Rumen Microbial Protein Synthesis Research Articles

Effect of nicotinic acid supplementation on digestion, metabolism, microbiome, and production in late-lactation Holstein cows.

The purpose of this experiment was to determine if nicotinic acid (NA) effects on dairy cows and rumen microbial characteristics are forage type dependent (corn silage, CS; grass silage, GS). Four late lactation (days in milk = 225 +/- 12 d) Holstein cows were used in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. The main effects were a CS (66.10% CS) based diet or a GS (79.59%) based diet with or without 12 g/d NA. Each experimental period lasted for 28 d. Milk production and milk components, blood metabolites, apparent total-tract nutrient digestibilities, minutes rumen pH were below 5.8 as an indicator of ruminal acidosis, and body temperature changes were analyzed as indicators of heat stress. Nicotinic acid supplementation did not improve apparent total-tract nutrient digestibility. Feeding a GS-based diet improved NDF and hemicellulose digestibility. Feeding a CS-based diet increased the apparent total-tract digestibility of fat, and minutes rumen pH below 5.8 for a greater proportion of the time. The CS-based diet also improved milk yield, milk fat and protein yields, and energy-corrected milk yield; however, somatic cell count and BHB were also increased. Supplementing NA tended to decrease nonesterified fatty acids, especially when combined with GS where DMI was low. There was a trend for the total protozoa population to increase when GS and NA were fed but decreased when CS and NA were fed. Nicotinic acid tended to decrease rumen protozoal populations of Dasytricha, but increased populations of Ophryoscolex and Diplodiniinae with GS diets and decreased with CS diets. Entodiniinae were increased with CS but NA had no effect. Body temperature was increased when a CS-based diet was fed when compared with a GS-based diet. More research is needed to determine how NA can affect rumen microbial protein synthesis and what kind of diets will provide the optimum effect.

Optimizing dietary rumen-degradable starch to rumen-degradable protein ratio improves lactation performance and nitrogen utilization efficiency in mid-lactating Holstein dairy cows.

The dietary rumen-degradable starch (RDS) to rumen-degradable protein (RDP) ratio, denoted as the RDS-to-RDP ratio (SPR), has been proven to enhance in vitro rumen fermentation. However, the effects of dietary SPR in vivo remain largely unexplored. This study was conducted to investigate the effect of dietary SPR on lactation performance, nutrient digestibility, rumen fermentation patterns, blood indicators, and nitrogen (N) partitioning in mid-lactating Holstein cows. Seventy-two Holstein dairy cows were randomly assigned to three groups (24 head/group), balanced for (mean ± standard deviation) days in milk (116 ± 21.5), parity (2.1 ± 0.8), milk production (42 ± 2.1 kg/d), and body weight (705 ± 52.5 kg). The cows were fed diets with low (2.1, control), medium (2.3), or high (2.5) SPR, formulated to be isoenergetic, isonitrogenous, and iso-starch. The study consisted of a one-week adaptation phase followed by an eight-week experimental period. The results indicated that the high SPR group had a lower dry matter intake compared to the other groups (p < 0.05). A quadratic increase in milk yield and feed efficiency was observed with increasing dietary SPR (p < 0.05), peaking in the medium SPR group. The medium SPR group exhibited a lower milk somatic cell count and a higher blood total antioxidant capacity compared to other groups (p < 0.05). With increasing dietary SPR, there was a quadratic improvement (p < 0.05) in the total tract apparent digestibility of crude protein, ether extract, starch, neutral detergent fiber, and acid detergent fiber. Although no treatment effect was observed in rumen pH, the rumen total volatile fatty acids concentration and microbial crude protein synthesis increased quadratically (p < 0.05) as dietary SPR increased. The molar proportion of propionate linearly increased (p = 0.01), while branched-chain volatile fatty acids linearly decreased (p = 0.01) with increasing dietary SPR. The low SPR group (control) exhibited higher concentration of milk urea N, rumen ammonia N, and blood urea N than other groups (p < 0.05). Despite a linear decrease (p < 0.05) in the proportion of urinary N to N intake, increasing dietary SPR led to a quadratic increase (p = 0.01) in N utilization efficiency and a quadratic decrease (p < 0.05) in the proportion of fecal N to N intake. In conclusion, optimizing dietary SPR has the potential to enhance lactation performance and N utilization efficiency. Based on our findings, a medium dietary SPR (with SPR = 2.3) is recommended for mid-lactating Holstein dairy cows. Nevertheless, further research on rumen microbial composition and metabolites is warranted to elucidate the underlying mechanisms of the observed effects.

