Ruminal Total Volatile Fatty Acid Research Articles

Effect of level of oat hay intake on apparent digestibility, rumen fermentation and urinary purine derivatives in Tibetan and fine-wool sheep

Tibetan sheep are indigenous to the Qinghai-Tibetan Plateau and are raised at an altitude between 3000–5000 m. In contrast, the crossbred fine-wool sheep were introduced to the plateau and are raised at an altitude between 2600 to 3500 m. Tibetan sheep graze grassland all year round while fine-wool sheep require feed supplements during the long cold season. Tibetan sheep were able to utilize dietary nutrients more efficiently than fine-wool sheep when offered adequate energy and protein diets. We questioned whether the responses would still favour Tibetan sheep with limited energy and protein intakes, as is often the case on the Qinghai-Tibetan Plateau. To answer this query, apparent nutrients digestibilities, rumen fermentation characteristics and urinary purine derivatives (PD) were compared between Tibetan and fine-wool sheep when fed oat hay at below maintenance levels: 0.3, 0.5, 0.7 and 0.9 voluntary intake. Five wethers of each breed of similar age and body weight (BW) were used in two concurrent 4 × 4 Latin square designs. Dry matter (DM), organic matter (OM) and neutral detergent fiber (NDF) digestibilities were higher in Tibetan than fine-wool sheep (P < 0.05), but were not affected by the level of oat hay intake (P > 0.10). As feed intake increased, ruminal pH decreased (P < 0.01) and total volatile fatty acid (VFA) concentration increased, both linearly (P < 0.001). Moreover, ruminal total VFA concentration (P < 0.05), ruminal soluble protein nitrogen (N) and saliva urea-N concentrations (P < 0.01) were higher in Tibetan than fine-wool sheep. Urinary total PD and its fractions increased linearly with feeding level (P < 0.01). Estimated microbial N synthesis was greater in Tibetan than fine-wool sheep (P < 0.05) and increased linearly with the level of oat hay intake (P < 0.001). It was concluded that both energy and protein metabolism were used more efficiently in Tibetan than in fine-wool sheep when offered below maintenance intakes, which would allow Tibetan sheep to cope better with the harsh, winter foraging conditions of the Qinghai-Tibetan Plateau.

Morphological adaptation of sheep\u2019s rumen epithelium to high-grain diet entails alteration in the expression of genes involved in cell cycle regulation, cell proliferation and apoptosis

BackgroundThe objectives of this study were to characterize changes in the relative mRNA expression of candidate genes and proteins involved in cell cycle regulation, cell proliferation and apoptosis in the ruminal epithelium (RE) of sheep during high-grain (HG) diet adaptation.ResultsTwenty sheep were assigned to four groups with five animals each. These animals were assigned to different periods of HG diet (containing 40% forage and 60% concentrate mix) feeding. The HG groups received an HG diet for 7 (G7, n = 5), 14 (G14, n = 5) and 28 d (G28, n = 5), respectively. In contrast, the control group (CON, n = 5) was fed the forage-based diet for 28 d. The results showed that HG feeding linearly decreased (P < 0.001) the ruminal pH, and increased the concentrations of ruminal total volatile fatty acid (linear, P = 0.001), butyrate (linear, P < 0.001), valerate (quadratic P = 0.029) and the level of IGF-1 (quadratic, P = 0.043) in plasma. The length (quadratic, P = 0.004), width (cubic, P = 0.015) and surface of the ruminal papillae (linear, P = 0.003) were all enlarged after 14 d of HG diet feeding. HG feeding cubically increased the number of cell layers forming the stratum corneum (SC, P < 0.001) and the thickness of the SC (P < 0.001) and stratum basale (P < 0.001). The proportion of basal layer cells in the RE decreased (linear, P < 0.001) in the G0/G1-phase, but it increased linearly (P = 0.006) in the S-phase and cubically (P = 0.004) in the G2/M-phases. The proportion of apoptosis cells in G7, G14 and G28 was reduced compared to the CON (quadratic, P < 0.001). HG diet feeding linearly decreased the mRNA expression of Cyclin E1 (P = 0.021) and CDK-2 (P = 0.001) and (P = 0.027) the protein expression of Cyclin E1. Feeding an HG diet linearly increased the mRNA expression of genes IGFBP-2 (P = 0.034) and IGFBP 5 (P < 0.009), while linearly decreasing (P < 0.001) the IGFBP 3 expression. The expression of cell apoptosis gene Caspase 8 decreased (quadratic, P = 0.012), while Bad mRNA expression tended to decrease (cubic, P = 0.053) after HG feeding.ConclusionsThese results demonstrated sequential changes in rumen papillae size, cell cycle regulation and the genes involved in proliferation and apoptosis as time elapsed in feeding a high-grain diet to sheep.

Influence of Nigella sativa seeds, Rosmarinus officinalis leaves and their combination on growth performance, immune response and rumen metabolism in Dorper lambs.

