Rumen Total Volatile Fatty Acids Research Articles

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.

Improving feed intake and rumen fermentation in lambs using mixed-dimensional attapulgite clay to adsorb naturally occurring mycotoxins.

This experiment was conducted to evaluate the effects of including a mixed-dimensional attapulgite clay (MDA) into a naturally moldly diet for Hu lambs. Fifty male Hu lambs with similar initial body weight (28.24 ± 1.80kg) were randomly allocated into five dietary treatments: a basal diet containing naturally occurring mycotoxins with 0, 0.5, 1.0, and 2.0kg/t MDA, and basal diet with a commercial mycotoxin adsorbent Solis with montmorillonite as the major component at 1kg/t. Both MDA and Solis increased average daily gain (ADG) and dry matter intake (DMI; P ≤ 0.004), and there was no difference in growth performance between MDA and Solis (P ≥ 0.26). The final body weight, DMI, and ADG were linearly increased with increasing MDA supplementation (P < 0.01). Lambs treated with both MDA and Solis demonstrated greater apparent digestibility of dry matter (DM), organic matter (OM), and energy compared with the control group (P ≤ 0.03), and there were no differences in nutrient digestibilities between MDA and Solis (P ≥ 0.38). Digestibility of CP was linearly increased with the increasing MDA supplementation (P = 0.01). Neither MDA nor Solis affected rumen total volatile fatty acid (TVFA) concentration (P ≥ 0.39), but decreased the acetate-to-propionate ratio and molar proportion of n-butyrate (P ≤ 0.01), and MDA also increased the concentration of ammonia (P = 0.003). Besides, increasing MDA supplementation linearly reduced the acetate-to-propionate ratio and molar proportion of n-butyrate (P = 0.01), but linearly and quadratically increased the concentration of ammonia (P ≥ 0.003). These results showed that the incorporation of MDA into a naturally moldy diet of Hu lambs yielded comparable results to the Solis product, with higher growth performance and nutrient digestibility but lower acetate-to-propionate ratio observed. In conclusion, including ≥ 1kg/t of MDA in high mycotoxin risk diets for growing lambs improves feed intake and rumen fermentation.

Effects of Feeding a Commercial Starch Binding Agent during Heat Stress on Enteric Methane Emission, Rumen Volatile Fatty Acid Contents, and Diet Digestibility of Merino Lambs

Twenty-four Merino lambs were allocated to three dietary treatment groups to determine the effects of a dietary starch and protein binding agent and heat stress on methane (CH4) emissions and rumen parameters. The diets were a wheat-based diet (WD), a 2% Bioprotect™ (Bioprotect™, RealisticAgri, Rutland, UK) treated wheat-based diet (BD), and a maize-based diet (MD) for 3 periods of 1-week duration. During Period 1 (P1) the lambs were maintained under thermoneutral conditions and at a 1.7 × Maintenance (M) level. During P2 and P3, the lambs were maintained under cyclic heat stress conditions and fed at 1.7 × M and 2.0 × M, respectively. Total CH4 production was lower for the BD diet than the WD diet, which in turn was lower than the MD diet (p &lt; 0.001). Total CH4 production was lower during P2 than P1 with P3 intermediate (p = 0.04). Rumen total volatile fatty acid (TVFA) concentrations were higher for the WD diet than the MD diet with the BD diet intermediate (p = 0.01). Rumen TVFA concentrations were lower during heat stress than under thermoneutral conditions (p &lt; 0.001). Whole tract starch digestibility was higher for the BD and WD diets than the MD diet (p &lt; 0.001). In conclusion, feeding Merino lambs the BD diet reduces CH4 emissions without reducing starch digestibility.