Starter protein content and supplemental soybean oil or hydrogenated palm fatty acids in Holstein dairy calves: growth performance, protozoa population, and nitrogen utilization efficiency

The study hypothesized that a 24% protein starter diet supplemented with inert fat (palm fatty acids; PLFs) instead of triglyceride-rich soybean oil (SBO) would promote the growth of dairy calves. The effects of different protein contents (20 vs 24% CP) and fat sources (SBO vs PLF at 2.5% DM) on growth, digestibility, blood metabolites, rumen protozoa and urinary nitrogen in dairy calves were investigated. A total of 52 female dairy calves (mean age 3 days and BW 40.7 kg) were allocated to the following treatments in a completely randomized design: (1) 20% CP starter diet supplemented with SBO (20CP-SBO), (2) 20% CP starter diet supplemented with PLF (20CP-PLF), (3) 24% CP starter diet supplemented with SBO (24CP-SBO), and (4) 24% CP starter diet supplemented with PLF (24CP-PLF). Calves were weaned on day 53, and the study ended on day 73. The 24CP diets enhanced starter feed intake, average daily gain (ADG), withers height, hip width, organic matter (OM) digestibility, and preweaning blood glucose compared to the 20CP diets. In contrast, SBO supplementation reduced feed intake, ADG, withers height, OM and CP digestibility, and pre- and postweaning blood glucose and beta-hydroxybutyrate levels, while increasing preweaning aspartate aminotransferase, compared to PLF. SBO supplementation led to lower urinary excretion of purine derivatives and microbial protein synthesis postweaning, and a reduction in protozoa population both pre- and postweaning. Calves fed PLF had higher starter intake than those fed SBO, regardless of the diet being 20CP or 24CP. Calves fed the 24CP-PLF diet had the highest ADG, while calves fed the 20CP-SBO diet had the lowest ADG. Calves fed the 20CP-SBO diet had lower feed efficiency than calves fed the other diets during the preweaning period and throughout the experimental period. Calves fed the 24CP-PLF diet had higher hip heights at weaning and on day 73 than calves fed the other diets. Calves fed the 20CP-SBO diet had lower neutral detergent fiber digestibility than calves fed the other diets. Calves fed the 24CP-SBO diet had higher postweaning blood urea nitrogen concentration than calves fed the other diets. Feeding the 20CP-SBO diet to dairy calves decreased urinary allantoin excretion and rumen microbial protein synthesis but increased urinary nitrogen excretion during the preweaning period. Our results suggest that PLF is more suitable than SBO in calf diets, especially when calves fed 24% CP, possibly due to improved nutrient digestibility.

Estimating Microbial Protein Synthesis in the Rumen-Can 'Omics' Methods Provide New Insights into a Long-Standing Question?

Rumen microbial protein synthesis (MPS) provides at least half of the amino acids for the synthesis of milk and meat protein in ruminants. As such, it is fundamental to global food protein security. Estimating microbial protein is central to diet formulation, maximising nitrogen (N)-use efficiency and reducing N losses to the environment. Whilst factors influencing MPS are well established in vitro, techniques for in vivo estimates, including older techniques with cannulated animals and the more recent technique based on urinary purine derivative (UPD) excretion, are subject to large experimental errors. Consequently, models of MPS used in protein rationing are imprecise, resulting in wasted feed protein and unnecessary N losses to the environment. Newer 'omics' techniques are used to characterise microbial communities, their genes and resultant proteins and metabolites. An analysis of microbial communities and genes has recently been used successfully to model complex rumen-related traits, including feed conversion efficiency and methane emissions. Since microbial proteins are more directly related to microbial genes, we expect a strong relationship between rumen metataxonomics/metagenomics and MPS. The main aims of this review are to gauge the understanding of factors affecting MPS, including the use of the UPD technique, and explore whether omics-focused studies could improve the predictability of MPS, with a focus on beef cattle.

