Saccharomyces cerevisiae fermentation products are commonly used in dairy cattle ration to improve production efficiency and health. However, whether these benefits will persist during feed-restriction-induced negative energy balance is unknown. The objective of this experiment was to examine the effect of a Saccharomyces cerevisiae fermentation product (NT, NutriTek, Diamond V) on performance, metabolic, inflammatory, and immunological responses to a feed-restriction challenge in mid-lactation dairy cows. Sixty Holstein cows were blocked by parity, days in milk, and milk yield and then randomly assigned to 1 of the 2 supplements: NT or placebo (CTL). The supplements were mixed in total mixed ration before feeding at a rate of 19 g/d per cow. The production phase of the experiment lasted 12 wk. Intake and milk yield were recorded daily, and milk composition was measured weekly. After the production trial, a subset of cows (NT: n = 16; CTL: n = 16) were immediately enrolled in a 5-d feed-restriction challenge with 40% ad libitum intake followed by a 5-d realimentation. Milk yield and composition were measured at each milking from d -2 to 10 relative to feed restriction. Blood samples were collected on d -2, -1, 1, 2, 3, 4, 5, 6, 8, and 10 relative to the initiation of feed restriction to measure circulating metabolites, insulin, cortisol, IL-10, tumor necrosis factor-α, lipopolysaccharide binding protein, and haptoglobin. Immune function assessments, including peripheral mononuclear cell proliferation and functional assays of circulating granulocytes, were performed on d -3 and 4 of the feed restriction. No differences were observed in dry matter intake, milk yield, or concentrations or yield of components except for fat yield. An interaction of parity and treatment was observed for milk fat yield that was lower for CTL than NT in primiparous cows, but no differences were observed among treatments in milk fat yield of multiparous cows. Feed restriction successfully induced negative energy balance and its associated metabolic changes, including reduced concentrations of plasma glucose and increased nonesterified fatty acids and β-hydroxybutyrate. Cows fed NT had a similar decrease in milk yield but had a more pronounced reduction in plasma glucose concentration and greater β-hydroxybutyrate concentration during feed restriction than those fed CTL. Feed restriction did not induce evidence of systemic inflammation but did reduce granulocyte functional activity. Compared with CTL, feeding NT improved the reactive oxygen species production by granulocytes after stimulation by extracellular antigens. In conclusion, feeding NT increased milk fat production of first-lactation cows but did not affect overall productive performance. However, supplementation with NT improved induced granulocyte oxidative burst. This may explain the greater glucose utilization by cows fed NT rather than CTL during feed restriction.

In Table 9, MUN values were incorrect. The correct values are shown in bold below.Table 9Effects of supplementation of a Saccharomyces cerevisiae fermentation product (SCFP) and carryover effects of starch content of fresh diets (ST) on DMI, BW and BCS changes, milk yield and composition during the post-fresh period (d 24 ± 3 to 44 ± 3 after calving), and the interval from calving to first ovulation postpartum1LS = low-starch fresh diets; HS = high-starch fresh diets; CON = control diet, no SCFP supplementation; SCFP = SCFP-supplemented diet.VariableLSHSSEP-valueCONSCFPCONSCFPSTSCFPST × SCFPDMI, kg/d20.719.920.619.80.470.770.100.98Initial BW,2Measured on d 23 and 24 ± 3 before morning feeding. kg5765785855889.940.330.780.94BW change, kg/d0.480.610.320.320.280.420.820.82Initial BCS2Measured on d 23 and 24 ± 3 before morning feeding.2.792.832.882.830.060.390.950.44BCS change,/21d−0.18−0.13−0.15−0.110.030.480.160.77Yield, kg/d Milk42.641.939.441.21.130.090.590.26 Fat1.561.661.601.630.050.910.210.46 CP1.211.241.181.240.030.640.230.64 Lactose1.981.951.871.960.060.340.530.28 Total solids5.165.275.055.240.130.630.260.78 3.5% FCM43.845.243.444.61.170.690.250.94 Solids-corrected milk39.640.939.340.51.040.770.220.963.5% FCM/DMI2.122.292.142.260.050.91<0.010.61Milk composition Fat, %3.74aMeans in the same row with different