EFFECTS OF FEEDING DIET CONTAINING RAW OR PARBOILED RICE OFFAL ON RUMEN METABOLITE OF BUNAJI BULLS

Twenty Bunaji bulls aged 2-3 years with an average weight of 230kg were assigned to five dietary treatments with four bulls per treatment in a 2x2 factorial configuration with common control to determine the effect of feeding diet containing varying inclusion of raw or parboiled rice offal on bull rumen metabolites which lasted for 90 days. Rumen fluid was collected at 0, 2, 4, and 6 hr intervals to assess rumen pH, rumen ammonia nitrogen (RAN), and rumen total volatile fatty acid (TVFA). Digitaria smutsii concentrate and basal diet were provided at 2% bogy weight. Crude Protein content of the experimental diets ranged from 19.69- 20.44%, while Metabolizable Energy content ranged from 10.86-11.16MJ/kg DM. Rice offal type had no effect on rumen parameters (P&gt;0.05). Rumen pH six hours after feeding at 0% (6.63) and 30% (6.76) inclusion levels was similar (P&gt;0.05), but differed considerably (P&lt;0.05) from the 20% (6.93) inclusion level. The highest and lowest TVFA values were found in bulls fed diets with 20% (44.70 mol) and 30% (23.49 mol) inclusion levels. Effects of varying RRO and PRO inclusion levels on rumen pH and TVFA at different sample times were not significant (P&gt;0.05). Bulls fed 30%PRO had the highest value (22.41g/100g), while bulls fed 20% PRO had the lowest value (14.80g/100g). This study indicated that RRO or PRO can be utilized to replace up to 30% of maize offal as a source of energy in the diet of Bunaji bulls with no negative effects on the bulls' rumen metabolite.

Cassava pulp added to fermented total mixed rations increased tropical sheep's nutrient utilization, rumen ecology, and microbial protein synthesis.

The price of animal production will be affected by the significant increase in feed costs. The objective of this research was to investigate the impact of adding waste cassava pulp to fermented total mixed ration (FTMR) on nutrient utilization, rumen ecology, and microbial protein synthesis in tropical sheep. A 3 × 3 replicated Latin square design was used to randomly arrange nine crossbreed lambs (Santa Inês × Dorper) with an initial body weight (BW) of 18.7 ± 1.6 kg (mean ± SD). During a 21-day trial, the animal was offered a random selection of concentrate diets and rice straw (control), total mixed ration (TMR), or FTMR. During the investigation, data on nutrition utilization, rumen ecology, and microbial protein synthesis were analyzed using analysis of variance. The finding shows that FTMR had significantly higher dry matter (DM) intake and DM intake per BW than either TMR or control (p < 0.05). Lamb fed on FTMR had significantly higher DM, organic matter protein, crude protein, and neutral detergent fiber digestion than those on control or TMR (p < 0.05). Rumen pH values for all treatments ranged from 6.68 to 6.73, with no significant differences. Growing lambs fed FTMR had greater rumen total volatile fatty acid and propionic acid concentrations than those given TMR and the control (p < 0.05). Protozoa were not different across the FTMR groups, although total bacterial and fungal zoospores were increased. In addition, when lambs were fed FTMR containing cassava pulp, ruminal microbial protein synthesis was significantly increased. It could indicate that feeding growing lambs with FTMR could improve nutrient utilization, ruminal fermentation, and microbial protein synthesis. However, studies on the effects of FTMR on sheep performance, meat quality, and milk quality are necessary.

PSI-19 Influence of cattle breed and forage type on organic dairy heifer performance

Abstract Many breeds of dairy cattle exist, but questions remain about their relative performance within exclusively forage-based systems in the United States. This paucity of data is especially apparent in relation to heifer development, which is the second largest expense on most dairy farms. We evaluated the performance of prepubertal heifers from four different genetic backgrounds (“breeds”) within a rotational grazing system in the Intermountain West. For each of two 105-day grazing seasons, 24 dairy heifers from each of four different breeds [Holstein (HO), Jersey (JE), Holstein/Jersey crossbred (HJ), and Swedish Red/Holstein/Montbeliarde crossbred (SHM)] were randomly assigned to one of two pasture treatments that consisted of either grass only (MONO) or grass interseeded with the legume birdsfoot trefoil (BFT; MIX). Main effects of treatment and breed (and potential interactions) on heifer average daily gain (ADG), change in percent mature body weight (CPMBW), fecal egg count (FEC), rumen volatile fatty acids (VFA), and body condition scores (BCS) were evaluated. There was a significant effect of pasture treatment on ADG, with MIX heifers averaging 0.48 kg of gain/day, whereas MONO heifers averaged 0.29 kg/day (P &amp;lt; 0.0001). Change in BCS was significantly affected by treatment (P = 0.0012) and breed (P &amp;lt; 0.0001). Significant effects of treatment (P &amp;lt; 0.0001), breed (P = 0.0005), and treatment*breed (P = 0.0005) on CPMBW were also found. Treatment and breed had no effect on FEC or total rumen VFA content (P &amp;gt; 0.05). Overall, we found that Jerseys were able to gain a higher percentage of their mature body weight and lose less body condition while on pasture than heifers of other breeds. We also found that grazing BFT can have significant positive effects on ADG, BCS, and CPMBW. Further research is needed to more thoroughly evaluate the influence of heifer genetics (breed) on metrics of growth, health, reproductive performance, and production in pasture settings.

