27Th Western Nutrition Conference Winnipeg Manitoba Canada 19 20 September 2006, 2006
Milk yields of North American dairy cows have increased substantially during recent years. This h... more Milk yields of North American dairy cows have increased substantially during recent years. This has created challenges, because, in order to meet the increased potential for milk production, dairy diets have to contain more grain and less forage. Feeding these high concentrate diets can result in high concentrations of organic acids in the rumen and a reduction in chewing, saliva production and rumen buffering (Kleen et al., 2003; Stone, 2004). This can lead to an increase in rumen acidity and a drop in rumen pH. When rumen pH is reduced for prolonged periods each day, subacute ruminal acidosis (SARA) can occur (Kleen et al, 2003; Stone, 2004). This metabolic disease affects rumen fermentation and digestion, but also impacts many other aspects of production and health of dairy cows.
Antimicrobial dry cow therapy (DCT) is an important component of mastitis control programs aimed ... more Antimicrobial dry cow therapy (DCT) is an important component of mastitis control programs aimed to eliminate existing intramammary infections and prevent the development of new ones during the dry period. However, to what extent the microbiota profiles of different niches of the udder change during the dry period and following administration of DCT remains poorly understood. Therefore, the main objective of the present study was to qualitatively evaluate dynamics of the microbiota of teat canal (TC) and mammary secretions (i.e., milk and colostrum) of healthy udder quarters subjected to DCT using a long-acting antimicrobial product, containing penicillin G and novobiocin, in combination with internal teat sealant. To this end, TC swabs (n = 58) and their corresponding milk (n = 29) and colostrum samples (n = 29) were collected at the time of drying off and immediately after calving from clinically healthy udder quarters of Holstein dairy cows from a commercial dairy farm. All samples were subjected to DNA extraction and high-throughput sequencing of the V1-V2 hypervariable regions of bacterial 16S rRNA genes. Overall, shifts were more pronounced within the microbiota of mammary secretions than the TC. In particular, microbiota of colostrum samples collected immediately after calving were less species-rich compared with the pre-DCT milk samples. Proportions of several bacterial genera belonging to the phylum Proteobacteria, including Pseudomonas, Stenotrophomonas, and unclassified Alcaligenaceae, were enriched within the microbiota of colostrum samples, whereas Firmicutes genera, including Butyrivibrio, unclassified Clostridiaceae, and unclassified Bacillales, were overrepresented in pre-DCT milk microbiota. Apart from shifts in the proportion of main bacterial genera and phyla, qualitative analysis revealed a high degree of commonality between pre-DCT and postpartum microbiota of both niches of the udder. Most importantly, a considerable number of bacterial genera and species commonly regarded as mastitis pathogens or opportunists (or both), including Staphylococcus spp., unclassified Enterobacteriaceae, and Corynebacterium spp., were shared between pre-DCT and postpartum microbiota of mammary secretions. Percentage of shared bacterial genera and species was even higher between pre-DCT and postpartum microbiota of TC samples, suggesting that the DCT approach of the present study had limited success in eliminating a considerable proportion of bacteria during the dry period.
Background: The aim of this study was to determine the ability of two feed additives, a fumarate-... more Background: The aim of this study was to determine the ability of two feed additives, a fumarate-malate (FM) and a polyphenol-essential oil mixture (PM), in attenuating the drop of ruminal pH and the metabolic and immune response resulting from an excessively high grain diet. Six heifers were used in a 3 × 3 Latin square experiment and fed a low starch (LS) diet for 14 d, followed by a high starch (HS) diet for 8 d (NDF 33.6%, starch 30.0% DM). In the last 5 days of each period, barley meal was added to decrease rumen pH. During HS feeding all animals were randomly assigned to one of the following three dietary treatments: no supplement/control (CT), a daily dose of 60 g/d of FM, or 100 g/d of PM. Reticular pH was continuously recorded using wireless boluses. On d 21 of each period, rumen fluid was collected by rumenocentesis (1400 h), together with blood (0800 h) and fecal samples (0800, 1400, and 2100 h). Results: The correlation coefficient of pH values obtained using the boluses and rumenocentesis was 0.83. Compared with CT and PM, the FM treatment led to a lower DMI. Nadir pH was lowest during CT (5.40, 5.69, and 5.62 for CT, FM and PM, respectively), confirming the effectiveness of both supplements in reducing the pH drop caused by high grain feeding. This result was confirmed by the highest average time spent daily below 5.6 pH (199, 16 and 18 min/d) and by the highest acetate to propionate ratio of the CT fed heifers. The PM decreased the concentrations of neutrophils (2.9, 3.2, and 2.8 10 9 /L) and acute phase proteins: SAA (37.1, 28.6 and 20.1 μg/mL), LBP (4.1, 3.8, and 2.9 μg/mL), and Hp (675, 695 and 601 μg/mL). Free lipopolysaccharides (LPS) were detected in blood and feces, but their concentrations were not affected by treatments, as the remaining blood variables. Conclusions: Data suggest that both additives could be useful in attenuating the effects of excessive grain feeding on rumen pH, but the PM supplement was more effective than FM in reducing the inflammatory response compared to CT.