333 Using Specific Bacillus Strains to Improve Digestibility and Performance of Growing Steers

Abstract Low fiber digestibility is an important factor restricting the growth performance of cattle in the dry tropics, both during the initial growth phase in grazing systems and later during finishing in high-starch diets. Due to concerns relating to the non-therapeutic use of antibiotics, including ionophores, there is interest in replacing these with probiotics. The objective was to evaluate the effects of specific strains of Bacillus spp. (Bovacillus, Chr. Hansen, Denmark) on intake and total tract nutrient digestibility of two diets. The first diet was forage based [100% Rhodes grass hay with 69% neutral detergent fiber (NDF)], the second was a high-energy diet (20% Rhodes grass hay, 40% finisher pellet, 30% peanut hull fiber pellet, 10% ground barley, 47% NDF, 18% starch). Twelve Bos indicus steers (267 ± 7.5 kg) were blocked by initial body weight and randomly assigned to receive the diets either without probiotic supplementation (n = 6, Control) or the diets plus 3 g per head of a probiotic containing a mixture of Bacillus licheniformis and Bacillus subtilis (3.2 x 109 CFU/g) for the duration of the trial. Each diet was fed for a 34-d period in individual pens followed by a 7-d sampling period during which the steers were housed in metabolism crates for total collection of urine and feces. On the high-fiber diet, supplementing with the probiotic increased organic matter digestibility by 7.8% (49.9 vs. 53.8%) and NDF digestibility by 8.4% (49.7 vs. 53.9%) resulting in greater (P &amp;lt; 0.05) digestible fiber intake (1.62 vs. 1.72 kg/d). There was no effect of probiotic supplementation on intake or digestibility in the high starch diet, and Bacillus supplements did not change rumen microbial protein synthesis in both diets. In conclusion, supplementing steers with a Bacillus-based probiotic has the potential to improve the nutrient digestibility and performance of beef steers, especially in tropical grazing systems.

Digestibility and nitrogen balance of goats on high and low protein rations supplemented with a commercial tannin feed-additive

ABSTRACTDespite the increasing importance of goat production in response to high demand for their products and their relative robustness to environmental stressors, and in contrast to other ruminant species, little data is available on how tannin extract feeding affects their feed intake, nutrient digestion and nitrogen (N) metabolism. Therefore, a trial in Oman investigated the respective variables by using a commercial tannin feed additive. In a 4 (treatments) x 3 (periods) x 2 (animals) Youden square, two weaned Batinah bucks each were fed a high or low protein diet of Rhodes grass hay and crushed barley grain, with or without the addition of a chestnut and quebracho tannin extract at 2 g/kg metabolic weight. Feed offered, feed refused and faeces and urine excreted were quantified to determine diet digestibility, total N excretion, N retention and rumen microbial protein synthesis (MPS). Due to their young age and low live weight, feed intake of goats was relatively low. Crude protein level and tannin addition had no statistically significant effect on dry matter (DM) and N intake, DM digestibility, N excretion in faeces and urine, as well as MPS. In consequence, no benefit of tannin feeding could be confirmed for the goats’ N retention, irrespective of diet composition. These results indicate, on one hand, an effective neutralisation of the tested tannin extract along the gastrointestinal tract of goats, but on the other hand, that stimulation of MPS or N retention by tannins cannot be evidenced when diet components are present that simultaneously release energy and protein, as is the case with barley.

Effects of Curcumin on Growth Performance, Ruminal Fermentation, Rumen Microbial Protein Synthesis, and Serum Antioxidant Capacity in Housed Growing Lambs.

