Rumen-protected Methionine Research Articles

Effect of pre-partum supplementation of rumen protected methionine plus lysine and choline on the performance of crossbred cows

The study was conducted to determine rumen escape potential (REP) of commercial rumen protected methionine (RPM), lysine (RPL) and choline (RPC) products and to examine the effect of supplementing RPM plus RPL and RPC on the performance of preparturient crossbred cows. Crossbred cows (27; 2nd to 4th lactation) were randomly assigned to 3 groups of 9 animals each, on the basis of most probable production ability (MPPA). Cows in control group (T1), were fed basal diet as per NRC (2001). The cows in second group (T2), were supplemented with 5 g RPM and 20 g RPL, and those in third group (T3), were fed 54 g RPC per cow/day for 40 days pre-partum. In sacco study revealed that REP of RPM, RPL and RPC was 75.20, 54.97 and 72.89%, respectively. Supplementation of RPM plus RPL and RPC resulted in higher body condition score (BCS) in crossbred cows on the day of parturition. Nutrient intake was similar among the groups, except that duodenal supply of methionine and lysine was higher in T2 group. Plasma triglycerides, VLDL (very low density lipoproteins) and phosphatidylcholine levels were higher in T2 and T3 groups while vitamin E level was higher in T3 group, on the day of parturition, indicating better immune status. It was concluded that fortification of ration with RPM plus RPL and RPC resulted in improved body condition score, duodenal supply of methionine and lysine and better immune status in cows during prepartum period.

Dietary Supplementation of Rumen-Protected Methionine, Lysine and Choline Improves Lactation Performance and Blood Metabolic Profile of Karan-Fries Cows

Twenty seven crossbred (Karan-Fries) cows between second and fourth lactation with most probable production ability of around 4500 kg milk were divided into three similar groups. Animals in the Control group were offered with a basal diet consisting of threshed wheat straw, chopped green maize forage and compounded concentrate mixture as per their requirements. In addition to basal diet, animals in second group (rpMetLys) were fed with 5 g of rumen-protected methionine and 20 g of rumen-protected lysine, and in third group (rpCholine), 54 g of rumen-protected choline was supplemented 40 days before and 120 days after calving. Results revealed higher (P < 0.01) intake of various nutrients along with better body condition score in rpMetLys group. Furthermore, milk yield and milk component (fat, protein and lactose) yield were higher (P < 0.01) in both the treatment groups with higher (P < 0.01) milk choline concentration in rpCholine group. Monounsaturated fatty acids and unsaturated fatty acids in milk tended to be higher (P < 0.05) in rpCholine group. Plasma metabolites like glucose, non-esterified fatty acids, cholesterol and plasma urea nitrogen were similar among all groups. Concentration of triglycerides and very low density lipoproteins was lower (P < 0.01) in rpMetLys and rpCholine than Control group. However, phosphatidylcholine and vitamin E levels were higher (P < 0.01) in rpCholine than other two groups. Methionine levels were higher (P < 0.01) in rpMetLys and rpCholine groups, whereas lysine was increased (P < 0.01) only in the former. Moreover, days open (service period) was decreased (P < 0.01) in animals belonging to rpCholine group. It was concluded from the present study that supplementation of rpMetLys and rpCholine to high-yielding crossbred cows was beneficial in terms of improving milk yield, composition as well as metabolic health status during early lactation period under Indian situation.

Hepatic global DNA and peroxisome proliferator-activated receptor alpha promoter methylation are altered in peripartal dairy cows fed rumen-protected methionine

The availability of Met in metabolizable protein (MP) of a wide range of diets for dairy cows is low. During late pregnancy and early lactation, in particular, suboptimal Met in MP limits its use for mammary and liver metabolism and also for the synthesis of S-adenosylmethionine, which is essential for many biological processes, including DNA methylation. The latter is an epigenetic modification involved in the regulation of gene expression, hence, tissue function. Thirty-nine Holstein cows were fed throughout the peripartal period (−21 d to 30 d in milk) a basal control (CON) diet (n=14) with no Met supplementation, CON plus MetaSmart (MS; Adisseo NA, Alpharetta, GA; n=12), or CON plus Smartamine M (SM; Adisseo NA; n=13). The total mixed ration dry matter for the close-up and lactation diets was measured weekly, then the Met supplements were adjusted daily and top-dressed over the total mixed ration at a rate of 0.19 (MS) or 0.07% (SM) on a dry matter basis. Liver tissue was collected on −10, 7, and 21 d for global DNA and peroxisome proliferator-activated receptor alpha (PPARα) promoter region-specific methylation. Several PPARα target and putative target genes associated with carnitine synthesis and uptake, fatty acid metabolism, hepatokines, and carbohydrate metabolism were also studied. Data were analyzed using PROC MIXED of SAS (SAS Institute Inc., Cary, NC) with the preplanned contrast CON versus SM + MS. Global hepatic DNA methylation on d 21 postpartum was lower in Met-supplemented cows than CON. However, of 2 primers used encompassing 4 to 12 CpG sites in the promoter region of bovine PPARA, greater methylation occurred in the region encompassing −1,538 to −1,418 from the transcription start site in cows supplemented with Met. Overall expression of PPARA was greater in Met-supplemented cows than CON. Concomitantly, PPARA-target genes, such as ANGPTL4, FGF21, and PCK1, were also upregulated overall by Met supplementation. The upregulation of PPARα target genes indicates that supplemental Met, likely through the synthesis of S-adenosylmethionine, activated PPARA-regulated signaling pathways. Upregulation of hepatic PPARA has been associated with improved lipid metabolism and immune function, both of which were reported in companion publications from this study. In turn, those positive effects resulted in improved postpartal health and performance. Further research is needed to study more closely the mechanistic connections between global DNA and promoter region-specific PPARA methylation with PPARA expression and functional outcomes in liver.