The effects of a grain-based subacute ruminal acidosis (SARA) challenge (GBSC) and an alfalfa-pel... more The effects of a grain-based subacute ruminal acidosis (SARA) challenge (GBSC) and an alfalfa-pellet SARA challenge (APSC) on fermentation and endotoxins in the rumen and in the cecum, as well as on endotoxins in peripheral blood, were determined. Six nonlactating Holstein cows with cannulas in the rumen and cecum were used in the study. A 3 × 3 Latin square arrangement of treatments with 4-wk experimental periods was adopted. During the first 3 wk of each experimental period, all cows received a diet containing 70% forages [dry matter (DM) basis]. In wk 4 of each period, cows received 1 of the following 3 diets: the 70% forage diet fed during wk 1 to 3 (control), a diet in which 34% of the dietary DM was replaced with grain pellets made of 50% ground wheat and 50% ground barely (GBSC), or a diet in which 37% of dietary DM was replaced with pellets of ground alfalfa (APSC). Rumen pH was monitored continuously using indwelling pH probes, and rumen fluid, blood, cecal digesta, and fecal grab samples were collected immediately before feed delivery at 0900 h and at 6 h after feed delivery on d 3 and 5 of wk 4. The time for which rumen pH was below 5.6 was 56.4, 225.2, and 298.8 min/d for the control, APSC, and GBSC treatments, respectively. Compared with the control, SARA challenges resulted in similar reductions in cecal digesta pH, which were 7.07, 6.86, and 6.79 for the control, APSC, and GBSC treatments, respectively. Compared with the control, only GBSC increased starch content in cecal digesta, which averaged 2.8, 2.6, and 7.4% of DM for the control, APSC, and GBSC, respectively. Free lipopolysaccharide endotoxin (LPS) concentration in rumen fluid increased from 10,405 endotoxin units (EU)/mL in the control treatment to 30,715 and 168,391 EU/mL in APSC and GBSC, respectively. Additionally, GBSC increased the LPS concentration from 16,508 to 118,522 EU/g in wet cecal digesta, and from 12,832 to 93,154 EU/g in wet feces. The APSC treatment did not affect LPS concentrations in cecal digesta and feces. All concentrations of LPS in blood plasma were below the detection limit of >0.05 EU/mL of the technique used. Despite the absence of LPS in blood, only GBSC increased the concentration of LPS-binding protein in blood plasma, which averaged, 8.9, 9.5, and 12.1 mg/L for the control, APSC, and GBSC treatments, respectively. This suggests that GBSC caused translocation of LPS from the digestive tract but that LPS was detoxified before entering the peripheral blood circulation. The higher LPS concentration in cecal digesta in the GBSC compared with the APSC suggests a higher risk of LPS translocation in the large intestine in GBSC than in APSC.
A survey was conducted on 40 randomly selected dairy farms across Manitoba to document nutritiona... more A survey was conducted on 40 randomly selected dairy farms across Manitoba to document nutritional practices and diet compositions, and study relationships between diet composition and milk production. Samples from all feeds, diets, and the bulk milk tank were collected and analyzed. Inclusion rates of feed ingredients were recorded. Production data were obtained from Western Canada Dairy Herd Improvement Services (WCDHIS). Component feeding and total mixed ration (TMR) feeding were used in 37.5 and 62.5% of herds, respectively. Only 24% of TMR-fed herds used two or more TMR. The medians of dietary contents of crude protein (CP), rumen degradable protein (RDP), rumen undegradable protein (RUP), and neutral detergent fibre (NDF), and milk urea nitrogen (MUN) were 18.3% dry matter (DM), 12.2% DM, 5.7% DM, 34.8% DM, and 15.6 mg dL-1, respectively. On average, diets contained 6.2% more net energy for lactation (NEl), 35.9% more RDP, 15.8% less RUP, 74.6% more calcium (Ca), 51.9% more ph...
Figure S1. PCR-RFLP Identification of BoLA-DRB3.2 variants. Figure S2. Beta-diversity of the bact... more Figure S1. PCR-RFLP Identification of BoLA-DRB3.2 variants. Figure S2. Beta-diversity of the bacterial communities of intramammary secretions during the first week of lactation. Figure S3. Beta-diversity of the fungal communities of intramammary secretions during the first week of lactation. Figure S4. Association of lactation stage and BoLA-DRB3.2 polymorphism with interrelationship patterns and hub species of intramammary bacterial communities. Figure S5. Bacterial co-occurrence and co-exclusion networks. Figure S6. Unsupervised cluster analysis of day 0 colostrum samples based on the distribution of fungal OTUs. Figure S7. Unsupervised cluster analysis of day 1 colostrum samples based on the distribution of fungal OTUs. Figure S8. Rarefaction curves of richness (Observed-OTUs and Chao1) and diversity (Shannon) indices for bacterial (a-c) and fungal (d-f) communities. (PDF 6512Â kb)
Milk yields of North American dairy cows have increased substantially during recent years. This h... more Milk yields of North American dairy cows have increased substantially during recent years. This has created challenges, because, in order to meet the increased potential for milk production, dairy diets have to contain more grain and less forage. Feeding these high concentrate diets can result in high concentrations of organic acids in the rumen and a reduction in chewing, saliva production and rumen buffering (Kleen et al., 2003; Stone, 2004). This can lead to an increase in rumen acidity and a drop in rumen pH. When rumen pH is reduced for prolonged periods each day, subacute ruminal acidosis (SARA) can occur (Kleen et al, 2003; Stone, 2004). This metabolic disease affects rumen fermentation and digestion, but also impacts many other aspects of production and health of dairy cows.