The objective of this study was to determine the effects of dietary supplementation of Nigella sativa L. seeds, Rosmarinus officinalis L. leaves and their combination on rumen metabolism, nutrient intake and digestibility, growth performance, immune response and blood metabolites in Dorper lambs. Twenty-four entire male Dorper lambs (18.68 ± 0.6kg, 4-5months old) were randomly assigned to a concentrate mixture containing on a dry matter basis either, no supplement (control, T1), 1% R. officinalis leaves (T2), 1% N. sativa seeds (T3) or 1% R. officinalis leaves +1% N. sativa seeds (T4). The lambs had ad libitum access to urea-treated rice straw (UTRS) and were raised for 90days. Supplemented lambs had greater (P <0.05) intake of DM and UTRS than the control lambs. The T4 lambs had lower (P <0.05) nutrient digestibility than those fed other treatments. Total and daily weight gain was greater (P <0.05) in T2 lambs than those fed other diets. The T3 and T4 lambs had greater (P <0.05) ruminal pH than the T1 and T2 lambs. Supplemented lambs had lower (P < 0.05) ruminal total volatile fatty acids, acetate, propionate, NH3-N and C18:0 than the control lambs. The T4 lambs had lower (P <0.05) population of Fibrobacter succinogenes, Ruminococcus albus, methanogens and total protozoa compared with those fed other diets. Supplemented lambs had lower (P <0.05) neutrophils, basophils and serum urea and greater (P < 0.05) serum IgA and IgG compared with the control lambs. The current results emphasised the variation in the efficacy of medicinal plants in ruminant nutrition.

Effects of altering total mixed ration conservation method when feeding dry-rolled versus steam-flaked hulled rice on lactation and digestion in dairy cows

We evaluated the effects of different methods of conserving the total mixed ration (TMR) and processing hulled rice (Oryza sativa L.) on intake, digestion, ruminal fermentation, lactation performance, and nitrogen utilization in dairy cows. Eight multiparous Holstein cows (126 ± 19 d in milk) were used in a replicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement of dietary treatments. The experimental diets used fresh TMR and ensiled TMR containing either dry-rolled (DR) hulled rice or steam-flaked (SF) hulled rice. The fresh TMR was prepared every morning. The ensiled TMR was prepared by baling fresh TMR and then sealing it with a bale wrapper; this was stored outdoors at 10 to 30°C for >4 mo. The method of grain processing did not affect the dry matter (DM) intake. The DM intake tended to be greater for ensiled TMR than for fresh TMR. Apparent total-tract DM digestibility and milk yield were increased by feeding ensiled TMR instead of fresh TMR and by replacing DR with SF. An interaction effect between the TMR conservation method and the grain processing method was detected for DM digestibility and milk yield; replacing DR with SF increased the DM digestibility and milk yield in cows fed fresh TMR, but this did not affect the cows fed ensiled TMR. The milk fat and lactose contents did not differ among dietary treatments. The milk protein concentration was higher for the cows fed SF processed hulled rice than those fed DR, but it was not influenced by the TMR conservation method. The ruminal total volatile fatty acid concentration was higher for the cows fed ensiled TMR compared with those fed fresh TMR, but it was not affected by the grain processing method. The molar proportion of acetate was decreased and propionate was increased by feeding ensiled TMR instead of fresh TMR and by replacing DR with SF. The concentrations of rumen ammonia N and plasma urea N were higher for the cows fed ensiled TMR than fresh TMR and were lower for SF than DR. Feeding ensiled TMR instead of fresh TMR increased the cows' urinary N excretion and decreased the retention N. Replacing DR with SF decreased the urinary N excretion, increased the milk N secretion, and then improved the nitrogen efficiency. These results show that feeding ensiled TMR instead of fresh TMR has an adverse effect on N utilization, but it increases digestion and milk production. Replacing DR with SF also increases digestion, milk yield, and milk protein content, and the improvement of milk yield by replacing DR with SF was prominent in the cows fed fresh TMR.

Effects of fumaric acid supplementation on methane production and rumen fermentation in goats fed diets varying in forage and concentrate particle size

BackgroundIn rumen fermentation, fumaric acid (FA) could competitively utilize hydrogen with methanogenesis to enhance propionate production and suppress methane emission, but both effects were diet-dependent. This study aimed to explore the effects of FA supplementation on methanogenesis and rumen fermentation in goats fed diets varying in forage and concentrate particle size.MethodsFour rumen-cannulated goats were used in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments: low or high ratio of forage particle size: concentrate particle size (Fps:Cps), without or with FA supplementation (24 g/d). Fps:Cps was higher in the diet with chopped alfalfa hay plus ground corn than in that with ground alfalfa hay plus crushed corn.ResultsBoth increasing dietary Fps:Cps and FA supplementation shifted ruminal volatile fatty acid (VFA) patterns toward more propionate and less acetate in goats. An interaction between dietary Fps:Cps and FA supplementation was observed for the ratio of acetate to propionate (A:P), which was more predominant when FA was supplemented in the low-Fps:Cps diet. Methane production was reduced by FA, and the reduction was larger in the low-Fps:Cps diet (31.72%) than in the high-Fps:Cps diet (17.91%). Fumaric acid decreased ruminal total VFA concentration and increased ruminal pH. No difference was found in ruminal DM degradation of concentrate or alfalfa hay by dietary Fps:Cps or FA. Goats presented a lower ruminal methanogen abundance with FA supplementation and a higher B. fibrisolvens abundance with high dietary Fps:Cps.ConclusionsAdjusting dietary Fps:Cps is an alternative dietary model for studying diet-dependent effects without changing dietary chemical composition. Fumaric acid supplementation in the low-Fps:Cps diet showed greater responses in methane mitigation and propionate increase.

