Production Performance and Milk Composition of Dairy Cows Fed Whole or Ground Flaxseed With or Without Monensin

Role of Chitin and Chitosan in Ruminant Diets and Their Impact on Digestibility, Microbiota and Performance of Ruminants

The slow progress in the development of the subsector, particularly of alternative feed sources such as agro-industrial byproducts and unconventional feed resources, has deepened the gap in the availability of and accessibility to animal feed. Production of animal feed is highly resource demanding. Recently, it has been shown that increasing climate change, land degradation, and the recurrence of droughts have worsened the feed gap. In the backdrop of these challenges, there has been attention to food-not-feed components, which have great potential to substitute human-edible components in livestock feeding. Chitosan, a non-toxic polyglucosamine, is widely distributed in nature and used as a feed additive. Chitosan is obtained from the de-acetylation process of the chitin and is mostly present in shrimp, crabs, and insect exoskeletons, and has antimicrobial and anti-inflammatory, anti-oxidative, antitumor, and immune-stimulatory hypo-cholesterolemic properties. This review article discusses the results of recent studies focusing on the effects of chitosan and chitin on the performance of dairy cows, beef steers, sheep, and goats. In addition, the effects of chitosan and chitin on feed intake, feed digestibility, rumen fermentation, and microbiota are also discussed. Available evidence suggests that chitosan and chitin used as a feed additive for ruminants including dairy cows, beef steers, sheep, goats, and yaks have useful biological effects, including immune-modulatory, antimicrobial, and other important properties. These properties of chitosan and chitin are different from the other feed additives and have a positive impact on production performance, feed digestibility, rumen fermentation, and bacterial population in dairy cows, beef steers, sheep, goats, and yaks. There is promising evidence that chitosan and chitin can be used as additives in livestock feed and that well-designed feeding interventions focusing on these compounds in ruminants are highly encouraged.

Effect of Whole or Ground Flaxseed Supplementation on Fatty Acid Profile, Fermentation, and Bacterial Composition in Rumen of Dairy Cows

Flaxseed is rich in α-linolenic acid (ALA) and can increase omega-3 polyunsaturated fatty acid in the milk of dairy cows. However, the response of rumen fermentation to different forms of flaxseed supplementation is unknown. This study aimed to investigate the effect of different forms of flaxseed on the fatty acid profile, fermentation, and composition of bacteria in the rumen of dairy cows. In total, 30 Holstein dairy cows were selected and randomly assigned into three groups (10/group). Cows were fed a basal diet (control check; CK) or basal diets supplemented with either 1,500 g per day whole flaxseed (WF) or 1,500 g per day ground flaxseed (GF). The WF group had the highest ALA content in rumen fluid, whereas no difference was found between the CK and GF groups. However, the molar proportion of acetate increased in the WF and GF groups and was the highest in the GF group, and a similar trend was shown by propionate, isobutyrate, butyrate, isovalerate, and valerate (CK < WF < GF). The abundance of Ruminococcaceae_NK4A214_group, Christensenellaceae_R-7_group, and Eubacterium_coprostanoligenes_group also showed the same trend (CK < WF < GF). Different forms of flaxseed release ALA by different mechanisms in the rumen, and the molar proportions of volatile fatty acids and the bacterial composition were potentially influenced mainly by the amount of ALA released into the rumen.

Effect of monensin on milk fatty acid profile in dairy cows and on the use of fatty acids for early diagnosis of elevated blood plasma concentrations of nonesterified fatty acids and hyperketonemia

This work examined the effects of precalving administration of continuous-release monensin capsule on postcalving milk fatty acid (FA) profile and on the accuracy of FA as a biomarker in the early identification of cows with elevated blood plasma nonesterified fatty acids (NEFA) and β-hydroxybutyrate (BHB) concentrations. Approximately 3 wk before expected calving, 203 multiparous Estonian Holstein cows were randomly divided into control (CO; n = 116) and experimental (MO; n = 87) groups, and a continuous-release capsule of monensin was administered to the MO cows. Blood samples were taken daily in the first 4 d postpartum, then on the sixth or seventh day in milk, twice in the second week, and thenceforth once per week until the end of the sixth week. Milk samples were taken once from 4 to 7 d in milk, twice in the second week, and thenceforth once per week. Blood samples were analyzed for NEFA and BHB, and milk was analyzed for FA concentrations. Cows with postpartum BHB concentrations ≥1.2 mmol/L at least once during the 6 wk were classified as hyperketonemic (HYK), and cows with NEFA concentrations ≥1.0 mmol/L as having elevated concentration of NEFA (NEFA_H). The ability of FA to predict NEFA_H and HYK cows was studied with logistic regression and receiver operating characteristic curve analysis and the identification accuracy was estimated by area under the receiver operating characteristic curve. For these analyses, we used FA measured on the ninth day after calving. Monensin administration affected FA mobilization and metabolism of the animals as blood NEFA were lower in the MO group on wk 1 and wk 3, and BHB values were considerably lower from wk 1 to wk 4 compared with the CO group. The FA dynamics were generally similar for MO and CO groups. Monensin administration resulted in higher concentrations of C15:0, C16:0, iso C17:0, anteiso C15:0, anteiso C17:0, total trans monounsaturated FA, and C18:2 cis-9,trans-11, and lower proportions of C18:0, C18:1 cis-9, and most of the iso FA. The identification accuracy of NEFA_H and HYK cows was higher in the CO compared with the MO group and for the identification of HYK compared with NEFA_H cows (0.75-0.77 vs. 0.78-0.80 in the CO group, and 0.61-0.66 vs. 0.68-0.75 in the MO group for NEFA_H vs. HYK, respectively). For all FA, the threshold values to identify NEFA_H and HYK cows were different in the CO and MO groups. Results suggest that specific threshold values for the identification of NEFA_H and HYK cows could be applicable only within similar feeding conditions and rumen environment.