Dietary Supplementation with Saccharomyces cerevisiae, Clostridium butyricum and Their Combination Ameliorate Rumen Fermentation and Growth Performance of Heat-Stressed Goats.

Simple SummaryHeat stress commonly happens to goats raised in the Jianghuai region of China during the summer and inevitably contributes to a loss of animal production. Dietary supplementation with probiotics is one of the practical approaches to improve animal production. By dietary supplementation with Saccharomyces cerevisiae, Clostridium butyricum, and their combination to the heat-stressed goats, the present study showed these probiotics effectively alleviate heat stress by improving the rumen fermentation function and growth performance. Therefore, this study provides a reference for the application of these two probiotics in ruminant production during heat stress.This study aimed to evaluate the effects of Saccharomyces cerevisiae, and their combination on rumen fermentation and growth performance of heat-stressed goats. Twelve heat-stressed goats (20.21 ± 2.30 kg) were divided equally into four groups: control group (CG, fed the basal diet, Saccharomyces cerevisiae supplemented group (SC, 0.60% Saccharomyces cerevisiae added to the basal diet), Clostridium butyricum supplemented group (CB, 0.05% Clostridium butyricum added to the basal diet), and their combination supplemented group (COM 0.60% Saccharomyces cerevisiae and 0.05% Clostridium butyricum added to the basal diet) and were assigned to a 4 × 3 incomplete Latin square design. The rumen fluid and feces were collected for fermentation parameters and feed digestibility analysis, and animal growth performance was also assessed during all the experiment periods. The results showed that rumen pH, rumen cellulolytic enzymes (avicelase, CMCaes, cellobiase, and xylanase) activities, and the concentrations of rumen total volatile fatty acid (TVFA), acetic acid, and propionic acid were significantly increased with Saccharomyces cerevisiae, Clostridium butyricum, and their combination supplementation (p < 0.05). Besides, the dry matter intake (DMI), average daily gain (ADG), and the digestibility of dry matter (DM), neutral detergent fiber (NDF), and acidic detergent fiber (ADF) were significantly increased (p < 0.05) with supplemented these probiotics. However, the ammonia nitrogen (NH3-N) concentration only significantly increased in CB and A/P ratio (acetic acid to propionic acid ratio) only significantly increased in SC and CB. These results indicated that the supplementation with these probiotics could ameliorate rumen fermentation and growth performance of heat-stressed goats.

Effects of faba bean, blue lupin and rapeseed meal supplementation on nitrogen digestion and utilization of dairy cows fed grass silage-based diets

There is increasing interest in using locally produced protein supplements in dairy cow feeding. The objective of this experiment was to compare rapeseed meal (RSM), faba beans (FBs) and blue lupin seeds (BL) at isonitrogenous amounts as supplements of grass silage and cereal based diets. A control diet (CON) without protein supplement was included in the experiment. Four lactating Nordic Red cows were used in a 4 × 4 Latin Square design with four 21 d periods. The milk production increased with protein supplementation but when expressed as energy corrected milk, the response disappeared due to substantially higher milk fat concentration with CON compared to protein supplemented diets. Milk protein output increased by 8.5, 4.4 and 2.7% when RSM, FB and BL were compared to CON. The main changes in rumen fermentation were the higher propionate and lower butyrate proportion of total rumen volatile fatty acids when the protein supplemented diets were compared to CON. Protein supplementation also clearly increased the ruminal ammonia N concentration. Protein supplementation improved diet organic matter and NDF digestibility but efficiency of microbial protein synthesis per kg organic matter truly digested was not affected. Flow of microbial N was greater when FB compared to BL was fed. All protein supplements decreased the efficiency of nitrogen use in milk production. The marginal efficiency (amount of additional feed protein captured in milk protein) was 0.110, 0.062 and 0.045 for RSM, FB and BL, respectively. The current study supports the evidence that RSM is a good protein supplement for dairy cows, and this effect was at least partly mediated by the lower rumen degradability of RSM protein compared to FB and BL. The relatively small production responses to protein supplementation with simultaneous decrease in nitrogen use efficiency in milk production suggest that economic and environmental consequences of protein feeding need to be carefully considered.

Effects of folic acid and cobalt sulphate supplementation on growth performance, nutrient digestion, rumen fermentation and blood metabolites in Holstein calves.

