. The aim of this study was to examine the progressive mechanisms of adaptation in the rumen and hindgut of cattle receiving increasing amounts of starch with or without dietary supplementation of a blended phytogenic feed additive (PFA; containing menthol, thymol and eugenol). We used 16S rRNA gene amplicon sequencing to assess the microbial composition and predicted metabolic pathways in ruminal solid and liquid digesta, and feces. Furthermore, we employed targeted liquid chromatography-mass spectrometry methods to evaluate rumen fluid metabolites. Results indicated a rapid microbial adaptation to diet change, starting on the second day of starch feeding for the particle associated rumen liquid (PARL) microbes. Solid rumen digesta- and feces-associated microbes started changing from the following day. The PARL niche was the most responsive to dietary changes, with the highest number of taxa and predicted pathways affected by the increase in starch intake, as well as by the phytogenic supplementation. Despite the differences in the microbial composition and metabolic potential of the different GIT niches, all showed similar changes toward carbohydrate metabolism. Metabolite measurement confirmed the high prevalence of glucose and volatile fatty acids (VFAs) in the rumen due to the increased substrate availability and metabolic activity of the microbiota. Families Prevotellaceae, Ruminococcaceae and Lachnospiraceae were found to be positively correlated with carbohydrate metabolism, with the latter two showing wide-ranging predicted metabolic capabilities. Phytogenic supplementation affected low abundant taxa and demonstrated the potential to prevent unwanted implications of feeding high-concentrate diet, such as reduction of microbial diversity. The inclusion of 50% concentrate in the diet caused a major shift in microbial composition and activity in the GIT of cattle. This study demonstrated the ability of microorganisms in various GIT niches to adjust differentially, yet rapidly, to changing dietary conditions, and revealed the potential beneficial effects of supplementation with a PFA during dietary adaptation.

Mycoplasma hyopneumoniae is a difficult-to-control bacterium since commercial vaccines do not prevent colonization and excretion. The present study aimed to evaluate the performance of an orally administered vaccine composed of antigens extracted from Mycoplasma hyopneumoniae and incorporated into mesoporous silica (SBA-15), which has an adjuvant-carrier function, aiming to potentiate the action of the commercial intramuscular vaccine. A total of 60 piglets were divided into four groups (n = 15) submitted to different vaccination protocols as follows, Group 1: oral SBA15 + commercial vaccine at 24 days after weaning, G2: oral vaccine on the third day of life + vaccine commercial vaccine at 24 days, G3: commercial vaccine at 24 days, and G4: commercial vaccine + oral vaccine at 24 days. On the first day, the piglets were weighed and, from the third day onwards, submitted to blood collections for the detection and quantification of anti-Mycoplasma hyopneumoniae IgG. Nasal swabs were collected to monitor IgA by ELISA, and oropharyngeal swabs were used to assess the bacterial load by qPCR. Biological samples were collected periodically from the third day of life until the 73rd day. At 41 days of life, 15 individuals of the same age, experimentally challenged with an inoculum containing M. hyopneumoniae, were co-housed with the animals from groups (1 to 4) in a single pen to increase the infection pressure during the nursery period. At 73 days, all piglets were euthanized, and lungs were evaluated by collecting samples for estimation of bacterial load by qPCR. Quantitative data obtained from physical parameters and laboratory investigation were analyzed by performing parametric or non-parametric statistical tests. Results indicate that animals from G2 showed smaller affected lung areas compared to G3. Animals from G2 and G4 had a low prevalence of animals shedding M. hyopneumoniae at 61 days of age. Additionally, no correlation was observed between lung lesions and M. hyopneumoniae load in lung and BALF samples in animals that received the oral vaccine, while a strong correlation was observed in other groups. In the present study, evidence points to the effectiveness of the oral vaccine developed for controlling M. hyopneumoniae in pig production under field conditions.

