Rumen-protected Methionine Supplementation Research Articles

Systematic review and meta-analysis of dairy cow responses to rumen-protected methionine supplementation before and after calving

Balancing dairy cow diets for AA is an effective strategy to reduce dietary CP concentration, maintain levels of productivity, and increase nitrogen use efficiency. Most studies evaluating supplemental rumen-protected Met (sRPMet) focus on cows in established lactation; however, there is an increasing body of evidence suggesting that initiating sRPMet feeding to transition dairy cows is beneficial to production, reproduction, and health. Therefore, the objective of this study was to evaluate the effects of feeding sRPMet before and after calving through meta-analysis on pre- and postpartum performance and selected metabolic parameter responses. A literature search was conducted for published papers reporting on the effects of feeding sRPMet starting before parturition and continuing through early lactation, resulting in 21 publications with 40 treatment comparisons. Studies provided sRPMet both before (average of 8.20 [±2.94 SD] g of metabolizable sRPMet/d, which began at 19.3 [±4.23 SD] d before calving) and after calving (10.53 [±3.30 SD] g of metabolizable sRPMet/d for an average of 85.9 [±38.36 SD] DIM). Prepartum DMI and pre- and postpartum BW and BCS were unaffected by sRPMet. In contrast, postpartum DMI, milk yield, milk fat and true protein yield, and milk fat and true protein concentration were increased by sRPMet. Most production responses to sRPMet declined as lactation progressed where the predicted response in milk fat and true protein yield was 118 and 92 g/d at 21 DIM, respectively. Postpartum circulating metabolites were unaffected by sRPMet; however, the sample sizes for these analyses were much lower than for production responses. This meta-analysis indicates that feeding sRPMet before and after calving results in increased productivity beyond that which would be expected by providing sRPMet in established lactation alone.

Rumen-protected methionine modulates body temperature and reduces the incidence of heat stress temperatures during the hottest hours of the day of grazing heat-stressed Bos indicus beef cows.

This study evaluated the effects of supplementation of rumen-protected methionine (RPM) on body thermoregulation and conception rate of Nelore cows exposed to high temperature-humidity index (THI). On -31 days before the artificial insemination protocol, 562 lactating, multiparous cows were assigned to receive (MG) or not (CG) RPM supplementation (3 g/cow mixed into 100 g of mineral supplement). Both groups remained in tropical pastures and received supplementation for 77 days. A subset of cows (n= 142) remained with an intravaginal thermometer collecting intravaginal temperature (IT). The respective minimum, average, and maximum environmental THI were 72.8, 78.0, and 83.3. Effects of treatment × hour of the day were detected (P< 0.0001) for IT. From 1330 to 1730 h and 1830 to 1900 h, IT was higher (P< 0.05) for CG versus MG cows when exposed to moderate and high THI. The supplementation with RPM did not affect conception rate (CG = 64.4% vs. MG = 58.2%; P> 0.05). In conclusion, 3g of RPM supplementation lowered internal body temperature and possibly altered critical THI threshold in Nelore cows with no impact on reproduction.

Rumen-protected methionine supplementation alters lipid profile of preimplantation embryo and endometrial tissue of Holstein cows.

Our objective is to evaluate the effects of feeding rumen-protected Met (RPM) throughout the transition period and early lactation on the lipid profile of the preimplantation embryos and the endometrial tissue of Holstein cows. Treatments consisted of feeding a total mixed ration with top-dressed RPM (Smartamine® M, Adisseo, Alpharetta, GA, United States; MET; n = 11; RPM at a rate of 0.08% of DM: Lys:Met = 2.8:1) or not (CON; n = 9, Lys:Met = 3.5:1). Endometrial biopsies were performed at 15, 30, and 73 days in milk (DIM). Prior to the endometrial biopsy at 73 DIM, preimplantation embryos were harvested via flushing. Endometrial lipid profiles were analyzed using multiple reaction monitoring-profiling and lipid profiles of embryos were acquired using matrix assisted laser desorption/ionization mass spectrometry. Relative intensities levels were used for principal component analysis. Embryos from cows in MET had greater concentration of polyunsaturated lipids than embryos from cows in CON. The endometrial tissue samples from cows in MET had lesser concentrations of unsaturated and monounsaturated lipids at 15 DIM, and greater concentration of saturated, unsaturated (specifically diacylglycerol), and monounsaturated (primarily ceramides) lipids at 30 DIM than the endometrial tissue samples from cows in CON. In conclusion, feeding RPM during the transition period and early lactation altered specific lipid classes and lipid unsaturation level of preimplantation embryos and endometrial tissue.