superscripts differ significantly (P < 0.05) when an interaction of main treatment effect was observed.4.00abMeans in the same row with different superscripts differ significantly (P < 0.05) when an interaction of main treatment effect was observed.4.05bMeans in the same row with different superscripts differ significantly (P < 0.05) when an interaction of main treatment effect was observed.3.95abMeans in the same row with different superscripts differ significantly (P < 0.05) when an interaction of main treatment effect was observed.0.100.190.410.08 CP, %2.862.952.952.960.040.150.170.27 Lactose, %4.654.634.644.650.020.920.860.63 Total solids, %12.2aMeans in the same row with different superscripts differ significantly (P < 0.05) when an interaction of main treatment effect was observed.12.6bMeans in the same row with different superscripts differ significantly (P < 0.05) when an interaction of main treatment effect was observed.12.6bMeans in the same row with different superscripts differ significantly (P < 0.05) when an interaction of main treatment effect was observed.12.5bMeans in the same row with different superscripts differ significantly (P < 0.05) when an interaction of main treatment effect was observed.0.130.090.260.08 MUN, mg/dL13.7abMeans in the same row with different superscripts differ significantly (P < 0.05) when an interaction of main treatment effect was observed.13.9abMeans in the same row with different superscripts differ significantly (P < 0.05) when an interaction of main treatment effect was observed.14.3aMeans in the same row with different superscripts differ significantly (P < 0.05) when an interaction of main treatment effect was observed.13.1bMeans in the same row with different superscripts differ significantly (P < 0.05) when an interaction of main treatment effect was observed.0.410.760.230.09 SCC, 103 cells/mL37.4aMeans in the same row with different superscripts differ significantly (P < 0.05) when an interaction of main treatment effect was observed.88.3abMeans in the same row with different superscripts differ significantly (P < 0.05) when an interaction of main treatment effect was observed.164bMeans in the same row with different superscripts differ significantly (P < 0.05) when an interaction of main treatment effect was observed.55.5abMeans in the same row with different superscripts differ significantly (P < 0.05) when an interaction of main treatment effect was observed.42.80.280.500.07Apparent dietary NEL3Calculated according to Dann et al. (2000). Mcal/d40.740.839.840.81.160.710.650.68 Mcal/kg of DMI1.982.071.962.070.050.840.050.86NEL balance,4Apparent dietary NEL (Mcal/d) minus NEL required for milk output and maintenance (Mcal/d). The NEL required for milk and maintenance were calculated according to Dann et al. (2000). Mcal/d2.351.361.601.550.740.750.560.59Days to FOP5Interval from calving to first ovulation postpartum (d).23.824.628.122.72.460.630.360.21a,b Means in the same row with different superscripts differ significantly (P < 0.05) when an interaction of main treatment effect was observed.1 LS = low-starch fresh diets; HS = high-starch fresh diets; CON = control diet, no SCFP supplementation; SCFP = SCFP-supplemented diet.2 Measured on d 23 and 24 ± 3 before morning feeding.3 Calculated according to Dann et al. (2000).4 Apparent dietary NEL (Mcal/d) minus NEL required for milk output and maintenance (Mcal/d). The NEL required for milk and maintenance were calculated according to Dann et al. (2000).5 Interval from calving to first ovulation postpartum (d). Open table in a new tab The authors regret the error. Effects of supplementing a Saccharomyces cerevisiae fermentation product during the periparturient period on performance of dairy cows fed fresh diets differing in starch contentJournal of Dairy ScienceVol. 102Issue 4PreviewThe objective of this study was to evaluate the effects of supplementing a Saccharomyces cerevisiae fermentation product (SCFP; NutriTek, Diamond V, Cedar Rapids, IA) during the periparturient period (d −28 ± 3 to 44 ± 3 relative to calving) on dry matter intake (DMI), milk production, apparent total-tract nutrient digestibility, and postpartum ovarian activity of dairy cows fed fresh diets varying in starch content. From d 28 ± 3 before the expected calving date until d 44 ± 3 after calving, 117 Holstein cows were fed diets with SCFP (SCFP; n = 59) or without (control, CON; n = 58). Full-Text PDF Open Access