Impacts of feeding monensin sodium on production and the efficiency of milk production in dairy cows fed total mixed rations: evaluation of a confounded literature

The amount of milk Canadian dairy farmers produce is limited to a production quota expressed in milk fat. Because milk economic value is primarily based on fat and protein, it can be advantageous to decrease the milk fat to protein ratio. Monensin sodium has been suggested to reduce milk fat proportion and outputs, but not milk protein. Publications using lactating dairy cows were utilized to assess predictability of production responses to monensin feeding based upon their base production characteristics and diet composition. Predicted animal output changes due to monensin had poor fits with low r2 (0.31–0.44) and unevenly distributed residuals. Further assessment revealed that cow characteristics, and diets, were not independent of monensin feeding level. Thus, the 43 comparisons were clustered into levels of 10–12, 14–18, or 20–24 mg kg−1 of diet dry matter (DM). Milk fat yield reductions due to monensin differed (P < 0.05; 10–12 and 14–18 mg kg−1 DM), or tended to differ (P = 0.057; 20–24 mg kg−1 DM), from zero (i.e., no change). Monensin addition to total mixed rations of lactating dairy cows negatively impacted milk fat yield to a greater extent than milk protein.

Natural Oregano Essential Oil May Replace Antibiotics in Lamb Diets: Effects on Meat Quality

A study was conducted to investigate the effect of oregano essential oil (OEO) and monensin sodium on the oxidative stability, colour, texture, and the fatty acid profile of lamb meat (m. Longissimus lumborum). Twenty Dorper x Pelibuey lambs were randomly divided into five treatments; control (CON), monensin sodium (SM, Rumensin 200® 33 mg/kg), a low level of OEO (LO, 0.2 g/kg dry matter (DM)), a medium level of OEO (MO, 0.3g/ kg DM), and a high level of OEO (HO, 0.4 g/kg DM). Dietary supplementation of OEO at any concentration lowered the compression strength in comparison with CON and SM. MO had the highest a* values (7.99) and fatty acid concentration (C16:1n7, C18:1n9c, C18:1n6c, C20:1n9, and C18:2n6c) during storage for 7 d at 3 °C. Lipid oxidation was not promoted (p > 0.05) by the moderated supplementation of oregano essential oil; however, OEO at 0.3 g/kg DM showed a slight lipid pro-oxidant effect. Dietary supplementation of MO and SM had the same effect on colour, tenderness, and the fatty acid profile of lamb (L. lumborum). It was demonstrated that oregano essential oil was beneficial for lambs feeding, and it could be a natural alternative to replace monensin in lamb diets with improvements in the quality of the meat.

Combination of pelleting and monensin does not affect antioxidant properties and fatty acids in milk of grazing dairy cows supplemented with a concentrate containing soybean seeds

This study was performed with the main objective of evaluating the effect of the combination of pelleting and monensin on fatty acids (FA) composition, the concentration of total polyphenols and flavonoids, and the oxidative stability of milk in cows fed a concentrate containing soybean seeds. Eight Holstein multiparous cows were distributed in a replicated Latin square design. The four supplement treatments consisted of the combination of two factors (pelleting and monensin) and one concentrate as follows: (1) unpelleted concentrate with no monensin (CO); (2) pelleted concentrate with no monensin (PE); (3) unpelleted concentrate with 96 mg of monensin/kg of dry matter, DM (MO); and (4) pelleted concentrate with 96 mg of monensin/kg of DM (PM). There was no interaction between pelleting and monensin for milk production and concentration of milk protein, lactose, total polyphenols, flavonoids, conjugated dienes (CD), and reducing power. Fat and total solids concentration in milk were decreased when cows were fed pelleted (PE and PM) concentrates. Feeding cows with PE and PM concentrates increased the CD concentration in milk. Regarding milk FA concentration, there was no difference among treatments for total saturated, monounsaturated, and polyunsaturated FA. The most prominent result was that pelleting increased the milk concentration of omega-3 FA. Altogether, the present study suggests that the pelleting process can improve the milk fat quality by increasing the omega-3 FA, while the combination of pelleting and monensin in the diet of grazing dairy cows fed soybean-based concentrate adds no further improvements to FA profiles and oxidative stability of milk.

