Supplementing flaxseed meal with sucrose, flaxseed oil, or both: Effects on milk enterolactone, ruminal microbiota profile, production performance, and nutrient utilization in dairy cows

Flaxseed is the richest source of secoisolariciresinol diglucoside, which is converted by ruminal microorganisms primarily to the mammalian lignan enterolactone. Our objective was to investigate the effect of diets containing soybean meal or flaxseed meal (FM) supplemented with sucrose, flaxseed oil, or both, on milk enterolactone concentration yield, diversity, and relative abundance of ruminal bacterial taxa, ruminal fermentation profile, production performance, milk fatty acids (FA) yield, and nutrient utilization in dairy cows. Sixteen Holstein cows (8 multiparous [4 ruminally cannulated] and 8 primiparous) averaging (mean ± SD) 134 ± 54.1 DIM and 679 ± 78.9 kg of BW in the beginning of the study were assigned to treatment sequences in a replicated 4 × 4 Latin square design. Each experimental period lasted 25 d, with 18 d for diet adaptation and 7 d for data and sample collection. Diets were formulated to contain a 60:40 forage:concentrate ratio and included the following (DM basis): (1) 8% soybean meal and 23% ground corn (SBM); (2) 15% FM, 10.7% ground corn, and 5% sucrose (FLX+S); (3) 15% FM, 15.4% ground corn, and 3% flaxseed oil (FLX+O); and (4) 15% FM, 10.2% ground corn, 5% sucrose, and 3% flaxseed oil (FLX+SO). Compared with SBM, the concentration and yield of milk enterolactone increased in cows fed the FM diets but did not differ among FLX+S, FLX+O, and FLX+SO. The relative abundances of the phyla Firmicutes, Verrucomicrobiota, and Actinobacteriota, and those of the bacterial genera Lachnospiraceae NK3A20 group, Eubacterium coprostanoligenes group, Anaeromusa-Anaeroarcus, WCHB1-41, and p-251-o5 decreased, whereas Prevotella and NK4A214 group increased when comparing SBM against at least 1 diet containing FM. Furthermore, the relative abundances of Firmicutes and Actinobacteriota and those of Prevotella, Lachnospiraceae NK3A20 group, Eubacterium coprostanoligenes group, Acetitomaculum, Lachnospiraceae unclassified, NK4A214 group, and Anaeromusa-Anaeroarcus changed (increased or decreased) across the FLX+S, FLX+O, and FLX+SO diets. However, all these changes in the relative abundance of the ruminal bacterial taxa were not conclusively associated with the effect of diets on milk enterolactone. Diets did not affect ruminal pH and concentrations of NH3-N and total VFA. Dry matter intake and yields of milk, milk fat, and milk true protein all decreased in cows fed FLX+O or FLX+SO. Yields of milk total odd-chain FA, branched-chain FA, total <16C FA, and total 16C FA decreased with feeding FLX+O and FLX+SO. The apparent total-tract digestibilities of DM and OM were lowest in the FLX+S and FLX+O diets, with CP and ADF digestibilities lowest in cows receiving FLX+S or FLX+O, respectively. Urinary excretion of total N was lowest with feeding SBM. Contrarily, diets did not affect the urinary excretion of total purine derivatives. In brief, despite the effect of diets on the relative abundance of several ruminal microbiota phyla and genera, we were unable to conclusively associate these changes with increased milk enterolactone in FM-containing diets versus SBM.

Feeding alfalfa-grass or red clover-grass mixture baleage: Effect on milk yield and composition, ruminal fermentation and microbiota taxa relative abundance, and nutrient utilization in dairy cows