This experiment was conducted to investigate growth performance, ruminal fermentation, rumen microbial protein synthesis, and serum antioxidant capacity with different doses of curcumin (CUR) included in the diet of housed growing lambs. Forty-eight four-month-old Dorper × Thin-tailed Han F1 crossbred male lambs (body weight = 20.89 ± 1.15 kg, age = 120 ± 10 days; mean ± SD) were randomly divided into four groups for a single-factor, completely randomized experiment. Treatments comprised the following: the basal diet supplemented with 0 (Control), 300 mg/kg (300 CUR), 600 mg/kg (600 CUR), or 900 mg/kg (900 CUR) CUR, respectively. The results showed that dietary CUR increased average daily gain (ADG), and the 300 CUR group evidenced the highest value. There were no significant effects on dry matter intake (DMI) and DMI/ADG. Lambs in the 300 CUR group showed higher totals of volatile fatty acids (VFA) and acetate than other groups, while decreased valerate was observed with supplementary CUR. The ruminal pH and ammonia N (NH3-N) concentration decreased with increasing CUR, with the greatest effect in the 300 CUR group. The quadratic effects were found in pectinase, carboxymethyl cellulose, and protease, with the greatest value in the 300 CUR group. The microbial populations of total bacteria and Ruminococcus albus also responded quadratically, and the methanogens, protozoan, and Fibrobacter succinogenes populations decreased linearly with increasing CUR. Lambs receiving additional CUR showed increased Prevotella ruminicola population. Microbial protein (MCP) synthesis was promoted by supplementary CUR. As supplementation with CUR increased, the serum activity of total antioxidant capacity (T-AOC), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) was enhanced, with the greatest value in the 300 CUR group. In conclusion, dietary CUR improved ruminal fermentation, promoted rumen microbial protein (MCP) synthesis, and enhanced serum antioxidant activity, as well as promoting growth performance in housed growing lambs.

Modelling rumen microbial protein synthesis in beef cattle

Modelling rumen microbial protein synthesis in beef cattle

Effects of Different Dietary Protein Level on Growth Performance, Rumen Fermentation Characteristics and Plasma Metabolomics Profile of Growing Yak in the Cold Season.

This experiment was aimed to compare the effects of two diets with different protein content on the growth performance, immune indexes, rumen fermentation characteristics and plasma metabolomics of growing yak in the cold season. A total of 24, 2-year-old healthy yaks with similar body weight (142.9 ± 3.56 kg) were randomly allocated to two isoenergetic diets with different protein content (10 vs 14%) according to a non-paired experimental design, and the protein of the diets was increased by increasing soybean meal, rapeseed meal and cottonseed meal. The growth performance experiment lasted 56 days. Four days before the end of the growth experiment, the digestion trial was conducted, and the rumen fluid and plasma was collected for measurement. The results showed that the average daily feed intake (p < 0.001) and average daily gain (p = 0.006) of yak fed a high-protein diet was significantly greater, while the feed conversion ratio was lower (p = 0.021) than that of yaks fed a low-protein diet. Plasma aspartate aminotransferase (p = 0.002), alanine aminotransferase (p < 0.001), malondialdehyde (p = 0.001), tumor necrosis factor-α (p = 0.032) and interferon-γ (p = 0.017) of the high-protein group were significantly lesser, whereas superoxide dismutase (p = 0.004) and interleukin-2 (p = 0.007) was significantly greater than that of the low-protein group. The rumen microbial crude protein (p < 0.047) and crude protein digestibility (p = 0.015) of yak fed a high-protein diet was significantly greater than that of the low-protein group. The metabolomics results showed that yaks fed a high-protein diet were elevated in protein digestion and absorption, arginine and proline metabolism, tryptophan metabolism, purine metabolism, butanoate metabolism, taste transduction, pyrimidine metabolism, pantothenate and CoA biosynthesis, glutathione metabolism and renin secretion pathways. It is concluded that a high-protein diet in the cold season can promote rumen microbial crude protein synthesis, enhance antioxidant and immune function and promote growth performance of yaks.

Effect of Dietary Rumen-Degradable Starch to Rumen-Degradable Protein Ratio on In Vitro Rumen Fermentation Characteristics and Microbial Protein Synthesis.