To investigate the influences of cobalt (Co) and folic acid (FA) on growth performance and rumen fermentation, Holstein male calves (n 40) were randomly assigned to four groups according to their body weights. Cobalt sulphate at 0 or 0·11 mg Co/kg DM and FA at 0 or 7·2 mg/kg DM were used in a 2 × 2 factorial design. Average daily gain was elevated with FA or Co supplementation, but the elevation was greater for supplementing Co in diets without FA than with FA. Supplementing FA or Co increased DM intake and total-tract nutrient digestibility. Rumen pH was unaltered with FA but reduced with Co supplementation. Concentration of rumen total volatile fatty acids was elevated with FA or Co inclusion. Acetate percentage and acetate to propionate ratio were elevated with FA inclusion. Supplementing Co decreased acetate percentage and increased propionate percentage. Activities of xylanase and α-amylase and populations of total bacteria, fungi, protozoa, Ruminococcus albus, Fibrobacter succinogenes and Prevotella ruminicola increased with FA or Co inclusion. Activities of carboxymethyl-cellulase and pectinase increased with FA inclusion and population of methanogens decreased with Co addition. Blood folates increased and homocysteine decreased with FA inclusion. Blood glucose and vitamin B12 increased with Co addition. The data suggested that supplementing 0·11 mg Co/kg DM in diets containing 0·09 mg Co/kg DM increased growth performance and nutrient digestibility but had no improvement on the effects of FA addition in calves.

Effects of bamboo leaf extract on the production performance, rumen fermentation parameters, and rumen bacterial communities of heat-stressed dairy cows.

ObjectiveAn experiment was conducted to evaluate the effects of bamboo leaf extract (BLE) on the production performance, rumen fermentation parameters, and rumen bacterial communities of heat-stressed dairy cows.MethodsThe experiment comprised a 14-day adaptation period and a 21-day experimental period and was conducted in a high-temperature and humidity environment (daily mean ambient temperature = 33.5°C±1.3°C; daily mean relative humidity = 64.9%±0.8%, daily mean temperature-humidity index = 86.2±0.4). Twelve Holstein dairy cows were randomly allocated into two groups. A total mixed ration supplemented with BLE at 0 (CON) and 1.3 g/kg dry matter (DM) were fed, respectively. Feed intake and milk yield were recorded daily. Milk samples were collected on 1, 11, and 21 d of the experimental period to analyze milk performance. Rumen fluid samples were collected on 21 d of the experimental period to analyze rumen fermentation parameters and rumen bacterial communities.ResultsCompared with the control group, supplementation of BLE increased milk yield (p<0.01), milk fat yield (p = 0.04), 4% fat-corrected milk (p<0.01) and milk fat content (p<0.01); reduced somatic cell count (p<0.01). No differences in DM intake and milk protein or lactose content were observed between two groups. Supplementation of BLE also increased the rumen total volatile fatty acid (p<0.01), acetate (p<0.01), butyrate (p<0.01), and valerate (p = 0.05) concentrations. However, no significant effects were observed on rumen pH, ammonia nitrogen, propionate, acetate/propionate ratio, isobutyrate, or isovalerate. Furthermore, BLE increased the rumen bacterial abundance and the diversity of the rumen bacterial community. The BLE reduced the Firmicutes/Bacteroidetes abundance ratio and increased the abundances of Butyrivibrio_2 (p<0.01) and Ruminococcus_2 (p<0.01).ConclusionThe BLE supplementation at 1.3 g/kg DM could improve production performance and rumen fermentation in dairy cows during heat stress.

Effects of riboflavin supplementation on performance, nutrient digestion, rumen microbiota composition and activities of Holstein bulls

To investigate the influences of dietary riboflavin (RF) addition on nutrient digestion and rumen fermentation, eight rumen cannulated Holstein bulls were randomly allocated into four treatments in a repeated 4 × 4 Latin square design. Daily addition level of RF for each bull in control, low-RF, medium-RF and high-RF was 0, 300, 600 and 900 mg, respectively. Increasing the addition level of RF, dry matter (DM) intake was not affected, average daily gain tended to be increased linearly and feed conversion ratio decreased linearly. Total-tract digestibilities of DM, organic matter, crude protein (CP) and neutral detergent fibre (NDF) increased linearly. Rumen pH decreased quadratically and total volatile fatty acids (VFA) increased quadratically. Acetate molar percentage and acetate to propionate ratio increased linearly, but propionate molar percentage and ammonia-N content decreased linearly. Rumen effective degradability of DM increased linearly, NDF increased quadratically but CP was unaltered. Activity of cellulase and populations of total bacteria, protozoa, fungi, dominant cellulolytic bacteria, Prevotella ruminicola and Ruminobacter amylophilus increased linearly. Linear increase was observed for urinary total purine derivatives excretion. The data suggested that dietary RF addition was essential for rumen microbial growth, and no further increase in performance and rumen total VFA concentration were observed when increasing RF level from 600 to 900 mg/d in dairy bulls.