Our goal was to investigate the effect of diets containing baleages harvested from alfalfa-grass or red clover-grass mixture on production performance, ruminal fermentation and microbiota taxa relative abundance, milk fatty acid profile, and nutrient utilization in dairy cows. Twenty Jersey cows (18 multiparous and 2 primiparous) averaging (mean ± SD) 148 ± 45.2 days in milk and 483 ± 65.4 kg of body weight in the beginning of the study were used in a randomized complete block design with repeated measures over time. The experiment lasted 9 wk, with a 2 wk covariate period followed by 7 wk of data and sample collection (wk 4 and 7 used in the statistical analyses). Cows were fed diets containing (dry matter basis) 35% of a concentrate mash and the following forage sources: (1) 65% second- and third-cut (32.5% each) alfalfa-grass mixture baleages (ALF) or (2) 65% second- and third-cut (32.5% each) red clover-grass mixture baleages (RC). Diets did not affect dry matter intake, milk yield, and concentrations of milk fat and true protein. In contrast, milk fat yield tended to decrease and energy-corrected milk yield decreased with feeding RC versus ALF. The apparent total-tract digestibilities of dry matter, organic matter, and ash-free neutral detergent fiber, milk proportions of trans-10 18:1, cis-9,cis-12,cis-15 18:3, and total n-3 fatty acids, ruminal molar proportion of acetate, and plasma concentrations of Leu, Phe, and Val all increased in RC versus ALF. Diet × week interactions were found for several parameters, most notably ruminal molar proportions of propionate and butyrate, ruminal NH3-N, milk urea N, plasma urea N, and plasma His concentrations, urinary N excretion, enteric CH4 production, and all energy efficiency variables. Specifically, ruminal NH3-N and plasma urea N concentrations, urinary excretion of N, and CH4 production decreased in cows fed RC in wk 4 but not in wk 7. Milk urea N concentration decreased and that of plasma His increased with feeding RC during wk 4 and 7, although the magnitude of treatments difference varied between the sampling periods. Efficiency of energy utilization calculated as milk energy/metabolizable energy decreased and that of tissue energy/ME increased in RC versus ALF cows in wk 4, suggesting that ME was portioned toward tissue and not milk in the RC diet. Interactions were also observed for the relative abundance of the rumen bacterial phyla Verrucomicrobiota and Fibrobacterota, with cows offered RC showing greater values than those receiving ALF in wk 4 but no differences in wk 7. Several diet × week interactions were detected in the present study implying short-term treatment responses and warranting further investigations.

Milk production and milk fatty acid profile as a response to feeding dairy cows with flax products during the persistence period

The response of enhanced dietary dairy cows with linolenic-rich sources during the persistence period was studied to determine its effectiveness on some blood constituents, milk yield and milk fatty acid profile. A complete randomized design experiment was conducted in the spring and involved 20 Friesian cows (60 days in milk) that were divided into four groups of five animals by milk production according to different types of flax source in isonitrogenous and isoenergetic rations: a traditional diet with no flax source (CO), a diet contains flaxseed meal (FLM), a diet contains whole flaxseed (FLS) and a diet contains flax oil (FLO). DM intake and DMI% of weight were increased for cows fed FLM. However, Omega-3 intake was reduced for cows fed on CO ration. Although, blood serum metabolites did not differ among treatments (p < 0.05) except serum cholesterol which was increased with FLO cows, and serum total lipid which was reduced with FLM cows. Cows fed on flax product and control peaked in milk production at the same time (8-week post-partum), and cows fed on FLM continued in peak production for a longer period. Using flax products enhanced milk production, cows fed FLM had higher milk yield than those fed CO (20.76 vs.16.32 kg/d), and there was no difference between cows fed FLO (17.87 kg/d) and those fed FLS (18.01 kg/d). Also, energy-corrected milk yield and 3.5 fat-corrected milk yield were increased with cows fed on FLM as compared with cows fed CO ration. Flax products had no significant effect on milk fat and protein %, whereas cows fed FLM had the greatest fat% value (3.35%) and FLS had the greatest protein% value (2.66%). Moreover, fat and protein yield increased significantly in treatment groups compared to the CO group, whereas they were the greatest in FLM g (0.700 and 0.540 kg/d), respectively. Concentrations of omega-3-fatty acids in milk fat were increased by using FLO in the ration; using flaxseed meal enhanced conjugated linoleic acids in milk fat and resulted in the highest omega-6-to-omega-3-fatty-acids ratio. The data suggest that flax seed meals can be used as a fat source in the diet of dairy cows during the persistence period with a good response to milk production and its health properties. Moreover, flax oil should be protected before use in rations to prevent its components from saturation or being changed in the rumen.