Fetal programming effect of rumen-protected methionine on primiparous Angus × Simmental offspring's performance and skeletal muscle gene expression.

Primiparous Angus × Simmental dams (n = 22) with an average body weight (BW) of 449 ± 32kg of BW were divided based on two nutritional treatments: control (CTRL) and rumen-protected methionine (RPM). The control group received bermudagrass hay, corn gluten, and soybean hulls pellets supplementation (base diet); whereas the RPM group received the base diet in addition to 0.07% of DM of RPM at a fixed rate during the last trimester of gestation and the first ~80d of lactation, in which calves (n = 17) were early weaned. Only male calves were included in this study. After weaning, calves born to RPM dams also received RPM from weaning (day 1) to day 100. Blood sampling and skeletal muscle biopsies for subsequent quantitative polymerase chain reaction (PCR) analysis were conducted on days 1, 25, 50, and 100 on calves. Quantitative PCR data were analyzed using GLIMMIX, and blood metabolites concentrations, BW, and body condition score (BCS) were analyzed using the MIXED procedure of SAS. There was no difference in maternal BW and BCS between treatments. Glucose and blood metabolites that served as biomarkers for liver health (e.g., aspartate transaminase, albumin, alkaline phosphatase, and alanine transaminase) were in the normal levels for all calves (P > 0.40). Calves in the RPM group had a greater expression of adipogenic genes (e.g., PPARG, LPL, and CEBPD) at day 100 compared with CTRL (P < 0.01). In addition, DNA methylation (DNMT1) and oxidative stress-related genes (SOD2 and NOS3) in the RPM group were upregulated at day 100 compared with CTRL (P < 0.01). These results may suggest that calves born to primiparous dams exposed to RPM supplementation are more prone to develop greater adipose tissue than CTRL calves. Furthermore, RPM supplementation may improve methylation processes, as shown by the upregulation of DNMT1. The results shown in our study aim at expanding the knowledge on fetal programming and early-life growth and development of beef cattle under supplementation with RPM.

12 Amino Acid Nutrition in Dairy Cattle: Beyond Milk Protein

Abstract The transition from gestation to lactation, also known as the transition period, is a critical time for dairy cows. This phase is typically defined as 3 weeks before parturition through 3 weeks after parturition. Peak disease incidence (shortly after parturition) corresponds with the time of greatest negative energy balance (NEB) and negative protein balance (NPB), the peak in blood concentrations of nonesterified fatty acids, and the greatest acceleration of milk yield. Decreased fertility in the face of increasing milk production may be attributable to greater severity of postpartum NEB and NPB resulting from inadequate transition management or increased disease rates. The depth and duration of NEB and NPB are highly related to dry matter intake. Formulating and delivering appropriate diets that limit total energy intake to requirements but also provide proper intakes of all other nutrients [including the indispensable amino acids (IAA) Met and Lys] before calving can help lessen the extent of NEB and NPB after calving. Supplementation of rumen-protected methionine (RPM) during the transition period improved uterine immune function through improved glandular morphology, increased neutrophil infiltration after calving, and discovery of neutrophil extracellular trap formation in bovine endometrial tissue. Its supplementation has been reported to reduce the incidence of health complications, better lactation performance, and more favorable biomarker and plasma AA profiles, common in cows with increased liver functionality index. Cows supplemented with rumen-protected lysine (RPL) had decreased liver oxidative stress (SOD1, superoxide dismutase 1) and acute phase response (SAA3, serum amyloid A3) and reduced gene expression of NFKB1 (nuclear factor kappa B1) leading to increased proinflammatory IL1B postpartum, likely indicating improved immune activation when cows consumed RPL, a necessary component of early postpartum health. Our group has reported that a prepartum supply of RPL altered uteroplacental metabolism and glucose transport. This was demonstrated through increased expression of uterine transcripts involved in energy metabolism (GLUT3, glucose transporter 3; PCK1, phosphoenolpyruvate carboxykinase 1) and placental metabolism (FGF2, fibroblast growth factor 2; FGF2R, fibroblast growth factor 2 receptor; and PGF, placental growth factor). We also have demonstrated that RPL prepartum increased the placental protein abundance of FGF2 and LRP1 (low-density lipoprotein receptor-related protein 1), indicating possible enhanced placental metabolic activity, probably linked to trophoblast proliferation and migration processes. Finally, calves from dams fed RPL prepartum had improved overall growth and intake than calves from dams not receiving RPL. In conclusion, providing RPM and RPL during the transition period impacts dairy cows' health, uterine environment, and offspring.