INFLUENCE OF BREWERS DRIED GRAINS ON THE RUMINAL VOLATILE FATTY ACIDS (VFA)PRODUCTION AND MILK CONSTITUENTS IN ZEBU COWS

Four lactating White Fulani (Zebu) cows fitted with permanent rumen cannular were fed four. diets: (A) Acha hay (Digitaria exilis Stapf, (B) 50% acha hay plus 50% brewers dried grains (BDG), (C) 75% BDG plus 25% hay and (D) 100% BDG in a 4 x 4 latin square design. Analysis of rumen total Volatile Fatty acids (VFAS), individual VFAs, ammonia-N and pH as well as some milk constituents were carried out simultaneously. Mean ruminal pH and total VFA (MM/100ml) were 7.1,6.2; 6.5, 8.0; 5.8, 14.9 and 5.8, 13.1 for A, B, C, and D respectively. The corresponding acetate to propionate (A/P) ratios were 4.97, 4.40, 3.20 and 3.40. The molar percent values of butyrate yielded by A and B were similar and less (P&lt;0.05) than the value for C or D. Ruminal ammonia-N (mg/100ml) ranged from 5.7 for A to 6.8 for D. Total VFA, NH3-N and pH of the rumen fluid were affected by time of feeding (P&lt;0.05). The correlations between ruminal pH and acetate (r = 0.98), pH and total VFA (r = -0.90), and acetate and propionate (r = -0.75) were significanct(P &lt;0.05). Cows on treatment A (acha hay) yielded higher percent milk fat (P&lt;0.05) and lower percent milk protein than those on B, C, or D. Treatment effects on milk pH and percentages of lactose, solids-not-fat (SNF) and ash were not significant. The observed depression in milk fat of cows on treatments B, C and D in comparison with cows on treatment A wasrelated to a decrease in rumen acetate and an increase in propionate. It was observed that the fermentation of BDG yielded acetate within limits required for efficient milk production.

Supplemental effect of Chaya (Cnidoscolus aconitifolius) leaf pellet on rumen fermentation, nutrients digestibility and microbial protein synthesis in growing crossbred bulls

This experiment was conducted to assess the effect of Chaya (Cnidoscolus aconitifolius) leaf pellet (CHYP) on rumen fermentation, nutrients digestibility and microbial protein synthesis in growing crossbred bulls. Four animals, with an average liveweight of 160 ± 10 kg were randomly arranged in a 4 × 4 Latin square design. There were four treatments: 0, 4, 6 and 8% CHYP supplementation of DMI. The study findings showed that increasing supplementation level of CHYP linearly enhanced (p < 0.05) DM, OM, and CP digestibilities. Rumen characteristics, namely NH3–N concentration and bacterial population were increased (p < 0.05) while, protozoal and fungal population remained unchanged, as level of CHYP supplementation increased. Total rumen volatile fatty acids (VFA) and propionic acid (C3) were enhanced (p < 0.05). Furthermore, N utilisation especially N absorption, N retention and efficiency of microbial nitrogen synthesis (EMNS) were significantly improved by increasing level of CHYP supplementation. Hence, CHYP supplementation is highly promising for ruminant feeding. HIGHLIGHTS Chaya leaf pellet (CHYP) contains high level of crude protein, essential amino acids and minerals. CHYP supplementation increased nutrient digestibility and propionic acid (C3) in rumen. CHYP enhanced N–balance, microbial nitrogen supply (MNS) and efficiency of microbial nitrogen synthesis (EMNS).

Direct heat stress-induced effects on rumen fermentation characteristics and nutrients degradability in sheep pair-fed alfalfa hay

