Undegradable Protein Research Articles

Influence of feeding different types feed blocks as supplementary feed on the reproductive performance of Awassi ewes grazing cereal stubble

This study was conducted to investigate the Influence of feeding different types feed blocks as supplementary feed on the reproductive performance of Awassi ewes grazing cereal stubble. These types were feed blocks enriched with cottonseed meal (CSM) or Brewers’ grain (BG) as sources undegradable protein (UDP). Ninety-six Awassi ewes (mean live weight 42.2 Kg), aged 3-4 years were allocated into three groups according to ewes live weight and body condition score.Group (C): Control (No Supplement) stubble grazing only.Group (FBC): FB enriched with CSM supplement plus stubble grazing.Group (FBB): FB enriched with BG supplement plus stubble grazing.All ewes were run as one flock during cereal stubble grazing. The feed blocks were fed to animals (supplementary groups) after their return from grazing wheat and barley stubble (28 days prior to mating and 54 days after introduction of rams). Rams run with the flock during the mating period. The results showed that feeding feed blocks enriched with CSM and BG as supplementary feed resulted considerable improvement in weight gain (P<0.05), body condition score (P<0.05), conception rate (13-16), lambing percentage (25-33%), twinning percentage (13-18%) and decreased the proportion of barren ewes (19 vs. 6 and 3%). Inclusion of small amount of high moisture brewers grain by-product (9%) as sources of undegradable protein in the feed blocks formula as replacement for costly cottonseed meal resulted a dramatic effects on the reproductive performance of Awassi ewes especially twinning rates and lambing rate.

Performance of Bos indicus beef cattle supplemented with mineral or with concentrates in tropical Urochloa decumbens pastures: A meta-regression approach

Models are useful to predict responses of beef cattle to supplementation and its interactions with pasture quality. Therefore, this study was conducted to quantitatively understand variables that influence the performance of cattle under grazing, with or without supplementation, in the tropics by using a meta-analytical approach. The database was composed of individual data of 577 heifers and 194 young bulls from 18 experiments. Information collected included: sex (male or female), total dry matter intake, supplement dry matter intake, forage crude protein (CPforage), forage indigestible neutral detergent fiber (iNDFforage), forage neutral detergent fiber, neutral detergent insoluble protein, crude protein intake from supplement (CPIsupp), metabolizable energy intake from supplement (MEIsupp), initial body weight (BW), final BW and average daily gain (ADG). Additionally, the intakes of rumen degradable protein (RDP), rumen undegradable protein (RUP), and metabolizable protein (MP) from the supplement of each study were calculated. To model animal performance, values within each experiment were divided into two components: ADG-pasture (ADG of non-supplemented animals) and ADG-supplement (differential ADG in relation to non-supplemented animals). Data were evaluated using a meta-analysis approach to estimate fixed and random effects of experiment using linear and nonlinear mixed models. There was no correlation between ADG-pasture and initial BW or final BW. The CPforage was positively correlated, and iNDFforage was negatively correlated with ADG-pasture. Therefore, two equations were developed to predict ADG-pasture, as follows: ADG-pasturemales (kg/day) = 0.007434 × CPforage – 0.001044 × iNDFforage; ADG-pasturefemales (kg/day) = 0.01445 × CPforage – 0.0000642 × CPforage2 – 0.001598 × iNDFforage. There was no correlation between ADG-supplement and total dry matter intake, initial BW, or final BW. The ADG-supplement was positively correlated with CPIsupp and MEIsupp. An exponential model was chosen to fit ADG-supplement. Equations to predict ADG-supplement were composed of three exponential compartments based on ADG-pasture, CPIsupp (or RDP, RUP or MP intakes from supplement), and MEIsupp. The replacement of CPIsupp by RDP, RUP or MP intakes from supplement demonstrated that all protein components could be used to predict the performance of grazing animals. Still, the best fit was observed when RUP intake from supplement was used. The validation process through cross-validation analyses demonstrated that all equations had high accuracy and moderate precision. In conclusion, our results indicate that ADG-pasture can be estimated from CPforage, iNDFforage. The ADG-supplement can be estimated from ADG-pasture, MEIsupp, and protein components intake in grazing heifers and young bulls.