Simple SummarySynchronizing the energy and nitrogen supply in the rumen was reported to improve feed efficiency; however, synchronization indicators were rarely reported. The present study was conducted using a batch culture technique to evaluate the optimal rumen-degradable starch (RDS) and rumen-degradable protein (RDP) ratio (SPR) for synchronizing the energy and nitrogen supply for dairy cows. The in vitro disappearance of dry matter and neutral and acid detergent fiber, gas production and microbial crude protein synthesis quadratically increased with increasing the SPR and peaked at 2.3. Although an in vivo study could be further needed, our results provided an optimal SPR range for dairy cows to synchronize the energy and nitrogen supply.The objective of this study was to investigate the effects of dietary rumen-degradable starch (RDS, g/kg of DM) to rumen-degradable protein (RDP, g/kg of DM) ratios (SPR) on in vitro rumen fermentation characteristics and microbial protein synthesis (MCPS). Treatments were eight diets with SPR of 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5 and 2.6 and were formulated to be isoenergetic, isonitrogenous, and isostarch. Substrates were anaerobically incubated in sealed culture vials (100 mL) for 6, 24 or 48 h. Three incubation runs were conducted within two consecutive weeks. With the increase of the dietary SPR, the gas production (GP), in vitro dry matter disappearance (IVDMD) and concentration of MCPS and total volatile fatty acids (TVFA) linearly increased after 6 h of incubation (p ≤ 0.01), whereas they quadratically increased and peaked at the SPR of 2.3 after 24 and 48 h of incubation (p < 0.05). In response to dietary SPR increasing, the in vitro neutral detergent fiber disappearance (IVNDFD) quadratically increased (p < 0.01), and the ammonia nitrogen (NH3-N) concentration linearly decreased (p < 0.01) after 6, 24 and 48 h of incubation. Based on the presented results, an SPR of 2.3 is recommended for formulating a diet due to its greatest IVDMD, IVNDFD, GP, TVFA and MCPS. However, as the results obtained are strictly dependent on the in vitro conditions, further in vivo studies are needed to verify our findings.

Effects of guanidinoacetic acid and betaine on growth performance, energy and nitrogen metabolism, and rumen microbial protein synthesis in lambs

In this study, we investigated the effects of guanidinoacetic acid (GAA) and betaine (BT) on growth performance, nutrient digestion, energy-nitrogen metabolism, and microbial protein synthesis in lambs. Forty-eight 3-month-old Dorper × Thin-tailed Han first crossbred generation ram lambs with similar body weight (22.03 ± 1.3 kg; mean ± SD) were randomly divided into 4 groups. According to the 2 × 2 factorial arrangement, lambs in each of the 4 groups were fed basal diets, or basal diets supplemented with 0.9 g GAA/kg dietary dry matter (DM), 5 g BT/day, or 5 g BT/day + 0.9 g GAA/kg dietary DM. Before the formal trial, all lambs were allowed to adapt to the facilities as well as the basal diet for 15 days. This study lasted for 71 days including a 60-day period for feeding trial and an 11-day period for digestion and metabolism trials. The results showed that supplementation with GAA or BT increased the average daily gain (ADG) and feed efficiency (FE). However, no further increase in ADG or FE was observed with the combination of GAA and BT compared to that induced by addition of GAA or BT alone. Moreover, the addition of GAA or BT improved the apparent digestibility of dry matter (DM) and neutral detergent fiber (NDF), while GAA increased acid detergent fiber (ADF). GAA or BT supplementation decreased ruminal pH but increased the concentration of total volatile fatty acids (T-VFA), propionate, and valerate. Ruminal ammonia N content was not influenced by GAA or BT supplementation. Addition of GAA or BT resulted in an increase in microbial protein (MCP) synthesis. Additionally, supplementation with GAA or BT promoted digestible nitrogen (N), retained N, digestible energy and apparent digestibility of gross energy, and reduced fecal N. Supplementation with GAA decreased urinary N and increased metabolizable energy. The addition of GAA or BT increased total protein and creatine levels in serum, but the addition of BT alone decreased blood homocysteine (Hcy) levels. GAA elevated blood insulin-like growth factors-1 (IGF-1). These results demonstrate that supplementation with GAA or BT improves growth performance, nutrient digestibility, and energy-nitrogen metabolism, but the addition of BT and GAA in combination does not further improve the growth of lambs.

Evaluation of Pre-ingestive Citronella Residues using Ruminal In Vitro Techniques