Effects of slow-release urea and rumen-protected methionine and histidine on performance of dairy cows

This experiment was conducted with the objective to investigate the effects of slow-release urea and rumen-protected (RP) Met and His supplementation of a metabolizable protein (MP)-deficient diet (according to NRC, 2001) on lactation performance of dairy cows. Sixty lactating Holstein cows were used in a 10-wk randomized complete block-design trial. Cows were fed a covariate diet for 2 wk and then assigned to one of the following treatments for an 8-wk experimental period: (1) MP-adequate diet [AMP; 107% of MP requirements, based on the National Research Council (NRC, 2001)]; (2) MP-deficient diet (DMP; 95% of MP requirements); (3) DMP supplemented with slow-release urea (DMPU); (4) DMPU supplemented with RPMet (DMPUM); and (5) DMPUM supplemented with RPHis (DMPUMH). Total-tract apparent digestibility of dry matter, organic matter, neutral detergent fiber, and crude protein, and urinary N and urea-N excretions were decreased by DMP, compared with AMP. Addition of slow-release urea to the DMP diet increased urinary urea-N excretion. Dry matter intake (DMI) and milk yield (on average 44.0±0.9kg/d) were not affected by treatments, except DMPUMH increased DMI and numerically increased milk yield, compared with DMPUM. Milk true protein concentration and yield were increased and milk fat concentration tended to be decreased by DMPUMH, compared with DMPUM. Cows gained less body weight on the DMP diet, compared with AMP. Plasma concentrations of His and Lys were not affected by treatments, whereas supplementation of RPMet increased plasma Met concentration. Plasma concentration of 3-methylhistidine was or tended to be higher for DMP compared with AMP and DMPU, respectively. Addition of RPHis to the DMPUM diet tended to increase plasma glucose and creatinine. In conclusion, feeding a 5% MP-deficient diet (according to NRC, 2001) did not decrease DMI and yields of milk and milk components, despite a reduction in nutrient digestibility. Supplementation of RPHis increased DMI and milk protein concentration and yield. These results are in line with our previous data and suggest that His may have a positive effect on voluntary feed intake and milk production and composition in high-yielding dairy cows fed MP-deficient diets.

The effect of rumen protected methionine (RPMet) on milk composition of lactating Cashmere Rayeni goat

BACKGROUND: Methionine has been suggested as the firstlimitingamino acid for milk production in ruminants. It is importanthow to increase milk protein yield and milk fat in dairy ruminants.OBJECTIVES: This study was set to investigate the effect of rumenprotected methionine (RPMet) on milk composition of lactatingCashmere Rayeni goats. METHODS: 40 healthy singletonCashmere Rayeni goats about 3 to 4 years of age, at the first day oflactation, were randomly divided into 2 equal control andexperimental groups. The experimental group was supplementedwith 5 gr/day RPMet for 60 days. Milk samples of 2 groups weretaken on 30th and 60th days of the study. Milk protein, milk fat, milklactose, and milk Solids-not-Fat (SNF) were determined usingautomatic analyzer. The results were statistically evaluated withSPSS. RESULTS: The supplementation with RPMet did not effectall of the above mentioned parameters during the 60 days of theexperiment (p>0.05), except for the milk fat percentage of theexperimental group which showed significant increase after 60days (p<0.05). CONCLUSIONS: Our results about milk protein,milk lactose, and SNF were in agreement with previous studies thathad not shown significant differences. Results about milk fat on the30th day were in agreement with the results of several authors whoreported that RPMet did not affect milk fat percentage or yield;however, in the present study milk fat increased significantly on the60th day (p<0.05). To the best of the authors' knowledge, no studyabout the effects of RPMet on milk composition of CashmereRayeni goat has been done.