Six non-lactating Holstein dairy cows received diets with forage to grain mixture ratios of 100:0... more Six non-lactating Holstein dairy cows received diets with forage to grain mixture ratios of 100:0 (G0), 75:25 (G25), and 50:50 (G50) that contained 0.5%, 10.0%, and 19.5% dry matter (DM) of starch, respectively. Rumen fluid and feces were sampled, and methane emissions were determined during the last week of 5 wk experimental periods. Taxonomic compositions of microbiota were determined using Illumina 16S rRNA sequencing. Increased grain feeding increased the acidity and volatile fatty acid concentrations of rumen fluid and feces, and decreased methane emissions expressed as L·kg−1 DM. Microbial diversities were highest for G25. The numbers of identified genera in rumen fluid were 185, 182, and 171 for G0, G25, and G50, respectively. In feces, these numbers were 197, 182, and 171 for these diets, respectively. In rumen digesta, seven genera were correlated positively to G0 and negatively to G50, and six genera were correlated negatively to G0 and positively to G50. In feces, 16 gene...
ABSTRACT Abstract Text: A survey was conducted on 10 dairy farms in Manitoba to quantify factors ... more ABSTRACT Abstract Text: A survey was conducted on 10 dairy farms in Manitoba to quantify factors that affect the utilization of phosphorus (P) by lactating cows. Farms were visited once to collect samples and data, including days in milk (DIM), milk yields (MY), parities (PAR), body condition scores (BCS), and body weights from 30 Holstein cows in different stages of lactation. Feeds were analyzed for crude protein (CP), fat (FAT), ash (ASH), NDF, starch (STARCH), P (DIETP) and acid insoluble ash (AIA). Feces were collected from the rectum and analyzed for P (FECALP) and AIA. Composite milk samples were analyzed for fat (MFAT), protein (MPROT), and P (MILKP). The apparent digestibilities of P (ADCP) of cows were determined using AIA as a marker. Dry matter intake was estimated using the equation of NRC(2001). The P utilization efficiencies (PEFF) of cows were determined as the ratio between the output of P in milk and the P intake. Descriptive statistics (Table 1) show the considerable variation of parameters among cows. Examination of dietary and fecal P concentrations and measures of P utilization suggested that approximately half of the cows received more P than required. Linear regression models were developed between dependent variables (FECALP, PEFF, ADCP) and independent diet and cow variables. Independent variables with a significance level greater than 0.25 were stepwise removed. Regression models were: ADCP = -152.9+1.00*PAR-2.06*MFAT+2.22*CP+3.63*FAT+1.18*ASH+2.52*NDF+114.06*DIETP (R2=0.39) PEFF = 45.91-0.45*PAR-0.04*DIM+0.34*MY–2.64*MFAT+313.80*PMILK-82.37*DIETP (R2=0.79) FECALP = 1.21+0.0005*DIM+0.03*CP-0.10*FAT+0.06*ASH-0.01*STARCH-0.04*NDF (R2 =0.25) Correlations among independent variables, including PDIET and other dietary variables, complicated assessing relationships between variables. The models show the complexity of factors that determine the efficiency of P for milk production, and generally suggest that this efficiency decreases in later stages of lactation when and milk yield decreases and diets are formulated accordingly. Table 1. Descriptive statistics Average SD Min. 25’th perc. 50’th perc. 75’th perc. Max. PAR 2.37 1.41 1 1 2 3 8 DIM 170 97 15 74 166 259 464 Milk yield, kg/d 35.6 9.0 9.5 28.7 34.4 41.3 65.1 Milk P, % 0.09 0.07 0.07 0.09 0.09 0.10 0.11 Milk P eff., % 34.6 8.3 16.1 28.3 33.3 39.5 61.4 CP, %DM 16.9 0.9 15.1 16.4 16.8 17.6 18.3 NDF, %DM 34.1 3.6 29.7 30.7 33.8 35.8 41.0 P, %DM 0.41 0.04 0.34 0.37 0.41 0.45 0.47 Feces P, %DM 0.70 0.19 0.30 0.55 0.69 0.83 1.28 ADC P, % 35.1 13.2 15.9 24.0 31.7 48.1 59.7 Keywords: phosphorus, effeciency, dairy
Ruminal acidosis is a common disease in high yielding dairy cows, during which the rumen pH is de... more Ruminal acidosis is a common disease in high yielding dairy cows, during which the rumen pH is depressed for several hours per day. There is no general agreement of the definition of the disease, and its diagnosis based on rumen pH measurement is invasive and inaccurate. As a result, the disease often goes unnoticed, and its impact is not well recognized. Surveys suggest a prevalence of between 19 and 26% in early and mid-lactation dairy cows in North America. Many symptoms have been attributed to subacute rumen acidosis (SARA), including feed intake depression, milk fat depression, reduced fiber digestion, inflammation of the rumen, systemic inflammation, dehydration, diarrhea, laminitis, liver abscesses, and increases in the concentrations of bacterial toxins in digesta throughout the digestive tract. These symptoms are not always obvious. The mechanisms of how, and even if, the rumen pH depression causes these symptoms are not always well understood. Cows may very in their suscep...