Feeding incremental amounts of ground flaxseed: effects on diversity and relative abundance of ruminal microbiota and enteric methane emissions in lactating dairy cows

We evaluated the effects of incremental amounts of ground flaxseed (GFX) on diversity and relative abundance of ruminal microbiota taxa, enteric methane (CH₄) emissions, and urinary excretion of purine derivatives (PD) in lactating dairy cows in a replicated 4 × 4 Latin square design. Twenty mid-lactation Jersey cows were used in the study. Of these 20 cows, 12 were used for ruminal sampling, 16 for enteric CH₄ measurements, and all for spot urine collection. Each period lasted 21 d with 14 d for diet adaptation and 7 d for data and sample collection. Diets were formulated by replacing corn meal and soybean meal with 0%, 5%, 10%, and 15% of GFX in the diet's dry matter. Ruminal fluid samples obtained via stomach tubing were used for DNA extraction. Enteric CH₄ production was measured using the sulfur hexafluoride tracer technique. Diets had no effect on ruminal microbiota diversity. Similarly, the relative abundance of ruminal archaea genera was not affected by diets. In contrast, GFX decreased or increased linearly the relative abundance of Firmicutes (P < 0.01) and Bacteroidetes (P < 0.01), respectively. The relative abundance of the ruminal bacteria Ruminococcus (P < 0.01) and Clostridium (P < 0.01) decreased linearly, and that of Prevotella (P < 0.01) and Pseudobutyrivibrio (P < 0.01) increased linearly with feeding GFX. A tendency for a linear reduction (P = 0.055) in enteric CH₄ production (from 304 to 256 g/d) was observed in cows fed increasing amounts of GFX. However, neither CH₄ yield nor CH₄ intensity was affected by treatments. Diets had no effect on the urinary excretion of uric acid, allantoin, and total PD. Overall, feeding GFX decreased linearly the relative abundance of the ruminal bacterial genera Ruminococcus and Clostridium and enteric CH₄ production, but no change was seen for CH₄ yield and CH₄ intensity, or urinary excretion of total PD, suggesting no detrimental effect of GFX on microbial protein synthesis in the rumen.

Effect of Flaxseed Supplementation on Milk and Plasma Fatty Acid Composition and Plasma Parameters of Holstein Dairy Cows

The objective of this study was to determine the effect of whole flaxseed and ground flaxseed supplementation on the composition of fatty acids in plasma and milk, particularly the content of omega-3 polyunsaturated fatty acids (n-3 PUFAs). Thirty Holstein dairy cows were randomly assigned to three treatment groups. Cows were fed a total mixed ration without flaxseed (CK), 1500 g of whole flaxseed (WF), and 1500 g of ground flaxseed (GF) supplementation. There were no differences observed in dry matter intake, milk yield, energy-corrected milk, and 4% fat-corrected milk (p > 0.05). Compared with the CK group, the contents of α-linolenic acid (ALA), eicosatrienoic acid, and eicosapentaenoic acid increased in the plasma and milk WF and GF groups, and the content of docosahexaenoic acid and total n-3 PUFA was higher in GF than the other groups (p < 0.001). The ALA yield increased to 232% and 360% in WF and GF, respectively, compared to the CK group. Compared with the WF group, GF supplementation resulted in an increased milk ALA/ALA intake ratio (p < 0.001). Flaxseed supplementation increased the activity of GSH-Px and decreased the concentration of MDA in milk (p < 0.001). Plasma parameters did not differ among the treatments (p > 0.05). This result indicated that compared with the WF group, GF supplementation in the diet showed higher efficiency in increasing the total n-3 PUFA levels and the milk ALA/ALA intake ratio, and decreased the ratio of n-6 PUFAs to n-3 PUFAs in milk.

Oilseed Supplementation Improves Milk Composition and Fatty Acid Profile of Cow Milk: A Meta-Analysis and Meta-Regression

Oilseed supplementation is a strategy to improve milk production and milk composition in dairy cows; however, the response to this approach is inconsistent. Thus, the aim of this study was to evaluate the effect of oilseed supplementation on milk production and milk composition in dairy cows via a meta-analysis and meta-regression. A comprehensive and structured search was performed using the following electronic databases: Google Scholar, Primo-UAEH and PubMed. The response variables were: milk yield (MY), atherogenic index (AI), Σ omega-3 PUFA, Σ omega-6 PUFA, fat, protein, lactose, linoleic acid (LA), linolenic acid (LNA), oleic acid (OA), vaccenic acid (VA), conjugated linoleic acid (CLA), unsaturated fatty acid (UFA) and saturated fatty acid (SFA) contents. The explanatory variables were breed, lactation stage (first, second, and third), oilseed type (linseed, soybean, rapeseed, cottonseed, and sunflower), way (whole, extruded, ground, and roasted), dietary inclusion level, difference of the LA, LNA, OA, forage and NDF of supplemented and control rations, washout period and experimental design. A meta-analysis was performed with the “meta” package of the statistical program R. A meta-regression analysis was applied to explore the sources of heretogeneity. The inclusion of oilseeds in dairy cow rations had a positive effect on CLA (+0.27 g 100 g−1 fatty acids (FA); p < 0.0001), VA (+1.03 g 100 g−1 FA; p < 0.0001), OA (+3.44 g 100 g−1 FA; p < 0.0001), LNA (+0.28 g 100 g−1 FA; p < 0.0001) and UFA (+8.32 g 100 g−1 FA; p < 0.0001), and negative effects on AI (−1.01; p < 0.0001), SFA (−6.51; p < 0.0001), fat milk (−0.11%; p < 0.001) and protein milk (−0.04%; p < 0.007). Fat content was affected by animal breed, lactation stage, type and processing of oilseed and dietary NDF and LA contents. CLA, LA, OA and UFA, desirable FA milk components, were affected by type, processing, and the intake of oilseed; additionally, the concentrations of CLA and VA are affected by washout and design. Oilseed supplementation in dairy cow rations has a positive effect on desirable milk components for human consumption. However, animal response to oilseed supplementation depends on explanatory variables related to experimental design, animal characteristics and the type of oilseed.