Impacts of rumen degradable or rumen undegradable protein supplement with or without salt on nutrient digestion and VFA concentrations

Impacts of rumen degradable or rumen undegradable protein supplement with or without salt on nutrient digestion and VFA concentrations

Assessment of dietary protein supplementation on milk productivity of commercial organic dairy farms during the grazing season

Variability of protein and energy supply from pasture during the grazing season is a primary factor that can influence milk production of grazing organic dairy herds in the Northeast United States. This study evaluated the effects of altering the crude protein (CP) content of dietary supplements included in dairy rations fed to grazing organic dairy herds, on milk production and composition. Six commercial organic farms participated in a 6-wk trial, consisting of a 2-wk baseline period and 4-wk experimental period. Farms were paired by their summer 2017 milk urea nitrogen profile, and farms within each pair were assigned by restricted randomization to (1) continuation of their regular supplements (n = 3, control group, CON), or (2) supplement with altered CP as percentage of dry matter, formulated using an organic barley and roasted soybean mix (n = 3, treatment group, TRT). Throughout the 6-wk trial, individual milk samples were collected at 2 consecutive milkings weekly, while pasture and supplement samples, pasture measurements, and management information were collected twice weekly per farm. Data were statistically analyzed using the MIXED procedure of SAS (version 9.4, SAS Institute Inc.) for all parameters, and effects of treatment, week, and their interaction (treatment × week) were determined. The supplement CP (percentage of dry matter) during the baseline period was 13.5% for CON and 15.3% for TRT and 14.8% for CON and 19.3% for TRT during the experimental period. Milk production was 21% higher during the experimental period for TRT compared with CON (24.1 vs. 19.9 kg of milk per day, respectively). Milk production decreased for CON from wk 1 to wk 6 (23.6 vs. 20.4 kg of milk per day), whereas TRT maintained milked production from wk 1 to wk 6 (22.8 vs. 22.7 kg of milk per day). Milk composition was different between groups, with CON having higher fat percent (4.21 vs. 3.73%, respectively) and protein percent (3.15 vs. 3.05%, respectively) compared with TRT for the 6 wk. The milk urea nitrogen concentrations were similar between TRT and CON for the baseline period (11.9 vs. 12.1 mg/dL) and the final week of the experimental period (14.5 vs. 14.2 mg/dL). Although the effects of different diet CP fractions, particularly rumen undegradable protein and soluble protein, must be further delineated, these results indicate that altering the CP content of dietary supplements fed to grazing organic dairy cattle during the summer period in the Northeast US could be a useful mechanism to maintain milk production.

Growth Performance, Eating Behavior, Digestibility, Blood Metabolites, and Carcass Traits in Growing-Finishing Fat-Tailed Lambs Fed Different Levels of Dietary Neutral Detergent Fiber with High Rumen Undegradable Protein

This study was conducted to investigate the effect of decreasing concentrations of dietary neutral detergent fiber (NDF) at high rumen undegradable protein (RUP) on performance, digestibility, chewing activity, blood attributes, and carcass characteristics in 32 weaned male Afshari lambs (90 days of age; 26 kg initial body weight; BW). Dietary metabolic energy (ME) was increased from 10.6–11.5 and 11.8 MJ/kg dry matter (DM) by replacing alfalfa hay with grain to achieve NDF concentrations of 270, 245, and 220 g/kg DM, respectively, at 66.6 g/kg DM of RUP. The control (CON) diet contained 10.9 MJ/kg ME, 270 g/kg NDF and 59.6 g/kg RUP on DM basis. Rations containedsimilar concentrations of crude protein (CP, 160 g/kg DM). Lambs were slaughtered after a 56-d feeding period. The increase in dietary RUP had no effect on BW and average daily gain (ADG) but tended to decrease apparent digestibility of CP and DM, significantlydecreasedplasma urea concentration, and increased carcass CP content. Other body or carcass characteristics were unchanged. Decreasing dietary fiber at high RUP did not result in adverse effects on BW, ADG, body length, withers height, apparent digestibility of DM and CP, and BFT, but decreased DM intake (1539 vs. 1706 g/d) and feed conversion ratio (FCR; 4.33 vs. 5.39) compared with CON. Gradual reduction in NDF and physically effective NDF did not affecteating, ruminating or chewing times. Plasma glucose concentration was greater for NDF220 than for the three other treatments (p = 0.015).Slaughtering traits were not affected by dietary treatment except for hot carcass weight, which increased in NDF220 and NDF245 compared with NDF270 (p = 0.021). The concentration of meat CP increased in NDF270 versus CON (167 vs. 152 g/kg). Quadratic effects occurred for meat ether extract concentration (highest in NDF220) and fat-tail weight (highest in NDF245). In conclusion, the results showed that increasing the proportion of RUP within dietary CP improves carcass protein accretion. Decreasing dietary NDF to 220 g/kg DM at high RUP does not impair eating behavior and improves FCR in 3-month-old fat-tailed lambs.

