Blood Metabolites In Dairy Cows Research Articles

Effects of biochanin A on lactational performance, nitrogen metabolism, and blood metabolites in dairy cows

Optimizing nitrogen utilization efficiency and mitigating nitrogen losses in cows plays a pivotal role in fostering economic sustainability within contemporary agricultural systems. Biochanin A (BCA), a natural component in red clover, has the potential to improve nitrogen metabolism in dairy cows. The primary objective of this study was to probe the impact of biochanin A supplementation on lactational performance, nitrogen metabolism, and blood metabolites in dairy cows. A complete randomized block design experiment was conducted over 28 d, involving 36 multiparous Holstein cows (comparable milk yield = 37.1 ± 2.90 kg, BW = 642 ± 70.0 kg, days in milk = 92 ± 8.0 d, and parity = 2.4 ± 0.50), which were allocated to three treatment groups: the control group (with 0 g/d BCA), the low group (with 10 g/d BCA), and the high group (with 40 g/d BCA). Biochanin A supplementation improved the lactational performance of cows by increasing milk yield by 6.3% (P = 0.007) and feed efficiency by 12.7% (P = 0.009). Total intestinal apparent digestibility was unaffected by BCA supplementation (P > 0.05), but microbial nitrogen was increased by 30.0% (P = 0.002) for promoting nitrogen utilization efficiency by 20.7% (P = 0.004). Milk competent yields (protein, lactose, and non-fat milk solid) were increased with increasing BCA supplementation (P < 0.05). Urea nitrogen levels in plasma and milk were both decreased by BCA supplementation (P < 0.05). Blood routine parameters and plasma biochemical parameters both received no effect by BCA supplementation (P > 0.05). BCA did not affect body health of dairy cows. Additionally, none of the plasma endocrine hormones were affected (P > 0.05). A total of 95 significantly different metabolites were screened from the plasma metabolites of cows in the BCA-added and non-added groups. After performing an enrichment analysis of the metabolic pathways associated with the different metabolites, six specific pathways were identified: bile acid biosynthesis, aspartate metabolism, pyrimidine metabolism, arginine and proline metabolism, the urea cycle, and ammonia recycling. The inclusion of BCA is suggested to enhance milk yield and modulate nitrogen metabolism by influencing relevant metabolites within the metabolic pathways.

Lactation performance, feed efficiency, and blood metabolites of dairy cows treated with recombinant bovine somatotropin: A systematic review and meta-analysis

A systematic review and meta-analysis were conducted to assess the impact of recombinant bovine somatotropin (rbST) on lactation performance, feed efficiency, and blood metabolites in dairy cows. In the systematic review, articles were selected based on the following criteria: (1) Data focusing on the influence of bovine somatotropin doses on milk production; (2) Submission of original data; (3) Articles published in journals; and (4) Articles in English or Portuguese. The analysis of variance was used with a completely randomized design and mixed models methodology. Polynomial regression was applied to significant fixed effects (rbST dose). The use of rbST resulted in increased milk yield and 4% fat-corrected milk yield, while fat, protein, and lactose contents remained unaffected. Dry matter and metabolizable energy intakes, as well as milk/feed efficiency, exhibited a linear increase, but body condition score (BCS) was negatively impacted. The administration of rbST led to higher blood concentrations of triglycerides and insulin. Cows treated with rbST showed a 23% increase in non-esterified fatty acid (NEFA) concentrations compared to non-treated cows. Additionally, growth factors IGF-1 and IGF-2 displayed a linear increase with rbST treatment. In summary, rbST administration increased milk yield and fat-corrected milk yield without affecting milk components. However, despite increasing intake, it resulted in BCS losses and alterations in blood parameters such as NEFA, IGF-1, and IGF-2.

Effect of Probiotic Bacillus coagulans on Performance and Blood Metabolites of Dairy Cows with Subclinical Mastitis

Effect of Probiotic Bacillus coagulans on Performance and Blood Metabolites of Dairy Cows with Subclinical Mastitis

Biochemical indicators of dairy cows affected by fermentative digestive disorders