Effect of Flaxseed Supplementation in Diet of Dairy Cow on the Volatile Organic Compounds of Raw Milk by HS-GC-IMS

Flaxseed supplementation in diet of dairy cow can effectively enhance the production of ω-3 polyunsaturated fatty acids (n-3 PUFA) in raw milk, which further give rise to the changes of volatile organic compounds (VOCs). In this study, we used headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) to investigate the VOCs in milk from cows fed three different diets (CK: supplemented with 0 g/d flaxseed; WF: 1,500 g/d whole flaxseed and GF: 1,500 g/d ground flaxseed). A total of 40 VOCs including three acids, six esters, 11 aldehydes, seven alcohols, 13 ketones were identified in all the raw milk samples. Compared with GF supplementation, suppling with WF could influence more compounds in raw milk (GF: five compounds; WF: 22 compounds). Supplementation with WF could increase the concentration of nonanal, heptanal, hexanal, which could cause the occurrence of off-flavors, and reduce the concentration of hexanoic acid (monomer; M), 2-hexanol, ethanol (M), 2-heptanone (dimer; D), 2-pentanone (M), 2-pentanone (D), acetoin (M) in raw milk. GF supplementation in diet could reduce the 2-pentanone (M), 2-pentanone (D). In addition, principal component analysis (PCA) based on the signal intensity of identified VOCs indicated that it is possible to distinguish between the CK and WF milk. However, GF milk could not be distinguished from CK milk. The results demonstrate that compared with GF milk, WF supplementation in diet of dairy cows could increase fishy (heptanal) cardboard-like (pentanal) flavor in milk and decrease sweet (hexanoic acid, 2-heptanone), fruity (ethyl butanoate, ethyl hexanoate, 2-heptanone) flavor which may lead the milk less acceptable. In conclusion, compared with WF, GF supplementation in diet of dairy cow showed higher increase in n-3 PUFA in raw milk, and less influence in VOCs of raw milk and this study might provide theoretical supports for the production of milk rich in n-3 PUFA.

Milk Odd and Branched Chain Fatty Acids in Dairy Cows: A Review on Dietary Factors and Its Consequences on Human Health

This review highlights the importance of odd and branched chain fatty acids (OBCFAs) and dietary factors that may affect the content of milk OBCFAs in dairy cows. Historically, OBCFAs in cow milk had little significance due to their low concentrations compared to other milk fatty acids (FAs). The primary source of OBCFAs is ruminal bacteria. In general, FAs and OBCFAs profile in milk is mainly affected by dietary FAs and FAs metabolism in the rumen. Additionally, lipid mobilization in the body and FAs metabolism in mammary glands affect the milk OBCFAs profile. In cows, supplementation with fat rich in linoleic acid and α-linolenic acid decrease milk OBCFAs content, whereas supplementation with marine algae or fish oil increase milk OBCFAs content. Feeding more forage rather than concentrate increases the yield of some OBCFAs in milk. A high grass silage rate in the diet may increase milk total OBCFAs. In contrast to saturated FAs, OBCFAs have beneficial effects on cardiovascular diseases and type II diabetes. Furthermore, OBCFAs may have anti-cancer properties and prevent Alzheimer's disease and metabolic syndrome.