In situ crude protein and starch degradation and in vitro evaluation of pea grains for ruminants

ABSTRACT Thirteen pea grain samples from different origins were used to examine the variation in in situ ruminal degradation of crude protein (CP) and starch as well as in vitro gas production (GP) kinetics. In vitro GP was used to estimate the digestibility of organic matter (dOM), metabolisable energy (ME) and utilisable CP at the duodenum (uCP). Protein fractions were also determined according to the Cornell Net Carbohydrate and Protein System. Degradation of CP and starch from all pea grains in the rumen was almost complete, with a high proportion of the instantly disappearing fraction. The variation in the degradation constants among pea grain variants was high, and degradation of CP and starch showed a significant initial lag phase in the rumen. The mean effective degradation (ED) calculated for a rumen outflow of k = 8%/h of CP (EDCP8) was higher than ED of starch (EDST8), averaging 77.0 and 71.5%, respectively, with low variation among variants. A correlation analysis between GP parameters and in situ degradation constants showed no clear relationship, but the rates of in vitro GP and in situ starch degradation were similar. Most of the protein in the pea grains was buffer-soluble with fast and intermediate degradation. Variation in the protein fractions among the pea grain variants was low and not suitable for predicting differences in in situ degradation characteristics. The mean in vitro uCP of pea grains was 198 g/kg dry matter (k = 8%/h) and variation was low and consistent with that of GP kinetics and in situ rumen undegradable crude protein values. The estimation of dOM and ME from 24 h GP led to very high values indicating that the existing prediction equations may not be suitable for pea grains as a single feed.

Effects of partial replacement of solvent-extracted soybean meal by amino resin-treated soybean meal in the concentrate supplement of high producing grazing dairy cows

We aimed to determine the effects of partially replacing conventional solvent-extracted soybean meal by amino resin-treated soybean meal in the concentrate supplement of lactating dairy cows grazing Guinea grass (Panicum maximum cv. Mombaça) on dry matter intake, milk production and composition, feed and nitrogen use efficiency, and nutrient digestibility. Eighteen Holstein x Gyr crossbred multiparous cows (79 ± 38 days in milk and 37.4 ± 4.69 kg/d of milk yield) were used in a replicated 3 × 3 Latin square design study with three experimental periods of 21 d The solvent extract soybean meal of the control diet (CON) was replaced by 1.0 (TSBM1.0) and 1.5 (TSBM1.5) kg as-fed basis of amino resin-treated soybean meal (29 and 43% as dry-matter basis, respectively) in the treatment diets. Dry matter intake, milk casein, protein, and fat contents, feed efficiency, nitrogen use efficiency, and nutrient digestibility did not differ among treatments (P > 0.05). The metabolizable protein was not increased by the treatments; however, cows fed with TSBM1.5 tended to produce 1.2 kg/d more milk (P = 0.09) and 64.3 g/d more lactose (P = 0.06) than CON cows. Although the supply of metabolizable protein was not affected by treatments, increasing rumen undegradable protein supply by 43% by replacing conventional solvent-extracted soybean meal with amino resin-treated soybean meal tended to increase milk production of high producing grazing cows.

Reformulation of dairy cow diets based on rumen degradable protein and total digestible nutrient with varying levels on in vitro fermentability and digestibility

Rumen degradable protein (RDP) needs to be balanced with the adequacy of rumen undegradable protein (RUP) and energy for optimal microbial growth. Therefore, this study aimed to determine the optimal level of the RDP:RUP ratio and the energy level of dairy cattle rations using the in vitro method. The rumen inoculum used to carry out this research, was obtained from two bull rumen fistulated of Friesian Holstein. The treatments consisted of 3 levels of RDP:RUP ratio, namely 50:50, 55:45 and 60:40, while the energy levels consisted of total digestible nutrient (TDN) levels of 65.6% and 68.6%. The experimental design was a factorial randomized block, while data were analyzed using ANOVA and Duncan multi range’s test. The result showed the ratio of RDP:RUP had an effect on DMD, OMD, NH3, and rumen microbe. Furthermore, the higher TDN content increased significantly DMD, OMD, total VFA, and partial VFA. The increase in the microbial population was associated with a rise in total VFA and NH3 concentrations. This research concluded, the rations with RDP:RUP (60:40) ratio increased the population of bacteria and protozoa, while the availability of ammonia in the rumen, and the high level of TDN provided a higher supply of VFA, DMD, and OMD.

