Responses of nutrient utilization, rumen fermentation and microorganisms to different roughage of dairy buffaloes.

Dairy buffaloes are typically fed a high-forage, low-quality diet with high fiber. These conditions result in an inherent energy and protein inefficiency. In order to make full and rational use of feed resources and improve the production level and breeding efficiency of dairy buffaloes, the effects of various roughages on nutrient digestibility, ruminal fermentation parameters, and microorganisms in dairy buffaloes were studied in this experiment. Three ternary hybrid buffaloes, with an average body weight of 365 ± 22.1 kg, were selected and fitted with permanent rumen fistulas. They were fed six different diets, each consisting of 1 kg concentrate supplement and one of six types of roughage, including alfalfa hay (A diet), oat hay (O diet), whole corn silage (W diet), king grass (K diet), sugarcane shoot silage (S diet), and rice straw hay (R diet) according to an incomplete Latin square design of 3 × 6, respectively. The pre-feeding period of each period was 12 d. From day 13 to 15 was the official experimental period. During the prefeeding period, free feed intake for each roughage was determined, and during the experiment, the roughage was fed at 90% of the voluntary feed intake. Digestion and metabolism tests were carried out using the total manure collection method to determine the feed intake and fecal output of each buffalo, and to collect feed and fecal samples for chemical analysis. On day 15, rumen fluid samples were collected two hours after morning feeding to determine rumen fermentation parameters and bacterial 16 S rRNA high-throughput sequencing was performed. The results showed that DM and OM digestibility were greatest for the W diet and lowest for the S diet. The rumen pH of the O diet was significantly greater than that of the W diet. The concentration of rumen fluid NH3-N (mg/dL) increased with increased CP content. The concentration of total volatile fatty acids (mmol/L) in the rumen decreased with increased NDF content but increased with increased NFC content. The relative abundances of Bacteroidetes, Firmicutes, and Spirochaetes were 57.03-74.84%, 14.29-21.86%, and 0.44-1.43% in the different quality roughage groups. Bacteroidetes were mainly Prevotellaceae1 and Rikenellaceae RC_gut_group with relative abundances of 30.17-45.75% and 3.23-7.82%. The relative abundance of Patescibacteria and Spirochaetes decreased with increasing roughage quality. These results provide a theoretical and practical basis for evaluating the nutritional value of dairy buffalo feed, utilizing feed resources, matching rations, feeding scientifically, and protecting animal health.

Feeding alfalfa-grass or red clover-grass mixture baleage: Effect on milk yield and composition, ruminal fermentation and microbiota taxa relative abundance, and nutrient utilization in dairy cows.

Our goal was to investigate the effect of diets containing baleages harvested from alfalfa-grass or red clover-grass mixture on production performance, ruminal fermentation and microbiota taxa relative abundance, milk fatty acid profile, and nutrient utilization in dairy cows. Twenty Jersey cows (18 multiparous and 2 primiparous) averaging (mean ± SD) 148 ± 45.2 days in milk and 483 ± 65.4 kg of body weight in the beginning of the study were used in a randomized complete block design with repeated measures over time. The experiment lasted 9 wk, with a 2 wk covariate period followed by 7 wk of data and sample collection (wk 4 and 7 used in the statistical analyses). Cows were fed diets containing (dry matter basis) 35% of a concentrate mash and the following forage sources: (1) 65% second- and third-cut (32.5% each) alfalfa-grass mixture baleages (ALF) or (2) 65% second- and third-cut (32.5% each) red clover-grass mixture baleages (RC). Diets did not affect dry matter intake, milk yield, and concentrations of milk fat and true protein. In contrast, milk fat yield tended to decrease and energy-corrected milk yield decreased with feeding RC versus ALF. The apparent total-tract digestibilities of dry matter, organic matter, and ash-free neutral detergent fiber, milk proportions of trans-10 18:1, cis-9,cis-12,cis-15 18:3, and total n-3 fatty acids, ruminal molar proportion of acetate, and plasma concentrations of Leu, Phe, and Val all increased in RC versus ALF. Diet × week interactions were found for several parameters, most notably ruminal molar proportions of propionate and butyrate, ruminal NH3-N, milk urea N, plasma urea N, and plasma His concentrations, urinary N excretion, enteric CH4 production, and all energy efficiency variables. Specifically, ruminal NH3-N and plasma urea N concentrations, urinary excretion of N, and CH4 production decreased in cows fed RC in wk 4 but not in wk 7. Milk urea N concentration decreased and that of plasma His increased with feeding RC during wk 4 and 7, although the magnitude of treatments difference varied between the sampling periods. Efficiency of energy utilization calculated as milk energy/metabolizable energy decreased and that of tissue energy/ME increased in RC versus ALF cows in wk 4, suggesting that ME was portioned toward tissue and not milk in the RC diet. Interactions were also observed for the relative abundance of the rumen bacterial phyla Verrucomicrobiota and Fibrobacterota, with cows offered RC showing greater values than those receiving ALF in wk 4 but no differences in wk 7. Several diet × week interactions were detected in the present study implying short-term treatment responses and warranting further investigations.