Effect of rumen-protected methionine on production and composition of early lactating Shami goats milk and growth performance of their kids

Abstract. This study was conducted at the Agricultural Research Station of the University of Jordan in the Jordan valley to evaluate the effect of supplementing rumen-protected methionine to early lactating Shami goats on milk production, composition, fatty acid profile, and growth performance of their kids. Twenty-four fresh lactating Shami goats were randomly assigned into three dietary treatment groups (eight each) in a completely randomized design. Diets were a control with no supplements or supplemented with either 2.5, or 5.0 g/head/d rumenprotected methionine. The experiment started exactly after kidding and lasted for 60 days thereafter. Production variables studied were milk production, milk composition, body weights, feed intake, kids weaning weight, and milk fatty acids. Daily milk production and energy corrected milk were not affected by protected me thionine supplementation. Milk Percentages of fat, protein, total solids, and casein were also not affected by protected methionine supplementation. Likewise, fat and protein yields were not different among dietary treatments of protected methionine. No differences in milk fatty acids composition were observed by supplementing rumen protected methionine in the experiment. Feed intake, feed to milk ratio, and final body weight of dams were not changed among treatments. No differences were observed in weaning weights, average daily gain, and milk to gain ratio of kids born to dams in the experiment regardless to sex of kids. In conclusion, results indicated that supplementing rumen protected methionine to dairy goats diet did not improve their milking performance, the composition of their milk, or growth performance of their kids.

Rumen-protected methionine supplementation and fibre production in alpacas (Vicugna pacos )

Sulphur-containing amino acids are a crucial requirement for fibre production and may be supplemented in the diet of fibre-producing animals to stimulate fibre growth. The alpaca fibre industry is a developing industry in Australia with high variability in fibre production. To date, there is no evidence whether supplementing the diet of alpacas with sulphur amino acids improves fibre production. We hypothesised that supplementation with the rumen-protected sulphur amino acid, methionine would increase fibre growth in alpacas. Three groups of eight huacaya alpaca wethers were fed daily a maintenance diet supplemented with 0, 2 or 4 g of rumen-protected methionine for 7 weeks. Fibre samples were taken at the beginning and end of the study with a blood sample taken by jugular venipuncture prior to feeding on the first day of each week. Methionine supplementation had no effect on fibre diameter (p = 0.92), fibre length (p = 0.91) or fibre yield (p = 0.33). The change of season over the study affected plasma glucose (p < 0.001), plasma urea nitrogen (p < 0.001) and fibre diameter (p < 0.001). The indifference between groups may be due to the maintenance diet supplying sufficient levels of methionine, the lack of genetic potential of the experimental animals to respond to additional methionine or that the supplemental methionine was not protected in alpacas and deaminated for glucose production.

Effects of metabolizable protein supply and amino acid supplementation on nitrogen utilization, milk production, and ammonia emissions from manure in dairy cows

Two experiments were conducted with the objective of investigating the effects of rumen-protected methionine (RPMet) supplementation of metabolizable protein (MP)-deficient or MP-adequate but Met-deficient diets on dairy cow performance. Experiment (Exp.) 1 utilized 36 Holstein dairy cows blocked in 12 blocks of 3 cows each. Cows within block were assigned to one of the following dietary treatments: (1) MP-adequate diet [AMP; positive MP balance according to the National Research Council (2001) dairy model]; (2) an MP-deficient diet supplemented with 100g of rumen-protected Lys (RPLys)/cow per day (DMPL); and (3) DMPL supplemented with 24g of RPMet/cow per day (DMPLM). Experiment 2 utilized 120 Holstein cows assigned to 6 pens of 20 cows each. Pens (3 per treatment) were assigned to one of the following dietary treatments: (1) AMP diet supplemented with 76g of RPLys/cow per day (AMPL); and (2) AMPL (74g of RPLys/cow per day) supplemented with 24g of RPMet/cow per day (AMPLM). Each experiment lasted for 10wk (2-wk adaptation and 8-wk experimental periods) following a 2-wk covariate period (i.e., a total of 12wk). In Exp. 1, the MP-deficient diets decreased apparent total-tract nutrient digestibility but had no statistical effect on dry matter intake (DMI), milk yield, or milk fat percentage and yield. Compared with AMP, DMPL decreased milk protein content; both DMPL and DMPLM diets decreased milk protein yield. Urinary N losses and milk urea-N concentration were decreased by the MP-deficient diets compared with AMP. The ammonia emitting potential of manure from the MP-deficient diets was decreased by about 37% compared with that of AMP manure. Plasma Lys and Met concentrations were not affected by treatment, but concentrations of His, Thr, and Val were lower for the MP-deficient diets compared with AMP. In Exp. 2, the AMPLM diet had lower milk yield than AMPL due to numerically lower DMI; no other effects were observed in Exp. 2. In conclusion, feeding MP-deficient diets supplemented with RPLys and RPMet did not statistically decrease milk yield in dairy cows in Exp. 1. However, without RPMet supplementation, milk protein content was decreased compared with the MP-adequate diet. Other amino acids, possibly His, may limit milk production in MP-deficient, corn or corn silage-based diets. A summary of 97 individual cow data from trials in which MP-deficient diets were fed suggested the National Research Council (2001) model under-predicts milk yield in cows fed MP-deficient diets (MP balance of –20 to –666g/d) in a linear manner: milk yield under-prediction [National Research Council (2001) MP-allowable milk yield, kg/d – actual milk yield, kg/d] = 0.0991 (±0.0905) + 0.0230 (±0.0003) × MP balance, g/d (R2=0.99).

