Efficiency Of Rumen Microbial Protein Synthesis Research Articles

Effects of Type of Concentrate and Timing of Supplementation on Feed Intake, Nitrogen Use, and Performance in Lactating Dairy Cows Grazing an Alfalfa-Ryegrass Sward.

Simple SummarySupplementing non-structural carbohydrates can enhance feed intake, performance, and nitrogen use in dairy cows grazing protein-rich swards. The present study thus analyzed the effects of feeding lactating cows two types of cereal grains, when their majority was either offered before or after grazing an alfalfa-ryegrass sward. Results showed that supplementing corn meal as a slowly degradable starch source after grazing and oat meal as a rapidly degradable starch source before grazing may improve milk yield and nitrogen use in grazing dairy cows. Hence, matching the choice of concentrate feed and the timing of its supplementation may aid to reduce nitrogen emissions from pasture-based dairy cattle systems while making use of the local, human-inedible forage resources from grasslands.The aim was to analyze the effects of two cereal grains differing in nutritional composition and starch degradation characteristics and the timing of their supplementation on feed intake, rumen microbial protein synthesis (MPS), performance, and nitrogen use of lactating dairy cows grazing an alfalfa-ryegrass sward. Four dietary treatments were tested in 24 lactating Brown Swiss cows in an incomplete 4 × 3 Latin square design. Cows were supplemented with 3.5 kg/d (as-fed basis) of a corn-based or an oat-based concentrate mixture (CM), of which either the majority (2.5 vs. 1.0 kg/d) was offered before or after grazing. Feed intake was similar across diets, but the interaction between type of CM and timing of supplementation affected eating time (p = 0.010), milk protein (p = 0.013) and energy-corrected milk yields (p = 0.025), efficiency of rumen MPS (p = 0.094), and nitrogen use efficiency (p = 0.081). Most of these variables were greater when the majority of the corn-based CM was offered after grazing and the oat-based CM before grazing. Supplementing slowly degradable starch sources after and rapidly degradable starch sources before grazing may improve the efficiency of rumen MPS, milk performance, and nitrogen use efficiency in dairy cows grazing alfalfa-ryegrass swards.

Effects of feed intake level on efficiency of microbial protein synthesis and nitrogen balance in Boran steers consuming tropical poor-quality forage

ABSTRACTThis study aimed at evaluating the effects of feed intake level on the efficiency of rumen microbial protein synthesis (EMPS), nitrogen (N) excretion, and N balance in twelve 18-months old Boran (Bos indicus) steers with initial average liveweight of 183 kg (standard deviation (SD) 15.2). The experiment followed a 4 × 4 complete Latin Square design with four dietary treatments tested in four periods. Each period ran for 5 weeks with 3 weeks of adaptation and 2 weeks of sample collection; separated by 2 weeks of re-feeding. Steers were fed at 100%, 80%, 60%, and 40% of their metabolisable energy requirement for maintenance (MER, referred to as MER100, MER80, MER60, and MER40, respectively). Steers receiving MER80, MER60, and MER40 were only fed Rhodes grass hay. MER100 steers were offered Rhodes grass hay at 80% of their MER and cottonseed meal and sugarcane molasses at each 10% of MER. Mean daily dry matter intake differed between treatments (p < 0.001) and ranged between 2.1 kg/animal (SD 0.13) in MER40 and 4.5 kg/animal (SD 0.31) in MER100. Urinary N excretion and N balance did not differ between MER80, MER60, and MER40. According to contrast test, declining feed intake level from MER80 to MER40 reduced duodenal microbial crude protein flow (p < 0.001), but did not alter the EMPS (g microbial N/kg digestible organic matter intake). Yet, if scaled to N intake, EMPS increased (p < 0.049), whereas total N and faecal N excretions decreased linearly with declining intake level (p < 0.001 for both variables). At similar grass hay intake, duodenal microbial crude protein flow was 41% higher in MER100 than in MER80 steers (p < 0.001). In cattle offered poor-quality tropical forage below their MER, the very low EMPS and thus microbial protein supply aggravate the negative effects of low dietary nutrient and energy intakes in periods of feed shortage.

Intake and digestion of wethers fed with dwarf elephant grass hay with or without the inclusion of peanut hay.

The aim of this study was to evaluate the effect of the inclusion of peanut (Arachis pintoi cv. Amarillo) hay in diets based on dwarf elephant grass (DEG, Pennisetum purpureum Schum cv. Kurumi) hay of different regrowth ages on forage intake and digestibility in wether lambs. The experimental treatments consisted of DEG hay with an interval of regrowth of 30 or 45 days offered as the only feed or in mixture with peanut hay (300 g/kg of total dry matter (DM)), which were tested in eight Texel × Suffolk crossbred wethers in a replicated 4 × 4 Latin square experiment. Both organic matter (OM) and digestible OM intakes were higher (P < 0.05) in animals receiving the legume forage. Total apparent OM digestibility was higher (P < 0.05) at an increased grass regrowth age. Ruminal OM digestibility increased (P < 0.05) with legume inclusion and at a higher grass regrowth age. The nitrogen (N) intake was higher (P < 0.05) in legume treatments and lower (P < 0.05) as the grass regrowth age increased, but retention of N was not affected by treatments. Duodenal flow of both, non-ammonia N and microbial N, were not affected by legume inclusion and were lower (P < 0.05) as grass regrowth age increased. The efficiency of rumen microbial protein synthesis (ERMPS) was negatively affected (P < 0.05) by legume inclusion and was lower (P < 0.05) as the grass regrowth age increased. Supplementation of dwarf elephant grass hay cut at the vegetative stage with peanut legume hay improves nutritional supply to wethers due to an increase in the forage intake.