The purpose of the present study was to evaluate blood metabolites in dairy cows affected by digestive disorders of fermentative nature. Sixty-six animals with clinical and laboratory diagnoses were distributed into six groups according to the diagnosis: G1 (n=5) acute ruminal acidosis; G2 (n=10) displacement of the abomasum to the right (RDA); G3 (n=16) displacement of the abomasum to the left (LDA); G4 (n=10) cecal dilation; G5 (n=6) simple indigestion; and G6 (n=19) frothy bloat. Biochemical variables related to the energy, protein, enzymatic, mineral, and hormonal profile were measured soon after diagnosis and at the time of clinical resolution. The data were submitted to analysis of variance (ANOVA) with the level of significance set at 5%. Abnormalities were found with the fermentative digestive disorders, such as a negative energy balance (NEB), liver and muscle damage, and a high level of stress. Among the conditions diagnosed, abnormalities were more evident in acute ruminal acidosis, displacement of the abomasum (RDA), and cecal dilation. The biochemical abnormalities reflected the impact caused by the digestive disorders. Thus, understanding of the dynamics of biochemical abnormalities is fundamental to the establishment of the diagnosis, evaluation of the therapeutic response, and a more precise assessment of the prognosis, thereby avoiding greater economic losses in dairy farming activities and contributing to the improvement in the animal welfare.

Concentrate allowance and corn grain processing influence milk production, body reserves, milk fatty acid profile, and blood metabolites of dairy cows in the early postpartum period

The study goal was to determine the effects of a fast (FAS) or slow (SLW) incremental rate of concentrate feeding and corn processing method during the early postpartum period on lactational performance, body reserves, blood metabolites, and milk fatty acid (FA) profile. Forty multiparous Holstein cows were used in a randomized block design with a 2 × 2 factorial arrangement of treatments. Treatment diets were either a FAS [1.0 kg of dry matter (DM)/d] or SLW (0.25 kg of DM/d) incremental rate of concentrate feeding (up to 12 kg of DM/d) with either dry ground corn (DGC) or steam-flaked corn (SFC) as the primary starch source in concentrate. Treatments were fed from 5 to 64 d postpartum. The basal diet consisted of forage, soybean meal, and 5 kg/d concentrate in the postpartum period. Throughout the experiment, dry matter intake (DMI) and milk yield were measured daily, and milk components, body condition score, and body weight were recorded at 16-d intervals, whereas blood metabolites and milk FA profile were measured at 16 and 32 d in milk. The incremental rate of concentrate feeding interacted with corn processing method to affect plasma concentration of glucose with greater glucose in SFC treatment compared with DGC in cows fed with the FAS strategy. Cows fed FAS and SFC had a greater total DMI than those fed SLW and DGC counterparts (22.8 versus 22.1 kg and 22.7 versus 22.1 kg, respectively), and also SFC increased yield of actual milk compared with the DGC counterpart (42.7 versus 41.6 kg). The milk fat and energy-corrected milk yields were not different among treatments whereas milk protein yield was greater when SFC was fed. Greater incremental rate of concentrate feeding tended to increase milk lactose yield during the first 64 d of lactation. The loss of body condition score increased when cows were fed SLW for the entire period and plasma nonesterified fatty acids and β-hydroxybutyrate concentrations increased with the SLW strategy. The proportions of total trans 18:1 and trans-11 18:1 FA in milk fat were higher in cows fed FAS. However, feeding SLW enhanced milk de novo and mixed FA proportions compared with FAS, whereas the proportions of milk FA were not affected by corn grain processing method. The incremental rate of concentrate feeding had significant effects on DMI, milk yield, and body reserve changes. Although feeding SFC instead of DGC had benefits on DMI and milk yield at 48 and 64 d postpartum, treatments did not interact to affect production responses when cows were fed with the SLW strategy.

Milk production responses, rumen fermentation, and blood metabolites of dairy cows fed increasing concentrations of forage rape (Brassica napus ssp. Biennis)