Agroecosystems are comprised of environmental compartments where associated microbial communities interact with one another. These microbial communities, called microbiomes, inhabit livestock, insects, and plants. Microbiomes are also present in the soil and watersheds. Clarifying the nature and extent of microbial interactions between compartments both at intra-farm and global scales can promote sustainable production systems, healthier animals, increased crop yields, and safer meat products. Early research on microbiomes was hindered by a lack of expertise and the high cost of molecular sequencing. However, these limitations have been largely resolved with advances in and reduced costs of sequencing technologies. In this paper, we summarize sequencing and bioinformatics approaches, and review the crucial roles of diverse microbiomes in livestock, plants and soil, as well as pollinators and pest insects. These crucial roles include nutrient cycling, nutrient acquisition, metabolism of toxins and enhanced host immune function. Additionally, we examine potentially undesirable effects of microbiomes associated with climate change and agri-food production such as their role in the release of greenhouse gases from cattle and their impact on meat safety and spoilage. By increasing the awareness of microbiomes and the growing ease with which they can be studied, we hope to foster a greater adoption of microbiome research. Further understanding of the diverse effects and interactions of microbiomes will advance our efforts to increase agricultural production while reducing its negative environmental footprint, thus making the agroecosystems more sustainable.

There is debate about the validity of the complex posttraumatic stress disorder (CPTSD) diagnosis and whether disturbances in self-organization (DSO) in CPTSD can be differentiated from borderline personality disorder (BPD). How PTSD is defined may matter. The present study used exploratory structural equation modeling (ESEM) to replicate and extend prior work by including two models to examine how PTSD (ICD-11, DSM-5), DSO, and BPD symptoms relate. Participants (N = 470; 98.1% women; 97.7% Black) were recruited from medical clinics within an urban hospital. PTSD, CPTSD, and BPD were assessed using semi-structured interviews and trauma-related avoidance, aggressive behavior, and anxious attachment were assessed using self-report measures. ESEM models of PTSD, DSO, and BPD symptoms were run. We found a three-factor ESEM model of CPTSD (ICD-11 PTSD and DSO symptoms) and BPD symptoms best fit the data and found support for discriminant validity between factors across trauma-related avoidance, aggressive behavior, and anxious attachment. For DSM-5 PTSD, a two-factor ESEM model was best-fitting (PTSD and DSO/BPD). The findings demonstrate clear distinguishing and overlapping features of ICD-11 PTSD, CPTSD, and BPD and the necessity to consider the diagnostic structure of PTSD in determining the additive value of CPTSD as a distinct construct.

The Veterans Health Administration (VHA) has called for improved assessment and intervention for survivors of military sexual trauma (MST) to mitigate deleterious sequalae, including posttraumatic stress disorder (PTSD). Research on the impact of MST-related PTSD (MST-IT) on men is limited, and few studies have examined the differential effects of treatment across genders and MST-IT. Additionally, studies have utilized varying definitions of MST (e.g., sexual assault only vs. including sexual harassment), contributing to disparate outcomes across studies. Utilizing data from 343 veterans seeking residential cognitive processing therapy (CPT) for PTSD in VHA, this study examined the impact of MST-IT and gender on differences in demographic characteristics; pre-treatment severity of PTSD (overall and clusters), depression, and negative posttraumatic cognitions (NPCs); and post-treatment severity of these variables after accounting for pre-treatment severity. Results from 2x2 factorial ANOVAs found no differences in pre-treatment depression or overall PTSD by MST-IT, gender, or their interaction; however, MST-IT survivors presented with greater pre-treatment avoidance, global NPCs, and self-blame. Results from hierarchical linear regression models found only pre-treatment symptom severity significantly predicted post-treatment severity for overall PTSD and all NPCs. These findings suggest veteran survivors of MST-IT appear to benefit similarly from CPT delivered in a VHA residential PTSD program compared to veterans with other index traumas, regardless of gender. Although there were minimal post-treatment differences in PTSD and NPCs by MST-IT status and gender, residual symptoms related to negative cognitions and mood appear to differ across gender and MST-IT status. Specifically, in individuals without MST-IT, post-treatment PTSD symptoms of negative alterations in cognition and mood were higher in men than women. Moreover, women with MST-IT reported more symptoms of depression than both men with MST-IT and women without MST-IT. These findings suggest depressive symptoms decrease through residential PTSD treatment differentially by MST-IT status and gender and warrant further examination.