Dairy cattle are subjected to oxidative stress, inflammation, and altered immune function during the transition to lactation. The objective of this study was to evaluate the effects of a dietary Saccharomyces cerevisiae fermentation product (SCFP; NutriTek, Diamond V) on oxidative status, inflammation, and innate and adaptive immune responses during the transition period. Holstein cows were blocked by parity, expected calving date, and previous milk yield and then randomly assigned to treatment within block. Treatment was a control total mixed ration (n = 30) or SCFP total mixed ration (n = 34) fed from -29 ± 5 to 42 d relative to calving (RTC). Blood was sampled during wk -4, -2, 1, 2, and 5 and liver tissue at wk -3 and 2 RTC. Oxidative status was evaluated in plasma by retinol, α-tocopherol, and malondialdehyde concentrations, glutathione peroxidase activity, and Trolox equivalent antioxidant capacity, and in liver by mRNA abundance of nuclear factor E2-related factor 2 (NFE2L2), metallothionein 1E (MT1E), and glutathione peroxidase 3 (GPX3). Inflammation was evaluated in plasma by haptoglobin (HP) and serum amyloid A (SAA) concentrations and in liver by mRNA abundance of HP, serum amyloid A3 (SAA3), and nuclear factor kappa-light-chain-enhancer of activated B cells (NFKB1). Innate immune response was measured by stimulated oxidative burst of polymorphonuclear cells (neutrophils) isolated from blood. Ovalbumin (OVA) was administered with adjuvant on d 7 and 21 RTC, and adaptive immune response was evaluated by serum anti-OVA IgG content on d 28 and 35. Mixed models were used to assess effects of treatment, time, parity, and all interactions. We previously reported that SCFP had limited effects on productivity in this cohort, although milk fat yield was transiently increased and subclinical ketosis incidence was increased. Supplementation with SCFP did not affect overall oxidative, inflammatory, or immune parameters. The only treatment × week interaction detected was for plasma α-tocopherol concentration, which tended to be greater in control cows during wk 2 RTC. A tendency for a treatment × parity interaction was detected for serum anti-OVA IgG titer, which tended to be greater for SCFP than for controls among primiparous cows. Plasma inflammatory biomarkers were not affected by SCFP but, unexpectedly, plasma HP was elevated at both prepartum time points and plasma SAA was elevated during wk -2 RTC compared with the expected increases in both biomarkers postpartum. In this cohort of transition cows with low disease incidence, SCFP generally did not affect oxidative, inflammatory, or immune parameters.

Objective: The aim of the study was to evaluate the effects of supplementing a Saccharomyces cerevisiae fermentation product (SCFP, NutriTek, Diamond V) on the prevention and control of digital dermatitis (DD) in lactating dairy cows.Materials and Methods: A blinded randomized, controlled field study on a commercial robot-milking farm was performed for 5 mo using the first 2.5 mo for the base phase and the last 2.5 mo for the test phase. A total of 968 lactating cows were enrolled in the trial distributed over 4 pens. The SCFP and control supplements were fed in their respective partial mixed ration. GoPro (https:// gopro.com) images of the cows' hind feet in the milking robots were scored to identify the presence of DD using an M-stage DD classification system.Results and Discussion: Pen-level analysis revealed no statistically significant differences in M-stage groups between the control and SCFP group during the base and test phases of the study. Cow level analysis indicated that the relative risk for having M2M2P lesions (ulcerated/active) versus having M0M4H lesions (healthy/contained) in the control group during the test phase was 1.8 times greater compared with the SCFP group. The transition from M0M4H to M2M2P lesions occurred more rapidly in the control group compared with the SCFP group.Implications and Applications: The supplementation of SCFP warrants further research as a potential DD prevention and control strategy in dairy cattle.