Metabolizable protein and energy supply in lambs fed annual ryegrass (Lolium multiflorumLam.) supplemented with sources of protein and energy

SUMMARYTen Polwarth×Texel lambs (26±2·1 kg live weight (LW)), housed in metabolism cages and offered ryegrass (Lolium multiflorum)ad libitum, were used in a 5×5 Latin Square experiment to evaluate the effect of supplement type on digestion processes and on amino acid and energy supplies. Five of the 10 lambs were fitted with a rumen catheter and duodenal cannulae. Treatments included no supplement (control); 7 g/kg LW daily of cassava meal (Manihot esculenta, high-starch low-nitrogen (HS-LN)), cassava meal plus corn gluten meal (2:1, high-starch high-undegradable N (HS-UN)), cassava meal plus calcium caseinate (2·8:1, high-starch high-degradable N (HS-DN)) or corn gluten feed (low-starch high-degradable N (LS-DN)). Total intake of dry matter (DM), organic matter (OM) and N, as well as digestible OM intake were increased with HS-UN, HS-DN and LS-DN (P⩽0·050). Forage DM intake was reduced by HS-LN (P=0·030). Apparent digestibility of DM and OM was increased by HS-LN and HS-DN (P⩽0·038). Digestibility of neutral detergent fibre (NDF) and OM true digestibility were similar for all treatments. Supplementation with HS-LN decreased duodenal flux of total N, amino acid N, ammonia N and feed residual N (P⩽0·023). None of the supplements affected rumen microbial protein entering the small intestine, whereas the efficiency of rumen microbial protein synthesis (EMPS) was reduced by HS-LN and HS-DN (P⩽0·036). Ruminal degradability of dietary N (RDN) was increased by HS-LN, HS-DN and LS-DN (P⩽0·050). In conclusion, supplementing lambs fed ryegrass with degradable or undegradable high-protein concentrate increased the amino acid supply without affecting the supply of digestible energy, regardless of either the starch content or the degree of ruminal degradability of the protein source. These results indicate that supplementation of ryegrass-based diets should include both starch and protein sources.

In vitro slow-release urea contained in rice straw-based diets to increase efficiency of rumen microbial protein synthesis.

Effect of slow-release urea on efficiency of rumen microbial protein synthesis (EMPS) was examined using an in vitro technique. The objective of this experiment was to reveal the in vitro slow-release urea characteristics of zinc-urea, zeolites-urea, and zeolites-zinc-urea in relation to EMPS observed in different incubation time. The experimental design employed was randomized block design with 4 x 3 factorial plus a control treatment, and conducted in two replications. Factors were various urea sources (urea, zinc-urea, zeolites-urea, and zeolites-zinc-urea) and molasses concentrations (0%, 6%, and 12%) in rice straw-based diets. The control treatment was the rice straw-based diets containing neither urea nor molasses. Diets consisting of 45% rice straw and 55% concentrates (DM basis) were formulated to have similar N and TDN levels. Responses of parameters measured were subjected to MANOVA using the GLM procedure of SPSS 16.00 and differences among mean values, if applicable, were examined using HSD-test. Orthogonal comparisons were used to determine the effects of the control treatment vs. various urea sources. Results indicated that treatment of UZ combined with 6% of molasses showed the highest microbial biomass production (2.71 mg/l) at 24 hours fermentation period with its peak production estimation (3.2 mg/l) reached at 33.5 hours of fermentation period. Moreover, UZ treatment resulted in the highest microbial protein synthesis (1,381.45 ± 77.1 mg/l) at 24 hours fermentation period with its peak microbial protein synthesis estimation (1,756.04 mg/l) reached at 33.7 hours of fermentation period. The highest EMPS (25.98 ± 1.21 mg/100 mg OMD) was achieved when ration contained 6% of molasses. Key words : Slow-Release Urea, Microbial Protein Synthesis, Microbial Biomass, In vitro

Rumen degradation and estimation of microbial protein yield and intestinal digestion of napier grass ( Pennisetum purpureum) and various concentrates

A study was conducted in a repeated measure arrangement using four rumen fistulated steers to determine degradation of napier grass ( Pennisetum purpureum), protein ingredients and concentrates. Cotton seed cake (CSC), poultry litter (PL), soyabean meal (SBM), and sunflower seed meal (SFM) were used in Trial 1. In Trial 2, a commercial concentrate, a PL-based concentrate, a SFM-based concentrate and two napier grass cuts; medium (MNG) and old (ONG) were used. Rumen degradation data was used to estimate yields of rumen microbial protein (RMP) and total protein digestion in the intestines (TPDI). The estimated yields of RMP and TPDI values were comparable to determined values in other studies. The protein ingredients had highest (37–88 g N kg −1 fermentable organic matter (FOM)), concentrates moderate (26–27 g N kg −1 FOM) and napier grass lowest (10–19 g N kg −1 FOM) efficiency of RMP synthesis. The yields of RMP (44–52 g kg −1 DM) and TPDI (49–79 g kg −1 DM) were lower in ONG than MNG ( P<0.05). Among the protein ingredients, yields of RMP (58–87 g kg −1 DM) and TPDI (89–219 g kg −1 DM) were lowest in PL and highest in SBM ( P<0.05). Among the concentrates, the PL-based concentrate had the lowest while the commercial concentrate had the highest yields of RMP (75–84 g kg −1 DM) and TPDI (96–118 g kg −1 DM) ( P<0.05). Supplementing animals with CSC, SBM, and SFM would support high performance while moderate levels of production would be obtained from commercial concentrate or SFM-based concentrate. Supplementing animals with PL or PL-based concentrate would, however, result in low levels of production. To sustain same levels of production, animals fed ONG should be offered supplements containing about 30 g kg −1 DM more TPDI than animals fed MNG.