Enhancing Metabolism and Milk Production Performance in Periparturient Dairy Cattle through Rumen-Protected Methionine and Choline Supplementation.

For dairy cattle to perform well throughout and following lactations, precise dietary control during the periparturient phase is crucial. The primary issues experienced by periparturient dairy cows include issues like decreased dry matter intake (DMI), a negative energy balance, higher levels of non-esterified fatty acids (NEFA), and the ensuing inferior milk output. Dairy cattle have always been fed a diet high in crude protein (CP) to produce the most milk possible. Despite the vital function that dairy cows play in the conversion of dietary CP into milk, a sizeable percentage of nitrogen is inevitably expelled, which raises serious environmental concerns. To reduce nitrogen emissions and their production, lactating dairy cows must receive less CP supplementation. Supplementing dairy cattle with rumen-protected methionine (RPM) and choline (RPC) has proven to be a successful method for improving their ability to use nitrogen, regulate their metabolism, and produce milk. The detrimental effects of low dietary protein consumption on the milk yield, protein yield, and dry matter intake may be mitigated by these nutritional treatments. In metabolic activities like the synthesis of sulfur-containing amino acids and methylation reactions, RPM and RPC are crucial players. Methionine, a limiting amino acid, affects the production of milk protein and the success of lactation in general. According to the existing data in the literature, methionine supplementation has a favorable impact on the pathways that produce milk. Similarly, choline is essential for DNA methylation, cell membrane stability, and lipid metabolism. Furthermore, RPC supplementation during the transition phase improves dry matter intake, postpartum milk yield, and fat-corrected milk (FCM) production. This review provides comprehensive insights into the roles of RPM and RPC in optimizing nitrogen utilization, metabolism, and enhancing milk production performance in periparturient dairy cattle, offering valuable strategies for sustainable dairy farming practices.

An Evaluation of the Supplementation of Rumen-Protected Lysine and Methionine on the Lactation Performance of Fall Parturition Grazing Holstein Cows in Southern Chile.

The aim of this study was to evaluate the effect of the supplementation of rumen-protected (RP) methionine and lysine on milk yield, solids, and body weight over time on fall-calving grazing multiparous Holstein cows from Chile. Four treatment groups were studied and compared for the outcomes over time. The treatments were as follows: (i) CON: control (n = 26); (ii) RP lysine group (LYS; 20 g per cow per day; n = 26); (iii) RP methionine group (MET; 20 g per cow per day; n = 26); and (iv) LYS × MET (RP lysine and RP methionine 20 g of each amino acid per cow per day; n = 26). Data were analyzed with general linear mixed model ANOVAs for repeated measures to primarily test the main effects of each amino acid and their interactions. The supplementation of the amino acids was conducted from 2 to 70 days postpartum. Overall, milk production tended to be higher in the MET and in the LYS × MET group when compared to the control group. Furthermore, CON produced significantly less milk protein (kg) and milk fat (kg) than the LYS, MET, and LYS × MET groups. Milk urea tended to be lower during the entire study in the CON group than the rest of the groups. There was a trend for a reduction in the losses of postpartum body weight in the LYS × MET than the CON. In conclusion, RP methionine and lysine improved milk fat and protein yield in grazing multiparous cows with fall parturitions; consequently, both RP amino acids can be used as a strategy for improving grazing cows' production performance.

Effects of Rumen-Protected Methionine Supplementation on Growth Performance, Nutrient Digestion, Nitrogen Utilisation and Plasma Amino Acid Profiles of Liaoning Cashmere Goats.

This study determined the effects of rumen-protected methionine (RPM) supplementation on the growth performance, nutrient digestibility, nitrogen (N) utilisation and plasma amino acid profiles of Liaoning cashmere goats during cashmere fibre growth. Twenty-four yearling male cashmere goats (body weight: 35.41 ± 1.13 kg) were randomly assigned to four dietary treatments: a corn-soybean meal basal diet deficient in methionine (negative control, NC) and a basal diet supplemented with 1, 2 and 3 g/kg of RPM. The RPM supplementation quadratically increased the average daily gain (ADG) and decreased the feed to gain ratio (p = 0.001) without affecting the final body weight and dry matter intake. In particular, compared to NC, 2 g/kg RPM supplementation increased the ADG by 35 g/d (p < 0.001) and resulted in the lowest feed to gain ratio (p < 0.001). RPM increased the apparent total tract digestibility of N and decreased the faecal N levels, both in a linear fashion (p = 0.005). Urinary N levels did not have an effect, but the N retention levels increased linearly with PRM (p = 0.032). Moreover, the RPM decreased the plasma urea N levels (p < 0.001) and increased the plasma Met levels quadratically (p < 0.001). In conclusion, RPM supplementation in the diet of cashmere goats can enhance the utilisation of N and improve ADG during the cashmere fibre growing period, and 2 g/kg of RPM in the diet is suggested.