Impact of fermented total mixed rations on intake, VFA and methane production of dairy heifers

The objective of this study was to determine the effect of feeding two fermented total mixed ration (FTMR) on methane production in dairy heifers. Four Holstein Friesian dairy heifers with mean body weight (BW) of 301.1 ± 42.2 kg were used in a simple cross-over design trial. Treatments consisted of 2 FTMR formulated to yield either low (LMD) or high CH4 production (HMD). No differences were observed in dry matter intake (DMI; 6.49 and 6.19 kg/d), BW change (-3.37 and -7.25 kg), or DM digestibility (50.64 and 46.99%) between diets. Ruminal pH, total volatile fatty acids (TVFA) and molar proportions of acetate, propionate and butyrate were not different among diets. Concentrations of blood glucose were higher (P=0.05) for HMD compared with LMD at 2 h post feeding; however, blood urea nitrogen was not different. Methane emissions were 236.32 L/d for LMD and 273.70 L/d for HMD and not different. Feeding the FTMR differing in CH4 potential did not affect DMI, digestibility, ruminal TVFA production or molar proportions of VFAs in dairy heifers.

Effects of different dietary protein levels and rumen-protected folic acid on ruminal fermentation, degradability, bacterial populations and urinary excretion of purine derivatives in beef steers

SUMMARYThe current experiment was conducted to evaluate the effects of different dietary protein levels and rumen-protected folic acid (RPFA) supplementation on ruminal fermentation, microbial enzyme activity, bacterial populations and urinary excretion of purine derivatives (PD) in growing beef steers. Low-protein (LP) or high-protein (HP) diets were fed to eight ruminally cannulated first-generation cross-bred (Blonde d'Aquitaine × Simmental) beef steers with or without RPFA supplementation. Steers were fed a total mixed ration, and dietary concentrate to maize silage ratio was 50 : 50 (dry matter (DM) basis). No interaction between dietary crude protein (CP) levels and RPFA supplementation was observed during the experiment. Ruminal pH was unaffected by RPFA supplementation, but decreased with increasing dietary CP levels. Ruminal total volatile fatty acid concentration increased with increasing dietary CP levels or RPFA supplementation. Molar proportion of acetate increased with RPFA supplementation, but tended to decrease with increasing dietary CP levels. The proportion of propionate decreased with RPFA supplementation, but was unaffected by dietary CP levels. As a result, the acetate to propionate ratio increased with RPFA supplementation, but tended to be lower for the HP diets than the LP diets. Ammonia-nitrogen content decreased with RPFA supplementation, but increased with increasing dietary CP levels.In situruminal degradability of maize straw and concentrate increased with increasing dietary CP levels or RPFA supplementation. Microbial enzyme (carboxymethyl-cellulase, cellobiase, xylanase, pectinase,α-amylase and protease) activity, bacterial populations (Ruminococcus albus,Ruminococcus flavefaciens,Butyrivibrio fibrisolvens,Prevotella ruminicola,Fibrobacter succinogenesandRuminobacter amylophilus) and urinary PD excretion increased with increasing dietary CP levels or RPFA supplementation. The current study showed that increasing dietary CP levels from 109·1 to 130·7 g/kg DM or supplementing 75 mg RPFA improved ruminal fermentation and microbial protein synthesis by increasing bacterial population and microbial enzyme activity.

Transient changes in milk production efficiency and bacterial community composition resulting from near-total exchange of ruminal contents between high- and low-efficiency Holstein cows