Impacts of Rumen Degradable or Undegradable Protein Supplementation with or without Salt on Nutrient Digestion, and VFA Concentrations.

Simple SummaryRuminant animals have two specific protein requirements: the protein required by the animal, and the protein required by the microorganisms that exist within the rumen of the animal. These requirements are satisfied by rumen undegradable (RUP) and rumen degradable protein (RDP), respectively. Within the rumen, RDP is hydrolyzed, while RUP is digested and absorbed in the small intestine. As these proteins are digested differently, we studied their impact on the digestion process of low-quality forage. Overall, we found that a RDP supplement, when fed in a self-fed form, may enhance the digestion and use of low-quality forages. This may assist producers in selecting supplementation programs for their operation. The objectives of this study were to evaluate the effect of differences in protein type and delivery method on rumen dynamics and nutrient digestion. Cows were allotted to rumen degradable protein (RDP) or rumen undegradable protein (RUP) and self-fed (SF) salt-limited pressed blocks or hand-fed (HF) loose supplement, resulting in four dietary treatments. There was a delivery effect (p = 0.04) on neutral detergent fiber (NDF) intake, as the SF animals consumed more NDF than HF animals. The RDP-SF animals had greater NDF digestibility (p = 0.04) and water intake (p = 0.03) than the three other treatments. Supplement intake displayed a protein type effect (p = 0.03), as RDP-supplemented animals consumed more supplement on a g·kg body weight (BW)−1 d−1 basis than RUP animals. There was an effect of protein type (p = 0.02) and delivery method (p = 0.03) on fluid flow rate, with RUP and HF cows having greater liquid flow rates. Ruminal pH was lower (p < 0.01) in RDP-HF cows than RDP-SF cows at all hours, except 4-h post-feeding. RDP-SF animals had the greatest (p < 0.01) concentrations of ruminal ammonia. Valerate ruminal concentrations were greater (p = 0.04) in RDP supplemented animals compared to RUP supplemented animals. In conclusion, self-fed supplements containing RDP may enhance the use of low-quality forages and increase ruminal ammonia concentrations.

Estimation rumen degradable protein of local feeds in dairy cattle using in sacco method

There is a lack of nutrition information on local feeds protein in Indonesia, especially to determine protein fraction of dairy feed. The objective of this study was to determine rumen degradable protein (RDP) of local feeds in dairy cattle using in sacco method. The local feeds are copra meal, palm kernel meal, coffee husk, tofu waste, soy-sauce waste, brewer waste, and habbatussauda waste. Two ruminal fistulated male Frisian Holstein were used to determine rumen degradable protein using in sacco method. The parameters observed include the estimated kinetic parameters, effective degradability (ED), and RDP. The parameters were evaluated with analysis of variance using SAS University software. The result showed that tofu waste and habbatussauda waste had high potential rapid degradation of CP following by brewer waste, palm kernel waste, soy-sauce waste, copra meal, and coffee husk. Habbatussauda waste had higher RDP followed by brewer waste, tofu waste, copra meal, palm kernel meal, soy-sauce waste, and coffee husk. There was a positive correlation between RDP and crude protein content, and a negative correlation between RDP and crude fiber. It is concluded that local feeds have various characteristics of quality feed protein, which is shown by rumen degradable protein and rumen undegradable protein.

Performance, nutrient use, and methanogenesis of Nellore cattle on a continuous grazing system of Urochloa brizantha and fed supplement types varying on protein and energy sources

Supplementation of grazing cattle may improve forage utilization, methane emission and efficiency of nutrients use. This study aimed to evaluate the effect of different supllementation strategies on performance, metabolic parameters and methane emission in Nellore cattle reared on well-managed marandu palisadegrass (Urochloa brizantha cv Marandu) pastures. Three supplementation strategies consisted of protein and energy sources from traditional ingredients compared to a novel feedstuff: TS) Traditional supplement (protein-energy) composed of ground corn and soybean meal; ES) energy supplement composed of ground corn; and DS) Distiller's coproduct supplement (protein-energy) composed of ground corn and dried distiller grain (DDG). All supplements were offered at 0.3% of body weight (BW). Sixty-nine growing Nellore bulls [251 kg of body weight (BW) ± 13.0 kg] were randomly distributed according to initial BW in nine paddocks (twenty-three animals per treatment, three paddocks per treatment) to evaluate liveweight gain. From these, eighteen bulls (381.83 kg BW ± 16.15 kg) were selected for methane emission measurements (six animals per treatment) using sulfur hexafluoride tracer gas technique. Six rumen cannulated steers (289.5 kg BW ± 19.6 kg) across six paddocks (two per treatment) were used in an incomplete double Latin square design (3 treatments x 4 periods) to evaluate metabolic parameters. Statistical analyses were done using the Mixed Procedure in SAS and adopting significance level at 5%. It was hypothesized that the use of DS or ES, could increase the N use efficiency because of a higher rumen undegradable protein content, and more energy available for microbial synthesis in the rumen, respectively. Overall, there were no differences on animal performance, intake, nutrients digestibility, ruminal parameters, and microbial protein synthesis among treatments indicating that any of the supplemental sources could be utilized. Although, animals in DS had lower urine N excretion. The ES supplement increased methane yield (g/DMI) and the methane conversion factor Ym (% of gross energy intake) when compared to other treatments, but not methane production, which was similar among all treatments.