Supplementation with Rumen-Protected Methionine Reduced the Parasitic Effect of Haemonchus contortus in Goats.

The present study investigated the impact of rumen-protected (RP) methionine supplementation on the resistance and resilience to Haemonchus contortus experimental infection of goat kids. Twenty-seven 6-month-old goat kids (14.55 ± 2.7 kg body weight) were placed in individual pens during an experimental period of forty-two days. Each kid was placed under one of three distinct diets (n = 9 animals/diet) corresponding to the following experimental groups: Control (C, Hay + concentrate), Low Methionine (LM, Hay + concentrate + 3.5 g/Kg of Dry Matter (DM) of RP methionine, or High Methionine (HM, Hay + concentrate + 11.5 g/Kg of DM of RP methionine). After a 4-week period of adaptation to the diets, all the animals were experimentally infected with a single oral dose of 10,000 H. contortus third-stage infective larvae (L3). No significant effect of RP methionine supplementation was observed for feed intake, digestibility and growth performance. The faecal egg counts (FEC) and worm burdens were not impacted by RP methionine supplementation either. In contrast, Packed cell volume (PCV) and haemoglobin concentration were higher in kids supplemented with RP methionine. Similarly, the level of serum IgA directed against adult H. contortus excretion and secretion products (ESP) was higher in supplemented kids. These results suggested that RP methionine supplementation improved goat kids' resilience against H. contortus infection.

The effects of rumen protected methionine supplementation on the performance of primiparous dairy cows using the Presynch-Ovsynch protocol.

The purpose of this study was to examine the effects of rumen-protected methionine (RPM) supplementation on the reproductive and productive performance of primiparous dairy cows fed two levels of protein. The Presynch-Ovsynch protocol was used to synchronize 36 lactating Holstein cows that were assigned randomly to one of six dietary treatments: (1) 14% CP and without RPM diet (14CP-0RPM; n = 6), (2) 14% CP and 15 g/head/day RPM (14CP-15RPM; n = 6), (3) 14% CP and 25 g/head/day RPM (14CP-25RPM; n = 6), (4) 16% CP and without RPM diet (16CP-0RPM; n = 6), (5) 16% CP and 15 g/head/day RPM (16CP-15RPM; n = 6), and (6) 16% CP and 25 g/head/day RPM (16CP-25RPM; n = 6). Independent of CP levels, feeding RPM had reduced the calving interval (P < 0.01). Feeding RPM increased (P < 0.01) overall plasma progesterone (P4). Feeding 16CP-15RPM increased (P < 0.01) overall plasma P4. Feeding 16% CP increased (P < 0.01) 4% fat corrected milk, energy corrected milk, milk fat and protein yield, and milk casein. Moreover, feeding the 25RPM has increased (P < 0.01) 4% fat corrected milk, energy corrected milk, milk fat, and protein yield. Compared with other treatments, feeding 16CP-25RPM or 16CP-15RPM enhanced (P < 0.01) milk yield and milk fat yield. In conclusion, feeding 16% CP with RPM boosted the productivity and reduced the calving interval in primiparous lactating dairy cows.

Effects of rumen-protected methionine supplementation on production performance, apparent digestibility, blood parameters, and ruminal fermentation of lactating Holstein dairy cows.

This study aimed to evaluate the effects of reducing dietary CP and supplementing rumen protected-methionine (RPM) on production performance, blood parameters, digestibility of nutrients or ruminal fermentation in lactating Holstein dairy cows. A total of 96 lactating cows were randomly assigned to 1 of 2 treatments: a diet containing 17.3% CP without RPM (control group; CON; n = 49) or a diet containing 16.4% CP and supplemented with 15.0 g/d of RPM (treatment group; RPM; n = 47). No effect was observed in the RPM group on milk yield, milk composition and digestibility of nutrients. The results of blood parameters showed that cows in the RPM group exhibited lower blood urea nitrogen concentration than in CON group. Rumen microbial crude protein (MCP) was higher in the RPM group compared to the CON group. Ruminal volatile fatty acid (VFA) concentrations were not different between treatments except for butyrate and isovalerate, which were higher in the RPM group than the CON group 2 h after feeding. In conclusion, reducing dietary CP with RPM supplementation did not limit milk yield, milk composition or digestibility of nutrients, but could improve nitrogen utilization, synthesis of MCP and partially increase VFA production 2 h after feeding cows.