The aim of this study was to determine animal performance, rumen fermentation, and health-related blood metabolites of dairy cows in mid lactation fed with increasing levels (30 and 45%) of forage rape (FR) in the diet. Twelve pregnant multiparous lactating Holstein-Friesian dairy cows were randomly allocated to 1 of 3 dietary treatments in a replicated 3 × 3 Latin square design. The experiment was divided into three 21-d periods. For the control diet, 13.0 kg (dry matter, DM) of grass silage, 3.0 kg DM of commercial concentrate, 2.7 kg of DM cold-pressed extracted canola meal, and 0.45 kg DM of solvent-extracted soybean meal were offered daily. For the other two treatments, 30 and 45% of the DM from silage, canola meal, and commercial concentrate were replaced in equal proportions with FR. Data were analyzed individually using linear and quadratic orthogonal polynomials. Ingestive behavior was altered by the inclusion of FR. We observed a linear increase in eating time at the expense of rumination time. Nevertheless, total DM intake was not affected by dietary treatments, averaging 19.5 ± 0.24 kg of DM/d. Milk yield increased linearly with increasing concentration of FR in the diet. Thus, feed efficiency of cows (kg of milk/kg of DM intake) increased linearly with the percentage of FR in the diet. Inclusion of FR in the diet had no effect on milk composition or milk sensory characteristics. Mean rumen pH of cows decreased linearly from the control to the 45% FR diet; however, dietary treatments had no effect on the daily amount of time that rumen pH was below 5.8 (252 ± 71.4), indicating no risk of subacute ruminal acidosis. Concentrations of total volatile fatty acids in the rumen and molar proportions of acetate and butyrate were increased with FR inclusion, whereas the proportion of propionate was linearly reduced. Excretion of uric acid and total purine derivatives tended to be greater for cows fed FR, which resulted in a trend toward a linear increase in estimated microbial N flow. However, N use efficiency was not affected by FR inclusion. Although differences for some hematological measures (increased white blood cell and neutrophils counts) and a quadratic response for glutamate dehydrogenase for cows fed FR in the diet (decreased with inclusion of 30% and increased with 45% in the diet) were observed, all values were within appropriate ranges for dairy cows. These results indicated that including FR to dairy cow diets, up to 45% of diet DM, improved milk production due to changes in volatile fatty acids and predicted microbial N flow and had no negative effects on dairy cow health or sensory characteristics of milk.

Effects of copper sulphate and coated copper sulphate addition on lactation performance, nutrient digestibility, ruminal fermentation and blood metabolites in dairy cows.

Coated copper sulphate (CCS) could be used as a Cu supplement in cows. To investigate the influences of copper sulphate (CS) and CCS on milk performance, nutrient digestion and rumen fermentation, fifty Holstein dairy cows were arranged in a randomised block design to five groups: control, CS addition (7·5 mg Cu/kg DM from CS) or CCS addition (5, 7·5 and 10 mg Cu/kg DM from CCS, respectively). When comparing Cu source at equal inclusion rates (7·5 mg/kg DM), cows receiving CCS addition had higher yields of fat-corrected milk, milk fat and protein; digestibility of DM, organic matter (OM) and neutral-detergent fibre (NDF); ruminal total volatile fatty acid (VFA) concentration; activities of carboxymethyl cellulase, cellobiase, pectinase and α-amylase; populations of Ruminococcus albus, Ruminococcus flavefaciens and Fibrobacter succinogenes; and liver Cu content than cows receiving CS addition. Increasing CCS addition, DM intake was unchanged, yields of milk, milk fat and protein; feed efficiency; digestibility of DM, OM, NDF and acid-detergent fibre; ruminal total VFA concentration; acetate:propionate ratio; activity of cellulolytic enzyme; populations of total bacteria, protozoa and dominant cellulolytic bacteria; and concentrations of Cu in serum and liver increased linearly, but ruminal propionate percentage, ammonia-N concentration, α-amylase activity and populations of Prevotella ruminicola and Ruminobacter amylophilus decreased linearly. The results indicated that supplement of CS could be substituted with CCS and addition of CCS improved milk performance and nutrient digestion in dairy cows.

Effects of betaine and rumen-protected folic acid supplementation on lactation performance, nutrient digestion, rumen fermentation and blood metabolites in dairy cows

This study evaluated the effects of betaine (BT) and rumen-protected folic acid (RPFA) on lactation performance, nutrient digestion, rumen fermentation and blood metabolites in dairy cows. Thirty-six mid-lactation Holstein dairy cows were assigned to one of four treatments in a 2 × 2 factorial randomized block design. Supplemental RPFA (0 [RPFA-] or 5.2 mg/kg dietary dry matter [DM] of folic acid [FA] from RPFA [RPFA+]) and BT (0 [BT-] or 4.0 g/kg DM of BT [BT+]) was mixed into the daily ration, respectively. The experiment lasted for 105 days with the first 15 days for adaptation and the following 90 days for sample collection. The RPFA × BT interaction was significant for blood folate concentration which decreased with BT addition in RPFA- diet but increased with BT addition in RPFA + diet. Dry matter intake and body weight change were similar among treatments. Dietary RPFA or BT addition increased yield of milk and milk fat but higher milk protein yield was only observed for RPFA addition. Feed efficiency was increased due to RPFA or BT addition. Apparent total-tract digestibility of DM, organic matter, crude protein, neutral detergent fibre and acid detergent fibre increased with RPFA or BT addition. Ruminal pH decreased with RPFA addition but was unchanged with BT addition. Dietary RPFA or BT addition increased ruminal total volatile fatty acids concentration and altered rumen fermentation mode to more acetate production. Ammonia-N concentration was unchanged with RPFA addition but decreased with BT addition. Addition of RPFA or BT increased activity of carboxymethyl-cellulase, xylanase and protease as well as population of total bacteria, protozoa, Ruminococcus (R.) albus and R. flavefaciens. Population of Prevotella ruminicola was higher for RPFA addition but activity of cellobiase and population of total fungi and Ruminobacter amylophilus was higher for BT addition. Blood concentrations of glucose, non-esterified fatty acid, beta-hydroxybutyrate and homocysteine were similar among treatments. Blood total protein and albumin concentrations were increased with RPFA addition but were not affected by BT addition. The data indicated that addition of RPFA or BT had beneficial impacts on lactation performance, nutrient digestion and ruminal fermentation and BT addition might increase FA utilization efficiency in dairy cows receiving diet without RPFA.