Aim of the study: To investigate the direct effect of heat stress on rumen fermentation characteristics and nutrients degradability of pair-fed rams to subsequently eliminate the confounding effects of dissimilar feed intake induced by heat stress exposure.Area of study: Saudi Arabia.Material and methods: Five rumen-cannulated desert rams (45 ± 1.63 kg body weight; 2–3 years of age) were placed individually in controlled climatic-chambers to be exposed to two successive periods. The 1st period was a control thermoneutral period (TN; 23.64 ± 0.14 °C; extended for 21 days) followed by a 2nd period of heat stress (HS; 44.26 ± 1.70 °C, for another 21 days). Each period was consisted of a temperature acclimation phase (7 days) and a data collection phase (14 days). Alfalfa hay was offered twice daily during both periods in a pair-fed manner (800 g DM per head and day).Main results: Exposing pair-fed desert rams to elevated ambient temperature had (p&lt;0.05) elevated their respiration rate and skin temperature, without noticeable (p&gt;0.05) changes in their rectal temperature. Most of the rumen fermentation characteristics and nutrients degradability were not affected by HS (p&gt;0.05). However, exposure to HS increased (p&lt;0.05) pre-feeding rumen total volatile fatty acids concentrations, pre-feeding molar proportion of acetate, and post-feeding rumen osmolality.Research highlights: HS had no direct effect on post-feeding rumen fermentation characteristics and nutrients degradability in desert sheep. This implies that strategic approaches to mitigate the adverse effects of HS have to be directed towards promoting feed intake and nutrients utilization under such conditions.

Effects of anise, clove and thyme essential oils supplementation on rumen fermentation, blood metabolites, milk yield and milk composition in lactating goats

The present study evaluated the effects of essential oil (EO) from anise (AO), clove (CO) and thyme (TO) on the performance of lactating Shame goats. Eight lactating Shame goats with average body weight 34.90 ± 0.9 kg and 3 years old were randomly assigned to four treatments in a duplicated 4 × 4 Latin square design, with four periods of 22 days. In each period, the goats were adapted to the treatments for 15 days and the remaining 7 days was used for sample collection. Goats were fed a basal diet without supplementation (control) or supplemented with anise (AO), thyme (TO) or clove (CO) at a daily dose of 2 mL/head/d. Feed intake was not affected by EO supplementations. Digestibility of organic matter, ether extract and acid detergent fibre was higher (P < 0.05) with EO supplementations when compared with the control. Supplementations of EO had no effect on milk (g/d) yield, protein and lactose, as well as the composition (g/kg) of protein and lactose. Fat yield (g/d) and fat content (g/kg) were greater (P < 0.05) in EO supplemented goats versus those on the control diet. Compared with control, ruminal ammonia-N was not affected whereas, ruminal pH was increased (P = 0.02) with EO supplementations. Rumen total volatile fatty acid concentration and molar proportion of acetate (C2) were higher (P < 0.05) in goats fed CO and TO compared to control, whereas propionate (C3) and butyrate (C4) and C2:C3 proportions were unchanged with EO inclusion. With the exception of a decrease (P = 0.05) in blood urea nitrogen (BUN) with EO supplementations, other blood parameters were not affected. Milk C8 and C12 fatty acids (FA) were lower (P < 0.05) with EO supplementations compared with control. Composition of unsaturated and monounsaturated FA was higher (P < 0.05) and polyunsaturated FA was decreased (P < 0.05) with EO supplementations compared with control. Proportions of C18:1 n-9 C18:3 n-3 and n-3 FA were increased (P < 0.05) and proportions of C18:3 n-6 C20:4 n-6 and n-6 FA were decreased (P < 0.05) in goats fed EO compared to the control group. Overall, all three EOs tested in this study had beneficial effects on digestion, rumen fermentation parameters and milk composition including milk FA profile. Supplementation of CO and TO tended to increase PUFA concentration in the milk which supports their recommendation in the diet of lactating ruminants.

Differing planes of pre- and postweaning phase nutrition in Holstein heifers: I. Effects on feed intake, growth efficiency, and metabolic and development indicators