Monensin Alters the Functional and Metabolomic Profile of Rumen Microbiota in Beef Cattle

Simple Summary

Monensin can enhance the efficiency of feed utilization by modulating rumen fermentation; however, its effects on rumen function has not been fully described. Thus, this study integrated metagenomics and metabolomics analysis to identify differences in functional attributes and metabolites of rumen microbiota in beef steers fed no or 200 mg/d of monensin. Our results showed differences in relative abundance of functional genes involved in lipid metabolism and amino acid metabolism as well as changes in rumen fluid metabolites and their metabolic pathways. This study revealed a better understanding of the effects of monensin, which may enable more effective use of this additive for beef cattle production.

Abstract

To identify differences in rumen function as a result of feeding monensin to beef cattle, rumen fluid metagenomics and metabolomics analyses were used to evaluate the functional attributes and metabolites of rumen microbiota in beef steers fed no or 200 mg/d of monensin. Eight rumen-fistulated steers were used in the study for a period of 53 days. Rumen fluid samples were collected on the last day of the experiment. Monensin increased the relative abundance of Selenomonas sp. ND2010, Prevotella dentalis, Hallella seregens, Parabacteroides distasonis, Propionispira raffinosivorans, and Prevotella brevis, but reduced the relative abundance of Robinsoniella sp. KNHs210, Butyrivibrio proteoclasticus, Clostridium botulinum, Clostridium symbiosum, Burkholderia sp. LMG29324, and Clostridium butyricum. Monensin increased the relative abundance of functional genes involved in amino acid metabolism and lipid metabolism. A total of 245 metabolites were identified. Thirty-one metabolites were found to be differentially expressed. Pathway analysis of the differentially expressed metabolites revealed upregulated metabolic pathways associated with metabolism of linoleic acid and some amino acids. These findings confirm that monensin affects rumen fermentation of forage-fed beef cattle by modulating the rumen microbiome, and by reducing amino acid degradation and biohydrogenation of linoleic acid in the rumen.

Pelleting in Associated with Sodium Monensin Increases the Conjugated Linoleic Acids Concentration in the Milk of Dairy Cows Fed Canola Seeds

To evaluate the effects of the pelleting and the addition of sodium monensin on production, the chemical and lipid composition of milk and butter physical characteristics, 4 Holstein dairy cows (135 days of lactation) with an average milk production of 14.7 kg/d, were supplemented with a concentrate containing ground canola seeds. The cows were assigned to a 4×4 Latin square design with a 2×2 factorial arrangement of treatments: i) ground maize, soybean meal, mineral and vitamin supplements, and ground canola seeds (CG); ii) CG concentrate with 31.5 mg of monensin added per kg of dry matter (DM); iii) CG pelleted concentrate; iv) CG concentrate with monensin addition pelleted. There was no difference in milk production and composition. The addition of monensin increased milk concentration of polyunsaturated fatty acids (PUFA), the PUFA/saturated fatty acids (SFA) ratio, and omega 6. The pelleting increased the concentration of monounsaturated fatty acids, the PUFA/SFA ratio, and the omega 6/omega 3 ratio, but decreased the concentration of SFA. The association between pelleting and the addition of monensin increased the concentration of conjugated linoleic acids by 46.9%. The physical characteristics of butter were not affected by the evaluated diets. We concluded that the concentrate with 31.5 mg of monensin added per kg DM basis combined with the pelleting improves the lipid composition of milk from Holstein cows that are on pasture and supplemented with ground canola seeds, without changing the production, milk composition, and spreadability of butter.

Effect of soybean roasting and monensin on microbial protein synthesis, ruminal parameters and plasma metabolites of lactating dairy cows

This study was conducted to evaluate the effects of inclusion of roasted whole soybean seed and monensin (MO) in the diets of lactating dairy cows on plasma metabolites, ruminal parameters, and microbial protein synthesised in the rumen. Four multiparous Holstein lactating dairy cows (third parity; 656 ± 55 kg of liveweight; 83 ± 10 days in milk; 35 ± 4 kg/day milk yield) were assigned to a balanced 4 × 4 Latin square design. Each experimental period lasted 21 days with 14 days of treatment adaptation and 7 days of data collection. The control diet (C) was a total mixed ration consisting of 40% forage and 60% concentrate mixture on a dry matter (DM) basis. These cows were randomly assigned to one of the four dietary treatments. The first treatment was the C diet of unprocessed whole soybean seed, second was the C diet supplemented with 24 mg of MO/kg of DM (M), the third was roasted whole soybean seed (R) and the fourth treatment was R diet supplemented with 24 mg of MO/kg of DM (RM). Urinary excretion of creatinine and purine derivatives, microbial protein synthesised in the rumen, rumen pH and rumen concentrations of volatile fatty acids and ammonia were similar among the dietary treatments (P > 0.05). Orthogonal contrasts showed that the rumen concentration of acetate was lower in MO-supplemented cows than non-supplemented cows (P < 0.05). Dietary treatments had no effects on plasma concentrations of glucose, total cholesterol, triglycerides and total protein (P > 0.05). Plasma concentration of urea was significantly lower in cows fed with the RM diet compared with cows fed the C and M diets (P < 0.05). In conclusion, dietary treatments had no effect on microbial protein synthesised in the rumen, plasma metabolites (except for plasma concentration of urea) and ruminal parameters of dairy cows.