BACKGROUND Climatic and dietary shifts predispose ruminal microbes to hyperthermal and hyperosmotic stress, leading to poor fermentation and subsequently adverse effects on ruminant productivity. Betaine may function as substrate, osmolyte, antioxidant, and methyl donor for microbes. However, its effect depends on the extent of microbial catabolism. This study revealed the ruminal disappearance kinetics of betaine and its dose effect on ruminal fermentation during thermal and osmotic stress using a rumen simulation technique. RESULTS Three different betaine doses were used: 0, 50, and 286 mg L−1; each was assigned to two incubation temperatures (39.5 and 42 °C) and two osmotic conditions (295 and 420 mOsmol kg−1). Betaine disappeared rapidly within the first 6 h of incubation; however, the rate was lower during hyperosmotic stress (P

The increased concentrate amounts in cow diets may initiate changes in both particle-associated (PaM) and epimural microbiota (EpM) with the potential for promoting the establishment of pathogens. Clay minerals have shown promising potentials in binding harmful microorganisms and metabolites due to their high adsorption capacity. This study evaluated the effects of a clay-mineral based product (CM) on PaM, EpM, fermentation parameters, and epithelial gene expression in cows fed a high-concentrate diet. Eight rumen-cannulated non-lactating Holstein cows received a concentrate mix supplemented with CM or not (CON) in a change-over design with an initial 100% roughage diet phase (RD, 1 week), followed by intermittent 65%-high-concentrate-diet phases (HC1, HC2; 1 and 2 week duration, respectively), interrupted by 1 week roughage only. Rumen samples for short-chain fatty acids, ammonia, and lactate quantification, as well as PaM, and epithelial biopsies for EpM examination and epithelial gene expression were collected via the cannula once during each feeding phase. Phylogenetic distance analysis of Illumina MiSeq sequencing of the 16S rRNA gene region V345 showed a clear clustering of RD microbiota compared to HC in PaM, showing the impact of the high-concentrate diet on the bacterial community. In the EpM this effect was less pronounced, due to higher variability in RD. In the PaM, a decrease (P 0.01) of community diversity occurred with the onset of HC feeding, while in the EpM there was an increase in diversity (P 0.05). In the PaM, CM increased the relative abundance of genus Butyrivibrio (P 0.01), a commensal bacterium of the rumen, which was, with 6.4%, the second most abundant genus. There, the CM supplementation decreased the genera Lactobacillus, Fusobacterium, and Treponema (P = 0.05), which are potentially either lactate producing or opportunistic pathogens. In the EpM, CM decreased the relative abundance of Succiniclasticum genus (P 0.01), a possible endotoxin producer, and increased bacteria that are associated with a normobiotic rumen, such as Campylobacter (P = 0.06). Barrier function genes were upregulated in HC2 and nutrient transport genes downregulated in HC1 (P 0.05); however, there was little effect on pro-inflammatory genes at the epithelium. The CM showed a significant decreasing effect on the cellular metabolism genes HMGCS1 (P = 0.04). Our results suggest that CM supplementation can increase the relative abundance of commensal microbiota and decrease bacteria that could negatively impact the rumen milieu and health during high-concentrate feeding.

This study aimed at testing the effects of three different formulations of feed supplements based on three different combinations of plant derived alkaloids, prebiotics, tannins, vitamins and minerals on rumen fermentation and the microbiome in vitro. A Rusitec experiment was conducted in 2 identical runs using a complete randomized design with 3 replicates per treatment resulting in total of 6 treatment combinations (n = 6). Each run lasted 12 d with sampling occurring in the last 5 d. Diets were a standard dairy ration (60:40; concentrate:forage) supplemented with one of 3 different plant-based combinations (PI, PII, and PIII) at a level of 100 mg/l and a non-supplemented control (basal diet, control). Microbial DNA samples were taken on the last day of each run and the 16S rRNA target gene sequenced using Illumina MiSeq technology. The supplementations had no effect on the pH, methane and carbon dioxide production. However, both total SCFA (P = 0.08) and molar concentrations of acetate (P = 0.06) tended to be increased in the treatment groups in comparison to control, with PII having the highest overall values (102.7 mmol/L and 43.3 mmol/L, respectively). Alpha diversity indices Shannon, Simpson and Chao1 showed no effect of supplementations or combinations. The addition of PII increased the relative abundance of Bacteroidetes compared to all other treatments (P = 0.05). Supplementation with plant-based combinations reduced the relative abundance of Pyramidobacter from the family Dethiosulfovibrionaceae in comparison with the control diet (P = 0.05). Evaluation of predicted gene function through PICRUSt analysis showed variation in predicted cellular function and metabolism between bacterial communities supplemented with plant-based combinations compared to the control diet. This shows that the addition of plant-based combinations can have the potential to modulate the metabolic function of rumen microbes, and likely the production of small-sized rumen metabolites, without disrupting the rumen microbial community structure and diversity.