Citronella residues (CR) have the potential to be used as an alternative to the fiber diet of ruminants. This study reports on the effects of pre-ingestive CR using ammonia (4 % dry matter (DM)) and fermentation (6 % DM) on in vitro rumen fermentation, metabolism, and methane (CH4) production. Four CR levels of 0, 25, 75, and 100 % DM were used. Each level was repeated 3 times and a complete randomized design method was used. The results showed that pre-ingestive CR significantly increased the pH rumen fluid but decreased ammonia-nitrogen concentration, total iso-volatile fatty acid (iso-VFA) production, and protozoa population (p &lt; 0.01). The pre-ingestive CR significantly decreased the acetic acid composition and rumen microbial protein synthesis (p &lt; 0.05), and significantly increased the proportion of propionic acid, n-butyric acid, and iso-valeric acid (p &lt; 0.05). The total VFA production and rumen CH4 production did not significantly change (p &gt; 0.05). In conclusion, pre-ingestive CR was compatible as a basal diet for ruminants.&#x0D; HIGHLIGHTS&#x0D; &#x0D; Pre-ingestive treated citronella residues used as substitute in ruminant fiber diet&#x0D; 100 % pre-ingestive citronella residues increased rumen fluid pH compared with napier grass&#x0D; 100 % pre-ingestive citronella residues reduced NH3, VFA, and protozoa&#x0D; 100 % pre-ingestive citronella residues had no effect on methane production&#x0D; Rumen fermentation profile of pre-ingestive residue treatments are suitable alternative diets&#x0D; &#x0D; GRAPHICAL ABSTRACT

Effects of Rubber Seed Kernel Fermented with Yeast on Feed Utilization, Rumen Fermentation and Microbial Protein Synthesis in Dairy Heifers

Yeast (Saccharomyces cerevisiae) has been used to improve the nutritive value of feedstuffs, especially rubber seed kernel. In the current study, rubber seed kernel was grated and subjected to solid-state fermentation with yeast to enhance the nutritive value. The yeast-fermented rubber seed kernel (YERSEK) was substituted for soybean meal in ruminant diets to evaluate the effect of YERSEK on feed intake, digestibility, rumen fermentation and microbial protein synthesis in dairy heifers. Five Holstein Friesian crossbred heifers with an initial body weight (BW) of 215 ± 20 kg were used in this research. The experimental design was a 5 × 5 Latin squared design and the dietary treatments were five levels of YERSEK at 0, 100, 150, 200 and 250 g/kg dry matter in concentrate at 1% of BW, with rice straw fed ad libitum. The supplementation with YERSEK reduced rice straw and total DM intake linearly (p &lt; 0.05). The intake of neutral detergent fiber and acid detergent fiber decreased linearly (p &lt; 0.05), while ether extract intake increased linearly (p &lt; 0.01) with YERSEK supplementation. The ether extract digestibility tended to be high (p &lt; 0.01) with increasing levels of YERSEK. Supplementation with the YERSEK did not change (p &gt; 0.05) ruminal pH and blood urea nitrogen in this study, but ruminal ammonia nitrogen was increased (p &lt; 0.01) in the heifers receiving YERSEK. Increasing the YERSEK levels did not adversely affect the proportion of volatile fatty acids (VFA), which included acetate, propionate and butyrate and the microbial population (p &gt; 0.05). Microbial protein synthesis was similar among the treatments (p &gt; 0.05). The inclusion of YERSEK at 250 g/kg DM in concentrate feed had no effect on the utilization of feed, rumen fermentation characteristics and microbial protein synthesis. The YERSEK could be used as a protein replacement for up to 86% of the soybean meal in feed concentrate for dairy heifers.

Review: Problems in determining metabolisable protein value of dairy cow diets and the impact on protein feeding

Accurate determination of dairy cow’s metabolisable protein (MP) requirements is essential for maximising milk yield and minimising N input in dairy production systems. The main objectives of feed evaluation systems are to predict accurately the nutritive value of feed resources and production responses to ingested nutrients. In recent years, protein evaluation systems have made progress in complexity but our analysis indicated that in comparison to simple MP models, or even models based on CP and metabolisable energy intake, new models have failed to improve milk protein yield predictions. Previous meta-analyses have indicated low marginal efficiencies for incremental CP intake even with high-quality feeds as protein supplements. Most current protein systems tend to overestimate MP supply from rumen undegradable protein and overlook the effects on rumen microbial protein synthesis. These findings suggest that there is scope for improving predictions of MP supply. This review highlights and discusses some evident problems in the current MP systems that may partly explain the modest progress achieved over the last few decades.

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.