Effect of flaxseed physical form on digestibility of lactation diets fed to Holstein steers

Four multicannulated (rumen, duodenum, and ileum) Holstein steers (459.7±46.4kg of initial body weight) were used in a 4×4 Latin square design to determine the effect of flaxseed processing method on ruminal fermentation and digestibility. Treatments were based on inclusion of (1) 7.5% linseed meal (control), (2) 10% whole flaxseed, (3) 10% rolled flaxseed, or (4) 10% ground flaxseed on a dry matter (DM) basis, and were formulated to mimic typical high-producing dairy cow lactation diets. The control diet contained linseed meal in a proportion to provide crude protein (CP) equal to the amount of CP contributed by the flaxseed in the other treatments. Diets were fed for ad libitum intake and contained 30% corn silage, 17% chopped alfalfa hay, 6% sugar beet pulp, and 47% concentrate (comprising ground corn, supplemental protein, trace minerals and vitamins, and either flaxseed or linseed meal (DM basis). Diets were formulated to contain 17% CP, 34% neutral detergent fiber, 21% acid detergent fiber, and 4% fatty acid (DM basis). Periods were 14 d long and consisted of 7 d of adaptation and 7 d of sample collection. Dry matter intake (as a % of body weight) was similar (2.41±0.17) for all treatments. The inclusion of flaxseed, regardless of processing method, tended to decrease total-tract organic matter digestibility relative to the linseed control, but no differences in CP intake, duodenal CP flow (bacterial, apparent feed, or total), ileal CP flow, fecal CP output, microbial efficiency, or CP digestibility (apparent ruminal, true ruminal, small intestine, large intestine, or total tract) were observed between treatments. Method of processing did not alter ruminal pH, ammonia, or volatile fatty acids production. The ground flaxseed treatment had the fastest rate of in situ DM degradation (11.25%/h), followed by the control (7.46%/h), rolled flaxseed (4.53%/h), and whole flaxseed (0.57%/h) treatments. Degradability of CP and fat followed the same pattern as DM degradability for processed flaxseed. In situ degradation rates of alfalfa hay neutral detergent fiber and acid detergent fiber tended to be fastest for the ground flaxseed treatment. Taken together, the digestibility, fermentation, and in situ data indicate that rolling and grinding are both acceptable methods of processing flaxseed. The in situ data strongly support the need for processing flaxseed before inclusion in lactation diets.

Effect of feeding extruded flaxseed with different grains on the performance of dairy cows and milk fatty acid profile

Sixteen Holsteins cows were used in a Latin square design experiment to determine the effects of extruded flaxseed (EF) supplementation and grain source (i.e., corn vs. barley) on performance of dairy cows. Extruded flaxseed diets contained 10% [dry matter (DM) basis] of an EF product that consisted of 75% flaxseed and 25% ground alfalfa meal. Four lactating Holsteins cows fitted with rumen fistulas were used to determine the effects of dietary treatments on ruminal fermentation. Intakes of DM (23.2 vs. 22.2 kg/d), crude protein (4.2 vs. 4.0 kg/d), and neutral detergent fiber (8.3 vs. 7.9 kg/d) were greater for cows fed EF diets than for cows fed diets without EF. Milk yield and composition were not affected by dietary treatments. However, 4% fat-corrected milk (30.5% vs. 29.6 kg/d) and solids-corrected milk (30.7 vs. 29.9 kg/d) were increased by EF supplementation. Ruminal pH and total volatile fatty acid concentration were not influenced by EF supplementation. However, feeding barley relative to corn increased molar proportions of acetate and butyrate and decreased that of propionate. Ruminal NH3-N was lower for cows fed barley than for cows fed corn. Milk fatty acid composition was altered by both grain source and EF supplementation. Cows fed EF produced milk with higher polyunsaturated and lower saturated fatty acid concentrations than cows fed diets without EF. Feeding EF or corn increased the milk concentration of C18:0, whereas that of C16:0 was decreased by EF supplementation only. Extruded flaxseed supplementation increased milk fat α-linolenic acid content by 60% and conjugated linoleic acid content by 29%. Feeding corn relative to barley increased milk conjugated linoleic acid by 29% but had no effect on milk α-linolenic concentration. Differences in animal performance and milk fatty acid composition were mainly due to EF supplementation, whereas differences in ruminal fermentation were mostly due to grain source.