Subacute ruminal acidosis (SARA) is a metabolic disorder in dairy cows that is associated with dysbiosis of rumen and hindgut microbiomes, translocation of immunogenic compounds from the gut lumen into blood circulation, and systemic inflammatory response. In this study we hypothesized that Saccharomyces cerevisiae fermentation products (SCFP) attenuate the increases in ruminal and peripheral bacterial endotoxin concentrations and the inflammation resulting from repeated induction of SARA. Lactating Holstein dairy cows (parity 2 and 3+, n = 32) were fed diets with or without SCFP (all from Diamond V) and subjected to 2 episodes of SARA challenges. Cows received a basal total mixed ration (TMR) containing 34% neutral detergent fiber and 18.6% starch, dry matter (DM) basis. Treatments were randomly assigned to control (basal TMR and 140 g/d of ground corn with no SCFP) or 1 of 3 SCFP treatments: basal TMR and 14 g/d Original XPC (SCFPa), 19 g/d NutriTek (SCFPb-1×), or 38 g/d NutriTek (SCFPb-2×) mixed with 126, 121, or 102 g/d of ground corn, respectively. Treatments were implemented from 4 wk before until 12 wk after parturition. During wk 5 (SARA1) and wk 8 of lactation (SARA2), grain-based SARA challenges were conducted by gradually replacing 20% of DM of the basal TMR over 3 d with pellets containing 50% wheat and 50% barley. Ruminal fluid, fecal, and blood samples were collected weekly during Pre-SARA1 (wk 4, as baseline), Post-SARA1 (wk 7), and Post-SARA2 (wk 10 for blood and wk 12 for rumen and fecal parameters) stages, and twice a week during the challenges SARA1 and SARA2. Rumen papillae samples were taken only during Pre-SARA1 and Post-SARA2. We measured the concentrations of free lipopolysaccharides (LPS) in the rumen fluid and feces; free LPS and lipoteichoic acid (LTA) endotoxins in peripheral plasma; interleukin (IL)-1β and IL-6 in peripheral serum; acute-phase proteins, serum amyloid A (SAA), and LPS-binding protein in peripheral plasma; haptoglobin (Hp) in peripheral serum; and myeloperoxidase (MPO) in rumen papillae. Induction of SARA episodes increased free LPS concentrations in rumen fluid and tended to increase LTA in peripheral plasma. The SARA episodes increased concentration of circulating SAA and tended to increase that of IL-1β compared with Pre-SARA1. Induction of SARA did not affect the concentrations of circulating IL-6, Hp, and MPO. The SCFP supplementation reduced plasma concentrations of LTA and SAA and serum concentration of IL-1β compared with control. Additionally, SCFPb-2× tended to reduce ruminal LPS in second-parity cows compared with control. Overall, SCFP supplementation appeared to stabilize the rumen environment and reduce proinflammatory status, hence attenuating adverse digestive and inflammatory responses associated with SARA episodes.