Energy: Protein Ratio in Ruminants: Insights from the Intragastric Infusion Technique.

Simple SummaryOne key question that has confounded nutritional scientists for years is how the ruminant responds metabolically with respect to energy and nitrogen utilisation when no exogenous energy is consumed. Fasting metabolism studies using the intragastric infusion technique (IIT) showed this to be a glucose-deficient state characterised by elevated nitrogen excretion and heat production. However, modern feeding systems continue to adopt fasting as the basis for measuring utilisation efficiency of nutritionally balanced diets, giving rise to the false concept of greater feed utilisation below than above energy maintenance. Another IIT finding was that given the animal’s genetic capacity for protein accretion and provided a rumen undegradable protein is fed, ruminants do not catabolise amino acids as an energy source but instead retain these to attain substantial gains in tissue protein deposition, fuelled by endogenous energy reserves. This suggests that endogenous fat reserves could be used to retain body protein when feed supplies are scarce or of poor nutritive value and questions the need to use high-energy diets in the finishing pre-slaughter period. Moreover, body protein and body fat deposition were also shown to be negatively correlated, contradicting current feeding systems which assume that nitrogen retention is always negative in an underfeeding situation.Studies on energy:protein ratio in ruminants are constrained by rumen fermentation since it governs nutrient metabolism and the ratio of energy:protein yielding nutrients available for absorption. By circumventing rumen fermentation, the total intragastric infusion technique (IIT) allowed objective quantification of maintenance energy and protein requirements, volatile fatty acid utilisation efficiency, efficiency of energy utilisation for maintenance (Km) and growth (Kf) and the origin of N retention responses to independent variation of energy and protein intake. This review outlines the key IIT findings and whether they are reflected in current feeding systems with implications for different production systems worldwide. Maintenance energy requirements are similar to those derived from comparative slaughter but maintenance N requirements are significantly lower. No differences in utilisation efficiency exist between acetic, propionic and butyric acids. At low energy intakes, endogenous energy reserves are utilised to retain amino acids and fuel substantial tissue protein gains. The use of fasting metabolism to measure the utilisation of nutritionally balanced diets is questioned since it is a glucose-deficient state. Inter-species differences in glucose metabolism appear to exist, suggesting that glucose requirements may be higher in cattle than sheep. The difficulty in predicting nutrient requirements, particularly protein, with any one technique is highlighted.

Importance of considering body weight change in response to dietary protein deficiency in lactating dairy cows

Our objective was to quantify the contribution of body weight (BW) change to the overall response of lactating dairy cows to a shortage of dietary protein. Lactating Holstein cows (n = 166; 92 primiparous, 74 multiparous) with initial milk yield of 41 ± 10 kg/d were fed high and low-protein diets in 7 blocks. Blocks were repeated in the same crossover design with periods of 28 to 35 d. Production of 69 of the 166 cows (42 primiparous, 27 multiparous) was also measured in late lactation. Low-protein diets were 14% crude protein (CP) in peak lactation and 13% CP in late lactation and were formulated to contain adequate rumen-degradable protein to maintain rumen function but inadequate rumen undegradable protein for the average cow in this study. High-protein diets were 18% CP in peak lactation and 16% CP in late lactation and contained extra expeller soybean meal to meet metabolizable protein requirements. Body weight changes were used to predict body energy and protein changes, which were added to milk components to calculate total captured energy and protein. Fixed effects of diet, parity, treatment sequence nested in each block, treatment period nested in block, interaction of diet and parity, and the random effects of block and cow nested within block were included in the model to compare cow responses to diets within each lactation stage. In peak lactation, reducing protein from 18 to 14% resulted in estimated daily losses of 2.9 Mcal of milk energy, 2.2 Mcal of body energy, 127 g of milk protein, and 16 g of body protein. Therefore, BW loss accounted for 43% of the decrease in captured energy and 11% of the decrease in captured protein when cows were fed deficient protein. In late lactation, BW loss accounted for 51% of the decrease in captured energy and 14% of the decrease in captured protein when cows were fed deficient protein. We suggest that BW change should be considered when assessing cow responses to changes in dietary protein.