The objectives of this study were to determine if milk production efficiency (MPE) is altered by near-total exchange of ruminal contents between high- (HE) and low-MPE (LE) cows and to characterize ruminal bacterial community composition (BCC) before exchange and over time postexchange. Three pairs of ruminally cannulated, third-lactation cows were selected whose MPE (energy-corrected milk per unit of dry matter intake) differed over their first 2 lactations. Approximately 95% of ruminal contents were exchanged between cows within each pair. Ruminal pH and volatile fatty acid (VFA) profiles, along with BCC (characterized by sequencing of the variable 4 region of 16S rRNA genes), were assessed just before feeding on d -8, -7, -5, -4, -1, 1, 2, 3, 7, 10, 14, 21, 28, 35, 42, and 56, relative to the exchange date. High-MPE cows had higher total ruminal VFA concentrations, higher molar percentages of propionate and valerate, and lower molar percentages of acetate and butyrate than did LE cows, and re-established these differences 1 d after contents exchange. Across all LE cows, MPE increased during 7 d postexchange but declined thereafter. Two of the 3 HE cows displayed decreases in MPE following introduction of the ruminal contents from the corresponding LE cow, but MPE increased in the third HE cow, which was determined to be an outlier. For all 6 cows, both liquid- and solids-associated BCC differed between individuals within a pair before contents exchange. Upon exchange, BCC of both phases in all 3 pairs was more similar to that of the donor inoculum than to preexchange host BCC. For 5 of 6 cows, the solids-associated community returned within 10 d to more resemble the preexchange community of that host than that of the donor community. Individual variability before the exchange was greater in liquids than in solids, as was the variability in response of bacterial communities to the exchange. Individual cows varied in their response, but generally moved toward re-establishment of their preexchange communities by 10 d after contents exchange. By contrast, ruminal pH and VFA profiles returned to preexchange levels within 1 d. Despite the small number of cows studied, the data suggest an apparent role for the ruminal bacterial community as a determinant of MPE.

Utilization of concentrate supplements containing varying levels of cassava leaf pellet by growing goats fed a basal diet of pangola hay

The objective of this study was to evaluate the effect of varying levels of cassava leaf pellet (CLP) on feed intake, digestibility and rumen fermentation of goats fed with pangola hay as roughages. Eight growing crossed (Thai native x Anglo-Nubian) goats between 10 to 12 months of age and pre-trial average body weight of 18.5 + 2.5 kg were allotted into two groups on the basis of body weight in a randomized double 4 x 4 Latin square design to investigate the utilization of concentrate mixtures of varying levels of CLP. The four concentrate mixtures had CLP included at 0% (control), 10 % (CLP1), 20% (CLP2) and 30% (CLP3) in concentrate as replacing soybean meal (SBM) with CLP as 25 %CP, 50%CP and 75%CP, respectively. On average, all parameters measured, including dry matter intake (DMI), nutrients digestibility, ruminal ammonia-N (NH3-N), ruminal total volatile fatty acid (total VFA), individual VFAs concentration (mM/L), microbial N supply, and N retention increased (P less than 0.05) with the addition of CLP in concentrate up to 20% (CLP2) in concentrate, thereafter decreased (P less than 0.05) in goats fed CLP 30% (CLP3). The results indicated that replacing SBM with CLP as 50 %CP (CLP2), resulted in higher animal performance as a consequence of improved ruminal fermentation, microbial yield and N balance, but decreased (P less than 0.05) with 30% CLP diet. It is concluded that cassava leaf pellet can successfully replace soybean meal 50% CP as a protein source in growing goats.

Abrupt weaning reduces postweaning growth and is associated with alterations in gastrointestinal markers of development in dairy calves fed an elevated plane of nutrition during the preweaning period

The benefits of feeding elevated quantities of milk to dairy calves have been well established. However, there is a reluctance to adopt this method of feeding in commercial dairy production because of concerns around growth, health, and ruminal development during weaning. The objective of this study was to characterize the effect of an abrupt (0 d step-down) or gradual (12 d step-down) feeding scheme when calves are fed an elevated plane of nutrition (offered 1.35 kg of milk replacer/d). For this experiment, a total of 54 calves were randomly assigned to an abrupt or a gradual weaning protocol before weaning at 48 d of life. Calves were housed and sampled in individual pens for the duration of the experiment, and milk, starter, and straw intake were measured on a daily basis. Body weight was measured every 6 d, whereas blood, rumen fluid, and fecal samples were collected on d 36 (pre-step-down), 48 (preweaning), and 54 (postweaning) of the experiment. Although the growth rates of the step-down calves were lower from d 37 to weaning (0.62 ± 0.04 vs. 1.01 ± 0.04 kg/d), the postweaning average daily gain was greater compared with the group that was abruptly weaned (0.83 ± 0.06 vs. 0.22 ± 0.06 kg/d). Total ruminal volatile fatty acid was greater in the step-down group on the day of weaning (d 48; 59.80 ± 2.25 vs. 45.01 ± 2.25 mmol), whereas the fecal starch percentage was lower during postweaning compared with the abruptly weaned calves (d 54; 3.31 ± 0.76 vs. 6.34 ± 0.76%). Analysis of the digestive tract of bull calves on d 55 revealed minimal differences between gross anatomy measurements of gut compartments as well as no morphological differences in rumen papillae development, yet the total mass of rumen when full of contents was larger in the step-down calves (7.83 ± 0.78 vs. 6.02 ± 0.78 kg). Under the conditions of this study, the results showcase the benefits of a step-down feeding strategy from an overall energy balance standpoint, due to increased adaptation of the gastrointestinal tract preweaning.