PSVI-1 Effects of Rumen-Protected Methionine on Reproduction and Body Temperature of Nelore Cows in hot and Humid Environments

Abstract This study aimed to evaluate the effects of dietary supplementation of rumen-protected methionine (RPM) on the body temperature and conception rate of Nelore cows exposed to high temperature and humidity index (THI) values. This study was realized on a commercial beef farm located in the north of Brazil (5º 31’ 39” S, 48º 49’ 18” W). At d-31, 31 days before the FTAI protocol, a total of 563 lactating multiparous Nelore cows were divided into two treatments, with three blocks each, the control group (CG) and methionine group (MG). Both groups were kept on tropical pastures and received a mineral supplement. The MG Group was supplemented with 3g RPM/100g during 77 days, and the expected mineral supplement intake of both groups was 100g/cow/day. Between d0 and d9 of the FTAI protocol, a subset of groups of cows (n=142) remained with a data logger attached to the progesterone device, to monitor intravaginal temperature (IT) every 30 min. During the period that the cows remained with the dataloggers the minimum, average, and maximum THI were 72.76, 78.02, and 83.28, respectively. Pregnancy diagnosis was realized 35 days after the artificial insemination and the conception rate was calculated as the number of pregnant cows/inseminated cows. Data were analyzed using the JMP GLIMMIX procedure. RPM supplementation did not affect the conception rate (CG = 64.36% vs. MG = 58.19%, P &amp;gt;0.05). Intravaginal temperature from day 1 to day 8, between 0630 and 2030 h and between 2200 and 0100 h were lower (P≤0.05) for MG in comparison with CG. The average and the maximum IT were, respectively, 38.94ºC, 40.88ºC for MG and 39.02ºC, and 41.38ºC for CG. In conclusion, the supplementation of rumen-protected methionine reduced the internal body temperature in Nelore cows submitted to high THI environments, during the hottest hours of the day, but does not affect the conception rate.

Increased supply of methionine during a heat-stress challenge in lactating holstein cows alters mammary tissue mTOR signaling and its response to lipopolysaccharide.

The first objective was to investigate the effects of feeding rumen-protected methionine (RPM) during a heat stress (HS) challenge on abundance and phosphorylation of mechanistic target of rapamycin (mTOR)-related signaling proteins in mammary gland. The second objective was to investigate how HS and RPM may modulate the response of mammary gland explants to an inflammatory challenge using lipopolysaccharide (LPS). Thirty-two multiparous, lactating Holstein cows (184 ± 59 DIM) were randomly assigned to 1 of 2 environmental treatment groups, and 1 of 2 dietary treatments [TMR with RPM (Smartamine M; Adisseo Inc.; 0.105% DM as top dress) or TMR without RPM (CON)] in a crossover design. There were two periods with two phases per period. In phase 1 (9 d), all cows were in thermoneutral conditions (TN) and fed ad libitum. During phase 2 (9 d), group 1 (n = 16) cows were exposed to HS using electric heat blankets, whereas group 2 cows (n = 16) remained in TN but were pair-fed to HS counterparts to control for DMI decreases associated with HS. After a washout period (14 d), the study was repeated (period 2). Environmental treatments were inverted in period 2 (sequence), whereas dietary treatments remained the same. Mammary tissue was harvested via biopsy at the end of both periods. Tissue was used for protein abundance analysis and also for incubation with 0 or 3 μg/mL of LPS for 2 h and subsequently used for mRNA abundance. Data were analyzed using PROC MIXED in SAS. Analysis of protein abundance data included the effects of diet, environment and their interaction, and period and sequence to account for the crossover design. The explant data model also included the effect of LPS and its interaction with environment and diet. Abundance of phosphorylated mTOR and ratio of phosphorylated eukaryotic translation elongation factor 2 (p-EEF2) to total EEF2 in non-challenged tissue was greater with RPM supplementation (P = 0.04 for both) and in both cases tended to be greater with HS (P = 0.08 for both). Regardless of RPM supplementation, incubation with LPS upregulated mRNA abundance of IL8, IL6, IL1B, CXCL2, TNF, NFKB1, and TLR2 (P < 0.05). An environment × LPS interaction was observed for NFKB1 (P = 0.03); abundance was greater in LPS-treated explants from non-HS compared with HS cows. Abundance of CXCL2, NFKB1, NOS2, NOS1, and SOD2 was lower with HS (P < 0.05). Although LPS did not alter mRNA abundance of the antioxidant transcription factor NFE2L2 (P = 0.59), explants from HS cows had lower abundance of NFE2L2 (P < 0.001) and CUL3 (P = 0.04). Overall, RPM supplementation may alter mTOR activation in mammary tissue. Additionally, although HS reduced explant immune and antioxidant responses, RPM did not attenuate the inflammatory response induced by LPS in vitro.