A meta-analysis of methane-mitigation potential of feed additives evaluated in vitro.

A systematic literature review of in vitro studies was performed to identify methane (CH4) mitigation interventions with a potential to reduce CH4 emission in vivo. Data from 277 peer-reviewed studies published between 1979 and 2018 were reviewed. Individual CH4 mitigation interventions were classified into 14 categories of feed additives based on their type, chemical composition, and mode of action. Response variables evaluated were absolute CH4 emission (number of treatment means comparisons = 1,325); total volatile fatty acids (n = 1,007), acetate (n = 783), propionate (n = 792), and butyrate (n = 776) concentrations; acetate to propionate ratio (n = 675); digestibility of dry matter (n = 489), organic matter (n = 277), and neutral detergent fiber (n = 177). Total gas production was used as an explanatory variable in the model for CH4 production. Relative mean difference between treatment and control means reported in the studies was calculated and used for statistical analysis. The robust variance estimation method was used to analyze the effects of CH4 mitigation interventions. In vitro CH4 production was decreased by antibodies (-38.9%), chemical inhibitors (-29.2%), electron sinks (-18.9%), essential oils (-18.2%), plant extracts (-14.5%), plant inclusion (-11.7%), saponins (-14.8%), and tannins (-14.5%). Overall effects of direct-fed microbials, enzymes, macroalgae, and organic acids supplementation did not affect CH4 production in the current meta-analysis. When considering the effects of individual mitigation interventions containing a minimum number of 4 degrees of freedom within feed additives categories, Enterococcus spp. (i.e., direct-fed microbial), nitrophenol (i.e., electron sink), and Leucaena spp. (i.e., tannins) decreased CH4 production by 20.3%, 27.1%, and 23.5%, respectively, without extensively, or only slightly, affecting ruminal fermentation and digestibility of nutrients. It should be noted, however, that although the total number of publications (n = 277) and treatment means comparisons (n = 1,325 for CH4 production) in the current analysis were high, data for most mitigation interventions were obtained from less than 5 observations (e.g., maximum number of observations was 4, 7, and 22 for nitrophenol, Enterococcus spp., and Leucaena spp., respectively), because of limited data available in the literature. These should be further evaluated in vitro and in vivo to determine their true potential to decrease enteric CH4 production, yield, and intensity. Some mitigation interventions (e.g., magnesium, Heracleum spp., nitroglycerin, ß-cyclodextrin, Leptospermum pattersoni, Fructulus Ligustri, Salix caprea, and Sesbania grandiflora) decreased in vitro CH4 production by over 50% but did not have enough observations in the database. These should be more extensively investigated in vitro, and the dose effect must be considered before adoption of mitigation interventions in vivo.

High-energy diet modify rumen microbial composition and microbial energy metabolism pattern in fattening sheep.