Replacing soybean meal with okara meal: Effects on production, milk fatty acid and plasma amino acid profile, and nutrient utilization in dairy cows

Okara meal is a byproduct from the production of soymilk and tofu and can potentially replace soybean meal (SBM) in dairy diets due to its high crude protein (CP) concentration and residual fat. The objective of this study was to investigate the effects of replacing SBM with okara meal on feed intake, yields of milk and milk components, milk fatty acid (FA) profile, nutrient utilization, and plasma AA concentration in lactating dairy cows. Twelve multiparous (65 ± 33 d in milk) and 8 primiparous (100 ± 35 d in milk) organically certified Jersey cows were paired by parity or days in milk, and within pair, randomly assigned to treatments in a crossover design with 21-d periods (14 d for diet adaptation and 7 d for data and sample collection). Diets were fed as total mixed ration formulated to be isonitrogenous and isofibrous and contained (dry matter basis) 50% mixed, mostly grass baleage, 2% sugarcane liquid molasses, 2% minerals-vitamins premix, and either (1) 8.1% SBM, 10% soyhulls, and 27.9% ground corn (CTRL); or (2) 15% okara meal, 8% soyhulls, and 23% ground corn (OKR). Dietary CP, ash-free neutral detergent fiber, and total FA averaged 15.4, 35.3, and 3.08% for CTRL and 15.9%, 36.3%, and 3.74% for OKR, respectively. Substitution of SBM with okara meal did not alter dry matter intake but increased intakes of CP and ash-free neutral detergent fiber. Additionally, no significant differences between treatments were observed for yields of milk and milk components, and concentrations of milk fat, lactose, and total solids. However, milk true protein concentration was lower in cows fed OKR (3.76%) versus CTRL (3.81%). Both milk urea N (8.51 vs. 9.47 mg/dL) and plasma urea N (16.9 vs. 17.8 mg/dL) concentrations decreased with OKR relative to the CTRL diet, respectively. Compared with CTRL, feeding OKR lowered the milk proportions of total odd-chain FA, de novo FA, and mixed FA and increased those of preformed FA, total n-6 FA, and total n-3 FA. The milk proportions of trans-10 18:1, trans-11 18:1, and cis-9,trans-11 18:2 were greater with feeding OKR versus the CTRL diet. The apparent total-tract digestibility of nutrients, urinary excretion of total purine derivatives (uric acid plus allantoin), and total N were not affected by treatments. Except for plasma Leu, which was lower in OKR compared with the CTRL diet, no other significant changes in the plasma concentrations of AA were observed. The plasma concentration of carnosine was lowest in cows receiving the OKR diet. Overall, our results revealed that okara meal can completely replace SBM without negatively affecting production and nutrient digestibility in early- to mid-lactation Jersey cows. Further research is needed to assess the economic feasibility of including okara meal in dairy diets, as well as the amount of okara meal that maximizes yields of milk and milk components in dairy cows in different stages of lactation.

In Vitro and In Vivo Studies of Rumen-Protected Microencapsulated Supplement Comprising Linseed Oil, Vitamin E, Rosemary Extract, and Hydrogenated Palm Oil on Rumen Fermentation, Physiological Profile, Milk Yield, and Milk Composition in Dairy Cows

The aim of the present study was to evaluate the effects of adding dietary rumen-protected microencapsulated supplements into the ruminal fluid on the milk fat compositions of dairy cows. These supplements comprised linseed oil, vitamin E, rosemary extract, and hydrogenated palm oil (MO; Microtinic® Omega, Vetagro S.p.A, Reggio Emilia, Italy). For in vitro ruminal fermentation, Holstein-Friesian dairy cows each equipped with a rumen cannula were used to collect ruminal fluid. Different amounts (0%, 1%, 2%, 3%, 4%, and 5%) of MO were added to the diets to collect ruminal fluids. For the in vivo study, 36 Holstein-Friesian dairy cows grouped by milk yield (32.1 ± 6.05 kg/d/head), days in milk (124 ± 84 d), and parity (2 ± 1.35) were randomly and evenly assigned to 0.7% linseed oil (LO; as dry matter (DM) basis) and 2% MO (as DM basis) groups. These two groups were fed only a basal diet (total mixed ration (TMR), silage, and concentrate for 4 weeks) (period 1). They were then fed with the basal diet supplemented with oil (0.7 LO and 2% MO of DM) for 4 weeks (period 2). In the in vitro experiment, the total gas production was found to be numerically decreased in the group supplemented with 3% MO at 48 h post in vitro fermentation. A reduction of total gas production (at 48 h) and increase in ammonia concentration (24 h) were also observed in the group supplemented with 4% to 5% MO (p < 0.05). There were no differences in the in vitro fermentation results, including pH, volatile fatty acids, or CH4 among groups supplemented with 0%, 1%, and 2% MO. The results of the in vitro study suggest that 2% MO is an optimal dosage of MO supplementation in cows' diets. In the in vivo experiment, the MO supplement more significantly (p < 0.01) increased the yield of total w3 fatty acids than LO (9.24 vs. 17.77 mg/100 g milk). As a result, the ratio of total omega-6 to omega-3 fatty acids was decreased (p < 0.001) in the MO group compared to that in the LO group (6.99 vs. 3.48). However, the milk yield and other milk compositions, except for milk urea nitrogen, were similar between the two groups (p > 0.05). Collectively, these results suggest that the dietary supplementation of 2% MO is beneficial for increasing omega-3 fatty acids without any negative effects on the milk yield of dairy cows.