Saliva facilitates feed ingestion, nutrient circulation, and represents an important pH buffer for ruminants, especially for cattle fed high-concentrate diets that promote rumen acidification. This experiment evaluated the short-term effects of nine phytogenic compounds on salivation, saliva physico-chemical composition as well as ingested feed boli characteristics in cattle. A total of nine ruminally cannulated Holstein cows were used. Each compound was tested in four of these cows as part of a high-concentrate meal (2.5 kg of total mixed ration in dry matter basis for 4 h) in low or high dose, and was compared to a control meal without compound. Saliva was sampled orally (unstimulated saliva) for physico-chemical composition analysis. Composition of the ingested saliva (stimulated saliva), salivation and feed boli characteristics were assessed from ingesta collected at the cardia during the first 30 min of the meal. Analysis of unstimulated saliva showed that supplementation with capsaicin and thyme oil increased buffer capacity, while supplementation with thymol, L-menthol and gentian root decreased saliva pH. In addition, supplementing angelica root decreased saliva osmolality. Regression analysis on unstimulated saliva showed negative associations between mucins and bicarbonate as well as with phosphate when garlic oil, thyme oil or angelica root was supplemented. Analysis of stimulated saliva demonstrated that supplementation with garlic oil increased phosphate concentration, thyme oil tended to increase osmolality, capsaicin and thymol increased buffer capacity, and ginger increased phosphate content. Furthermore, salivation rate increased with ginger and thymol, and tended to increase with garlic oil, capsaicin, L-menthol and mint oil. Feed ensalivation increased with capsaicin. A positive association was found between feed bolus size and salivation rate when any of the phytogenic compounds was supplemented. Overall, our results demonstrate positive short-term effects of several phytogenic compounds on unstimulated and stimulated saliva physico-chemical properties, salivation or feed boli characteristics. Thus, the phytogenic compounds enhancing salivary physico-chemical composition have the potential to contribute to maintain or improve ruminal health in cattle fed concentrate-rich rations.

Physical effective fiber in the diet promotes chewing, contributing to the regulation of ruminal pH through saliva production, which leads to rumen health. However, lower dietary fiber content in high-grain diets may reduce rumination time and compromise ruminal pH regulation. The objective of this experiment was to evaluate rumination behavior and rumino-reticular pH variations during an 8-day adaptation to a 65% concentrate diet. For this study nine ruminally cannulated non-lactating Holstein cows were used. Prior to the initiation of the adaptation, cows were transitioned from a forage-only grass silage diet to a 65% DM concentrate diet over eight days. Rumination was monitored using RumiWatch halters (RumiWacthSystem ITIN+HOCH). Rumino-reticular pH was measured using eCow indwelling pH systems in five of nine cows recording data every 15 minutes. Data were analysed with SAS, the statistical model included day as fixed effect and cow was considered as random effect. Adaptation days had an effect (P < 0.01) on rumination time, number of rumination chews per minute, and mean daily (rumino-reticular) pH. Especially, rumination time decreased from 439 to 327±62.8 minutes per day from day 1 to 8, respectively. Concomitantly, rumination chews per minute decreased from 68.8 to 65.6±2.06, and mean daily pH decreased from 6.54 and 6.26±0.07, respectively. Nevertheless, daily dry matter intake (P = 0.23) and eating time (P = 0.37) were not affected during the adaptation period. In conclusion, adaptation to a high-grain diet and the associated decrease in physically effective fiber gradually reduced chewing activity and ruminal/reticular pH. However, compared to the forage-only diet, significant reduction in rumination time was only noted at the 65% concentrate level.