Higher dietary energy is often used to achieve better animal performance in mutton sheep production. Notably, changing the diet formula affects rumen fermentation and the microbiota of ruminants. In this study, we investigated the effect of dietary energy on rumen fermentation and ruminal microbiota in fattening sheep. Fifteen 2-month-old white-headed Suffolk sheep (♂) × Hu sheep (♀) crossbred lambs were randomly divided into three treatments based on the dietary energy of the feeds fed: 8.67 MJ/kg (Low energy (LE); n = 5), 10.38 MJ/kg (standard energy (CON); n = 5), and 12.31 MJ/kg (high energy (HE); n = 5) groups. After 70 days of feeding, sheep were slaughtered and the ruminal fluids were collected and analyzed to determine fermentation parameters. Microbiota was determined using metagenomics sequencing. Notably, the microbial cell protein (MCP) and butyric acid concentrations were significantly high in the HE group. Metagenomic sequencing revealed that ACE and Chao indexes of the HE group were significantly decreased. Four genera among the major classified taxa across all the kingdoms differed in relative abundance in the three dietary energy levels. The relative abundances of Prevotella_brevis, Succiniclasticum_ruminis, Prevotellace-ae_bacterium, and Lachnospiraceae_bacterium were significantly correlated with rumen fermentation. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis further revealed that a high-energy diet increased lipid metabolism of microbiota. The Carbohydrate Active enzymes (CAZy) gene, which participates in energy metabolism, was upregulated, while genes regulating plant cell wall degradation were downregulated in the HE group. These results suggest that a high-energy diet had minimal influence on the rumen fermentation pattern but altered the composition of the rumen microbiota, enhancing microbial lipid metabolism and limiting crude fiber metabolism. The findings of this study provide scientific evidence of the effect of dietary energy on ruminant fermentation and fattening sheep production.

A meta-analysis of methane mitigation potential of feed additives evaluated in vitro.

A systematic literature review of in vitro studies was performed to identify methane (CH4) mitigation interventions with a potential to reduce CH4 emission in vivo. Data from 277 peer-reviewed studies published between 1979 and 2018 were reviewed. Individual CH4 mitigation interventions were classified into 14 categories of feed additives based on their type, chemical composition, and mode of action. Response variables evaluated were absolute CH4 emission (number of treatment means comparisons = 1,325); total volatile fatty acids (VFA; n = 1,007), acetate (n = 783), propionate (n = 792), and butyrate (n = 776) concentrations; acetate to propionate ratio (A:P; n = 675); digestibility of dry matter (DM; n = 489), organic matter (OM; n = 277), and neutral detergent fiber (NDF; n = 177). Total gas production was used as an explanatory variable in the model for CH4 production. Relative mean difference between treatment and control means reported in the studies were calculated and used for statistical analysis. Robust variance estimation method was used to analyze the effects of CH4 mitigation interventions. In vitro CH4 production was decreased by antibodies (-38.9%), chemical inhibitors (-29.2%), electron sinks (-18.9%), essential oils (-18.2%), plant extracts (-14.5%), plants inclusion (-11.7%), saponins (-14.8%), and tannins (-14.5%). Overall effects of direct fed microbials, enzymes, macroalgae, and organic acids supplementation did not affect CH4 production in the current meta-analysis. When considering the effects of individual mitigation interventions containing a minimum number of 4 degrees of freedom within feed additives categories, Enterococcus spp. (i.e., direct fed microbial), nitrophenol (i.e., electron sink), and Leucaena spp. (i.e., tannins) decreased CH4 production by 20.3, 27.1, and 23.5%, respectively, without extensively, or only slightly, affecting ruminal fermentation and digestibility of nutrients. It should be noted, however, that although the total number of publications (n = 277) and treatment means comparisons (n = 1,325 for CH4 production) in the current analysis were high, data for most mitigation interventions were obtained from less than 5 observations (e.g., maximum number of observations was 4, 7, and 22 for nitrophenol, Enterococcus spp., and Leucaena spp., respectively), because of limited data available in the literature. These should be further evaluated in vitro and in vivo to determine their true potential to decrease enteric CH4 production, yield, and intensity. Some mitigation interventions (e.g., magnesium, Heracleum spp., nitroglycerin, ß-cyclodextrin, Leptospermum pattersoni, Fructulus Ligustri, Salix caprea, and Sesbania grandiflora) decreased in vitro CH4 production by over 50% but did not have enough observations in the database. These should be more extensively investigated in vitro, and the dose effect must be considered before adoption of mitigation interventions in vivo.

Microbial composition, rumen fermentation parameters, enteric methane emissions, and lactational performance of phenotypically high and low methane-emitting dairy cows.