Symposium review: Comparisons of feed and milk nitrogen efficiency and carbon emissions in organic versus conventional dairy production systems

Evaluation of feed efficiency (FE; calculated as energy-corrected milk yield/dry matter intake) and milk nitrogen efficiency (MNE; calculated as milk N yield/N intake) is needed to help farmers make decisions regarding the economic and environmental sustainability of dairy farms. Our primary objective was to compare FE and MNE data obtained from studies conducted with organic versus conventional dairy cows. Specifically, 3 data sets were constructed to meet this goal: (1) the organic Jersey data set (ORG-JE) built with studies (n = 11) done at the University of New Hampshire Burley-Demeritt Organic Dairy Research Farm (Lee, NH), (2) the conventional Jersey data set (CON-JE) constructed using 19 experiments reported in the literature, and (3) the organic non-Jersey-breed (mostly Holstein, Swedish Red, and Norwegian Red) data set (ORG-NJE) created with 11 published studies. Comparisons were made between ORG-JE and CON-JE and between ORG-JE and ORG-NJE. A second objective was to compare the enteric methane (CH₄) emission data set from studies using organic Jerseys (n = 5) with those using conventional Jerseys (n = 4). Cows used in the ORG-JE data set had lower FE (-16%) and MNE (-15.5%) than cows used in the CON-JE counterpart, possibly because dry matter intake increased by an average of 10.4% in organic cows. Feed efficiency and MNE computed from cows belonging to the ORG-NJE data set were intermediate between ORG-JE and CON-JE. Measured CH₄ intensity (g/kg of energy-corrected milk) from cows in the ORG-JE CH₄ data set increased by 71% compared with that from cows in the CON-JE CH₄ data set. Estimated FE and enteric CH₄ emissions revealed that Wisconsin organic dairies with the heaviest reliance on forage sources and longest grazing time during the summer were the least feed efficient and emitted the greatest amount of CH₄ per kilogram of energy-corrected milk at the animal and whole-farm levels. Overall, the comparisons of FE, MNE, and enteric CH₄ emissions between organic and conventional dairies and within organic systems made in this symposium review should be interpreted cautiously because they are based on study means and small data sets. Research is needed to better characterize the performance, efficiency, profitability, and carbon emissions of forage-based organic dairies in the United States, including the fast-growing "grass-fed" segment, which relies exclusively on forage diets. The effect of large organic dairies on the economic and social sustainability of small and mid-size organic dairy operations nationwide also deserves further investigation.

Production, milk iodine, and nutrient utilization in Jersey cows supplemented with the brown seaweed Ascophyllum nodosum (kelp meal) during the grazing season