Intensive dairy production systems encourage feeding of high-concentrate diets to increase milk production efficiency. However, there is limited information regarding the effect of a SARA challenge diet on chewing behavior and rumino-reticular short chain fatty acid (SCFA) concentration. The objective of this study was to evaluate chewing activity and SCFA production in the rumen and reticulum, using nine ruminally cannulated non-lactating Holstein cows. Preceding the trial, cows were transitioned from 100% forage to 65% DM concentrate over eight days. Trial day 1 began once cows reached 65% DM concentrate and monitoring during 23 days. RumiWatch halters were used to monitor chewing activity. SCFA analysis was conducted on rumen and reticulum fluid collected 4 hours after feeding using gas chromatography. Data were analyzed with SAS, with the fixed effect of days and cow as random effect. There was an increase in DM intake during the first four hours after feeding: 1.97 and 2.25 ± 0.12 kg for day 1 and 23, respectively (P < 0.05). There was no difference in rumination time (P = 0.16) with 29 ± 8.5 minutes during the first four hours of feeding. However, chewing index (P = 0.08) tended to decrease from 36.7 to 29.4 ± 4.4 minutes of chewing/kg of DM for day 1 and 23, respectively. Moreover, on day 1, propionate increased from 19.9 ± 1.02 to 20.1 ± 1.02% and from 24.04 ± 0.93 to 25.4 ± 1.02% compared to day 23 for rumen and reticulum, respectively (P < 0.05). In addition, from day 1 to day 23, the rumen and reticulum acetate/propionate ratio declined from 3.2 ± 0.15 and 3.1 ± 0.1, to 2.5 ± 0.15, respectively, and reticulum SCFA decreased from 87 to 67 µmol/g, respectively. Overall, there was no effect of the 23-day SARA challenge diet on chewing activity. However, there was a reduction of SCFA concentration in reticulum, which may be due to enhanced SCFA absorption or increased feed bolus neutralizing capacity.

Feeding grain-rich diets often results in subacute ruminal acidosis (SARA), a condition associated with ruminal dysbiosis and systemic inflammation. Yet, the effect of SARA on hindgut microbiota, and whether this condition is aggravated by exogenous immune stimuli, is less understood. Therefore, the aims of this study were to determine the effects of an intermittent high-grain SARA model on the hindgut microbial community, and to evaluate whether the effects of SARA on the fecal microbiome and fermentation were further affected by an intramammary lipopolysaccharide (LPS) challenge. A total of 18 early-lactating Simmental cows were divided into 3 groups (n = 6); 2 were fed a SARA-inducing feeding regimen (60% concentrate), 1 was fed a control (CON) diet (40% concentrate). On d 30, 1 SARA group (SARA-LPS) and the CON group (CON-LPS) were intramammarily challenged with a single dose of 50 µg of LPS from Escherichia coli O26:B6, whereas the remaining 6 SARA cows (SARA-PLA) received a placebo. Using a longitudinal randomized controlled design, with grouping according to parity and days in milk), statistical analysis was performed with baseline measurements used as a covariate in a mixed model procedure. The SARA-inducing feeding challenge resulted in decreased fecal pH and increased butyrate as a proportion of total short-chain fatty acids in the feces. On d 30, SARA-challenged cows had decreased fecal diversity as shown by the Shannon and Chao1 indices and a decrease in the relative abundance of Euryarchaeota and cellulolytic genera, and numerical increases in the relative abundance of several Firmicutes associated with starch and secondary fermentation. The LPS challenge did not affect the fecal pH and short-chain fatty acids, but increased the Chao1 richness index in an interaction with the SARA challenge, and affected the relative abundance of Verrucomicrobia (1.13%), Actinobacteria (0.19%), and Spirochaetes (0.002%), suggesting an effect on the microbial ecology of the hindgut during SARA conditions. In conclusion, the SARA-inducing feeding regimen promoted important microbial changes at d 30, including reduced diversity and evenness compared with CON, whereas the external LPS challenge led to changes in the microbial community without affecting fecal fermentation properties.