Background We aimed to characterize the protective effects and the molecular mechanisms of action of a Saccharomyces cerevisiae fermentation product (NTK) in response to a mastitis challenge. Eighteen mid-lactation multiparous Holstein cows ( n = 9/group) were fed the control diet (CON) or CON supplemented with 19 g/d NTK for 45 d (phase 1, P1) and then infected in the right rear quarter with 2500 CFU of Streptococcus uberis (phase 2, P2). After 36-h, mammary gland and liver biopsies were collected and antibiotic treatment started until the end of P2 (9 d post challenge). Cows were then followed until day 75 (phase 3, P3). Milk yield (MY) and dry matter intake (DMI) were recorded daily. Milk samples for somatic cell score were collected, and rectal and udder temperature, heart and respiration rate were recorded during the challenge period (P2) together with blood samples for metabolite and immune function analyses. Data were analyzed by phase using the PROC MIXED procedure in SAS. Biopsies were used for transcriptomic analysis via RNA-sequencing, followed by pathway analysis. Results DMI and MY were not affected by diet in P1, but an interaction with time was recorded in P2 indicating a better recovery from the challenge in NTK compared with CON. NTK reduced rectal temperature, somatic cell score, and temperature of the infected quarter during the challenge. Transcriptome data supported these findings, as NTK supplementation upregulated mammary genes related to immune cell antibacterial function (e.g., CATHL4 , NOS2 ), epithelial tissue protection (e.g. IL17C ), and anti-inflammatory activity (e.g., ATF3 , BAG3 , IER3 , G-CSF , GRO1 , ZFAND2A ). Pathway analysis indicated upregulation of tumor necrosis factor α, heat shock protein response, and p21 related pathways in the response to mastitis in NTK cows. Other pathways for detoxification and cytoprotection functions along with the tight junction pathway were also upregulated in NTK-fed cows. Conclusions Overall, results highlighted molecular networks involved in the protective effect of NTK prophylactic supplementation on udder health during a subclinical mastitic event.

Effects of Saccharomyces cerevisiae fermentation products (SCFP) and subacute ruminal acidosis (SARA) on rumen and hindgut fermentation, feed intake, and total tract nutrient digestibilities were determined in 32 lactating Holstein cows between weeks 4 and 9 of lactation. Treatments included control, 14 g·d−1 Diamond V Original XPC™ (SCFPa; Diamond V, Cedar Rapids, IA, USA), 19 g·d−1 NutriTek® (SCFPb-1X; Diamond V), and 38 g·d−1 NutriTek® (SCFPb-2X; Diamond V). During weeks 5 and 8, SARA challenges were conducted by switching from a 18.6% to a 27.9% dry matter (DM) starch diet. This reduced the rumen and feces pH. The durations of the rumen pH below 5.6 during these challenges averaged 175.0, 233.8, 246.9, and 79.3 min·d−1 for the control, SCFPa, SCFPb-1X, and SCFPb-2X treatments, respectively. Hence, SARA was not induced under the SCFPb-2X treatment. The feces pH during the SARA challenges was lowest during SCFPb-2X, suggesting this treatment shifted fermentation from the rumen to the hindgut. The SARA challenges reduced the total tract digestibility of DM, neutral detergent fiber digestibility (NDFd), and phosphorus, but tended to increase that of starch. The SCFPb-2X treatment increased the NDFd from 52.7% to 61.8% (P < 0.05). The SCFPb-2X treatment attenuated impacts of SARA.

The objective of this study was to evaluate the effects of supplementing a Saccharomyces cerevisiae fermentation product (SCFP) on body temperature indices, metabolism, acute phase protein response, and production variables during heat stress (HS). Twenty multiparous lactating Holstein cows (body weight = 675 ± 12 kg; days in milk = 144 ± 5; and parity = 2.3 ± 0.1) were used in an experiment conducted in 2 replicates (10 cows/replicate). Cows were randomly assigned to 1 of 2 dietary treatments: control diet (CON; n = 10) or the CON diet supplemented with 19 g/d of SCFP (n = 10; NutriTek, Diamond V, Cedar Rapids, IA). Cows were fed their respective diets for 21 d before initiation of the study. The experiment consisted of 2 periods: thermoneutral (period 1; P1) and heat stress (period 2; P2). During P1 (4 d), cows were fed ad libitum and housed in thermoneutral conditions for collecting baseline data. During P2 (7 d), HS was artificially induced using an electric heat blanket (EHB; Thermotex Therapy Systems Ltd., Calgary, AB, Canada). Cows were fitted with the EHB for the entirety of P2. Rectal temperature, respiration rate, and skin temperature were obtained twice daily (0600 and 1800 h) during both periods. Overall, HS increased rectal temperature, skin temperature, and respiration rate (1.4°C, 4.8°C, and 54 breaths/min, respectively) relative to P1, but no dietary treatment differences were detected. Compared with P1, HS decreased dry matter intake and milk yield (36 and 26%, respectively), and the reductions were similar between dietary treatments. Relative to P1, HS increased milk fat content and milk urea nitrogen (17 and 30%, respectively) and decreased milk protein and lactose contents (7 and 1.4%, respectively). Overall, HS increased (52%) plasma cortisol concentrations of CON, but circulating cortisol did not change in SCFP-fed cows. Heat stress increased circulating lipopolysaccharide binding protein and serum amyloid A (SAA; 2- and 4-fold, respectively), and SCFP supplementation tended to decrease peak SAA (∼33%) relative to CON cows. Overall, although HS did not influence circulating white blood cells and neutrophils, SCFP increased circulating white blood cells and neutrophils by 9 and 26%, respectively, over CON in P2. In conclusion, HS initiated an acute phase protein response and feeding SCFP blunted the cortisol and SAA concentrations and altered some key leukocyte dynamics during HS.