Milk production, milk composition, live weight change and milk Fatty Acid composition in lactating dairy cows in response to whole linseed supplementation

The objective of this study was to determine the effects of whole linseed supplementation on performances and milk fatty acid composition of dairy cows. Thirty six Holstein Friesian crossbred lactating dairy cows were blocked by milking days first and then stratified random balanced for milk yields and body weight into three groups of 12 cows each. The control group received 300 g of palm oil. The second group was supplemented with 344 g/d of top-dressed whole linseed plus 150 g of palm oil and the third group was supplemented with 688 g/d of top-dressed whole linseed. All cows also received ad libitum grass silage (Brachiaria ruziziensis), had free access to clean water and were individually housed in a free-stall unit and individually fed according to treatments. Residual feeds were collected on 2 consecutive days weekly and at the end of the experiment. Feed samples were pooled to make representative samples for proximate and detergent analyses. Daily milk yields were recorded. Milk samples were collected on 2 consecutive days weekly. Live weights were recorded at the start and at the end of the experiment. Milk samples were taken on d 56 of the experiment and subjected to milk fatty acid composition. The results showed no statistical significant differences in intakes, live weight change, milk yields and milk compositions, however, C18:1, C18:3 and unsaturated FAs were increased while saturated FAs were reduced by whole linseed supplementation. It is recommended that the addition of 300 g/d oil from whole linseed could be beneficial to lactating dairy cows in early lactation.

Short communication: effect of oilseed supplementation of an herbage diet on ruminal fermentation in continuous culture

A 4-unit continuous culture fermentor system was used to evaluate the effects of oilseed supplementation of an herbage-based diet on nutrient digestibility, fermentation profile, and bacterial nitrogen (N) synthesis. Treatments were randomly assigned to fermentors in a 4×4 Latin square design with 7d for diet adaptation and 3d for data and sample collection. Dietary treatments were an herbage-only diet (HERB), or the following ground oilseeds supplemented to an herbage-based diet at 10% of total dry matter (DM) fed: flaxseed (FLAX), canola (CAN), or sunflower (SUN). Apparent DM, organic matter, and neutral detergent fiber digestibility were not affected by diet, averaging 62, 68, and 78%, respectively. True DM and organic matter digestibility were not affected by diet, averaging 78 and 82%, respectively. Fermentor pH and total volatile fatty acids were not affected by diet. Branched-chain volatile fatty acids tended to be lower for HERB compared with the 3 oilseed diets. Ammonia N concentrations were lowest for the HERB diet. Crude protein digestibility was not affected by diet. Flow of NH3-N was lowest for the HERB diet reflecting the lowest culture concentration of NH3-N. Bacterial N flows were lowest for HERB and SUN diets, intermediate for FLAX, and greatest for CAN. Flows of total N, non-NH3-N, and dietary N were not affected by diet. Likewise, efficiency of bacterial N synthesis was not affected by diet. Supplementation with FLAX, CAN, or SUN at 10% of total DM fed did not affect nutrient digestibility or ruminal fermentation compared with an all-herbage diet. The oilseeds tested herein may be considered as alternative energy supplements for grazing dairy cows, particularly during times of low availability of corn. However, in vivo studies are needed to further evaluate the effects of oilseeds supplementation of an herbage-based diet on milk production and composition (specifically human-beneficial fatty acids).

Supplementation of increasing amounts of linseed oil to dairy cows fed total mixed rations: effects on digestion, ruminal fermentation characteristics, protozoal populations, and milk fatty acid composition

The effect of linseed oil (LO) supplementation on nutrient digestibility, forage (i.e., timothy hay) in sacco ruminal degradation, ruminal fermentation characteristics, protozoal populations, milk production, and milk fatty acid (FA) profile in dairy cows was investigated. Four ruminally cannulated, primiparous lactating cows were used in a 4 × 4 Latin square design (28-d periods). They were fed a total mixed ration (50:50 forage:concentrate (F:C) ratio [dry matter (DM) basis] without supplementation (control, CTL), or supplemented (wt/wt; DM basis) with LO at 2, 3, or 4%. Supplementation with LO had no effect on DM intake (19 kg/d) and apparent total-tract digestibility of nutrients (organic matter, neutral detergent fiber, acid detergent fiber, starch, and gross energy). Ruminal pH, ammonia, and total volatile FA concentrations were not changed by LO supplementation to diets. Extent of changes in volatile FA pattern and effective ruminal degradability of DM of timothy hay were minor. Neither the total numbers nor the genera distribution of protozoa was changed by the addition of increasing amounts of LO to the diet. Milk yield increased linearly (26.1, 27.3, 27.4, and 28.4 kg/d for CTL to LO4, respectively) as the amount of LO added to the diet increased. Milk fat content was not affected by LO supplementation, whereas milk protein content decreased linearly with increasing amounts of LO in the diet. Milk fat proportions of several intermediates of ruminal biohydrogenation of polyunsaturated FA (i.e., trans-10 18:1, trans-11 18:1, cis-9,trans-11 18:2, trans-11,cis-15 18:2, and cis-9,trans-11,cis-15 18:3) increased linearly with LO addition to the diet. The proportion of cis-9,cis-12 18:2 decreased linearly (2.06, 1.99, 1.91, and 1.83% for CTL to LO4, respectively) as the amount of LO in the diet increased. Milk fat content of cis-9,cis-12,cis-15 18:3 increased as the level of LO in the diet increased up to 3% but no further increase was observed when 4% of LO was fed (0.33, 0.79, 0.86, and 0.86% for CTL to LO4, respectively). A similar quadratic response to LO supplementation was also observed for cis-5,cis-8,cis-11,cis-14,cis-17 20:5 and cis-5,cis-7,cis-10,cis-13,cis-16 22:5. The results of the present study show that LO can be safely supplemented up to 4% in forage-based diets of dairy cows to enrich milk with potential health beneficial FA (i.e., n-3 FA) without causing any detrimental effects on rumen function, digestion, and milk production.