The effect of propylene glycol delivery method on blood metabolites in dairy cows

Four dairy cows in a positive energy balance were used to study the effect of propylene glycol supplementation variants on blood indices. The treatments were: without glycol, glycol mixed with the total mixed ration (TMR), glycol delivered as top dressing (TD), and glycol administered as an oral drench (OD). Oral drenching had the positive effect of higher blood insulin concentration 1.5 and 2.5 h after supplementation compared to the TD method (P ≤ 0.05). Glycol supplemented as TD had the negative effect of higher concentration of non-esterified fatty acids (NEFA) 3.5 h after supplementation (P ≤ 0.05) with a trend towards a higher mean concentration of this marker (P ≤ 0.1). A decreasing tendency was recorded for the NEFA concentration 1.5 h after glycol supplementation with TMR or OD (P ≤ 0.1). Glycol supplemented as OD had the positive effect of lowering the β-hydroxybutyric acid concentration 1.5 and 2.5 h after feeding (P ≤ 0.05). A downward trend in the mean β-hydroxybutyric acid level after glycol delivery as OD was also observed (P ≤ 0.1). Glycol supplemented as TD had the negative effect of decreasing dry matter intake of the diet (P ≤ 0.05). Glycol supplemented as OD had a more glucogenic effect than as part of the TMR. Due to reduction of dry matter intake and the lowest glucogenic effect, using glycol as TD is unjustified. The results confirm that the best method of propylene glycol administration is OD, which can be useful in the prevention of ketosis, however, it should be confirmed in a long-term experiment covering the transition and early lactation periods.

Prediction of blood metabolites from milk mid-infrared spectra in early-lactation cows

Dairy cows commonly experience an unbalanced energy status in early lactation, and this condition can lead to the onset of several metabolic disorders. Blood metabolic profile testing is a valid tool to monitor and detect the most common early lactation disorders, but blood sampling and analysis are time-consuming and expensive, and the procedure is invasive and stressful for the cows. Mid-infrared (MIR) spectroscopy is routinely used to analyze milk composition, being a cost-effective and nondestructive method. The present study aimed to assess the feasibility of using routine milk MIR spectra for the prediction of main blood metabolites in dairy cows, and to investigate associations between measured blood metabolites and milk traits. Twenty herds of Holstein Friesian, Brown Swiss, or Simmental cows located in Northeast Italy were visited 1 to 4 times between December 2017 and June 2018, and blood and milk samples were collected from all lactating cows within 35 d in milk. Concentrations of main blood metabolites and milk MIR spectra were recorded from 295 blood and milk samples and used to develop prediction models for blood metabolic traits through backward interval partial least squares analysis. Blood β-hydroxybutyrate (BHB), urea, and nonesterified fatty acids were the most predictable traits, with coefficients of determination of 0.63, 0.58, and 0.52, respectively. On the contrary, predictive performance for blood glucose, triglycerides, cholesterol, glutamic oxaloacetic transaminase, and glutamic pyruvic transaminase were not accurate. Associations of blood BHB and urea with their respective contents in milk were moderate to strong, whereas all other correlations were weak. Predicted blood BHB showed an improved performance in detecting cows with hyperketonemia (blood BHB ≥ 1.2 mmol/L), compared with commercial calibration equation for milk BHB. Results highlighted the opportunity of using milk MIR spectra to predict blood metabolites and thus to collect routine information on the metabolic status of early-lactation cows at a population level.