On page 9637, the final sentence of the Results should read (correction shown in bold): “There was a treatment × period interaction on circulating platelets, as they remained unchanged in CON cows but decreased in SCFP-fed cows during P2 (31%; P = 0.05; Table 5).” Effects of a Saccharomyces cerevisiae fermentation product on heat-stressed dairy cowsJournal of Dairy ScienceVol. 103Issue 10PreviewThe objective of this study was to evaluate the effects of supplementing a Saccharomyces cerevisiae fermentation product (SCFP) on body temperature indices, metabolism, acute phase protein response, and production variables during heat stress (HS). Twenty multiparous lactating Holstein cows (body weight = 675 ± 12 kg; days in milk = 144 ± 5; and parity = 2.3 ± 0.1) were used in an experiment conducted in 2 replicates (10 cows/replicate). Cows were randomly assigned to 1 of 2 dietary treatments: control diet (CON; n = 10) or the CON diet supplemented with 19 g/d of SCFP (n = 10; NutriTek, Diamond V, Cedar Rapids, IA). Full-Text PDF Open Access

The objective of this study was to evaluate the effects of supplementing a Saccharomyces cerevisiae fermentation product (SCFP; NutriTek, Diamond V, Cedar Rapids, IA) during the periparturient period (d -28 ± 3 to 44 ± 3 relative to calving) on mRNA abundance of genes in the rumen epithelium, inflammation indicators, oxidative status, and adaptive immunity of dairy cows fed diets with different starch content after calving. From d 28 ± 3 (± standard deviation) before the expected calving date to calving, Holstein cows (n = 38) received a common basal controlled-energy close-up diet (1.43 Mcal/kg, net energy for lactation; 13.8% starch) with (SCFP; n = 19) or without (CON; n = 19) SCFP, and cows within each treatment (CON or SCFP) were fed either a low- (LS; 22.1% starch) or high-starch (HS; 28.3% starch) diet from d 1 to 23 ± 3 after calving (fresh period). There were 4 treatment groups: LS + CON (n = 9), LS + SCFP (n = 10), HS + CON (n = 10), and HS + SCFP (n = 9). From d 24 ± 3 to 44 ± 3 after calving, all cows were fed the HS diets (post-fresh period). Animal assignment to treatments was balanced for parity, body condition score, and expected calving date. An interaction was observed between dietary starch content and SCFP on indices of oxidative stress; plasma concentrations of total antioxidant capacity tended to be reduced on d 21 after calving for SCFP compared with CON cows when a LS fresh diet was fed, but did not differ for cows fed HS fresh diets. Regardless of starch content, SCFP supplementation increased plasma concentrations of malondialdehyde at d 21 after calving compared with CON. Supplementing with SCFP reduced serum concentrations of haptoglobin on d 7 after calving, indicating reduced inflammation, and feeding LS fresh diets reduced mRNA abundance of IL receptor associated kinase-1 in rumen tissue at d 21 after calving, suggesting reduced immune activation in rumen tissue. Other than the anti-inflammatory effects indicated by lower serum haptoglobin concentration, no other effects of treatment on adaptive immunity were detectable. These results indicate that supplementing SCFP through the transition period and feeding low-starch diets during the fresh period may reduce inflammation.