Kelp meal (KM) is a supplement made from the brown seaweed Ascophyllum nodosum, known to bioaccumulate iodine (I) and to be the richest source of phlorotannins, which can inhibit ruminal proteolysis and microbial growth. The objective of this study was to investigate the effects of KM on production, milk I, concentrations of blood metabolites, apparent total-tract digestibility of nutrients, and CH4 emissions in grazing dairy cows. Eight multiparous Jersey cows averaging (mean ± SD) 175 ± 60 d in milk and 12 primiparous Jersey cows averaging 142 ± 47 d in milk at the beginning of the study were assigned to either 0 g/d of KM (control diet, CTRL) or 113 g/d of KM (brown seaweed diet, BSW) in a randomized complete block design. Diets were formulated to yield a 70:30 forage-to-concentrate ratio and consisted of (dry matter basis): 48% cool-season perennial herbage and 52% partial TMR (pTMR). Each experimental period (n = 3) lasted 28 d, with data and sample collection taking place during the last 7 d of each period. Cows had approximately 16.5 h of access to pasture daily. Herbage dry matter intake increased, and total dry matter intake tended to increase in cows fed BSW versus the CTRL diet. Milk yield and concentrations and yields of milk components were not affected by diets. Similarly, blood concentrations of cortisol, glucose, fatty acids, and thyroxine did not change with feeding CTRL or BSW. However, a diet × period interaction was observed for milk I concentration; cows offered the BSW diet had greater milk I concentration during periods 1, 2, and 3, but the largest difference between BSW and CTRL was observed in period 2 (579 vs. 111 µg/L, respectively). Except for period 2, the concentration of milk I in cows fed KM did not exceed the 500 µg/L threshold recommended for human consumption. Diet × period interactions were also found for serum triiodothyronine concentration, total-tract digestibilities of crude protein and acid detergent fiber, CH4 production, and urinary excretion of purine derivatives. Overall, the lack of KM effects on milk yield and concentrations and yields of milk components indicate that dairy producers should consider costs before making KM supplementation decisions during the grazing season. Future research is needed to evaluate the concentration of I in retail organic milk because of the high prevalence of KM supplementation in northeastern and midwestern US organic dairies and possibly in other regions of the country.

Production, milk fatty acid profile, and nutrient utilization in grazing dairy cows supplemented with ground flaxseed

Flaxseed has been extensively used as a supplement for dairy cows because of its high concentrations of energy and the n-3 fatty acid (FA) cis-9,cis-12,cis-15 18:3. However, limited information is available regarding the effect of ground flaxseed on dry matter intake (DMI), ruminal fermentation, and nutrient utilization in grazing dairy cows. Twenty multiparous Jersey cows averaging (mean ± standard deviation) 111 ± 49 d in milk in the beginning of the study were used in a randomized complete block design to investigate the effects of supplementing herbage (i.e., grazed forage) with ground corn-soybean meal mix (control diet = CTRL) or ground flaxseed (flaxseed diet = FLX) on animal production, milk FA, ruminal metabolism, and nutrient digestibility. The study was conducted from June to September 2013, with data and sample collection taking place on wk 4, 8, 12, and 16. Cows were fed a diet formulated to yield a 60:40 forage-to-concentrate ratio consisting of (dry matter basis): 40% cool-season perennial herbage, 50% partial total mixed ration, and 10% of ground corn-soybean meal mix or 10% ground flaxseed. However, estimated herbage DMI averaged 5.59 kg/d or 34% of the total DMI. Significant treatment by week interactions were observed for milk and blood urea N, and several milk FA (e.g., trans-10 18:1). No significant differences between treatments were observed for herbage and total DMI, milk yield, feed efficiency, concentrations and yields of milk components, and urinary excretion of purine derivatives. Total-tract digestibility of organic matter decreased, whereas that of neutral detergent fiber increased with feeding FLX versus CTRL. No treatment effects were observed for ruminal concentrations of total volatile FA and NH3-N, and ruminal proportions of acetate and propionate. Ruminal butyrate tended to decrease, and the acetate-to-propionate ratio decreased in the FLX diet. Most saturated and unsaturated FA in milk fat were changed. Specifically, milk proportion of cis-9,cis-12,cis-15 18:3, Σn-3 FA, and Σ18C FA increased, whereas that of cis-9,cis-12 18:2, Σn-6 FA, Σ odd-chain FA, Σ<16C FA, and Σ16C FA decreased with feeding FLX versus the CTRL diet. In conclusion, feeding FLX did not change yields of milk and milk components, but increased milk n-3 FA. Therefore, costs and industry adoption of premiums for n-3-enriched milk will determine the adoption of ground flaxseed in pasture-based dairy farms.