Reformulation of Dairy Cattle Concentrate Based on Rumen Degradable Protein to Undegradable Protein Ratio at Different Energy Levels: In Vitro Study

Abstract Asynchronous releasing rumen degradable protein (RDP) and energy reduces rumen microbial protein synthesis (MPS) and increases excess nutrients to the environment. Moreover, the ratio of RDP to rumen undegradable protein (RUP) was also important in improving the utilization of protein, especially for high-producing cows. However, the issue has not been a concern of most dairy concentrate manufacturers in tropical areas. The objective of this study was to determine the optimal ratio of RDP to RUP (RDUP) at different energy levels (TDN) of dairy cattle concentrate using in vitro method. The study used a 4 × 3 factorial randomized block design. The first factor was RDUP (1.50; 1.22; 1.00; 0.82) and the second factor was TDN levels (65%; 70%; 75%). Data were analyzed using ANOVA and followed by Duncan’s test. RDUP and TDN treatments affected NH3 concentration without interaction. Total VFA concentration, rumen bacteria, and protozoa population did not affect by the treatments. Dry matter and organic matter digestibility increased with increasing RDUP and TDN levels with an average of 71.58% and 70.67%, respectively. It is concluded that dairy concentrate based on RDP:RUP ratio at 1.50 (60:40) and 75% TDN improves fermentability and in vitro digestibility.

Effect of urea and molasses fermented cassava pulp on rumen fermentation, microbial population and microbial protein synthesis in beef cattle

ABSTRACT This study aimed to investigate the effects of fermented cassava pulp with urea and molasses on feed intake, nutrient digestibility, rumen fermentation and microbial protein synthesis. All brahman crossbred beef cattle were randomly assigned according to a 4 × 4 Latin Square Design to receive four dietary treatments; cassava pulp (control), cassava pulp fermented with urea 4%, cassava pulp fermented with molasses 4%, and cassava pulp fermented with urea 4% and molasses 4%. All animals were fed concentrate pellet at 1.5% BW and supplemented 0.5% BW of cassava pulp. The results showed that rumen NH3-N concentration was increased in cattle fed with both cassava pulp fermented with urea and/or molasses (P < 0.05). The total VFA was not affected by dietary treatments while there was an increase in propionic acid when cattle were supplemented with fermented cassava pulp. However, methane production and protozoal population were lower in treatments with fermented cassava pulp (P < 0.05). Feeding of fermented cassava pulp resulted in an increase in microbial protein synthesis (P < 0.05). Based on the present findings, it could be concluded that fermented cassava pulp with urea and molasses can increase propionic acid, microbial protein synthesis while reducing protozoal population and CH4 production.

Excreção de creatinina e derivados de purina e síntese microbiana em cordeiros alimentados com farinha de vagem de Samanea saman

ABSTRACT Evaluated the levels of rain tree (Samanea saman) pod meal (RTPM) (0, 10, 15, 20 and 25%) replacing maize in the dry matter of the diet on intake of DM, CP and ME, creatinine and total purine derivatives excretion in urine and microbial protein synthesis in lambs. Twenty-five uncastrated Bergamasca lambs were used, with an initial body weight of 24±5kg and an average age of 120 days. The experimental design was completely randomized, with five treatments and five replications. The trial lasted 84 days and the 24h and spot urine collections were performed in the last day of the experiment. The intake was not affected (P&gt;0.05), the urine volume and daily creatinine excretion were influenced (P&lt;0.05) by RTPM replacing maize, observing increasing linear effect and cubic variation (P&lt;0.05), respectively. The cubic and quadratic components were significant (P&lt;0.05) for the excretion of total purine derivatives, absorbed purines, and microbial synthesis. The cubic variation, with peaks at 5% and 18% replacement for urinary excretion of creatinine and purine derivatives, indicates that the levels used of RTPM affected the renal activity of lambs. Substitution of maize by RTPM up to 10% enhances efficiency of rumen microbial crude protein synthesis.

Effect of Grape Marc Added Diet on Live Weight Gain, Blood Parameters, Nitrogen Excretion, and Behaviour of Sheep.