Effects of Saccharomyces cerevisiae fermentation products (SCFP) and subacute ruminal acidosis (S... more 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 accuracy of the milk fatty acid profile as a diagnostic tool for the diagnosis of sub-acute r... more The accuracy of the milk fatty acid profile as a diagnostic tool for the diagnosis of sub-acute ruminal acidosis (SARA) has been determined when SARA was experimentally induced. This had not yet been done not on commercial dairy farms, where SARA can occur naturally. The objective of this study was to determine this accuracy in individual cows on commercial dairy farms. A total of 336 cows from 24 commercial dairy farms in Quebec were included. Farms were blocked based on geographical location and management, with each block having one high risk SARA farm and one low risk SARA farm. Farm Risk of SARA was determined based on the milk fat content and the proportions of de novo fatty acids and long chain unsaturated fatty acids in the bulk tank. On each farm, 7 early/mid-lactation (< 150 days in milk DIM) and 7 mid/late lactation (< 150 DIM) cows were randomly selected. The fatty acid profile of pooled milk samples from these cows were determined by gas chromatography. Farm risk ...
Thirty-two dairy cows receiving a basal diet containing 34.9% NDF, and 18.6 % starch, were random... more Thirty-two dairy cows receiving a basal diet containing 34.9% NDF, and 18.6 % starch, were randomly assigned to four treatments: supplementation either with 140 g/d of ground corn (Control), 126 g/d of ground corn and 14 g/d of XPC (SCFPa, Diamond V Original XPC Cedar Rapids, IA), 121 g/d of ground corn and 19 g/d of NutriTek (SCFPb-1x, NutriTek, Diamond V), or 102 g/d of ground corn and 38 g/d of NutriTek (SCFPb-2x) from 4 wk before until 12 wk after calving. SARA was induced during wk 5 and wk 8 after calving by replacing 20% of the basal diet with pellets containing 50% barley and 50% wheat. Ruminal fluid samples were collected at 6 h after feeding on the second day of wk 4 to wk 10 after calving. Weeks 4, 7 and 10 were considered to be non-SARA. Microbial DNA was extracted, llumina sequenced at the V1–V2 regions of the 16S rRNA gene, and operational taxonomic units (OUT) were assigned using QIIME2. Correlation network analysis (CoNet) determined connections between the relative ...
In order to test the validity of milk amyloid A (MAA) as a biomarker for inflammation and subacut... more In order to test the validity of milk amyloid A (MAA) as a biomarker for inflammation and subacute ruminal acidosis (SARA), 320 milk samples from 24 commercial dairy farms in Quebec were tested for milk amyloid A using a commercial kit. These farms were divided into low risk of SARA farms and high risk of SARA farms according to the proportions of short chain and polyunsaturated fatty acids content in the bulk tank of the farms. It was assumed that farms at risk of SARA had a lower proportion of short chain and a higher proportion of polyunsaturated fatty acids compared to farms that were not at risk of SARA. Farms were also blocked in groups of two farms by geographical location and management. Each block included an at-risk and a not-at-risk farm. On each farm, 7 early- to mid-lactation and 7 mid- to late-lactation cows were randomly selected for MAA analysis. Cows with a somatic cell count (SCC) of over 200,000 in pooled milk samples were not included. Data were analyzed using SA...
Effects of the duration of moderate grain feeding on the taxonomic composition of gastrointestina... more Effects of the duration of moderate grain feeding on the taxonomic composition of gastrointestinal microbiota were determined in 15 Holstein yearling steers. Treatments included feeding a diet of 92% dry matter (DM) hay (D0), and feeding a 41.5% barley grain diet for 7 (D7) or 21 d (D21) before slaughter. At slaughter, digesta samples were collected from six regions, i.e., the rumen, jejunum, ileum, cecum, colon, and rectum. Extracted DNA from these samples was analyzed using MiSeq Illumina sequencing of the V4 region of the 16S rRNA gene. Three distinct PCoA clusters existed, i.e., the rumen, the jejunum/ileum, and the cecum/colon/rectum. Feeding the grain diet for 7 d reduced microbial diversity in all regions, except the ileum. Extending the duration of grain feeding from 7 to 21 d did not affect this diversity further. Across regions, treatment changed the relative abundances of 89 genera. Most of the changes between D0 and D7 and between D7 and D21 were opposite, demonstrating ...
Background Within complex microbial ecosystems, microbe-microbe interrelationships play crucial r... more Background Within complex microbial ecosystems, microbe-microbe interrelationships play crucial roles in determining functional properties such as metabolic potential, stability and colonization resistance. In dairy cows, microbes inhabiting different ecological niches of the udder may have the potential to interact with mastitis pathogens and therefore modulate susceptibility to intramammary infection. In the present study, we investigated the co-occurrence patterns of bacterial communities within and between different niches of the bovine mammary gland (teat canal vs. milk) in order to identify key bacterial taxa and evaluate their associations with udder health parameters and mastitis susceptibility. Results Overall, teat canal microbiota was more diverse, phylogenetically less dispersed, and compositionally distinct from milk microbiota. This, coupled with identification of a large number of bacterial taxa that were exclusive to the teat canal microbiota suggested that the intra...