Effect of Diets Differing in Crude Protein and Undegraded Intake Protein Level on Total-Tract Nutrient Digestibility and Nitrogen Metabolism in Sheep

Effect of Diets Differing in Crude Protein and Undegraded Intake Protein Level on Total-Tract Nutrient Digestibility and Nitrogen Metabolism in Sheep

Effects of protein sources and inclusion levels on nitrogen metabolism and urea kinetics of Nellore feedlot steers fed concentrate-based diets.

Urea recycling occurs in all mammalian species and represents an important source of ruminal nitrogen (N) for ruminants fed protein-restricted diets. However, its importance for cattle fed adequate amounts of protein and energy remains unclear. Six Nellore feedlot steers fed concentrate-based diets were used in a 6 × 6 Latin square design with a 3 × 2 factorial arrangement of treatments to evaluate ruminal fermentation, urea kinetics, and N excretion. Treatments consisted of 3 protein sources (PS: soybean meal plus urea [SU], corn gluten meal [CGM], and dry distillers grains [DDG]) and 2 inclusion levels (PL; 11% and 14%). Steers were adapted to the diets for 14 d followed by 8 d of sample collection. Feed intake, fecal output, and urine production were measured from day 18 to day 22 of each period. Blood samples were collected every 6 h on day 18. [15N-15N]-urea was infused into the jugular vein for 82 h over day 19 to day 22, and measurement of 15N in background (day 18) and enriched feces and urine (day 21) were used to evaluate urea kinetics. To evaluate the incorporation of recycled urea N into microbial protein (MICP), ruminal and duodenal fluid were collected on day 22. Steers fed SU diets had lower (P < 0.05) nitrogen use efficiency (NUE), greater (P < 0.05) urea-N entry rate (UER), and tended (P < 0.10) to have greater gastrointestinal entry rate of urea-N (GER) compared with those fed CGM or DDG. In addition, steers fed SU had greater (P < 0.05) urea-N returned to ornithine cycle (ROC) compared with those fed CGM or DDG. Increasing PL tended (P < 0.10) to increase UER. The proportion of total microbial N from recycled urea-N was greater (P < 0.05) for steers fed CGM compared with those fed SU and also greater for steers fed diets with 11% CP than for those fed with 14% CP. Diets with 11% CP can be used for Nellore feedlot cattle fed concentrate-based diets without negatively affecting intake, digestibility, and ruminal fermentation. Moreover, diets containing rumen undegradable protein (RUP) feed sources (CGM or DDG) compared with diets with SU markedly increased NUE, while maintaining microbial protein (MICP) synthesis. Results from this study suggest that the equation adopted by NASEM (NASEM. 2016. Nutrient requirements of beef cattle. 8th revised ed. Washington, DC: The National Academies Press) was not accurate in estimating the urea-N used for anabolism (UUA) in Nellore feedlot cattle fed concentrate-based diets.

Effect of feeding hydrolyzed feather meal and rumen-protected lysine on milk protein and energy utilization in late-lactation Jersey cows

Hydrolyzed feather meal (HFM) is a feed that is high in rumen undegradable protein; however, it is low in Lys compared with other high rumen undegradable protein sources. Additionally, processing methods differ by facility, which affects AA composition and protein digestibility. The objective of this study was to use lactating dairy cows to determine the effects of feeding 2 sources of HFM that differed by the amount of blood they contained and also to study the effects of supplementing rumen-protected (RP) Lys when these sources of HFM are fed. In this study, 12 multiparous Jersey cows were enrolled in a triplicated 4 × 4 Latin square with 4 periods 28 d in length. Cows were fed 2 total mixed rations that differed by source of HFM. The HFM was included at 4.5% of the diet dry matter, and one source was produced with the addition of poultry blood. Cows were randomly assigned to 1 of 4 treatment sequences. Treatments were as follows: HFM without added blood and no RP-Lys, HFM with added blood and no RP-Lys, HFM without blood and with RP-Lys (22 g of digestible Lys), and HFM with added blood and RP-Lys. The source of HFM containing blood tended to increase dry matter intake (18.3 vs. 17.3 ± 0.72 kg/d), and increased milk yield (20.5 vs. 18.4 ± 1.31 kg/d) and protein yield (0.788 vs. 0.694 ± 0.040 kg/d). The inclusion of RP-Lys did not affect milk or protein yield. In cows fed HFM containing blood, plasma concentration of Lys (82.1 vs. 70.8 ± 4.06 μM) and His (27.8 vs. 17.9 ± 3.15 μM) was higher. The addition of RP-Lys had no effect on the concentration of either plasma Lys or His. Gross energy intake tended to increase for HFM containing more blood (81.4 vs. 77.3 ± 3.29 Mcal/d); however, no difference was observed for intake of digestible energy (52.0 ± 2.20 Mcal/d) or metabolizable energy (46.4 ± 2.02 Mcal/d). Similar to dry matter intake, N intake increased with the inclusion of HFM containing blood, but crude protein digestibility decreased (61.6 vs. 66.0%). Results of this study highlight that source of HFM can be a factor that affects milk production and that this in part is due to differences in the profile of AA. Additionally, the observation that plasma His and milk protein increased with the consumption of HFM containing more blood suggests that His may have played a role in increasing milk and milk protein yield.