Effects of Dietary Alkyl Polyglycoside Supplementation on Lactation Performance, Blood Parameters and Nutrient Digestibility in Dairy Cows

Simple SummaryThis project investigated the effects of alkyl polyglycoside (APG), a non-ionic surfactant, on lactation performance, blood metabolites and nutrient digestibility of lactating dairy cows, and found that the addition of APG at doses up to 22 mL/kg of pelleted concentrate (around 9 mL/kg of diet or 100 mL/day/head) had positive effects on milk quality in dairy cows.This study evaluated the effects of alkyl polyglycoside (APG), which is a non-ionic surfactant, on lactation performance, nutrient digestibility and blood metabolites in dairy cows. Twenty dairy cows were randomly divided into four groups and fed a basal diet that included pelleted concentrate, distillers grains, and fresh limpograss. The four treatments included 0, 5.5, 11 and 22 mL APG per kg of pelleted concentrate on a dry matter basis; treatments were defined as APG0, APG5.5, APG11, and APG22, respectively. Dry matter intake was not affected by APG supplementation. There was an increase in milk yield (from 13.96 to 16.71 kg/day) and increases in milk fat (quadratic, p = 0.04), protein (quadratic, p = 0.10), and lactose concentrations (linear, p = 0.07) with increasing APG supplementation. In addition, APG supplementation increased (p ≤ 0.03) the milk fat, protein, solid non-fat, and total solid yields, while the lactose yield increased (linear, p = 0.01) as the APG level increased. Dietary APG supplementation had no effect on nutrient digestibility and blood metabolites. It was concluded that the addition of APG at doses up to 22 mL/kg of pelleted concentrate had positive effects on the milk composition in dairy cows.

Effects of rumen-protected folic acid and rumen-protected sodium selenite supplementation on lactation performance, nutrient digestion, ruminal fermentation and blood metabolites in dairy cows.

Considering the insufficient ruminal synthesis of folic acid (FA), the higher degradability of FA, and the reduction of sodium selenite (SS) by ruminal microbes into non-absorbable elemental Se, this study evaluated the effects of rumen-protected FA (RPFA) and rumen-protected SS (RPSS) on lactation performance, nutrient digestion and blood metabolites in dairy cows. Dry matter (DM) intake and milk composition were unaltered, milk and milk fat yields were higher for both supplements, and milk protein yield was higher for RPFA addition. Digestibility of DM, neutral detergent fibre and acid detergent fibre was higher for both supplements, whereas that of organic matter and crude protein was higher for RPFA addition. Ruminal pH and ammonia N were lower, and concentration of total volatile fatty acids was higher for both supplements. Activity of cellobiase and xylanase was higher for RPFA addition, whereas that of pectinase and protease was higher for both supplements. The populations of total ruminal fungi, protozoa, Ruminococcus flavefaciens and Butyrivibrio fibrisolvens were higher for both supplements. The RPFA × RPSS interaction was significant for α-amylase activity, total ruminal bacteria and R. albus populations; these three variables were increased by RPSS but the increase was greater when cows were also fed RPFA. The results indicated that addition of RPFA or RPSS improved lactation performance, nutrient digestibility and ruminal fermentation in dairy cows by stimulating ruminal microbial growth and enzyme activity. © 2019 Society of Chemical Industry.

Effects of rumen-protected folic acid and branched-chain volatile fatty acids supplementation on lactation performance, ruminal fermentation, nutrient digestion and blood metabolites in dairy cows

This study evaluated the effects of branched-chain volatile fatty acids (BCVFA) and rumen protected folic acid (RPFA) supplementation on lactation performance, ruminal fermentation, nutrient digestion and blood metabolites in dairy cows. Fifty-six multiparous Chinese Holstein cows (3.2 ± 1.1 of parity, 631 ± 16.4 kg of body weight [BW], 65 ± 2.6 days in milk [DIM] and 30.2 ± 2.1 kg of milk yield per day, mean ± SD) were blocked by lactation number, milk yield per day and DIM and were arranged into one of four groups in a randomized block design with a 2 × 2 factorial arrangement. Supplemental BCVFA (0 g/d [BCVFA-] or 80 g/d [BCVFA+]) and RPFA (0 mg/d [RPFA-] or 128 mg/d [RPFA+]) were hand-mixed into the top one-third of total mixed ration. Dietary concentrate to forage ratio was 50:50 based on a dry matter (DM) basis. Experimental periods comprised 105 days with 15 d of adaptation followed by 90 d of data collection. DM intake was increased with BCVFA supplementation, but was unaffected by RPFA. The BW changes were similar among treatments. Yields of milk, milk fat and lactose were increased, and milk true protein yield tended to increase with BCVFA or RPFA supplementation. Milk fat percentage was increased with BCVFA supplementation, but was unaffected by RPFA. Percentage of milk true protein was increased, lactose was unaltered and feed conversion ratio was decreased with BCVFA or RPFA supplementation. Ruminal pH and ammonia N concentration were decreased, but total volatile fatty acids concentration was increased with BCVFA or RPFA supplementation. Molar proportion of acetate was increased and propionate was decreased, resulting in an increased ratio of acetate to propionate with BCVFA supplementation. Acetate and propionate molar proportion and the ratio of acetate to propionate were not affected by RPFA. Digestibilities of DM, organic matter, crude protein, non-fiber carbohydrates, neutral detergent fibre and acid detergent fibre were increased with BCVFA or RPFA supplementation. Similarly, activities of caboxymethyl-cellulase, cellobiase, xylanase, pectinase, α-amylase and protease and abundance of R. albus, R. flavefaciens, F. succinogenes, B. fibrisolvens and P. ruminicola were increased. However, R. amylophilus abundance was not affected by BCVFA and increased with RPFA supplementation. Serum concentrations of glucose and non-esterified fatty acids (NEFA) were unaltered and total protein was increased with BCVFA or RPFA supplementation. Serum acetoacetate (ACAC) and BHBA were increased by BCVFA, but were decreased by RPFA. Supplementation of BCVFA or RPFA increased serum growth hormone releasing hormone, growth hormone and insulin-like growth factor-1. These results indicated that lactation performance, ruminal fermentation, nutrient digestion and hormone secretion improved due to the stimulated ruminal bacteria growth and enzyme activity with BCVFA or RPFA supplementation, but no BCVFA × RPFA interaction was detected during the trial.