Effects of rumen-protected methionine on plasma amino acid concentrations during a period of weight loss for late gestating beef heifers

This study determined changes in plasma amino acid concentration in late-gestating (beginning 58 ± 1.02 days prior to calving), primiparous, winter-grazing range heifers receiving wheat middling-based supplement without (CON) or with rumen-protected methionine (MET) to provide 15 g DL-MET each day. Plasma was collected on days -2 and 0 (start of MET supplementation just prior to individually receiving supplement at 0700 hours). Plasma was sampled again on days 40, 42 and 44 prior to supplementation at 0700 and 1100 hours (4 h after receiving daily supplement). Data were analyzed with cow as the experimental unit. Continuous variables were analyzed by the main effects of treatment, date, or time and their interaction when appropriate. Comparable BW (P = 0.32) and BCS (P = 0.83) over the 44-day metabolism trial were found between both CON- and MET-fed heifers. MET-supplemented heifers had greater (P < 0.01) plasma concentrations of methionine indicating that the rumen-protection technology successfully delivered methionine to the small intestine. Supplementation with rumen-protected DL-MET caused a significant supplement × date interaction for glutamine (P = 0.03), glycine (P = 0.02), methionine (P < 0.01), and serine (P = 0.05). In addition, trends for supplement × date interactions were detected for leucine (P = 0.07), threonine (P = 0.09), valine (P = 0.08), total amino acids (TAA; P = 0.08), non essential amino acids (NEAA; P = 0.08), branched chain amino acids (BCAA; P = 0.08), and glucogenic amino acids (GLUCO; P = 0.08). These results suggest that the BCAA (leucine and valine) were utilized more efficiently with MET supplemented heifers compared to CON supplemented heifers. Plasma AA concentrations for glutamic acid (P < 0.01), histidine (P = 0.01), tyrosine (P < 0.01), and EAA (P < 0.01), all decreased throughout the study. These results further confirm methionine is a limiting amino acid in forage fed late-gestating heifers and further suggests the limitation when grazing dormant range forages as shown by improved utilization of other plasma amino acids when supplemental methionine was provided.

Effects of feeding methylthio butyric Acid isopropyl ester on postpartum performance and metabolism in dairy cows.

The present experiment aimed to evaluate the effect of HMBi on the production performance and metabolism in dairy cows. Thirty multiparous Holstein dairy cows under similar conditions were randomly assigned to three dietary treatments; i) Control, a basal diet; ii) T1, a basal diet plus HMBi (0 g prepartum and 18 g postpartum); and iii) T2, a basal diet plus HMBi (10 g prepartum and 18 g postpartum). Treatments were initiated 21 d before expected calving and continued through 91 d postpartum. HMBi was top-dressed onto the total mixed ration of each cow. Treatments did not affect dry matter intake, plasma urea nitrogen, peak milk yield, days to peak milk yield, nonesterified fatty acid, glutamate pyruvate transaminase, glutamic oxalaetic transaminase, milk fat content, milk protein content, milk lactose content, and milk solid non-fat content. The milk composition yields were increased by the HMBi-supplemented treatment. The T1 and T2 treatments increased the yields of 4% fat-corrected milk yield, milk fat, milk protein, and milk lactose compared with the control. Although there was no difference in the milk composition of the control and T2-treated cows, the T2-treated cows exhibited higher milk fat yield (increased by 74 g/d), lower milk urea nitrogen (reduced by 3.41%), and plasma β-hydroxy butyrate than the control cows. The results indicate that HMBi supplementation to diet has beneficial effects, and that there is no difference between supplementation at prepartum and starting only at parturition.