The purpose of this study was to evaluate the effects of Saccharomyces cerevisiae fermentation product (SCFP) supplementation and to compare to common in-feed antibiotics on growth performance and carcass traits of finishing beef steers. Seventy-five Angus steers were blocked by body weight (BW) then randomly assigned within block to 1 of 5 treatments (15 head/treatment) for a 112-d feeding period. The treatments were: (1) CON (without supplementation); (2) ANT (antibiotics; 330 mg monensin + 110 mg tylosin/d); (3) LOW (12 g); (4) MED (15 g); and (5) HIGH (18 g SCFP/d). Steers were fed ad libitum a diet containing 10% barley silage and 90% barley concentrate (dry matter [DM] basis). Intake of DM, final BW and average daily gain (ADG) did not differ among treatments, whereas, feed efficiency tended to linearly improve with increasing SCFP doses. Proportion of severely abscessed livers tended to be lower with LOW or HIGH SCFP and ANT than CON. These results suggest that feeding SCFP to feedlot cattle may potentially improve feed efficiency and liver health.

The objective of this study was to determine the effects Saccharomyces cerevisiae fermentation product (SCFP, NaturSafe®, DiamondV) on ruminal fermentation and site and extent of feed digestion in beef heifers. Five ruminally and duodenally cannulated beef heifers (BW=561 ± 11.7 kg) were used in a 5 × 5 Latin square design with 28-d periods (21-d adaption and 7-d data collection). Five treatments were: 1) control diet (10% barley silage and 90% barley concentrate, DM basis); 2) control diet supplemented with antibiotics (ANT; 330 mg/d monensin and 110 mg/d tylosin); 3) ruminal (top dress) delivery of SCFP (rSCFP; 18 g/d SCFP); 4) duodenal delivery of SCFP (dSCFP; 18 g/d SCFP); and 5) combination of rSCFP and dSCFP (rdSCFP; 18 g/d rSCFP and 18 g/d dSCFP). Data were analysed using MIXED procedure of SAS with model including fixed effect of treatment and random effects of heifer and period. Intake of DM tended (P<0.10) to be greater with rdSCFP than control (13.0 vs. 12.2 kg/d). Heifers fed rSCFP vs. control diet showed greater (P<0.05) minimum ruminal pH (5.30 vs. 5.02), shorter (P<0.10) duration of ruminal pH (5.6 vs. 11.6 h/d) and greater (P<0.10) acetate proportion (51.8% vs. 47.2%). Truly fermented OM was greater (P<0.03) with rdSCFP (7.2 kg/d) than other treatments (5.9 kg/d). Treatment with rSCFP and rdSCFP vs. control showed greater(P<0.05) ruminal digestibility of OM (63.8 vs. 53.1%) and NDF (52.7 vs. 41.3%). Total tract digestibility of OM (P<0.07) and NDF (P<0.01) was greater with rSCFP (80.7 and 67.7%) and rdSCFP (81.7 and 66.1%) than control (77.2 and 56.2%) and ANT (77.4 and 55.1%). These results demonstrate that supplementation of SCFP improved ruminal pH status and ruminal digestibility of OM and NDF, with limited effects on nutrient digestibility in the intestine and suggest the SCFP could serve as natural alternative for antibiotics for beef cattle.