Effects of dietary physical or nutritional factors on morphology of rumen papillae and transcriptome changes in lactating dairy cows based on three different forage-based diets

BackgroundRumen epithelial tissue plays an important role in nutrient absorption and rumen health. However, whether forage quality and particle size impact the rumen epithelial morphology is unclear. The current study was conducted to elucidate the effects of forage quality and forage particle size on rumen epithelial morphology and to identify potential underlying molecular mechanisms by analyzing the transcriptome of the rumen epithelium (RE). To achieve these objectives, 18 mid-lactation dairy cows were allocated to three groups (6 cows per group), and were fed with one of three different forage-based diets, alfalfa hay (AH), corn stover (CS), and rice straw (RS) for 14 weeks, respectively. Ruminal volatile fatty acids (VFAs) and epithelial thickness were determined, and RNA-sequencing was conducted to identify the transcriptomic changes of rumen epithelial under different forage-based diets.ResultsThe RS diet exhibited greater particle size but low quality, the AH diet was high nutritional value but small particle size, and CS diet was low quality and small particle size. The ruminal total VFA concentration was greater in AH compared with those in CS or RS. The width of the rumen papillae was greater in RS-fed cows than in cows fed AH or CS. In total, 31, 40, and 28 differentially expressed (DE, fold change > 2, FDR < 0.05) genes were identified via pair-wise comparisons including AH vs. CS, AH vs. RS, and RS vs. CS, respectively. Functional classification analysis of DE genes revealed dynamic changes in ion binding (such as DSG1) between AH and CS, proliferation and apoptotic processes (such as BAG3, HLA-DQA1, and UGT2B17) and complement activation (such as C7) between AH or RS and CS. The expression of HLA-DQA1 was down-regulated in RS compared with AH and CS, and the expression of UGT2B17 was down-regulated in RS compared with CS, with positive (R = 0.94) and negative (R = -0.96) correlation with the width of rumen epithelial papillae (P < 0.05), respectively.ConclusionOur results suggest that both nutrients (VFAs) and particle sizes can alter expression of genes involved in cell proliferation/apoptosis process and complement complex. Our results suggest that particle size may be more important in regulating rumen epithelial morphology when animals are fed with low-quality forage diets and the identified DE genes may affect the RE nutrient absorption or morphology of RE. Our findings provide insights into the effects of the dietary particle size in the future management of dairy cow feeding, that when cows were fed with low-quality forage (such as rice straw), smaller particle size may be beneficial for nutrients absorption and milk production.

Effects of Saccharomyces cerevisiae fermentation products on performance and rumen fermentation and microbiota in dairy cows fed a diet containing low quality forage

BackgroundA possible option to meet the increased demand of forage for dairy industry is to use the agricultural by-products, such as corn stover. However, nutritional value of crop residues is low and we have been seeking technologies to improve the value. A feeding trial was performed to evaluate the effects of four levels of Saccharomyces cerevisiae fermentation product (SCFP; Original XP; Diamond V) on lactation performance and rumen fermentation in mid-lactation Holstein dairy cows fed a diet containing low-quality forage. Eighty dairy cows were randomly assigned into one of four treatments: basal diet supplemented with 0, 60, 120, or 180 g/d of SCFP per head mixed with 180, 120, 60, or 0 g of corn meal, respectively. The experiment lasted for 10 wks, with the first 2 weeks for adaptation.ResultsDry matter intake was found to be similar (P > 0.05) among the treatments. There was an increasing trend in milk production (linear, P ≤ 0.10) with the increasing level of SCFP supplementation, with no effects on contents of milk components (P > 0.05). Supplementation of SCFP linearly increased (P < 0.05) the N conversion, without affecting rumen pH and ammonia-N (P > 0.05). Increasing level of SCFP linearly increased (P < 0.05) concentrations of ruminal total volatile fatty acids, acetate, propionate, and butyrate, with no difference in molar proportion of individual acids (P > 0.05). The population of fungi and certain cellulolytic bacteria (Ruminococcus albus, R. flavefaciens and Fibrobacter succinogenes) increased linearly (P < 0.05) but those of lactate-utilizing (Selenomonas ruminantium and Megasphaera elsdenii) and lactate-producing bacteria (Streptococcus bovis) decreased linearly (P ≤ 0.01) with increasing level of SCFP. The urinary purine derivatives increased linearly (P < 0.05) in response to SCFP supplementation, indicating that SCFP supplementation may benefit for microbial protein synthesis in the rumen.ConclusionsThe SCFP supplementation was effective in maintaining milk persistency of mid-lactation cows receiving diets containing low-quality forage. The beneficial effect of SCFP could be attributed to improved rumen function; 1) microbial population shift toward greater rumen fermentation efficiency indicated by higher rumen fungi and cellulolytic bacteria and lower lactate producing bacteria, and 2) rumen microbial fermentation toward greater supply of energy and protein indicated by greater ruminal VFA concentration and increased N conversion. Effects of SCFP were dose-depended and greater effects being observed with higher levels of supplementation and the effect was more noticeable during the high THI environment.