252 Effects of Increasing Urea in Corn Silage Diets and Duration of Ensiling on the Rumen Undegradable Protein Content of Corn Silage

Abstract Two experiments were conducted to evaluate the effects of increasing urea in a corn silage cattle diet and ensiling time (ET) impact on rumen undegradable crude protein (RUP) content of corn silage. In Exp. 1, ten ruminally- and duodenally cannulated heifers (body weight 265 ± 16 kg) were utilized in a 4 × 4 Latin square design and treatments were urea included at 0, 0.5, 1, or 1.5% of dietary dry matter (DM). In Exp. 2, corn silage samples were collected during feedout at 32-d intervals from the time of ensiling (d 0) to 160 d post-ensiling followed by separation in water to forage and grain components. Forage and grain samples were ruminally incubated in two steers to calculate RUP content of corn silage. In Exp. 1, DM intake increased linearly from 5.7 to 6.8 kg/d as urea inclusion increased (P &amp;lt; 0.001). Apparent total tract digestibility of DM and organic matter increased linearly from 55.8% to 60.8%, and 60.1% to 64.9%, respectively (P &amp;lt; 0.001). Total tract digestibility of neutral and acid detergent fiber increased linearly with increasing urea inclusion (P ≤ 0.004). In Exp. 2, the RUP content of the corn grain component decreased from 43.7% of CP at day 0 to 15.8% and 10.0% of CP after 32 and 96 d of ensiling, respectively (quadratic, P &amp;lt; 0.01). The RUP content of the forage averaged 19.3% of CP across ET ranging from 21.5 to 17.8% of CP (P ≥ 0.28). Estimated from the individual components, the RUP content of whole corn silage decreased from 32% to 17.1% of CP after 160 d in storage, a portion of which is digestible. Urea supplementation improved digestibility of corn silage diets and RUP content of corn silage decreased with storage time, primarily driven by changes in the corn grain component.

157 Effects of Monensin and Protein Type on Performance of Yearling Steers Grazing Smooth Brome

Abstract A two-yr study was conducted to evaluate the effects of monensin on sparing ruminal degradable protein in yearling steers grazing smooth bromegrass pastures (n = 288, initial BW = 332 kg, SD = 7). Treatment design was a 2 x 3 factorial with the following factors: 1) 0 or 200 mg monensin/steer daily; 2) no protein supplement, 1.25 kg soybean meal (SBM) as a source of RDP, or 1.31 kg non-enzymatically browned SBM as a source of RUP. Steers receiving supplemental protein were provided isonitrogenous amounts equivalent to dried distillers grains plus solubles at 0.50% BW. Steers were weighed approximately every 34 d to adjusted the amount of protein supplement. There was no interaction (P &amp;gt; 0.41) of monensin by protein type for average daily gain (ADG). Rate of gain for steers supplemented monensin was not different (P = 0.26) from steers not supplemented monensin. However, monensin supplemented steers numerically gained 7.9% more than steers not provided monensin when no supplemental protein was provided. Compared to steers supplemented with no protein, supplementing RDP increased ADG by 0.19 kg/steer (P &amp;lt; 0.001). Likewise, RUP supplementation increased ADG by 0.24 kg/steer (P &amp;lt; 0.001) compared to steers supplemented no protein. Supplementing RUP increased ADG by 0.05 kg/steer (P &amp;lt; 0.001) compared to steers supplemented RDP. Supplementing protein, especially rumen undegradable protein, improved yearling steer rate of gain on smooth bromegrass pastures. Monensin supplementation did not improve rate of gain. These data do not support the protein-sparing effects of monensin for steers supplemented with RDP.