27Th Western Nutrition Conference Winnipeg Manitoba Canada 19 20 September 2006, 2006
Milk yields of North American dairy cows have increased substantially during recent years. This h... more Milk yields of North American dairy cows have increased substantially during recent years. This has created challenges, because, in order to meet the increased potential for milk production, dairy diets have to contain more grain and less forage. Feeding these high concentrate diets can result in high concentrations of organic acids in the rumen and a reduction in chewing, saliva production and rumen buffering (Kleen et al., 2003; Stone, 2004). This can lead to an increase in rumen acidity and a drop in rumen pH. When rumen pH is reduced for prolonged periods each day, subacute ruminal acidosis (SARA) can occur (Kleen et al, 2003; Stone, 2004). This metabolic disease affects rumen fermentation and digestion, but also impacts many other aspects of production and health of dairy cows.
Antimicrobial dry cow therapy (DCT) is an important component of mastitis control programs aimed ... more Antimicrobial dry cow therapy (DCT) is an important component of mastitis control programs aimed to eliminate existing intramammary infections and prevent the development of new ones during the dry period. However, to what extent the microbiota profiles of different niches of the udder change during the dry period and following administration of DCT remains poorly understood. Therefore, the main objective of the present study was to qualitatively evaluate dynamics of the microbiota of teat canal (TC) and mammary secretions (i.e., milk and colostrum) of healthy udder quarters subjected to DCT using a long-acting antimicrobial product, containing penicillin G and novobiocin, in combination with internal teat sealant. To this end, TC swabs (n = 58) and their corresponding milk (n = 29) and colostrum samples (n = 29) were collected at the time of drying off and immediately after calving from clinically healthy udder quarters of Holstein dairy cows from a commercial dairy farm. All samples were subjected to DNA extraction and high-throughput sequencing of the V1-V2 hypervariable regions of bacterial 16S rRNA genes. Overall, shifts were more pronounced within the microbiota of mammary secretions than the TC. In particular, microbiota of colostrum samples collected immediately after calving were less species-rich compared with the pre-DCT milk samples. Proportions of several bacterial genera belonging to the phylum Proteobacteria, including Pseudomonas, Stenotrophomonas, and unclassified Alcaligenaceae, were enriched within the microbiota of colostrum samples, whereas Firmicutes genera, including Butyrivibrio, unclassified Clostridiaceae, and unclassified Bacillales, were overrepresented in pre-DCT milk microbiota. Apart from shifts in the proportion of main bacterial genera and phyla, qualitative analysis revealed a high degree of commonality between pre-DCT and postpartum microbiota of both niches of the udder. Most importantly, a considerable number of bacterial genera and species commonly regarded as mastitis pathogens or opportunists (or both), including Staphylococcus spp., unclassified Enterobacteriaceae, and Corynebacterium spp., were shared between pre-DCT and postpartum microbiota of mammary secretions. Percentage of shared bacterial genera and species was even higher between pre-DCT and postpartum microbiota of TC samples, suggesting that the DCT approach of the present study had limited success in eliminating a considerable proportion of bacteria during the dry period.
Background: The aim of this study was to determine the ability of two feed additives, a fumarate-... more Background: The aim of this study was to determine the ability of two feed additives, a fumarate-malate (FM) and a polyphenol-essential oil mixture (PM), in attenuating the drop of ruminal pH and the metabolic and immune response resulting from an excessively high grain diet. Six heifers were used in a 3 × 3 Latin square experiment and fed a low starch (LS) diet for 14 d, followed by a high starch (HS) diet for 8 d (NDF 33.6%, starch 30.0% DM). In the last 5 days of each period, barley meal was added to decrease rumen pH. During HS feeding all animals were randomly assigned to one of the following three dietary treatments: no supplement/control (CT), a daily dose of 60 g/d of FM, or 100 g/d of PM. Reticular pH was continuously recorded using wireless boluses. On d 21 of each period, rumen fluid was collected by rumenocentesis (1400 h), together with blood (0800 h) and fecal samples (0800, 1400, and 2100 h). Results: The correlation coefficient of pH values obtained using the boluses and rumenocentesis was 0.83. Compared with CT and PM, the FM treatment led to a lower DMI. Nadir pH was lowest during CT (5.40, 5.69, and 5.62 for CT, FM and PM, respectively), confirming the effectiveness of both supplements in reducing the pH drop caused by high grain feeding. This result was confirmed by the highest average time spent daily below 5.6 pH (199, 16 and 18 min/d) and by the highest acetate to propionate ratio of the CT fed heifers. The PM decreased the concentrations of neutrophils (2.9, 3.2, and 2.8 10 9 /L) and acute phase proteins: SAA (37.1, 28.6 and 20.1 μg/mL), LBP (4.1, 3.8, and 2.9 μg/mL), and Hp (675, 695 and 601 μg/mL). Free lipopolysaccharides (LPS) were detected in blood and feces, but their concentrations were not affected by treatments, as the remaining blood variables. Conclusions: Data suggest that both additives could be useful in attenuating the effects of excessive grain feeding on rumen pH, but the PM supplement was more effective than FM in reducing the inflammatory response compared to CT.