Simple SummaryThis experiment explored how feeding grape wine production waste product grape marc impacts on sheep production. Forty merino sheep were divided into two groups; one group received a sheep industry standard diet (control), and one group received a treatment diet which had 20% of the control diet replaced by grape marc. The results showed that the grape marc diet led to a higher intake and faecal nitrogen/urinary nitrogen ratio, but no difference in sheep live weight gain, behaviour, and parasitic egg count compared with control diet-fed sheep. Overall, the results showed that feeding grape wine production waste product grape marc as a cheap feed, to replace 20% of the control ration, can maintain sheep productivity, health, and environmental sustainability.A 39-day field experiment was conducted to assess the effect of grape marc (GM) feeding on sheep productivity, health, and environmental sustainability. Forty merino sheep were divided into two dietary groups, each having five replications (n = 4 sheep/replication). Experimental diet consisted of: (i) control: 55% lucerne hay + 40% wheat grain + 5% faba bean; (ii) GM treatment: control diet with 20% replaced by GM on a dry matter (DM) basis. The GM treatment contained 2–10% higher phytochemical contents than the control. The DMI from the GM treatment was 15% higher than the control (p < 0.001). No difference was found in sheep live weight gain, behaviour, and quality between groups (p > 0.05). No difference was found in total faecal production, faecal organic matter, and nitrogen contents (p > 0.05) and parasitic egg count. The GM treatment led to higher nitrogen intake (23.1 vs. 27.2 g/d) and faecal nitrogen excretion (6.3 vs. 8.7 g/d) compared to the control. Urinary creatinine, allantoin, and purine derivatives were lower in the GM treatment than control (p < 0.05). However, both groups had similar purine derivatives/DMI (i.e., indicator of rumen microbial protein synthesis efficiency; p > 0.05). Overall, the results showed that GM can replace 20% of the control ration to maintain sheep productivity, health, and environmental sustainability.

Effects of mild water restriction on nutrient digestion and protein metabolism in desert-adapted goats

• Mildly restricting drinking water intake by ≤ 21 % does not reduce feed intake in desert-adapted goats. • Declining drinking water intake enhances rumen fermentation, but reduces microbial growth. • Lowering drinking water intake shifts nitrogen excretion from urine to faeces. • Effects of drinking water restriction differ depending on diet and animal factors. The aim of the present study was to determine the effects of mild drinking water restriction ( WR ) on feed intake, diet digestibility, rumen fermentation, and nitrogen ( N ) balance in a desert-adapted goat breed of Oman. Two feeding trials were conducted during the dry summer months (August-October) in 2013 and 2014. In each trial, nine adult male Batinah goats were exposed to two levels of mild WR (WR: 85 % (WR15) and 70 % (WR30) of individual ad libitum consumption; 100 % (WR0)) in a 3 × 3 Latin Square design. Drinking water intake, feed offered and refused, and excretion of urine and faeces were quantified and samples analysed for crude nutrient and fibre fractions. Moreover, rumen microbial protein synthesis was estimated from urinary purine derivatives excretion. In trial 2, rumen fermentation characteristics were additionally studied in three rumen-fistulated goats. Linear and quadratic effects of WR in each trial were assessed by mixed model analysis, whereas correlations between drinking water intake and response variables were determined across both trials. For WR30, drinking water intake was 79 % and 90 %, respectively, of the water intake of WR0 goats in trial 1 and WR15 goats in trial 2. Water restriction had no effect on feed intake, rumen microbial protein synthesis, and N balance in both trials. However, apparent total tract digestibilities of neutral and acid detergent fibre tended to decrease linearly ( p ≤ 0.081) with increasing WR level in trial 1, whereas those of dry matter and organic matter were lower ( p ≤ 0.028) for WR15 than for WR0 and WR30 in trial 2. Proportions of butyrate ( p ≤ 0.046) and isovalerate ( p = 0.087) in rumen fluid were greater and those of propionate ( p = 0.079) and valerate ( p = 0.062) lower for WR30 as compared to one or both of the other WR levels. Duodenal microbial N flow and efficiency of microbial protein synthesis did not differ between WR levels. Yet, across both trials, both variables correlated positively with drinking water intake. Similarly, declining drinking water intake increased the ratio between faecal and urine N excretion (r=−0.55) and the N concentration in faeces (r=−0.42), but reduced the fibre concentration (r=0.38) and the proportion of undigested feed N in faeces (r=0.49). Mild restriction of drinking water intake to ≥ 79 % of the ad libitum consumption, which is expected to occur more frequently with advancing climate change in the semi-arid tropics and subtropics, may impair feed nutrient use and thus performance of regionally adapted small ruminants, while improving the quality of their manure.