Use of Jerusalem artichoke tops silage to replace corn silage in sheep diet

This study was performed to assess the effects of dietary substitution of different levels of Jerusalem artichoke (Helianthus tuberosus) tops silage (JATS) for corn silage (CS) on feed intake, digestibility, rumen parameters, blood metabolites, microbial nitrogen (N) synthesis (MNS) and N retention in Shal sheep (live body weight of 65.3±2.3). Four iso-energetic and iso-nitrogenous diets were formulated, in which CS was replaced by different levels (0, 180, 360 or 540g/kg of diet dry matter [DM]) of JATS. The diets were assigned randomly to one of the groups (5 sheep/group) in a completely randomized design for a 31-days period (21days for adaptation and 10days for sample collection). Diets were offered as total mixed ration to ensure 10% orts. Daily feed intake, diet digestibility, rumen and blood parameters, MNS and N retention were determined. The data were analyzed using the PROC MIXED of SAS. The DM intake (DMI) and DM digestibility (DMD) were not affected by dietary treatments. With replacing CS by JATS, the ruminal ammonia-N concentration tended to increase (L, P=0.088), total volatile fatty acids (VFA) tended to decrease (L, P=0.089), but rumen protozoa, molar proportions of individual VFA and pH remained unchanged. Feeding sheep with diets containing JATS instead of CS had no effects on blood parameters, except urea-N, which was increased (L, P=0.032) as the level of JATS rose in diet. No difference was observed in urinary purine derivatives and MNS. Urinary N tended to enhance (L, P=0.080) and N retention tended to decrease (L, P=0.065) when the sheep received diets with the increasing levels of JATS. Overall, the partial substitution of JATS for CS, up to 540g/kg of DM, was possible in diet of Shal sheep without adverse effects on DMI, DMD, rumen fermentation, blood parameters and MNS, although blood urea-N raised slightly and total ruminal VFA and N retention somewhat declined. The aerial parts of the fresh JA can be preserved as a valuable silage to use in sheep diets.

Influence of zeolite (clinoptilolite) supplementation on characteristics of digestion and ruminal fermentation of steers fed a steam-flaked corn-based finishing diet

Four Holstein steers (328 ± 14 kg) with ruminal and duodenal cannulas were used in a 4 × 4 Latin square design to examine the effect of level of zeolite supplementation (0, 10, 20 or 30 g clinoptilolite-Ca/kg of diet) in a steam-flaked corn-based finishing diet on the characteristics of ruminal fermentation and nutrient digestion. Zeolite was top-dressed with the basal diet at time of feeding; therefore, intake of organic matter (OM), neutral detergent fibre (NDF), starch and N was equal in all treatments. Zeolite supplementation did not affect site and extent of digestion of N or NDF. Zeolite linearly decreased (P &lt; 0.01) NH3-N flow to duodenum, but did not affect duodenal flow of microbial N, feed N, or microbial efficiency. Inclusion of zeolite linearly increased (P = 0.02) ruminal OM digestion and tended (linear, P = 0.08) to increase ruminal digestion of starch. Zeolite supplementation increased (linear effect, P &lt; 0.01) faecal excretion of ash, resulting in decreased total tract DM digestion (linear effect, P = 0.04). However, total tract digestion of OM tended to increase (P = 0.06) with increasing zeolite supplementation. Thus, dilution of the diet with zeolite did not depress dietary digestible energy. There were no treatment effects on ruminal pH. Total ruminal volatile fatty acid concentration tended (P = 0.08) to increase as zeolite increased. Zeolite supplementation decreased ruminal molar proportion of acetate and increased molar proportion of propionate (linear effect, P &lt; 0.01), resulting in decreased (linear effect, P &lt; 0.01) of acetate: propionate ratio. Supplementation with zeolite at levels of up to 30 g of zeolite/kg of diet may enhance ruminal OM digestion, largely due to the tendency of increased ruminal starch digestion. Zeolite supplementation altered ruminal volatile fatty acid molar proportions (decreased acetate : propionate ratio), and therefore may have an positive impact on energy efficiency.

The Effect of increasing levels of date palm (Phoenix dactylifera L.) seed on the performance, ruminal fermentation, antioxidant status and milk fatty acid profile of Saanen dairy goats.