Influence of flaxseed with rumen undegradable protein level on milk yield, milk fatty acids and blood metabolites in transition ewes

An experiment was conducted to determine the effects of two levels of rumen undegradable protein (RUP) without or with whole or extruded flaxseed on milk yield, milk component, milk fatty acids (FAs) profile and plasma metabolites in transition ewes. Three weeks before and after lambing, seventy-two Baluchi ewes were used in a completely randomized design with a 3 × 2 factorial arrangement of treatments. The treatments contained 1) no flaxseed + 20% RUP (no flaxseed, low RUP [NFLR]); 2) no flaxseed + 40% RUP (no flaxseed, high RUP [NFHR]); 3) 10% whole flaxseed + 20% RUP (whole flaxseed, low RUP [WFLR]); 4) 10% whole flaxseed + 40% RUP (whole flaxseed, high RUP [WFHR]); 5) 10% extruded flaxseed + 20% RUP (extruded flaxseed, low RUP [EFLR]), and 6) 10% extruded flaxseed + 40% RUP (extruded flaxseed, high RUP [EFHR]). Ewes fed 10% extruded flaxseed exhibited higher (p < 0.001) dry matter intake (DMI) and colostrum yield (p < 0.1) compared to other treatments. Two types of flaxseed and RUP levels had no significant effect on milk yield, but milk fat and protein contents decreased and increased in diets containing 40% RUP, respectively. Ewes fed extruded flaxseed produced milk with lower concentrations of saturated fatty acids (SFA) and higher α-linolenic and linoleic acids and also polyunsaturated fatty acids (PUFA) compared to other groups (p < 0.05). During post-lambing, the ewes fed diets containing flaxseed exhibited higher concentration of serum non-esterified FAs (NEFA) compared to diets without flaxseed (p < 0.01). The concentration of serum β-hydroxybutyric acid (BHBA) decreased in the diets containing flaxseed types at pre-lambing, but increased in diets containing extruded flaxseed at post-lambing (p < 0.01). The serum glucose concentration of ewes (pre and post-lambing) which consumed diets containing extruded flaxseed or 40% RUP increased, but blood urea concentration was elevated following supplementation of diet with whole flaxseed or 40% RUP (p < 0.001). In conclusion, utilization of 10% extruded flaxseed in the diets of transition ewes had positive effects on animal performance with favorable changes in milk FAs profile. However, there is no considerable advantage to supply more than 20% RUP level in the diet of transition dairy sheep.

Effects of inclusion different level of low-quality forage and ruminal undegradable protein to degradable protein ratio in starter diet on growth performance, ruminal fermentation, and urinary purine derivatives in young lambs

Forty 12-day-old lambs with an average BW of 6.37 kg were allocated in a completely randomized design with a 2 × 2 factorial arrangement to evaluate the effects of wheat straw feeding level (WS; 10% vs. 25%, DM basis) and rumen undegradable to degradable protein ratio [RUP:RDP; low ratio (LR) = 27:73; high ratio (HR) = 38:62] on growth performance, nutrient digestibility, ruminal fermentation, microbial protein yield (MPY), blood metabolites, and liver enzymes. Treatments (10 lambs/each; 5 males and 5 females) were: (1) 10% WS with low RUP:RDP ratio (10WS-LR); (2) 10% WS with high RUP:RDP ratio (10WS-HR); (3) 25% WS with low RUP:RDP ratio (25WS-LR); and (4) 25% WS with high RUP:RDP ratio (25WS-HR). Lambs were weaned on d 82 of the experiment and remained in the study until d 92. Lambs had free access to starter diet throughout the experiment. Results show that starter intake, average daily gain, and feed efficiency did not change among experimental treatments. Organic matter digestibility was reduced in 25WS diets. Greater organic matter digestibility, fibre digestibility (tendency; p = 0.064), wither height (d 82), and urinary allantoin was found in HR compared to LR diets. However, ruminal NH3-N concentration and urinary nitrogen excretion was greater in LR diets indicating lower nitrogen utilization efficiency. The greatest ruminal butyrate concentration as well as the greatest concentration of blood beta-hydroxybutyrate was found for 25WS-HR diet at d 90 of experiment. The blood urea concentration was reduced in HR diets compared to LR diets. In summary, high RUP:RDP ratio is advisable when young lambs received high level of WS in starter diet due to improve nutrient digestibility and nitrogen efficiency.