Subacute ruminal acidosis caused by high-grain feeding can cause dysbiosis of the rumen microbiome, which is associated with the pathogenesis of the rumen disorders. Saccharomyces cerevisiae fermentation products (SCFP) have been widely used as rumen fermentation modifiers to stabilize the rumen conditions. The objective of this study was to investigate if SCFP can attenuate the impact of SARA on microbial communities in the rumen. Thirty two Holstein lactating dairy cows were assigned into four treatment groups (n=8/trt) that received a base TMR (34.9 DM NDF, 18.6 % DM starch) supplemented daily with 1) 140 g of ground corn (Control), 2) 14 g Diamond V Original XPCTM mixed in 126 g of ground corn (XPC), 3) 19 g Diamond V NutriTek® mixed in 121 g of ground corn (NTL), and 4) 38 g Diamond V NutriTek® mixed in 102 g of ground corn (NTH) in a randomized complete block design. The experiment lasted from 4 weeks before until 12 weeks after calving. The SARA challenges were conducted on week 5 (SARA1) and 8 (SARA2) after calving by replacing 20% of the base TMR with pellets containing 50% barley and 50% wheat. Rumen liquid and solid samples were collected weekly. DNA was extracted from each sample and subjected to Illumina sequencing of V1–V2 regions of 16S rRNA gene and analyzed by QIIME2. Differential abundance analysis with gneiss was used to analyze the microbial composition. Alpha- and beta-diversities were analyzed using MIXED procedure of SAS and PERMANOVA, respectively. Both SARA challenges decreased (P < 0.05) richness and evenness of rumen liquid and solid microbial communities in the control, XPC and NTL groups. NTH treatment however prevented these reductions in the rumen liquid microbiota during SARA challenges. Supplementation with NTH was able to prevent rumen microbiota from losing their diversity during the SARA challenges.

The transition period in dairy cattle is characterized by many stressors, including an abrupt diet change, but yeast product supplementation can alter the rumen environment to increase dairy cattle productivity. Saccharomyces cerevisiae fermentation product (SCFP) was fed from -29 ± 5 to 42 d relative to calving (RTC) to evaluate the effects on feed intake, milk production, and metabolism. Treatments were control (n = 30) or SCFP (n = 34) incorporated into a total mixed ration. Cows were individually fed 3×/d prepartum and 2×/d postpartum. Blood samples were collected once during each of the following time points RTC: d -28 to -24 (wk -4), d -14 to -10 (wk -2), d 3 to 7 (wk 1), d 12 to 16 (wk 2), and d 31 to 35 (wk 5). Liver biopsies were taken once between d -19 and d -12 (wk -3) and at 14 d in milk. Cows were milked 2×/d, and samples were taken 2 d/wk for composition analysis. Dry matter intake did not differ by treatment, but SCFP increased meals per day and decreased time between meals. Body weight (measured at enrollment, d 0, and d 42 RTC) and body condition score (scored weekly) were not affected by treatment. Milk, energy-corrected milk, and fat-corrected milk yields did not differ by treatment. Milk fat concentration was greater for SCFP, with significant differences in wk 4 and 5. Milk lactose concentration tended to be greater for the control and milk urea nitrogen tended to be lesser for the control, but there were no treatment effects on milk protein concentration or somatic cell count. Assuming equal digestibility, energy balance deficit was greater for SCFP than for the control (-6.15 vs. -4.34 ± 0.74 Mcal/d), with significant differences in wk 4 and 5. Plasma concentrations of free fatty acids, β-hydroxybutyrate, glucose, and insulin did not differ with treatment, but cholesterol was greater for SCFP. Liver triglyceride increased and liver cholesterol decreased with time. Liver triglyceride did not differ by treatment, but liver cholesterol tended to be lesser in SCFP. Relative mRNA abundance of cholesterol-related genes (SREBF2, HMGCS1, HMGCR, MTTP, SPOB100, APOA1), FGF21, and CPT1A did not differ by treatment, but PCK1 tended to be greater for SCFP. The ketogenic transcript HMGCS2 was greater for SCFP, which aligns with SCFP increasing incidence of subclinical ketosis; however, BDH did not differ between treatments. In conclusion, SCFP supplementation increased meals per day with less time between meals, increased milk fat concentration, altered cholesterol metabolism, and increased incidence of subclinical ketosis, but early-lactation milk yield and metabolism were generally unaffected.