Effects of rumen-protected pantothenate supplementation on lactation performance, ruminal fermentation, nutrient digestion and blood metabolites in dairy cows.

Lactation performance of dairy cow has considerably increased with animal breeding and management improvement in recent years. Ruminal net synthesised pantothenic acid is insufficient to meet the requirement of high producing dairy cows. The objective was to investigate the effects of rumen-protected pantothenate (RPP) on lactation performance, ruminal fermentation, nutrient digestion and blood metabolites in dairy cows. Dry matter (DM) intake tended to increase, whereas milk yields, milk fat percentage and yield, body condition score (BCS) changes and net energy output except for maintenance increased linearly with increasing RPP supplementation. Ruminal pH and ammonia N concentration tended to decrease, total VFA tended to increase, while acetate-to-propionate ratio increased linearly with increasing RPP supplementation. Digestibilities of DM, organic matter and crude protein increased linearly, but neutral detergent fibre and acid detergent fibre digestibility tended to increase. Blood glucose, total protein, non-esterified fatty acids, pantothenic acid, pantothenate kinase, succinyl CoA, acyl carrier protein and acetyl CoA also increased linearly with increasing RPP supplementation. The results indicated that supplementary RPP improved lactation performance, nutrient digestion and blood parameters in a dose-dependent manner, and the optimal dose was 12 g RPP per cow per day in the current study. © 2017 Society of Chemical Industry.

Evaluation of blood metabolites in dairy cows grazing under two pasture allowances and supplemented with corn silage under restricted grazing conditions

This study was conducted to evaluate the influence of management tools - daily pasture allowance and corn silage supplementation - during periods of forage shortage on the metabolism of dairy cows grazing low-mass pasture in temperate regions. Forty lactating Holstein cows were used during an experimental period of seventy days (April 15 to June 23, 2012). Blood metabolites and milk production were determined in fall-calving dairy cows grazing under two daily pasture allowances (PA) (moderate, 17 kg vs. high, 25 kg dry matter (DM)) and supplemented with corn silage (CS) (low, 4.5 kg vs. high, 9.0 kg DM). All cows received 3 kg DM of concentrate. Plasma concentrations of β-hydroxybutyrate (BHBA), non-esterified fatty acids (NEFA), and urea were determined using an automated spectrophotometer, and milk production was electronically measured at each milking time during the trial. The experimental design was completely randomized using a 2 × 2 factorial arrangement of treatments. The increase in daily PA decreased plasma concentrations of BHBA (0.91±0.36 vs. 1.12±0.43 mmol L−1), provided an increase in milk yield (23.18±3.26 vs. 21.99±3.37 kg d−1), and did not modify the concentrations of NEFA and urea. The increased CS supplementation increased mildly the plasma concentrations of BHBA (1.07±0.36 vs. 0.96±0.44 mmol L−1) and NEFA (92.77±54.14 vs. 92.77±55.31 µmol L−1), and decreased the concentrations of urea (4.08±1.40 vs. 4.64±1.30 mmol L−1), but did not change milk production. The positive effect of increasing PA was associated with a high herbage intake, while the lack of response to increasing CS supplementation was attributed to a high substitution of pasture intake (0.9 kg DM pasture/kg DM CS). Low corn silage supplementation is recommended.