Effects of calcium salts of long-chain fatty acids and rumen-protected methionine on plasma concentrations of ghrelin, glucagon-like peptide-1 (7 to 36) amide and pancreatic hormones in lactating cows

Our objective was to determine the effects of calcium salts of long-chain fatty acids (CLFAs) and rumen-protected methionine (RPM) on plasma concentrations of ghrelin, glucagon-like peptide-1 (7 to 36) amide, and pancreatic hormones in lactating cows. Four Holstein cows in midlactation were used in a 4 by 4 Latin square experiment in each 2-wk period. Cows were fed corn silage-based diets with supplements of CLFAs (1.5% added on dry matter basis), RPM (20 g/d), CLFAs plus RPM, and without supplement. Jugular blood samples were taken from 1 h before to 2 h after morning feeding at 10-min intervals on day 12 of each period. CLFAs decreased dry matter intake, but RPM did not affect dry matter intake. Both supplements of CLFAs and RPM did not affect metabolizable energy intake and milk yield and composition. Plasma concentrations of NEFAs, triglyceride (TG), and total cholesterol (T-Cho) were increased with CLFAs alone, but increases of plasma concentrations of TG and T-Cho were moderated by CLFAs plus RPM. Calcium salts of long-chain fatty acids increased plasma ghrelin concentration, and the ghrelin concentration with CLFAs plus RPM was the highest among the treatments. Plasma concentrations of glucagon-like peptide-1, glucagon, and insulin were decreased with CLFAs, whereas adding RPM moderated the decrease of plasma glucagon concentration by CLFAs. These results indicate that the addition of methionine to cows given CLFAs increases plasma concentrations of ghrelin and glucagon associated with the decrease in plasma concentrations of TG and T-Cho.

Effect of Selenium Depletion on Oxidative Stress in Mature Horses

s / Journal of Equine Veterinary Science 31 (2011) 230-356 257 [5] Bryden WL. Amino acid requirements of horses estimated from tissue composition. Proc Nutr Soc 1991;16:53. [6] Wilson JA, Graham-Thiers PM. Muscle and plasma amino acids in pregnant/lactating mares and their weanling foals. J Equine Vet Sci 2009;29:370. [7] Nutrient Requirements of Horses. 6th ed. Washington, DC: The National Academies Press; 2007. [8] Waggoner JW, LOxest CA, Mathis CP, Hallford DM, Petersen MK. Effects of rumen-protected methionine supplementation and bacterial lipopolysaccharide infusion on nitrogen metabolism and hormonal responses of growing beef steers. J Anim Sci 2009;87:681. Effect of Selenium Depletion on Oxidative Stress in Mature Horses M. Brummer, S. Hayes, J.E. Earing, S.M. McCown, and L.M. Lawrence University of Kentucky, Lexington, KY, USA Introduction: Glutathione peroxidase (GPx) plays an important role in the neutralization of hydroperoxides andhydrogenperoxide. Hydrogen peroxide can generate hydroxyl radicals which are regarded as a very harmful reactive oxygen species [1]. Selenium (Se) deficiency can result in decreased GPx activity; therefore our aim was to investigate the effect of low Se status on oxidative stress in mature idle horses. We hypothesized that Se depletion would result in a decrease in GPx activity, serum total antioxidant capacity (TAC) and an increase in oxidative stress, measured as serum malondialdehyde concentration (MDA). Type I deiodinase, is a selenoenzyme responsible for the conversion of inactive T4 to active T3. Therefore as additional indicators of Se status we measured triiodothyronine (T3), thyroxine (T4), and the T3:T4 ratio as changes in these hormones or in their ratio has been evaluated in horses fed varying levels of Se before [2]. Materials and Methods: Twenty eight mature horses (6 24 yr) were used in this study. The 28 horses included 8 geldings and 20 mares that had resided on the farm for at least 60 days prior to the study. The study period was 28 wks. Horses were kept on pasture ( .05). MDA concentrationwas not different between AS and LS at the initial or final time point, howeverMDAdid increaseover time (P< .05) in LS (from3.40 .86 nmol/mL to 4.04 .89 nmol/mL) while it remained similar in AS (4.68 1.78 nmol/mL to 5.09 1.09 nmol/mL). Two traditional indicators of Se status were measured: whole blood Se concentration and GPx activity. In addition the serum T3/ T4 ratio was determined. Type I deiodinase, the enzyme responsible for converting T4 to T3, has a greater ranking in terms of priority of Se supply than cytosolic GPx [2]. A change in this ratio is generally not observed during a marginal Se deficiency [2], so the increased ratio of T3/T4 in the LS horses along with the changes in whole blood Se and GPx suggests that the LS horses were at, or approaching, deficient Se status. TAC was expected to decrease in LS horses, but it was unaffected. The lack of change in TAC may point towards a compensatory mechanism within the antioxidant system, or lack of sensitivity of the assay as a measure of the GPx-associated antioxidant capacity in serum. GPx is only one of several compounds that contribute to total antioxidant capacity. MDA is a byproduct of lipid peroxidation [4]. We hypothesized that MDA concentrations would increase with decreasing Se status. Although MDA concentrations increased over time in the LS horses, the magnitude of the changes were relatively small. Much larger changes in MDA have been reported in response to exercise or disease in other studies [4] and some type of oxidative challenge might be necessary to produce more marked differences in MDA in the horses studied here. Conclusion: In this study feeding a low Se diet for 28 wks altered indicators of Se status, but appears to have hadminimal effects on the indicator of oxidative damage. However, more marked effects might have been observed if the horses had been challenged with an oxidative stressor such as exercise or disease. Further research in this area may provide better insight into the importance of Se in oxidative stress.