Supplementation of guanidinoacetic acid and rumen-protected methionine increased growth performance and meat quality of Tan lambs.

ObjectiveTan lambs (n = 36, 3 mo old, 19.1±0.53 kg) were used to assess effects of dietary guanidinoacetic acid (GAA) and rumen-protected methionine (RPM) on growth performance, carcass traits, meat quality, and serum parameters.MethodsLambs were randomly assigned to three treatment groups, with 6 pens per group and 2 lambs per pen. Dietary treatments were: basal diet alone (I); basal diet supplemented with 0.08% GAA+0.06% RPM (II); and basal diet supplemented with 0.08% GAA+0.08% RPM (III). Diets were provided three times a day for 90 d. Intake per pen was recorded daily and individual lamb body weight (BW) was measured monthly. Carcass traits were measured after slaughter and meat quality at the end of the experiment, blood samples were taken on a subgroup of lambs for analysis of indicators mostly related to protein metabolism.ResultsFinal BW and average daily gain for the first and second month, and for the entire experiment were greater in Treatment II compared to Treatment I (p<0.05), whereas feed to gain ratio was lower (p<0.05). Treatment II had the optimal dressing percentage and net meat weight proportion, as well as crude protein and intramuscular fat concentrations in muscles. Treatment II improved meat quality, as indicated by the greater water holding capacity, pH after 45 min and 48 h, and lower shear force and cooking loss. Dietary supplementation of GAA and RPM also increased the meat color a* and b* values at 24 h. Finally, Treatment II increased total protein, and serum concentrations of albumin and creatinine, but decreased serum urea nitrogen concentrations, indicating improved protein efficiency.ConclusionIn this study, 0.08% GAA+0.06% RPM supplementation improved growth performance and meat quality of Tan lambs.

Effect of supplemental rumen-protected methionine on reproduction and production of Awassi ewes

The effect of rumen-protected methionine (RPM) was investigated in Awassi ewes (0, 3 or 5 g/head/d, n = 20) on reproductive and productive performance (initial body weight [BW] = 70.9 − 71.8 kg, 3 − 5 years). Supplementation started with the flushing feeding regime (at the breeding time) and lasted for 42 d. RPM was reused during the last 60 d of pregnancy and the first 60 d of lactation. RPM increased (p < .05) progesterone concentration with a higher lambing rate at the 5RPM level. The number of lambs born for each ewe exposed to the ram was also higher (p < .05) with 3RPM and 5RPM. Methionine levels in the plasma were greater (p < .05) with RPM mainly at 5RPM level. Birth weights of the lambs were higher (p < .05) with RPM regardless of the level. Contrary to this, weaning weights and rate of gain for lambs were reduced (p < .05) with RPM addition. RPM did not affect milk production of ewes during the first 60 d of lactation or on energy corrected milk and feed to milk ratio. However, milk protein content was increased (p < .05) at the 5RPM level while milk fat content was decreased. Regardless of the level of RPM addition, milk casein content increased (p < .05). At all levels, the effect of RPM on milk fatty acid profile was minor. It can be concluded that supplementing RPM might be a valuable tool to enhance the reproductive and productive performance of ewes during their breeding season.