Influence of a blend of functional oils or monensin on nutrient intake and digestibility, ruminal fermentation and milk production of dairy cows

Cashew nut shell liquid (CNSL) and castor oil (CO) are considered functional oils since they present antitumor, antioxidant, gastroprotective, and antibiotic properties. The objective of this study was to evaluate the effects a commercial blend of functional oils (CNSL and CO) and monensin supplementation on nutrient intake and total tract apparent digestibility, ruminal fermentation, milk yield and composition, N utilization, microbial protein synthesis, and blood metabolites of dairy cows. Twenty-four multiparous Holstein cows (150.2±61.4days in milk, 619±76kg of BW and 29.1±4.0kg/d of milk yield, mean±SD) were used in a replicated 3×3 Latin square experimental design, in which six ruminally cannulated cows were used to assess ruminal fermentation. The animals were randomly assigned to one of the following three treatments: control (CON; without additive); 500mg/kg DM of functional oil (FO; commercial blend of CNSL and CO), and 22mg/kg DM of monensin sodium (MON). The treatments did not affect either nutrient intake or digestibility of diets. Both feed additives provided an increase in ruminal propionate molar proportion compared to CON. In addition, FO increased ruminal propionate concentration when compared to MON and CON. Although both additives increased (P<0.01) milk and protein yields, MON had lower milk fat concentration compared to CON, not differing from FO. Monensin and FO increased milk nitrogen excretion.Neither rumen microbial N synthesis nor blood glucose concentration were changed by the supplements. Finally, FO decreased (P<0.001) blood urea concentration compared to CON or MON, besides increasing milk yield without altering nutrient intake; thus, it might be an alternative to monensin in lactating cow diets.

Performance and plasma concentration of metabolites in transition dairy cows supplemented with vitamin E and fat

The objective of this study was to evaluate the effects of vitamin E (VE; 1 500 or 3 000 international units (IU) d−1) and fat (2% of dry matter calcium salt of soybean oil) supplementation during the transition period on feed intake, milk yield and composition and blood metabolites of dairy cows. 48 multiparous Holstein cows were randomly assigned into one of four treatments in a 2×2 factorial arrangement of vitamin E and supplemental dietary fat during the transition period. Treatments were: 1) 1 500 IU d−1 vitamin E without fat supplementation (1 500VE–F); 2) 1 500 IU d−1 vitamin E with fat supplement (1 500VE+F); 3) 3 000 IU d−1 vitamin E without fat supplementation (3 000VE–F); and 4) 3 000 IU d−1 vitamin E with fat supplement (3 000VE+F). Dietary treatments were initiated at approximately 28 d before expected calving dates and continued through 28 d postpartum. Dry matter intake (DMI) was unaffected (P>0.05) by prepartum treatment. Regardless of vitamin E supplementation, DMI was greater (P<0.01) in fat-supplemented cows compared with un-supplemented cows (19.60 vs. 18.45 kg d−1; SEM=0.42) during the postpartum period. Energy balance and body weight were not affected (P>0.05) by treatments. Postpartum diets had no significant effect on milk yield or milk composition. Plasma concentrations of non-esterified fatty acids, glucose, and insulin were not affected (P>0.05) by treatments. Regardless of vitamin E supplementation, plasma β-hydroxybutyrate concentration was greater (P<0.05) in fat-supplemented cows compared with un-supplemented cows during the postpartum period. These results showed no indication of positive effects on lactation performance associated with vitamin E and dietary fat supplement in transition cows.

Effect of dietary sugar concentration and sunflower seed supplementation on lactation performance, ruminal fermentation, milk fatty acid profile, and blood metabolites of dairy cows