Effect of feeding different sources of rumen-protected methionine on milk production and N-utilization in lactating dairy cows

Objectives of this study were to quantify production responses of lactating dairy cows to supplying absorbable Met as isopropyl-2-hydroxy-4-(methylthio)-butanoic acid (HMBi), or rumen-protected Met (RPM, Smartamine M; Adisseo, Alpharetta, GA) fed with or without 2-hydroxy-4-(methylthio)-butanoic acid (HMB), and to determine whether Met supplementation will allow the feeding of reduced dietary crude protein (CP). Seventy cows were blocked by parity and days in milk into 14 blocks and randomly assigned within blocks to 1 of the 5 dietary treatments based on alfalfa and corn silages plus high-moisture corn: 1 diet with 15.6% CP and no Met source (negative control); 3 diets with 15.6% CP plus 0.17% HMBi, 0.06% RPM + 0.10% HMB, or 0.06% RPM alone; and 1 diet with 16.8% CP and no Met supplement (positive control). Assuming that 50% of ingested HMBi was absorbed from the gastrointestinal tract and 80% of the Met in RPM was absorbed at intestine, the HMBi and RPM supplements increased metabolizable Met supply by 9g/d and improved the Lys:Met ratio from 3.6 to 3.0. After a 2-wk covariate period during which all cows received the same diet, cows were fed test diets continuously for 12 wk. Diet did not affect dry matter intake (mean ± SD, 25.0±0.3kg/d), body weight gain (0.59±0.2kg/d), or milk yield (41.7±0.6kg/d). However, feeding HMBi increased yield of energy-corrected milk and milk content of protein and solids-not-fat. Moreover, trends were observed for increased milk fat content and yield of fat and true protein on all 3 diets containing supplemental Met. Apparent N efficiency (milk N/N intake) was highest on the RPM treatment. Feeding 16.8% CP without a Met source elevated milk urea N and urinary excretion of urea N and total N and reduced apparent N efficiency from 34.5 to 30.2%, without improving production. Overall results suggested that feeding HMBi or RPM would give similar improvements in milk production and N utilization.

The effect of rumen-protected methionine and choline on plasma metabolites of Holstein dairy cows

SUMMARYForty Holstein dairy cows in their first and second lactations were used from 4 weeksprepartumto 10 weekspostpartumto investigate the effects of feeding ruminally protected methionine and choline on plasma metabolites. Cows were randomly assigned to one of the following treatments in a 2×2 factorial design 4 weeks before their expected calving dates, using randomized blocks based on parity: no supplement (control), 18 g/d of rumen-protected methionine (RPM) product, 60 g/d of rumen-protected choline (RPC) product, or 18 g/d of RPM+60 g/d of RPC. Treatments did not affect plasma triglycerides, glucose, total protein, nonesterified fatty acids (NEFA),β-hydroxybutyrate (BHBA), plasma urea nitrogen (PUN) or aspartate aminotransferase (AST) during theprepartumperiod. Forpostpartumplasma NEFA concentrations, there were interactions between RPC or RPM and weekpostpartum. Feeding RPM increased plasma AST concentrations (P&lt;0·05) and decreased plasma protein concentrations (P&lt;0·05) inpostpartumcows. After calving, feeding RPC increased (P&lt;0·05) dry matter intake (DMI), milk yield, 40 g/kg fat-corrected milk (FCM) yield and energy-corrected milk (ECM) yield. This suggests that supplemental RPC can improve lactation performance of dairy cows.