The objectives of this study were to determine the effects of pre- and postweaning planes of nutrition on feed and metabolizable energy (ME) intake, growth, concentrations of glucose, insulin, insulin-like growth factor 1 (IGF-1), and β-hydroxybutyrate (BHB) in blood and rumen volatile fatty acids (VFA) from birth to 25 wk of age in Holstein heifers. Heifer calves (n = 36) were randomly assigned to receive either a low (5 L/d of whole milk) or high (10 L/d of whole milk) preweaning plane of nutrition from 1 to 7 wk of age, and either a low (70% concentrate dry total mixed ration) or high (85% concentrate dry total mixed ration) postweaning plane of nutrition from 11 to 25 wk of age. From birth to 25 wk of age, feed intake was recorded daily, and body measures were obtained weekly. Circulating hormone and metabolite concentrations were measured biweekly and total ruminal VFA, fecal starch, and body condition were assessed monthly. Overall, average daily gain and body weight were greater for heifers offered increased planes of nutrition during both the pre- and postweaning phases. Heifers offered the high preweaning plane had greater milk intake (7.7 ± 0.1 vs. 4.5 ± 0.1 L/d) but lower starter intake (0.3 ± 0.04 vs. 0.7 ± 0.04 kg/d) during the preweaning phase than those offered the low plane. High preweaning plane heifers also had greater ME intake from wk 1 to 7, but less ME intake at wk 9 (5.3 ± 0.3 vs. 6.6 ± 0.2 Mcal/kg) than those offered the low plane. Furthermore, overall glucose (118.8 ± 2.9 vs. 110.1 ± 2.9 mg/dL) and IGF-1 (101.6 ± 3.6 vs. 75.9 ± 3.6 ng/mL) concentrations were greater for high versus low preweaning plane heifers, although circulating insulin and BHB did not differ between preweaning plane groups. However, heifers offered the high preweaning plane had reduced total rumen VFA concentrations compared with heifers offered the low plane in the preweaning phase (47.3 ± 2.0 vs. 55.6 ± 2.1 mM). During the postweaning phase, dry matter intake and ME were consistently greater in heifers offered the high postweaning plane. Overall insulin (2.0 ± 0.1 vs. 1.8 ± 0.1 ng/mL), glucose (97.1 ± 0.6 vs. 92.1 ± 0.6 ng/mL), IGF-1 (178.0 ± 4.8 vs. 155.8 ± 4.8 ng/mL), and BHB concentrations (8.8 ± 0.2 vs. 8.1 ± 0.2 ng/mL) were greater in heifers offered the high than the low postweaning plane. In addition, heifers offered the high postweaning plane had increased VFA concentrations in the postweaning phase (73.4 ± 1.3 vs. 63.9 ± 1.3 mM) compared with heifers offered the low postweaning plane. The results indicated that increasing the pre- and postweaning planes of nutrition along with energy levels positively influenced several indicators associated with heifer development before 25 wk of age. Nevertheless, there was limited interaction in growth and development indicators between the 2 phases.

Effect of nano-ZnO, compared to ZnO and Zn-methionine, on performance, nutrient status, rumen fermentation, blood enzymes, ferric reducing antioxidant power and immunoglobulin G in sheep

This study was conducted to assess the effect of nano-ZnO, compared to ZnO and Zn-methionine, on dry matter (DM) intake (DMI), performance, nutrient status, digestibility, rumen fermentation, microbial nitrogen (N) synthesis (MNS), blood enzymes, ferric reducing antioxidant power (FRAP) and immunoglobulin G (IgG) in sheep. Thirty-six healthy male Shal sheep were divided into four experimental groups (n = 9) in a completely randomized design, and assessed for 40 days. The control animals received the basal diet without Zn supplementation, containing a native Zn content of 22.6 mg/kg DM. Other sheep were fed with the diets containing 28 mg supplementary Zn/kg DM in the form of ZnO, Zn-methionine or nano-ZnO. The DMI of sheep receiving Zn-methionine was higher (P = 0.035) than the control group, but was similar among the Zn-supplemented groups. Although supplementation of the basal diet with Zn increased (P < 0.05) the digestibility, rumen total volatile fatty acids (VFA), average daily gain and feed efficiency, the chemical forms of Zn did not affect these variables. The intake, daily absorption, retention and blood concentration of Zn were not affected by using nano-ZnO instead of ZnO and Zn-methionine. The animals receiving Zn-methionine had higher (P = 0.019) rumen fluid Zn than the ZnO fed sheep. Compared to the control diet, the Zn supplementations increased retained N (P = 0.037) and decreased rumen ammonia-N (P = 0.046). Using nano-ZnO instead of ZnO and Zn-methionine had no effect on rumen ammonia-N, retained N and MNS. The blood urea-N (BUN) concentration was lower (P = 0.027) for the Zn-methionine and nano-ZnO fed animals versus the control and ZnO groups. The nano-ZnO and Zn-methionine fed sheep had higher (P < 0.05) rumen and blood FRAP and Zn absorbability than the ZnO group. The blood IgG concentration was higher (P = 0.028) for the Zn-methionine and nano-ZnO fed animals versus the control sheep, and nano-ZnO group versus the ZnO fed animals. There were no differences among sheep in terms of the ruminal pH, individual VFA proportions and protozoa counts, Cu status and blood alkaline phosphatase, aspartate aminotransferase and alanine aminotransferase. Overall, using nano-ZnO in the diet of sheep had advantages over ZnO in terms of increasing the Zn absorbability, rumen and blood FRAP and blood IgG, and decreasing BUN. However, there were no differences between the animals consuming nano-ZnO or Zn-methionine.

Effect of air temperature on growth performance, apparent digestibilities, rumen fermentation and serum metabolites in Altay and Hu lambs.