This study was conducted to examine the effect of date palm (Phoenix dactylifera L.) seed (DPS) on the performance, ruminal fermentation, antioxidant status and milk fatty acid (FA) profile of dairy goats. Eight multiparous Saanen dairy goats, averaging 97±7days in milk (DIM) and 2150±130g of milk production, were used in a 4×4 replicated Latin square design. Experimental diets contained 0% (control), 6% (DPS6), 12% (DPS12) and 18% (DPS18) of DPS. Dry matter intake (DMI), milk production, and the composition and digestibility of the dry matter (DM), organic matter (OM), neutral detergent fibre (NDF) and crude protein (CP) were not affected by the diets. Adding DPS to the diet increased linearly total antioxidant capacity (TAC) in milk and blood (p<0.05). No significant difference was found in the malondialdehyde (MDA) content in milk and blood. Superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in the blood, ruminal pH, NH3 -N, ruminal total volatile fatty acid (VFA), acetate, butyrate, isovalerate and valeric acid concentration had no significant effect among the diets. The propionate acid concentration decreased linearly as DPS was added to the diet, and DPS18 had minimum propionate acid concentration (p<0.05). The inclusion of DPS18 to diets increased linearly the proportion of C18:0 (compared to control) as well as cis-18:1, trans-18:1 (compared to control and DPS6) and decreased C14:1 (compared to control) in milk fat (p<0.05). The concentration of conjugated linoleic acid (CLA) in DPS18 was higher than other diets (p=0.04). The results of this study implied that replacing DPS with a part of dairy goats' ration had no negative effects on the performance of the animals and could also improve the antioxidant activity and increase the concentration of CLA in their milk.

Effects of dietary physically effective neutral detergent fiber content on the feeding behavior, digestibility, and growth of 8- to 10-month-old Holstein replacement heifers

The objective of this study was to evaluate the effects of dietary physically effective neutral detergent fiber (peNDF) content on the feeding behavior, digestion, ruminal fermentation parameters, and growth of 8- to 10-mo-old dairy heifers and to predict the adequacy of dietary fiber in growing dairy heifers. Twenty-four Holstein dairy heifers (245 ± 10.8 d of age, 305.6 ± 8.5 kg initial live weight) were randomly divided into 4 treatments with 6 replicates as a completely randomized design. During the 60-d period with a 10-d adaptation, heifers were offered 1 of 4 diets, which were chemically identical but included different peNDF8.0 (particle size is >8 mm and <19 mm) content (% DM): 10.8, 13.5, 18.0, or 19.8%, which was achieved by chopping forage into different lengths (fine = 1 cm, short = 3 cm, medium = 5 cm, and long = 7 cm). The concentrate and silage were mixed and fed restrictedly and exclusive of forage (Chinese ryegrass hay) were offered ad libitum. The body weight and frame size of the heifers were measured every 15 d during the experimental period. Samples of the rumen content (2 h after the morning feeding) were taken for pH, ammonia, and volatile fatty acid determination. The dry matter intake and average daily gain of the heifers were not significantly affected by peNDF8.0 content. The body frame size (including withers height, body length, and heart girth) of the heifers was not increased significantly by enhanced peNDF8.0 content. Ruminal pH and ammonia concentration were both increased with increasing dietary peNDF8.0 content. The ruminal total volatile fatty acid concentration and percentage of acetate and butyrate profiles were not significantly affected by dietary peNDF8.0 content. However, the enhanced peNDF8.0 content led to a decrease in the propionate percentage. The ratio of acetate to propionate in the 13.5% treatment was highest among the treatments. Increasing the particle size and dietary peNDF8.0 content resulted in increased eating and chewing time but had no effect on rumination time. Heifer total eating and chewing time and eating and chewing time per kilogram of dry matter intake were increased with increasing dietary peNDF8.0 content. The apparent digestibility of acid detergent fiber and crude protein was improved with an increasing content of dietary peNDF8.0. The results suggest that an optimal or advisable dietary particle size and peNDF8.0 content improves chewing activity, rumen fluid pH, and ruminal fermentation. The data based on feeding behavioral and growth responses of heifers as well as rumen fermentation and digestion by improving total eating and chewing time indicate that 18.0% dietary peNDF8.0 content is the most suitable for 8- to 10-mo-old Holstein heifers.

Effects of &lt;i&gt;Prosopis laevigata&lt;/i&gt; pods on growth performance, ruminal fermentation and blood metabolites in finishing lambs

Twenty-one non-castrated male Rambouillet lambs (21±1.44 kg body weight) were used to evaluate the effects of increasing dietary levels of Prosopis laevigata pods (PLP) in a 72 d growth performance trial. Three dietary treatments defined as PLP0 (control, 0 g PLP/kg DM), PLP250 (250 g PLP/kg DM), and PLP500 (500 g PLP/kg DM) were evaluated. Animals fed PLP250 and PLP500 had higher daily weight gain (P<0.05) and feed intake (P<0.01) than lambs fed PLP0. Feed conversion was improved by PLP addition in the diets. Feeding cost decreased linearly as the level of PLP in the diet increased. Blood urea-N concentration increased linearly as PLP increased in the diet. Lambs fed PLP500 had higher (P<0.05) blood uric acid concentrations than lambs fed PLP0 and PLP250. Ruminal total volatile fatty acid (VFA) increased linearly with increasing dietary PLP. Lambs fed PLP250 and PLP500 had higher ruminal ammonia N concentrations (P<0.05) than lambs fed PLP0. Dietary inclusion of PLP did not affect health status of lambs. Prosopis laevigata pods can be used safely in finishing lambs’ diets at 500 g/kg. Keywords: carcass, feed cost, performance