Effect of supplementation with urea, blood meal, and rumen-protected methionine on growth performance of Holstein heifers grazing kikuyu pasture

Supplements with corn grain, molasses cane, and different nitrogen sources were evaluated in 16 growing Hosltein heifers [227 ± 33 kg body weight (BW)] grazing kikuyu (Pennisetum clandestinum) pasture in a 10-ha sward (rotational grazing with electric fences) during 90 days in the summer season. The nitrogen sources were urea (U); urea and blood meal (U+BM); and urea, blood meal, and rumen-protected methionine (U+BM +RPM). Heifers were randomly assigned to four experimental supplements defined as follows: control (no supplementation), U, U+BM, and U+BM +RPM. Two kilograms (as fed) of supplement was offered daily. The final BW of heifers fed U+BM +RPM was higher (P<0.05) than heifers not supplemented. The total and average daily weight gain of heifers supplemented with U+BM +RPM were higher than heifers not supplemented or supplemented with U and U+BM (P<0.05). The average daily gain of heifers supplemented with U and U+BM were higher than heifers not supplemented (P<0.05). Grass intake was not affected by supplementation, but total dry matter intake was increased by supplements with U, U+BM, and U+BM +RPM (P<0.05). Feed conversion was improved by U+BM +RPM (P<0.05). Total tract digestion was not affected by supplements. Blood urea nitrogen concentrations of heifers supplemented with U, U+BM, and U+BM +RPM were higher than heifers not supplemented (P<0.05). It is concluded that supplements with U+BM +RPM improved growth performance and feed conversion in heifers grazing kikuyu pasture.

Effect of rumen-protected choline and methionine on physiological and metabolic disorders and reproductive indices of dairy cows

The objective of this study was to investigate the effect of feeding different levels of ruminally protected methionine and choline on the incidence of physiological and metabolic disorders, production, and some of the reproductive indices of Holstein dairy cows. Forty Holstein dairy cows in their first and second lactation were used from 4-week pre-partum through 20-week post-partum and randomly assigned to receive one of the following treatments: 18 g/day of rumen-protected methionine (RPM), 60 g/day of rumen-protected choline (RPC), 18 g/day of RPM + 60 g/day of RPC, and neither supplement (control). The treatments significantly affected services per conception and open days of lactating dairy cows (p < 0.05), but did not affect significantly on days to first oestrus and number of pregnant cows. RPM + RPC-fed cows had the lowest open days, days to first oestrus and services per conception compared with other groups. The effect of treatments was significant on the incidence of metabolic and physiological problems except for foot/leg problems. Cows fed RPM+RPC had the lowest health problems compared with other groups (p < 0.05). Results indicate that the supplementation of RPM and RPC can improve reproductive performance and health status of dairy cows.

Milk yield persistency and its relationship with health problems in Holstein dairy cows supplemented with different levels of ruminally protected methionine and choline

Abstract. Forty Holstein dairy cows in their first and second lactation were used in a lactation study from 4-week prepartum through 14-week postpartum to investigate the potential effect of feeding different levels of ruminally protected methionine and choline on milk yield persistency of Holstein dairy cows. Cows were randomly assigned to receive one of the following treatments: 18 g/d of rumen-protected methionine (RPM), 60 g/d of rumenprotected choline (RPC), 18 g/d of RPM + 60 g/d of RPC, or neither supplement (control). The use of polynomial equations revealed that the polynomial coefficients of regression were closer (P&lt;0.05) to zero for RPM+RPC-fed cows than for other cows. Therefore, RPM+RPC-fed cows had a more persistent (P&lt;0.05) early-lactation milk yield than did other cows. Cows fed RPM+RPC had the lowest health problems compared with other groups. The treatments significantly affected actual milk yield (P&lt;0.05), 4 % fat-corrected milk (FCM) (P&lt;0.01) and energy-corrected milk (ECM) (P&lt;0.01) across lactation weeks. The treatments significantly affected average dry matter intake (DMI) for the first 14 week postpartum (P&lt;0.05). Also, treatments significantly affected lactose percentage of milk across lactation weeks (P&lt;0.01). In general, it was expected that RPM+RPC-fed cows with greater persistency of lactation would be healthier because the incidence of metabolic and reproductive disorders and negative energy balance that originate from the physiological stress of high milk yield would be lower.

Effects of fat and rumen-protected methionine supplementation on production response of first-lactation cows

To determine whether supplementation of rumen-protected methionine (RPM) and fat, from 0 to 150 days in milk, improves milk production, milk quality, and energy balance (EB), in a completely randomized design, 32 first-lactation cows fed diets with 0 or 3.5% added fat and 0 or 0.15% added RPM. Fat, RPM, and fat plus RPM increased milk yield. Supplemental RPM increased milk protein (%) and decreased milk fat (%). Fat, RPM, and fat plus RPM increased (kg) milk fat, milk protein, and milk lactose. Cows fed fat and RPM alone had greater negative EB values than cows non-supplemented. Cows fed fat plus RPM had similar EB to cows non-supplemented. Supplemental RPM induced higher plasma glucose and lower urea-N. Fat induced higher plasma cholesterol. In conclusion, supplemental fat or RPM, and fat plus RPM increased milk production, but fat plus RPM enhanced EB as compared to fat or RPM alone.