Improvement of conception rate in postpartum flaxseed supplemented buffalo with Ovsynch+CIDR protocol

The present study was conducted on lactating Murrah buffalo to assess the effect of crushed flaxseed (a source of omega-3 fatty acids) supplementation (300g/100kg bwt/day for 60 days), over and above the routine feed, on luteolytic signal (PGF2α), luteal function (progesterone) and conception rate. In first experiment, on day 50 post-calving, six non-supplemented buffalo were treated to synchronize time of ovulation using an Ovsynch+Controlled Internal Drug Release (CIDR) protocol followed by intravenous oxytocin treatment (OT; 100IU) on day 15 post-ovulation. Blood samples were collected at 15min interval, 1h before to 4h after OT challenge. Thereafter, the same buffalo were supplemented with flaxseed, treated to synchronize time of ovulation starting on day 35 post-supplementation using the same protocol and subjected to OT treatment and blood sampling on day 15 post-ovulation. The PGF2α response was measured as the venous concentration of 13,14-dihydro-15-keto PGF2α (PGFM). The mean hourly concentration of PGFM subsequent to flaxseed supplemented was less (P<0.05) than in the pre-supplementation period at all the occasions. Flaxseed supplementation did not affect plasma fatty acids and other plasma metabolites except for an increase (P<0.05) in plasma cholesterol and plasma alanine transaminase. In the second experiment, 31 buffalo were randomly assigned to a control (n=16) and flaxseed supplemented (n=15) group. The latter group was supplemented with flaxseed starting from day 15 post-calving. On day 50-post-calving, buffalo of both groups were treated to synchronize time of ovulation among animals as described for the first experiment followed by artificial insemination (AI). Post-AI luteal phase plasma progesterone was greater (P<0.05) in the supplemented group compared to controls. Conception rate on day 63 post-AI was 66.7% in supplemented and 31.2% in controls (P<0.05). The present study indicated the beneficial impact of dietary supplementation of crushed flaxseed on conception rate through attenuation of luteolytic signal and improvement in post-breeding luteal profile.

Nutrients balances and milk fatty acid profile of mid lactation dairy cows supplemented with monensin

The aim of this study was to evaluate the nutrients balance and milk fatty acids profile of dairy cows supplemented with monensin. Twelve Brazilian Holstein dairy cows were distributed into four balanced 3x3 Latin squares, and fed with the following diets: control (C), basal diet without addition of monensin, monensin 24 (M24), addition of 24mg/kg DM of monensin, and monensin 48 (M48), addition of 48mg/kg DM. The experimental diets influenced the efficiency of net energy of lactation utilization. A quadratic effect was observed for the energy balance. It was observed effect of diets on nitrogen balance. It was observed effect of monensin in the milk yield, composition and in the milk fatty acids profile. Monensin in diets of dairy cows in mid lactation, using corn silage, improved the nutrients balance and milk fatty acid profile with 24mg/kg DM.

Effect of monensin and vitamin E on milk production and composition of lactating dairy cows

Feeding unsaturated oils to lactating dairy cows impair ruminal biohydrogenation (BH) of unsaturated fatty acids (USFA) and increase ruminal outflow of BH intermediates such as trans-10, cis-12 CLA that are considered to be potent inhibitors of milk fat synthesis. Supplementing lactating dairy cow's rations containing plant origin oils with monensin and/or vitamin E may minimise the formation of trans-10 isomers in the rumen, thereby preventing milk fat depression. Therefore, this study was conducted to evaluate the effects of monensin and vitamin E supplementation in the diets of lactating dairy cows containing whole cottonseed, as the main source of FA on feed intake, milk production and composition, milk fatty acid profile, efficiency of nitrogen (N) utilisation, efficiency of net energy (NE) utilisation and nutrients digestibilities. Four multiparous Holstein lactating dairy cows (86±41 days in milk) were assigned to a balanced 4 × 4 Latin square design. Each experimental period lasted 21 days with a 14 days of treatment adaptation and a 7 days of data collection. The control diet was a total mixed ration (TMR) consisted of 430 g/kg forage and 570 g/kg of a concentrate mixture on dry matter (DM) basis. Cows were randomly assigned to one of the four dietary treatments including control diet (C), control diet supplemented with 150 mg of vitamin E/kg of DM (E), control diet supplemented with 24 mg of monensin/kg of DM (M) and control diet supplemented with 150 mg of vitamin E and 24 mg of monensin/kg of DM (EM). Dry matter intake (DMI) ranged from 19.1 to 19.5 kg/d and was similar among the dietary treatments. Dietary supplementation with vitamin E or monensin had no effect on milk production, milk fat, protein and lactose concentrations, efficiency of utilisation of nitrogen and net energy for lactation (NEL ). Digestibility of DM, organic matter (OM), crude protein (CP) and ether extract (EE) was not affected by the dietary treatments. Digestibility of neutral detergent fibre (NDF) was higher in cows fed with the M and EM diets in relation to those fed the C and E diets. The concentrations of C4:0, C6:0, C8:0, C10:0, C12:0, C14:0, C15:0, trans-10-16:1, cis-9-16:1, 17:0, 18:0, trans-11-18:1, cis-9-18:1, cis-9, trans-11 conjugated linoleic acid (CLA), trans-10, cis-12 CLA, and 18:3n-3 FA in milk fat were not affected by the dietary supplementations. While feeding the M diet tended to decrease milk fat concentration of C16:0, the milk fat concentration of C18:2n-6 FA tended to be increased. Dietary supplementation with vitamin E or monensin had no effect on milk fat concentrations of saturated, unsaturated, monounsaturated, polyunsaturated, short chain and long chain FA, but feeding the M diet numerically decreased milk fat concentration of medium chain fatty acids (MCFA). The results showed that vitamin E and/or monensin supplementations did not improve milk fat content and did not minimise the formation of trans-10 FA isomers in the rumen when whole cottonseed was included in the diet as the main source of fatty acids.