Fermentation quality and nutritive value of fresh and fermented total mixed rations containing Chinese wildrye or corn stover

AbstractNutritive value of fresh or fermented total mixed ration (TMR) containing Chinese wildrye (Leymus chinensis (Trin.) Tzval.) or dry corn (Zea mays L.) stover was determined. The experimental treatments included fermentation and dietary roughage. The fermentation treatments included fresh and fermented TMR, while the dietary roughage treatments included Chinese wildrye and corn stover. Compared to the fresh TMR, the fermented TMR had higher (P &lt; 0.05) contents of ether extract, lactic acid, acetic acid and ammonia‐nitrogen (N) but lower (P &lt; 0.05) organic matter, non fibrous carbohydrate and neutral detergent fiber, and inhibited growth of molds in silages; moreover, the fermented TMR increased (P &lt; 0.05) the digestibility of ether extract and neutral detergent fiber, and tended to increase (P &lt; 0.05) the digestibility of acid detergent fiber, but also increased the concentration of ruminal total volatile fatty acid and valeric acid at 2 h of feeding, and ammonia‐N at 2 or 4 h of feeding. The silage with 10 mm corn stover had a higher (P &lt; 0.05) lactic acid content, and reduced (P &lt; 0.05) losses of non fibrous carbohydrate during fermentation compared with 50 mm treatment. Almost all chopped‐corn stover TMR had similar nutrient digestibility to Chinese wildrye. Among the eight TMRs, the fermented TMR with 10 mm corn stover had the highest intake ration of dry matter, while the fermented TMR with Chinese wildrye was the lowest. These results suggest that fermentation inhibit growth of molds in silage, decrease neutral detergent fiber, and then improve the nutrient digestibility. Chopped corn stover TMR had similar nutrient digestibility to Chinese wildrye TMR, and could replace Chinese wildrye in TMRs for ruminants.

Effects of substituting corn with steam-flaked sorghum on growth, digestion and blood metabolites in young cattle fed feedlot diets

The objective of the present study was to evaluate the effects of substituting ground corn grain with steam-flaked sorghum (SFS) grain on growth performance, nutrient utilisation and blood metabolites in beef bulls. Fifty-six Simmental beef bulls averaging 12 months of age and 356.4 ± 2.6 kg of bodyweight were randomly assigned to four groups. The treatments were control, low-SFS, medium-SFS and high–SFS, with 0, 1/3, 2/3 and 3/3 SFS grain, respectively, substituting ground corn grain of diets(dry matter (DM) basis). Diets consisted of 50% corn silage and 50% concentrate (DM basis). The average daily gain and feed conversion rate improved quadratically with increasing the proportion of SFS grain. Ruminal pH and ammonia-nitrogen (N) concentration decreased quadratically, whereas ruminal total volatile fatty acid concentration increased quadratically. Ratio of acetate to propionate decreased quadratically (P = 0.027) due to the quadratic decrease in acetate production and the quadratic increase in propionate production. Digestibilities of DM, organic matter and crude protein increased quadratically, whereas that of neutral detergent fibre and acid detergent fibre decreased quadratically. The digestible N, retention N and the retention N to digestible N ratio improved quadratically. Inclusion of SFS grain in diets quadratically increased blood concentrations of glucose, total protein, albumin and triglyceride, but quadratically decreased the concentration of urea N. The results indicated that partly substituting ground corn grain with SFS grain could improve growth performance by improving ruminal fermentation and N utilisation; the optimum substitution rate was 2/3 (DM basis).

EFFECT OF SYNCHRONIZATION OF CARBOHYDRATE AND PROTEIN SUPPLY IN THE SUGARCANE BAGASSE BASED DIET ON MICROBIAL PROTEIN SYNTHESIS IN SHEEP

The experimental research was conducted to clarify the effect of synchronization of ruminal carbohydrate and protein releases from sugarcane bagasse based diet (SBBD) on microbial protein synthesis in sheep. The first experiment was the formulation of three SBBD with similar nutrient content but differed in synchronization indexes (namely 0.36; 0.50 and 0.63). The in sacco nutrient degradability coefficient was used to calculate the synchronization index of each feedstuff. The second experiment was determination of post feeding ruminal pH, ruminal concentrations of total volatile fatty acids (TVFA) and ammonia nitrogen (NH3-N), and blood urea nitrogen (BUN) level in sheep fed on experimental SBBD. The third experiment was determination of feed digestibility and estimation of microbial nitrogen synthesis (MNP) on the basis of excreted urinary allantoin. The alteration of dietary synchronization index did not change nutrient intake, but the digestibilities of DM, OM and CP were increased (P&lt;0.05). The post feeding ruminal pH was decreased (P&lt;0.05) but concentrations of post feeding ruminal TVFA and NH3-N, and level of BUN were increased (P&lt;0.05) by the treatment of dietary synchronization index. The treatment of dietary synchronization index improved MNP (P&lt;0.05), although dietary synchronization index at 0.63 lowered the MNP (P&lt;0.05).