The effects of a grain-based subacute ruminal acidosis (SARA) challenge (GBSC) and an alfalfa-pel... more The effects of a grain-based subacute ruminal acidosis (SARA) challenge (GBSC) and an alfalfa-pellet SARA challenge (APSC) on fermentation and endotoxins in the rumen and in the cecum, as well as on endotoxins in peripheral blood, were determined. Six nonlactating Holstein cows with cannulas in the rumen and cecum were used in the study. A 3 × 3 Latin square arrangement of treatments with 4-wk experimental periods was adopted. During the first 3 wk of each experimental period, all cows received a diet containing 70% forages [dry matter (DM) basis]. In wk 4 of each period, cows received 1 of the following 3 diets: the 70% forage diet fed during wk 1 to 3 (control), a diet in which 34% of the dietary DM was replaced with grain pellets made of 50% ground wheat and 50% ground barely (GBSC), or a diet in which 37% of dietary DM was replaced with pellets of ground alfalfa (APSC). Rumen pH was monitored continuously using indwelling pH probes, and rumen fluid, blood, cecal digesta, and fecal grab samples were collected immediately before feed delivery at 0900 h and at 6 h after feed delivery on d 3 and 5 of wk 4. The time for which rumen pH was below 5.6 was 56.4, 225.2, and 298.8 min/d for the control, APSC, and GBSC treatments, respectively. Compared with the control, SARA challenges resulted in similar reductions in cecal digesta pH, which were 7.07, 6.86, and 6.79 for the control, APSC, and GBSC treatments, respectively. Compared with the control, only GBSC increased starch content in cecal digesta, which averaged 2.8, 2.6, and 7.4% of DM for the control, APSC, and GBSC, respectively. Free lipopolysaccharide endotoxin (LPS) concentration in rumen fluid increased from 10,405 endotoxin units (EU)/mL in the control treatment to 30,715 and 168,391 EU/mL in APSC and GBSC, respectively. Additionally, GBSC increased the LPS concentration from 16,508 to 118,522 EU/g in wet cecal digesta, and from 12,832 to 93,154 EU/g in wet feces. The APSC treatment did not affect LPS concentrations in cecal digesta and feces. All concentrations of LPS in blood plasma were below the detection limit of >0.05 EU/mL of the technique used. Despite the absence of LPS in blood, only GBSC increased the concentration of LPS-binding protein in blood plasma, which averaged, 8.9, 9.5, and 12.1 mg/L for the control, APSC, and GBSC treatments, respectively. This suggests that GBSC caused translocation of LPS from the digestive tract but that LPS was detoxified before entering the peripheral blood circulation. The higher LPS concentration in cecal digesta in the GBSC compared with the APSC suggests a higher risk of LPS translocation in the large intestine in GBSC than in APSC.
A survey was conducted on 40 randomly selected dairy farms across Manitoba to document nutritiona... more A survey was conducted on 40 randomly selected dairy farms across Manitoba to document nutritional practices and diet compositions, and study relationships between diet composition and milk production. Samples from all feeds, diets, and the bulk milk tank were collected and analyzed. Inclusion rates of feed ingredients were recorded. Production data were obtained from Western Canada Dairy Herd Improvement Services (WCDHIS). Component feeding and total mixed ration (TMR) feeding were used in 37.5 and 62.5% of herds, respectively. Only 24% of TMR-fed herds used two or more TMR. The medians of dietary contents of crude protein (CP), rumen degradable protein (RDP), rumen undegradable protein (RUP), and neutral detergent fibre (NDF), and milk urea nitrogen (MUN) were 18.3% dry matter (DM), 12.2% DM, 5.7% DM, 34.8% DM, and 15.6 mg dL-1, respectively. On average, diets contained 6.2% more net energy for lactation (NEl), 35.9% more RDP, 15.8% less RUP, 74.6% more calcium (Ca), 51.9% more ph...
Figure S1. PCR-RFLP Identification of BoLA-DRB3.2 variants. Figure S2. Beta-diversity of the bact... more Figure S1. PCR-RFLP Identification of BoLA-DRB3.2 variants. Figure S2. Beta-diversity of the bacterial communities of intramammary secretions during the first week of lactation. Figure S3. Beta-diversity of the fungal communities of intramammary secretions during the first week of lactation. Figure S4. Association of lactation stage and BoLA-DRB3.2 polymorphism with interrelationship patterns and hub species of intramammary bacterial communities. Figure S5. Bacterial co-occurrence and co-exclusion networks. Figure S6. Unsupervised cluster analysis of day 0 colostrum samples based on the distribution of fungal OTUs. Figure S7. Unsupervised cluster analysis of day 1 colostrum samples based on the distribution of fungal OTUs. Figure S8. Rarefaction curves of richness (Observed-OTUs and Chao1) and diversity (Shannon) indices for bacterial (a-c) and fungal (d-f) communities. (PDF 6512Â kb)
Milk yields of North American dairy cows have increased substantially during recent years. This h... more Milk yields of North American dairy cows have increased substantially during recent years. This has created challenges, because, in order to meet the increased potential for milk production, dairy diets have to contain more grain and less forage. Feeding these high concentrate diets can result in high concentrations of organic acids in the rumen and a reduction in chewing, saliva production and rumen buffering (Kleen et al., 2003; Stone, 2004). This can lead to an increase in rumen acidity and a drop in rumen pH. When rumen pH is reduced for prolonged periods each day, subacute ruminal acidosis (SARA) can occur (Kleen et al, 2003; Stone, 2004). This metabolic disease affects rumen fermentation and digestion, but also impacts many other aspects of production and health of dairy cows.