Effects of chemically or technologically treated linseed products and docosahexaenoic acid addition to linseed oil on biohydrogenation of C18:3n-3 in vitro

Rumen biohydrogenation kinetics of C18:3n-3 from several chemically or technologically treated linseed products and docosahexaenoic acid (DHA; C22:6n-3) addition to linseed oil were evaluated in vitro. Linseed products evaluated were linseed oil, crushed linseed, formaldehyde treated crushed linseed, sodium hydroxide/formaldehyde treated crushed linseed, extruded whole linseed (2 processing variants), extruded crushed linseed (2 processing variants), micronized crushed linseed, commercially available extruded linseed, lipid encapsulated linseed oil, and DHA addition to linseed oil. Each product was incubated with rumen liquid using equal amounts of supplemented C18:3n-3 and fermentable substrate (freeze-dried total mixed ration) for 0, 0.5, 1, 2, 4, 6, 12, and 24h using a batch culture technique. Disappearance of C18:3n-3 was measured to estimate the fractional biohydrogenation rate and lag time according to an exponential model and to calculate effective biohydrogenation of C18:3n-3, assuming a fractional passage rate of 0.060/h. Treatments showed no differences in rumen fermentation parameters, including gas production rate and volatile fatty acid concentration. Technological pretreatment (crushing) followed by chemical treatment applied as formaldehyde of linseed resulted in effective protection of C18:3n-3 against biohydrogenation. Additional chemical pretreatment (sodium hydroxide) before applying formaldehyde treatment did not further improve the effectiveness of protection. Extrusion of whole linseed compared with extrusion of crushed linseed was effective in reducing C18:3n-3 biohydrogenation, whereas the processing variants were not different in C18:3n-3 biohydrogenation. Crushed linseed, micronized crushed linseed, lipid encapsulated linseed oil, and DHA addition to linseed oil did not reduce C18:3n-3 biohydrogenation. Compared with the other treatments, docosahexaenoic acid addition to linseed oil resulted in a comparable trans11,cis15-C18:2 biohydrogenation but a lesser trans10+11-C18:1 biohydrogenation. This suggests that addition of DHA in combination with linseed oil was effective only in inhibiting the last step of biohydrogenation from trans10+11-C18:1 to C18:0.

Milk composition, milk fatty acid profile, digestion, and ruminal fermentation in dairy cows fed whole flaxseed and calcium salts of flaxseed oil

Four ruminally lactating Holstein cows averaging 602+/-25 kg of body weight and 64+/-6 d in milk at the beginning of the experiment were randomly assigned to a 4 x 4 Latin square design to determine the effects of feeding whole flaxseed and calcium salts of flaxseed oil on dry matter intake, digestibility, ruminal fermentation, milk production and composition, and milk fatty acid profile. The treatments were a control with no flaxseed products (CON) or a diet (on a dry matter basis) of 4.2% whole flaxseed (FLA), 1.9% calcium salts of flaxseed oil (SAL), or 2.3% whole flaxseed and 0.8% calcium salts of flaxseed oil (MIX). The 4 isonitrogenous and isoenergetic diets were fed for ad libitum intake. Experimental periods consisted of 21 d of diet adaptation and 7 d of data collection and sampling. Dry matter intake, digestibility, milk production, and milk concentrations of protein, lactose, urea N, and total solids did not differ among treatments. Ruminal pH was reduced for cows fed the CON diet compared with those fed the SAL diet. Propionate proportion was higher in ruminal fluid of cows fed CON than in that of those fed SAL, and cows fed the SAL and CON diets had ruminal propionate concentrations similar to those of cows fed the FLA and MIX diets. Butyrate concentration was numerically higher for cows fed the SAL diet compared with those fed the FLA diet. Milk fat concentration was lower for cows fed SAL than for those fed CON, and there was no difference between cows fed CON and those fed FLA and MIX. Milk yields of protein, fat, lactose, and total solids were similar among treatments. Concentrations of cis-9 18:1 and of intermediates of ruminal biohydrogenation of fatty acids such as trans-9 18:1 were higher in milk fat of cows fed SAL and MIX than for those fed the CON diet. Concentration of rumenic acid (cis-9, trans-11 18:2) in milk fat was increased by 63% when feeding SAL compared with FLA. Concentration of alpha-linolenic acid was higher in milk fat of cows fed SAL and MIX than in milk of cows fed CON (75 and 61%, respectively), whereas there was no difference between FLA and CON. Flaxseed products (FLA, SAL, and MIX diets) decreased the n-6 to n-3 fatty acid ratio in milk fat. Results confirm that flax products supplying 0.7 to 1.4% supplemental fat in the diet can slightly improve the nutritive value of milk fat for better human health.