Previous research has shown that both sunflower seed (SF) and sucrose (SC) supplementation can result in variation in milk fat concentration and composition, possibly due to altered fermentation patterns and biohydrogenation of fatty acids in the rumen. The objective of this study was to determine the effects of different sugar concentrations with or without SF supplementation on lactation performance, ruminal fermentation, and milk fatty acid profile in lactating dairy cows. Eight multiparous Holstein dairy cows (body weight=620±15kg, 60±10 d in milk, mean ± standard deviation) were randomly assigned to treatments in a replicated 4×4 Latin square design with a 2×2 factorial arrangement of treatments. Each 21-d period consisted of a 14-d diet adaptation period and 7-d collection period. Dairy cows were fed 1 of the following 4 diets: (1) no additional SC without SF supplementation (NSC-SF), (2) no additional SC with SF supplementation (NSC+SF), (3) SC without SF supplementation (SC-SF), and (4) SC with SF supplementation (SC+SF). The diets contained the same amount of forages (corn silage and alfalfa hay). Four isonitrogenous and isoenergetic diets were formulated by replacing corn grain with SC and SF and balanced using change in proportions of canola meal and sugar beet pulp. No interaction was detected between SC and SF supplementation with respect to dry matter intake, milk yield, and composition. A tendency was found for an interaction between inclusion of SC and SF on energy-corrected milk with the highest amount in the SC-SF diet. Ruminal pH and the molar proportion of acetate were affected by SC inclusion, with an increase related to the SC-SF diet. Diets containing SF decreased the concentrations of short-chain fatty acids (4:0 to 10:0) and medium-chain fatty acids (12:0 to 16:0) in milk fat. The addition of SC tended to decrease the concentration of total trans-18:1. These data provide evidence that exchanging SC for corn at 4% of dietary dry matter influenced milk fat content and rumen pH, resulting in a tendency for decreased concentration of trans-18:1 in milk fat. Sucrose alone did not alter the milk fatty acid profile when cows were fed a combination of unsaturated fat and sugar, although several significant interactions between sugar and unsaturated fat were observed.

Effects of polymer-coated slow-release urea on performance, ruminal fermentation, and blood metabolites in dairy cows

The objective of this experiment was to quantify the effects of feeding polymer-coated slow-release urea on nutrient intake and total tract digestion, milk yield and composition, nutrient balances, ruminal fermentation, microbial protein synthesis, and blood parameters in dairy cows. Sixteen Holstein cows (580±20 kg of live weight (mean ± standard deviation); 90 to 180 days in milk (DIM); and 28 kg/d of average milk yield) were used in a replicated 4 × 4 Latin square experimental design. The animals were assigned to each square according to milk yield and DIM. The animals were randomly allocated to receive one of the following experimental diets: 1) control (without urea addition); urea (addition of 1% on the diet DM basis); polymer-coated slow release urea 1 (addition of 1% on the diet DM basis); and polymer-coated slow release urea 2 (addition of 1% on the diet DM basis). All diets contained corn silage as forage source and a 50:50 forage:concentrate ratio. Milk and protein yield, production of volatile fatty acids, and propionate decreased when cows were fed diets containing urea. Addition of urea decreased nitrogen efficiency and nitrogen excreted in the feces. However, the diets did not change the cows' microbial protein synthesis, ruminal pH, or ammonia concentration. The inclusion of urea in cow diets decreases milk and protein yield due to lower production of volatile fatty acids. No advantages are observed with supplementation of polymer-coated slow-release urea when compared with feed-grade urea.

Milk yield and composition, body condition, rumen characteristics, and blood metabolites of dairy cows fed diet supplemented with palm oil

An addition of rumen-protected fat to the diet of cows may limit negative energy balance and/or shorten its duration, leading to increased milk production with reduced risk of metabolic disorders in dairy cows. The aim of the study was to test the effect of rumen-inert fat supplement of palm oil on milk production, milk composition, rumen characteristics, and metabolic variables of early lactating dairy cows. For this purpose, 24 Holstein-Friesian cows were divided into two equal groups and fed a corn silage-based diet, without palm oil supplementation (control) or with 300 g palm oil (Palm Fat 99, Noack & Co. GmbH, Vienna, Austria) per cow for 8 weeks starting from day 30 after parturition. Milk, rumen, and blood samples were taken three times during experiment at days 30, 58, and 86 of lactation. Body condition scores of cows were determined in the same time periods. Milk yields were measured at the morning and evening milking (600 and 1800). Milk samples were analyzed for milk fat and milk protein content. Rumen content was tested for electrochemical reaction. A native slide was prepared for microscopical examination of the rumen protozoa motility that was numerically estimated. Protozoa were counted in whole rumen contents by light microscopy. Blood samples were tested for total protein, albumin, urea, tryglicerides, cholesterol, total bilirubin, beta-hydroxybutyrate, Ca, and P. Compared with the control, palm oil supplementation resulted in an increase of the average milk yield and milk fat content. The loss in body condition was significantly lower in the group fed palm oil than in the control group. Rumen pH, total number, and motility of protozoa in the group fed palm oil were significantly higher than those in the control group. Palm oil supplementation did not influence blood metabolite concentrations except for urea and glucose which were significantly lower and Ca and cholesterol which were significantly higher in the palm oil-supplemented group. Our results indicate that supplementation with palm oil in weeks 4 to 12 postpartum spared postpartum body weight loss, increased milk yield and milk fat content, and had positive effects on rumen characteristics.