Six non-lactating Holstein dairy cows received diets with forage to grain mixture ratios of 100:0... more Six non-lactating Holstein dairy cows received diets with forage to grain mixture ratios of 100:0 (G0), 75:25 (G25), and 50:50 (G50) that contained 0.5%, 10.0%, and 19.5% dry matter (DM) of starch, respectively. Rumen fluid and feces were sampled, and methane emissions were determined during the last week of 5 wk experimental periods. Taxonomic compositions of microbiota were determined using Illumina 16S rRNA sequencing. Increased grain feeding increased the acidity and volatile fatty acid concentrations of rumen fluid and feces, and decreased methane emissions expressed as L·kg−1 DM. Microbial diversities were highest for G25. The numbers of identified genera in rumen fluid were 185, 182, and 171 for G0, G25, and G50, respectively. In feces, these numbers were 197, 182, and 171 for these diets, respectively. In rumen digesta, seven genera were correlated positively to G0 and negatively to G50, and six genera were correlated negatively to G0 and positively to G50. In feces, 16 gene...
ABSTRACT Abstract Text: A survey was conducted on 10 dairy farms in Manitoba to quantify factors ... more ABSTRACT Abstract Text: A survey was conducted on 10 dairy farms in Manitoba to quantify factors that affect the utilization of phosphorus (P) by lactating cows. Farms were visited once to collect samples and data, including days in milk (DIM), milk yields (MY), parities (PAR), body condition scores (BCS), and body weights from 30 Holstein cows in different stages of lactation. Feeds were analyzed for crude protein (CP), fat (FAT), ash (ASH), NDF, starch (STARCH), P (DIETP) and acid insoluble ash (AIA). Feces were collected from the rectum and analyzed for P (FECALP) and AIA. Composite milk samples were analyzed for fat (MFAT), protein (MPROT), and P (MILKP). The apparent digestibilities of P (ADCP) of cows were determined using AIA as a marker. Dry matter intake was estimated using the equation of NRC(2001). The P utilization efficiencies (PEFF) of cows were determined as the ratio between the output of P in milk and the P intake. Descriptive statistics (Table 1) show the considerable variation of parameters among cows. Examination of dietary and fecal P concentrations and measures of P utilization suggested that approximately half of the cows received more P than required. Linear regression models were developed between dependent variables (FECALP, PEFF, ADCP) and independent diet and cow variables. Independent variables with a significance level greater than 0.25 were stepwise removed. Regression models were: ADCP = -152.9+1.00*PAR-2.06*MFAT+2.22*CP+3.63*FAT+1.18*ASH+2.52*NDF+114.06*DIETP (R2=0.39) PEFF = 45.91-0.45*PAR-0.04*DIM+0.34*MY–2.64*MFAT+313.80*PMILK-82.37*DIETP (R2=0.79) FECALP = 1.21+0.0005*DIM+0.03*CP-0.10*FAT+0.06*ASH-0.01*STARCH-0.04*NDF (R2 =0.25) Correlations among independent variables, including PDIET and other dietary variables, complicated assessing relationships between variables. The models show the complexity of factors that determine the efficiency of P for milk production, and generally suggest that this efficiency decreases in later stages of lactation when and milk yield decreases and diets are formulated accordingly. Table 1. Descriptive statistics Average SD Min. 25’th perc. 50’th perc. 75’th perc. Max. PAR 2.37 1.41 1 1 2 3 8 DIM 170 97 15 74 166 259 464 Milk yield, kg/d 35.6 9.0 9.5 28.7 34.4 41.3 65.1 Milk P, % 0.09 0.07 0.07 0.09 0.09 0.10 0.11 Milk P eff., % 34.6 8.3 16.1 28.3 33.3 39.5 61.4 CP, %DM 16.9 0.9 15.1 16.4 16.8 17.6 18.3 NDF, %DM 34.1 3.6 29.7 30.7 33.8 35.8 41.0 P, %DM 0.41 0.04 0.34 0.37 0.41 0.45 0.47 Feces P, %DM 0.70 0.19 0.30 0.55 0.69 0.83 1.28 ADC P, % 35.1 13.2 15.9 24.0 31.7 48.1 59.7 Keywords: phosphorus, effeciency, dairy
Ruminal acidosis is a common disease in high yielding dairy cows, during which the rumen pH is de... more Ruminal acidosis is a common disease in high yielding dairy cows, during which the rumen pH is depressed for several hours per day. There is no general agreement of the definition of the disease, and its diagnosis based on rumen pH measurement is invasive and inaccurate. As a result, the disease often goes unnoticed, and its impact is not well recognized. Surveys suggest a prevalence of between 19 and 26% in early and mid-lactation dairy cows in North America. Many symptoms have been attributed to subacute rumen acidosis (SARA), including feed intake depression, milk fat depression, reduced fiber digestion, inflammation of the rumen, systemic inflammation, dehydration, diarrhea, laminitis, liver abscesses, and increases in the concentrations of bacterial toxins in digesta throughout the digestive tract. These symptoms are not always obvious. The mechanisms of how, and even if, the rumen pH depression causes these symptoms are not always well understood. Cows may very in their suscep...