Ruminal fermentation characteristics and fatty acid profile of ruminal fluid and milk of dairy cows fed flaxseed hulls supplemented with monensin

Flaxseed hull, a co-product obtained from flax processing, is a rich source of n-3 fatty acids (FA) but there is little information on its value for dairy production. Monensin supplementation is known to modify biohydrogenation of FA by rumen microbes. Therefore, the main objective of the experiment was to determine the effect of feeding a combination of monensin and flaxseed hulls on ruminal fermentation characteristics and FA profile of ruminal fluid and milk. Four ruminally fistulated multiparous Holstein cows averaging 665 ± 21 kg body weight and 190 ± 5 d in milk were assigned to a 4×4 Latin square design (28-d experimental periods) with a 2×2 factorial arrangement of treatments. Treatments were: 1) control, neither flaxseed hulls nor monensin; 2) diet containing (dry matter basis) 19·8% flaxseed hulls; 3) diet with monensin (16 mg/kg dry matter); 4) diet containing 19·8% (dry matter basis) flaxseed hulls and 16 mg monensin/kg. Flaxseed hull supplementation decreased the acetate to propionate ratio in ruminal fluid and monensin had no effect. Concentrations of trans-18:1 isomers (trans9,trans11,trans13/14+6/8) and cis9,12,15-18:3 in ruminal fluid and milk fat were higher and those of cis9,12-18:2 in milk fat tended (P=0·07) to be higher for cows supplemented with flaxseed hulls than for cows fed no flaxseed hulls. Monensin had little effect on milk fatty acid profile. A combination of flaxseed hulls and monensin did not result in better milk fatty acid profile than when feeding only flaxseed hulls.

Greenhouse gas, animal performance, and bacterial population structure responses to dietary monensin fed to dairy cows

The present study investigated the effects of a feed additive and rumen microbial modifier, monensin sodium (monensin), on selected variables in lactating dairy cows. Monensin fed cows (MON, 600 mg d(-1)) were compared with untreated control cows (CON, 0 mg d(-1)) with respect to the effects of monensin on the production of three greenhouse gases (GHG), methane (CH(4)), nitrous oxide (N(2)O), and carbon dioxide (CO(2)), along with animal performance (dry matter intake; DMI), milk production, milk components, plasma urea nitrogen (PUN), milk urea nitrogen (MUN), and the microbial population structure of fresh feces. Measurements of GHG were collected at Days 14 and 60 in an environmental chamber simulating commercial dairy freestall housing conditions. Milk production and DMI measurements were collected twice daily over the 60-d experimental period; milk components, PUN, and MUN were measured on Days 14 and 60. The microbial population structure of feces from 6 MON and 6 CON cows was examined on three different occasions (Days 14, 30, and 60). Monensin did not affect emissions of methane (CH(4)), nitrous oxide (N(2)O), and carbon dioxide (CO(2)). Over a 24-h period, emissions of CH(4), N(2)O, and CO(2) decreased in both MON and CON groups. Animal performance and the microbial population structure of the animal fresh waste were also unaffected for MON vs. CON cows.

The interaction of monensin and flaxseed hulls on ruminal and milk concentration of the mammalian lignan enterolactone in late-lactating dairy cows

Four ruminally fistulated multiparous Holstein cows were assigned to a 4×4 Latin square design with a 2×2 factorial arrangement of treatments to study the effects of dietary supplementation of monensin and flaxseed hulls on ruminal and milk concentration of the mammalian lignan enterolactone (EL) and ruminal and faecal activity of β-glucuronidase. The hypothesis was that monensin supplementation has no effect on the incorporation of EL into milk when cows are fed flaxseed hulls. Treatments were: 1) control, neither flaxseed hulls nor monensin (CO); 2) diet containing (dry matter basis) 20% flaxseed hulls (FH); 3) diet with monensin (16 mg/kg of dry matter; MO); 4) diet containing 20% (dry matter basis) flaxseed hulls and 16 mg/kg monensin (HM). Intake of dry matter was higher for CO and MO than for FH and HM and monensin had no effect. Milk production decreased in cows fed flaxseed hulls while monensin had no effect. Production of 4% fat-corrected milk and concentrations of milk fat, lactose, urea N, and total solids were similar among treatments. Although there was a decrease in ruminal activity of β-glucuronidase when feeding flaxseed hulls, the metabolism of plant into mammalian lignans may be increased as shown by enhanced concentration of EL in the rumen and milk. Supplementation with flaxseed hulls then may contribute to favourably change milk composition for better human health by enhancing mammalian lignan EL concentration.