Effect of rumen-protected methionine on feed intake, milk production, true milk protein concentration, and true milk protein yield, and the factors that influence these effects: A meta-analysis

A meta-analysis of published studies was used to investigate the effect of rumen-protected methionine (RPM) added to the diets of lactating dairy cattle on dry matter intake, milk production, true milk protein (TMP) production, and milk fat yield. Differences in responses between 2 commonly used RPM products, Mepron (Evonik Industries, Hanau, Germany) and Smartamine (Adisseo, Antony, France), were investigated as well as dietary and animal factors that could influence responses. Diets were coded with respect to the amino acid (AA) deficiency of the control diet as predicted by the AminoCow model (version 3.5.2, http://www.makemilknotmanure.com/aminocow.php; 0=no AA deficiency, 1=Met deficiency, 2=Met and Lys deficiency, 3=Met and Lys plus at least 1 other AA deficiency) to test the effect of AA deficiencies on RPM response. Thirty-five studies were identified, 17 studies evaluating Mepron, 18 studies evaluating Smartamine, and 1 study evaluating both. This permitted 75 dietary comparisons between control and RPM-added diets. Diets were entered into the AminoCow and the 2001 National Research Council models to compare predictions of Met, Lys, and metabolizable protein (MP) flow. Mean Met and Lys in diets where RPM was fed were estimated to be 2.35 and 6.33% of MP, respectively. Predictions of flows between models were similar. Overall, RPM addition to diets increased production of TMP, both as percentage (0.07%) and yield (27 g/d). Dry matter intake and milk fat percentage were slightly decreased, whereas milk production was slightly increased. Differences between products were detected for all production variables, with Mepron-fed cows producing less TMP percentage but greater milk production, resulting in twice as much TMP yield. Milk protein response to RPM was not related to predicted AA deficiency, calculated Met deficiency, or Met as a percentage of MP. Other dietary factors, including Lys flow (g/d), Lys as percentage of MP, neutral detergent fiber percentage, crude protein percentage, or energy balance, had no detectable effects on TMP response. When cows with a predicted positive AA balance were fed RPM, milk production increased, but when AA balance was negative, milk production decreased. Amount of RPM added to the diet was not correlated to TMP response. This study does not support the necessity of a high Lys level as a prerequisite to obtaining a TMP response to feeding RPM or the MP requirement suggested by the National Research Council model (2001). However, more dose–response studies over a wide range of milk production and dietary regimens will be required to more clearly establish AA requirements and to predict responses to RPM supplementation.

Effects of supplementary folic acid and vitamin B12 on hepatic metabolism of dairy cows according to methionine supply

The present experiment was undertaken to study the interactions between dietary supplements of rumen-protected methionine (RPM) and intramuscular injections of folic acid and vitamin B12, given from 3 wk before calving to 16 wk of lactation, on hepatic metabolism of lactating dairy cows. Sixty multiparous Holstein cows were assigned to 10 blocks of 6 cows each according to their previous milk production. Within each block, 3 cows were fed a diet calculated to supply Met as 1.83% of metabolizable protein, whereas the 3 other cows were fed the same diet supplemented with 18g of RPM calculated to provide Met as 2.23% of metabolizable protein. Within each level of Met, the cows received no vitamin supplement or weekly intramuscular injections of 160mg of folic acid alone or combined with 10mg of vitamin B12. Liver biopsies were taken at 2, 4, 8, and 16 wk of lactation. Liver concentrations of folates and vitamin B12 were increased by their respective supplements but this response to vitamin supplements was altered by methionine supply. Concentrations of total lipids and triglycerides increased in livers of cows fed RPM, whereas concentrations of cholesterol ester, cholesterol, diglycerides, phosphatidylethanolamine, and phosphatidylcholine were not affected. Folic acid, alone or combined with vitamin B12, tended to increase the ratio of phosphatidylcholine to phosphatidylethanolamine. Gene expression of 5,10-methylene-tetrahydrofolate reductase, microsomal transfer protein, and phosphatidylethanolamine methyltransferase were higher in liver of cows fed RPM supplements. The relative mRNA abundance of 5,10-methylene-tetrahydrofolate reductase and methylmalonyl-CoA mutase were increased by the combined injections of folic acid and vitamin B12, whereas those of methionine synthase and methionine synthase reductase were not affected by treatments. These results suggest that increasing supply of methyl groups, as preformed labile methyl groups or through methylneogenesis, affected the methylation cycle but had a limited effect on dairy cow performance. The observed effects of the combined supplement of folic acid and vitamin B12 on lactational performance of dairy cows probably result from an improvement of energy metabolism during early lactation.