Effects of Saccharomyces cerevisiae fermentation products (SCFP) and subacute ruminal acidosis (S... more 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 accuracy of the milk fatty acid profile as a diagnostic tool for the diagnosis of sub-acute r... more The accuracy of the milk fatty acid profile as a diagnostic tool for the diagnosis of sub-acute ruminal acidosis (SARA) has been determined when SARA was experimentally induced. This had not yet been done not on commercial dairy farms, where SARA can occur naturally. The objective of this study was to determine this accuracy in individual cows on commercial dairy farms. A total of 336 cows from 24 commercial dairy farms in Quebec were included. Farms were blocked based on geographical location and management, with each block having one high risk SARA farm and one low risk SARA farm. Farm Risk of SARA was determined based on the milk fat content and the proportions of de novo fatty acids and long chain unsaturated fatty acids in the bulk tank. On each farm, 7 early/mid-lactation (< 150 days in milk DIM) and 7 mid/late lactation (< 150 DIM) cows were randomly selected. The fatty acid profile of pooled milk samples from these cows were determined by gas chromatography. Farm risk ...
Thirty-two dairy cows receiving a basal diet containing 34.9% NDF, and 18.6 % starch, were random... more Thirty-two dairy cows receiving a basal diet containing 34.9% NDF, and 18.6 % starch, were randomly assigned to four treatments: supplementation either with 140 g/d of ground corn (Control), 126 g/d of ground corn and 14 g/d of XPC (SCFPa, Diamond V Original XPC Cedar Rapids, IA), 121 g/d of ground corn and 19 g/d of NutriTek (SCFPb-1x, NutriTek, Diamond V), or 102 g/d of ground corn and 38 g/d of NutriTek (SCFPb-2x) from 4 wk before until 12 wk after calving. SARA was induced during wk 5 and wk 8 after calving by replacing 20% of the basal diet with pellets containing 50% barley and 50% wheat. Ruminal fluid samples were collected at 6 h after feeding on the second day of wk 4 to wk 10 after calving. Weeks 4, 7 and 10 were considered to be non-SARA. Microbial DNA was extracted, llumina sequenced at the V1–V2 regions of the 16S rRNA gene, and operational taxonomic units (OUT) were assigned using QIIME2. Correlation network analysis (CoNet) determined connections between the relative ...
In order to test the validity of milk amyloid A (MAA) as a biomarker for inflammation and subacut... more In order to test the validity of milk amyloid A (MAA) as a biomarker for inflammation and subacute ruminal acidosis (SARA), 320 milk samples from 24 commercial dairy farms in Quebec were tested for milk amyloid A using a commercial kit. These farms were divided into low risk of SARA farms and high risk of SARA farms according to the proportions of short chain and polyunsaturated fatty acids content in the bulk tank of the farms. It was assumed that farms at risk of SARA had a lower proportion of short chain and a higher proportion of polyunsaturated fatty acids compared to farms that were not at risk of SARA. Farms were also blocked in groups of two farms by geographical location and management. Each block included an at-risk and a not-at-risk farm. On each farm, 7 early- to mid-lactation and 7 mid- to late-lactation cows were randomly selected for MAA analysis. Cows with a somatic cell count (SCC) of over 200,000 in pooled milk samples were not included. Data were analyzed using SA...
Effects of the duration of moderate grain feeding on the taxonomic composition of gastrointestina... more Effects of the duration of moderate grain feeding on the taxonomic composition of gastrointestinal microbiota were determined in 15 Holstein yearling steers. Treatments included feeding a diet of 92% dry matter (DM) hay (D0), and feeding a 41.5% barley grain diet for 7 (D7) or 21 d (D21) before slaughter. At slaughter, digesta samples were collected from six regions, i.e., the rumen, jejunum, ileum, cecum, colon, and rectum. Extracted DNA from these samples was analyzed using MiSeq Illumina sequencing of the V4 region of the 16S rRNA gene. Three distinct PCoA clusters existed, i.e., the rumen, the jejunum/ileum, and the cecum/colon/rectum. Feeding the grain diet for 7 d reduced microbial diversity in all regions, except the ileum. Extending the duration of grain feeding from 7 to 21 d did not affect this diversity further. Across regions, treatment changed the relative abundances of 89 genera. Most of the changes between D0 and D7 and between D7 and D21 were opposite, demonstrating ...
Background Within complex microbial ecosystems, microbe-microbe interrelationships play crucial r... more Background Within complex microbial ecosystems, microbe-microbe interrelationships play crucial roles in determining functional properties such as metabolic potential, stability and colonization resistance. In dairy cows, microbes inhabiting different ecological niches of the udder may have the potential to interact with mastitis pathogens and therefore modulate susceptibility to intramammary infection. In the present study, we investigated the co-occurrence patterns of bacterial communities within and between different niches of the bovine mammary gland (teat canal vs. milk) in order to identify key bacterial taxa and evaluate their associations with udder health parameters and mastitis susceptibility. Results Overall, teat canal microbiota was more diverse, phylogenetically less dispersed, and compositionally distinct from milk microbiota. This, coupled with identification of a large number of bacterial taxa that were exclusive to the teat canal microbiota suggested that the intra...
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