Milk performance and oxidative status responses to rumen protected methionine supplementation in genotyped α-S1 casein lactating dairy goats fed two levels of metabolizable protein diets

In dairy goats, responses to rumen-protected Methionine (RPM) supplementation on milk performance and milk protein synthesis were inconsistent. The objective of the study was to evaluate the effects of supplemental RPM in diets differing in CP content on milk performance, milk composition, plasma concentration of amino-acids (AA) and parameters of oxidative status in goats genotyped for their genetic variant for alpha-S1 casein (CNS1). Sixteen goats (Body weight = 66.6 ± 8.5 kg, days in milk = 89 ± 5) were grouped into 2 blocks (High vs Low) according to their secretion of CNS1 in milk, and within each CNS1 block, goats were selected to make blocks comparable for milk yield, milk protein content, body weight and days in milk. Goats within CNS1 blocks were allotted to 2 periods cross-over (4 wks for each period with one washout week) nested in 2 × 2 factorial design with dietary CP (LP vs HP, 14 vs 16 % CP in TMR fed ad libitum) and RPM supplementation (CTL vs RPM, 0 vs 4 g/d). Dry matter intake and milk yield were individually recorded daily, whereas milk samples for milk composition determination, and blood samples were obtained individually twice weekly, and once weekly, respectively. Blood was sampled for glucose, NEFA, BHB, urea, insulin, total or oxidized glutathion, superoxide dismutase, catalase, malondialdehyde, and protein carbonyl. At the end of each period, blood was sampled during two consecutive wks to determine plasma AA profile. Goats fed HP diet had higher CP, PDIE, and LysDi (lysine digestible in intestine) intake than those fed LP diet, whereas goats supplemented with RPM had higher MetDi (methionine digestible in intestine) intake (P < 0.001) than those fed the CTL diet. Goats fed HP diet had similar milk performance, milk composition and yields, and similar feed, energy and PDI efficiencies, but higher milk urea concentration than those fed LP diet. Goats supplemented with RPM had higher milk yield only when fed the LP diet (RPM x dietary CP: P < 0.02). Compared to goats fed CTL diet, those supplemented with RPM had higher milk protein content, but this was observed only in those fed HP diet (RPM x dietary CP: P < 0.008), especially for Low CNS1 goats (RPM x CNS1: P < 0.05; RPM x dietary CP x CNS1: P < 0.11). Efficiencies of PDI, feed and energy were not altered by RPM supplementation, but CNS1 x dietary CP x RPM interaction was significant for these efficiencies. Goats supplemented with RPM tended to have higher plasma MDA (P < 0.07) and total glutathione concentrations (P < 0.09). In conclusion, increasing dietary CP failed to improve DMI, milk performance, milk protein content and protein yield, which suggest that Net Energy for lactation was a limiting factor of our experimental diets. With RPM supplementation, increase in milk production in the low CP group, and increase in milk protein content in the high CP group suggests that changes in metabolic partition of nutrients between milk secretion vs milk protein synthesis occurs according to the level of limitation of methionine in diet, which may affect the methionine requirement for goat milk production.

Effects of supplemental lysine and methionine on performance of nursing Awassi ewes fed two levels of dietary protein.

The objective of this study was to investigate the effects of rumen-protected lysine (RPL) and methionine (RPM) supplementation on production performance of nursing ewes fed two levels of dietary protein. Individually housed Awassi ewes (n = 34) nursing single lambs were randomly assigned (2 × 2 factorial design) to one of four dietary treatments with two levels of protein (170 or 151g/kg; HP or MP) and two levels of RPL and RPM (0 or 8.5 plus 4g/day/ewe of RPL and RPM, respectively; no or yes). The trial lasted for 5weeks. Ewes fed the MP diets had (P < 0.01) lower protein intake compared to those fed the HP diets. Intake of other nutrients and milk composition were not significantly (P > 0.13) affected by dietary treatments. Ewes fed the MPYES diet produced more (P < 0.05) milk compared to those fed the MPNO and HPYES diets and tended (P = 0.08) to be more than the HPNO diet. Additionally, milk composition yields for the MPYES diet were significantly (P < 0.05) more than the HPYES diets and tended (P ≤ 0.10) to be more than the MPNO and HPNO diets. Milk efficiency was highest (P < 0.05) for the MPYES diet. Final BW, total gain, and growth rate of lambs were greater when their dams were fed the MPYES diet compared to MPNO and HPNO diets. Under our conditions, decreasing dietary protein from 170 to 151g/kg did not negatively affect the performance of ewes and their lambs. Supplemental RPL and RPM were beneficial for ewes fed diets containing 151g/kg, but not 170, protein.