Production, milk and plasma fatty acid profile, and nutrient utilization in Jersey cows fed flaxseed oil and corn grain with different particle size

We aimed to compare the effects of ground (GC) or cracked corn (CC), with or without flaxseed oil (FSO), on milk yield, milk and plasma fatty acid (FA) profile, and nutrient digestibility in Jersey cows fed diets formulated to contain similar starch concentrations. Twelve multiparous organic-certified Jersey cows averaging (mean ± standard deviation) 455 ± 41.9 kg of body weight and 152 ± 34 d in milk and 4 primiparous organic-certified Jersey cows averaging (mean ± standard deviation) 356 ± 2.41 kg of body weight and 174 ± 30 d in milk in the beginning of the experiment were used. Cows were randomly assigned to treatment sequences in a replicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. Each period lasted 24 d with 18 d for diet adaptation and 6 d for data and sample collection. Treatments were fed as total mixed rations consisting of (dry matter basis): (1) 0% FSO + 27.1% GC, (2) 0% FSO + 28.3% CC, (3) 3% FSO + 27.1% GC, and (4) 3% FSO + 28.3% CC. All cows were offered 55% of the total diet dry matter as mixed grass-legume baleage and treatments averaged 20% starch. Significant FSO × corn grain particle size interactions were observed for some variables including milk concentration of lactose and proportions of cis-9,cis-12,cis-15 18:3 in milk and plasma. The proportion of cis-9,cis-12,cis-15 18:3 in milk and plasma decreased slightly when comparing GC versus CC in 0% FSO cows, but a larger reduction was observed in 3% FSO cows. Dry matter intake did not differ and averaged 16.1 kg/d across diets. Feeding 3% FSO increased yields of milk and milk fat and lactose and feed and milk N efficiencies, but decreased fat, true protein, and MUN concentrations and apparent total-tract digestibility of fiber. The Σ branched-chain, Σ<16C, Σ16C, and Σn-6 FA decreased, whereas Σ18C, Σcis-18:1, and Σtrans-18:1 FA increased in 3% versus 0% FSO cows. No effect of corn particle size was observed for production and milk components. However, the apparent total-tract digestibility of starch was greater in GC than CC cows. Compared with CC, GC increased Σ branched-chain, Σ<16C, Σ16C, Σn-6 FA, and decreased Σ18C and Σ cis-18:1 FA in milk fat. Overall, results of this study are more directly applicable to dairy cows fed low starch, mixed grass-legume baleage-based diets.

A comparison of the effect of soybeans roasted at different temperatures versus calcium salts of fatty acids on performance and milk fatty acid composition of mid-lactation Holstein cows

To evaluate the effect of soybeans roasted at different temperatures on milk yield and milk fatty acid composition, 8 (4 multiparous and 4 primiparous) mid-lactation Holstein cows (42.9±3 kg/d of milk) were assigned to a replicated 4×4 Latin square design. The control diet (CON) contained lignosulfonate-treated soybean meal (as a source of rumen-undegradable protein) and calcium salts of fatty acids (Ca-FA, as a source of energy). Diets 2, 3, and 4 contained ground soybeans roasted at 115, 130, or 145°C, respectively (as the source of protein and energy). Dry matter intake (DMI) tended to be greater for CON compared with the roasted soybean diets (24.6 vs. 23.3 kg/d). Apparent total-tract digestibilities of dry matter, organic matter, and crude protein were not different among the treatments. Actual and 3.5% fat-corrected milk yield were greater for CON than for the roasted soybean diets. Milk fat was higher for soybeans roasted at 130°C than for those roasted at either 115 or 145°C. No differences were observed between the CON and the roasted soybean diets, or among roasting temperatures, on feed efficiency and nitrogen concentrations in rumen, milk, and plasma. Milk from cows fed roasted soybeans had more long-chain fatty acids and fewer medium-chain fatty acids than milk from cows fed Ca-FA. Compared with milk from cows fed the CON diet, total milk fat contents of conjugated linoleic acid, cis-9,trans-11 conjugated linoleic acid, cis-C18:2, cis-C18:3, and C22:0 were higher for cows fed the roasted soybean diets. Polyunsaturated fatty acids and total unsaturated fatty acids were greater in milk from cows fed roasted soybean diets than in milk from cows fed CON. Concentrations of C16:0 and saturated fatty acids in milk fat were greater for CON than for the roasted soybean diets. Cows fed roasted soybean diets had lower atherogenic and thrombogenic indices than cows fed CON. Milk fatty acid composition did not differ among different roasting temperatures. In summary, results showed that cows fed CON had higher DMI and milk yield than cows fed roasted soybean diets. Among different roasting temperatures (115, 130, and 145°C), soybeans roasted at 115°C led to higher milk production and lower DMI. Cows fed roasted soybeans, regardless of the roasting temperature, had more unsaturated fatty acids in milk. Using roasted soybeans in dairy cow rations could, therefore, improve the health indices of milk for human nutrition.