Fat-tailed Altay sheep are indigenous to the Altay prefecture and well adapted to severe cold and sparse pasture of poor quality. Hu sheep were introduced to this region in the 1970s and are raised mainly in feedlots. We hypothesized that the dietary energy utilization would differ between breeds and predicted that Altay sheep would be more efficient than Hu sheep, in particular at a low air temperature. To test this prediction, we examined growth performance, apparent digestibilities, rumen fermentation and serum metabolites in Altay (32±2.6kg) and Hu sheep (31±2.7kg) at air temperatures of -5 and 20°C. Average daily gain (ADG), feed and metabolizable energy intakes were greater in Altay than in Hu sheep (p<.01), and all were greater at -5°C than 20°C (p<.01). Body mass gain-to-feed intake ratio was higher in Altay than in Hu sheep (p<.001), but was not affected by air temperature (p>.10). Rumen total volatile fatty acid (VFA) concentration was greater in Hu than in Altay sheep (p<.05) and was greater at 20°C than at -5°C (p<.05), while rumen microbial protein concentration was greater in Altay than in Hu sheep (p<.05). Rectal temperature was higher at -5°C than 20°C (p<.05) and was similar between breeds (p>.05). Serum glucose, non-esterified fatty acid (NEFA) and urea-N concentrations were higher in Hu than in Altay sheep (p<.05). It was concluded that Altay sheep are better able to cope with poor quality diets as they had higher digestibility of nutrients, ADG and body mass gain-to-feed intake ratio than Hu sheep.

Lactation performance and rumen fermentation in dairy cows fed a diet with alfalfa hay replaced by corn stover and supplemented with molasses.

ObjectiveThe objective of current study was to investigate the lactation performance and rumen fermentation characteristics of dairy cows fed a diet with alfalfa hay replaced by corn stover but supplemented with molasses.MethodsSixteen Holstein cows in mid-lactation were randomly assigned to 1 of 2 dietary treatments: i) alfalfa based diet (AH), and ii) corn stover based diet supplemented with molasses (CSM). The experiment was conducted according to a 2×2 crossover design with 22-d each period, consisting of 17 d for adaptation and 5 d for data and samples collection.ResultsDry matter intake and milk yield were higher for cows fed AH than CSM (p<0.01). Milk protein content and nitrogen conversion were higher (p<0.05), while milk urea nitrogen was lower (p<0.01) for cows fed AH than CSM-fed cows. Contents of milk total solids, fat and lactose were not different between two groups (p>0.10). Total rumen volatile fatty acid concentration tended to be higher (p = 0.06) for cows fed AH than CSM-fed cows. Molar proportion of acetate was lower (p = 0.04), but valerate was higher (p = 0.02) in cows fed AH than CSM-fed cows. Rumen concentration of propionate, and isobutyrate, and ratio of acetate to propionate tended to be different (p<0.10) between two groups. The feed cost per kilogram of milk was lower in CSM than AH (p<0.01). No differences were found in feed efficiency and most plasma parameters tested (p>0.10).ConclusionIn comparison with AH diet, CSM diet could be fed to dairy cows without negative effect on feed efficiency, ruminal fermentation, but economically beneficial, indicating that CSM could be an alternative choice for dairy farms instead of AH to feed mid-lactation dairy cows.

INFLUENCE OF DIETARY PROBIOTICS SUPPLEMENTATION ON BODY WEIGHT AND SELECTED RUMINAL PARAMETERS IN LAMB

This experiment was carried out to evaluate the possible effects of the probiotic Saccharomyces cerevisiae dietary supplement on body weight and some rumen parameters in lambs. Totally fifteen native growing male lambs (with initial age and body weight of 4.88±0.91 months and 23.21±2.75 kg respectively) were randomly divided to three equal groups (five lambs/each). The first group (C) fed the basal ration without any supplementation, the second group (Y) fed the basal ration supplemented with 0.5 g of live yeast (levucell SC 20.)® daily for each lamb and the third group (YC) fed the basal ration supplemented with 7 g of yeast culture (Diamond V XP™)® daily for each lamb. Rumen liqour samples were collected before supplementation of probiotics and then every 15 days until the day 90th. Rumen liquor pH, ammonia-nitrogen, protozoa counts and total volatile fatty acids concentrations (TVFAs) were estimated. Further, body weight and daily weight gain were calculated. Rumen parameters were significantly affected by treatments (P ≤ 0.05). Also, body weights and weight gain were significantly increased (P ≤ 0.05) in both supplemented groups (Y and YC).