Effect of Rumen Protected Methionine and Choline on Blood Biochemical Metabolites, Milk Yield and its Composition during Transition Period in Surti Buffaloes

Background: Methionine and choline supplementation can aid in nutritionally managing transition Surti buffaloes. Present study has evaluated blood biochemical metabolites, milk yield and its changes in composition on supplementation of rumen protected methionine (RPM) and choline (RPC) in transition Surti buffaloes. Methods: Twenty-seven pregnant multiparous Surti buffaloes in three groups (n=9) from -15 d to 30 d postpartum received supplementation as: T1 (Control: basal diet), T2 (basal diet + RPM@10 gm/animal/day) and T3 (basal diet + RPM@10 gm/animal/day + RPC@ 50 gm/animal/day). Sample was collected at beginning, 1st, 3rd and 6th week for blood and at 1st, 3rd, 6th, 9th and 12th week postpartum for milk. Milk yield was recorded upto 100 days postpartum. Result: Postpartum TC, HDL and VLDL differed significantly (P less than 0.05) being highest in T3 and lowest in control (T1) whereas it was reverse for NEFA and BHBA. Supplemented groups had significantly lower TG levels at 1st and 3rd week postpartum. Milk fat upto 9th and SNF, protein, lactose, TAS, Ca, P and Mg upto 6th week were significantly (P less than 0.05) highest in T3, followed by T2 and T1. It was concluded that RPC along with RPM supplementation is more beneficial than only RPM supplementation in terms of enhancing liver health, reducing negative energy balance and improving milk quality.

294 Effect of Supplementing Rumen-protected Methionine on Production, Apparent Digestibility and Economic Effectiveness in Lactating Holstein Dairy Cows

Abstract The aim of the present study was to evaluate the effects of reducing dietary crude protein (CP) levels and supplementing rumen-protected methionine (RPM) on production, apparent digestibility of nutrients and economic effectiveness of lactating Holstein cows. A total of 96 (60 ± 7 d in milk; 34.39 ± 5.74 kg/d of milk production; mean ± SD) lactating Holstein dairy cows were randomly assigned to 1 of 2 treatments: diet containing 17.3% CP without RPM (control group; CON); diet containing 16.4% CP with supplementing 15.0 g/d of RPM (treatment group; RPM). All the data were analyzed using one-way analysis of variance (ANOVA) of SAS (SAS version 9.2, SAS Institute Inc., Cary, NC.). No effects were observed of reducing dietary CP on somatic cell counts, milk yield and milk composition including fat, protein, lactose, total solid, solids-not-fat and milk urea nitrogen. The total apparent digestibility of nutrients was similar between treatments, while RPM group had higher calcium digestion (44.24% vs. 42.75% ± 10.13%) and phosphorus digestion (48.50% vs. 45.96% ± 12.90%) numerically. In addition, supplying the diet of 16.4% CP with RPM supplementation to cows could reduce feeding cost by 0.5 $/d per cow and boost net profits. In conclusion, lower dietary CP with RPM supplementation did not limit milk yield, milk composition and apparent digestibility of nutrients, and also could improve the economic benefits of the dairy farms.

256 Effects of Transition Period Nutrition on Uterine Health

Abstract The transition from gestation to lactation, also known as the transition period, is a critical time for dairy cows. This phase is typically defined as 3 wk before parturition through 3 wk after parturition. Peak disease incidence (shortly after parturition) corresponds with the time of greatest negative energy balance (NEB), the peak in blood concentrations of nonesterified fatty acids, and the greatest acceleration of milk yield. Decreased fertility in the face of increasing milk production may be attributable to greater severity of postpartal NEB resulting from inadequate transition management or increased rates of disease. The depth and duration of NEB is highly related to dry matter intake. Formulation and delivery of appropriate diets that limit total energy intake to requirements but also provide proper intakes of all other nutrients (including the most limiting amino acids Met and Lys) before calving can help lessen the extent of NEB after calving. Cows that received controlled-energy diets during the last 3 wk prepartum had shorter days to pregnancy than cows that consumed high-energy diets in this time period. Additionally, a fully acidified prepartum diet formulated with a higher Ca concentration improved reproductive performance and uterine immune function in the postpartum period through the decrease of days to first ovulation, a tendency to decrease service per conception rate, improved glandular morphology, a tendency to increase polymorphonuclear neutrophil infiltration, and a tendency to increase the tight-junction protein occludin. Supplementation of rumen-protected methionine during the transition period resulted in improved uterine immune function through improved glandular morphology, increased neutrophil infiltration number after calving, and discovery of neutrophil extracellular trap formation in bovine endometrial tissue. In conclusion, nutritional strategies during the transition impact uterine health and fertility in dairy cows.