This experiment was designed to investigate the relation of high and low methane-yield phenotypes with body weight (BW), dry matter intake (DMI), lactation performance, enteric CH4 emissions, and rumen fermentation parameters in lactating dairy cows. A total of 130 multi- and primiparous Holstein cows were screened for enteric CH4 emissions using the GreenFeed system (C-Lock Inc.). Out of these 130 cows, 5 were identified as phenotypically high (HM) and 5 as phenotypically low (LM) CH4 emitters. Cows in the LM group had lower daily enteric CH4 emissions than cows in the HM group (on average 346 vs. 439 g/d, respectively), lower CH4 yield (15.5 vs. 20.4 g of CH4/kg of DMI), and CH4 intensity (13.2 vs. 17.0 g of CH4/ kg of energy-corrected milk yield). Enteric emissions of CO2 and H2 did not differ between HM and LM cows. These 10 cows were blocked by parity, days in milk, and milk production, and were used in a 5-wk randomized complete block design experiment. Milk composition, production, and BW were also not different between LM and HM cows. The concentration of total volatile fatty acids in ruminal contents did not differ between CH4 phenotypes, but LM cows had a lower molar proportion of acetate (57 vs. 62.1%), a higher proportion of propionate (27.5 vs. 21.6%, respectively), and therefore a lower acetate-to-propionate ratio than HM cows. Consistently, the 16S cDNA analysis revealed the abundance of Succinivibrionaceae and unclassified Veillonellaceae to be higher in LM cows compared with HM cows, bacteria that were positively correlated with ruminal propionate concentration. Notably, Succinivibrionaceae trigger the formation of propionate via oxaloacetate pathway from phosphoenolpyruvate via Enzyme Commission: 4.1.1.49, which showed a trend to be higher in LM cows compared with HM cows. Additionally, LM cows possessed fewer transcripts of a gene encoding for methyl-CoM reductase enzyme compared with HM. In this study, low and high CH4-yield cows have similar production performance and milk composition, but total-tract apparent digestibility of organic matter and fiber fractions was lower in the former group of animals.

Effect of nitrate supplementation, dietary protein supply, and genetic yield index on performance, methane emission, and nitrogen efficiency in dairy cows.

The objective was to investigate the effect of nonprotein nitrogen source, dietary protein supply, and genetic yield index on methane emission, N metabolism, and ruminal fermentation in dairy cows. Forty-eight Danish Holstein dairy cows (24 primiparous cows and 24 multiparous cows) were used in a 6 × 4 incomplete Latin square design with 4 periods of 21-d duration. Cows were fed ad libitum with the following 6 experimental diets: diets with low, medium, or high rumen degradable protein (RDP):rumen undegradable protein (RUP) ratio (manipulated by changing the proportion of corn meal, corn gluten meal, and corn gluten feed) combined with either urea or nitrate (10 g NO3-/kg of dry matter) as nonprotein nitrogen source. Samples of ruminal fluid and feces were collected from multiparous cows, and total-tract nutrient digestibility was estimated using TiO2 as flow marker. Milk samples were collected from all 48 cows. Gas emission (CH4, CO2, and H2) was measured by 4 GreenFeed units. We observed no significant interaction between dietary RDP:RUP ratio and nitrate supplementation, and between nitrate supplementation and genetic yield index on CH4 emission (production, yield, intensity). As dietary RDP:RUP ratio increased, intake of crude protein, RDP, and neutral detergent fiber and total-tract digestibility of crude protein linearly increased, and RUP intake linearly decreased. Yield of milk, energy-corrected milk, and milk protein and lactose linearly decreased, whereas milk fat and milk urea nitrogen concentrations linearly increased as dietary RDP:RUP ratio increased. The increase in dietary RDP:RUP ratio resulted in a linear increase in the excretion of total purine derivatives and N in urine, but a linear decrease in N efficiency (milk N in % of N intake). Nitrate supplementation reduced dry matter intake (DMI) and increased total-tract organic matter digestibility compared with urea supplementation. Nitrate supplementation resulted in a greater reduction in DMI and daily CH4 production and a greater increase in daily H2 production in multiparous cows compared with primiparous cows. Nitrate supplementation also showed a greater reduction in milk protein and lactose yield in multiparous cows than in primiparous cows. Milk protein and lactose concentrations were lower for cows receiving nitrate diets compared with cows receiving urea diets. Nitrate supplementation reduced urinary purine derivatives excretion from the rumen, whereas N efficiency tended to increase. Nitrate supplementation reduced proportion of acetate and propionate in ruminal volatile fatty acids. In conclusion, no interaction was observed between dietary RDP:RUP ratio and nitrate supplementation, and no interaction between nitrate supplementation and genetic yield index on CH4 emission (production, yield, intensity) was noted. Nitrate supplementation resulted in a greater reduction in DMI and CH4 production, and a greater increase in H2 production in multiparous cows than in primiparous cows. As the dietary RDP:RUP ratio increased, CH4 emission was unaffected and RDP intake increased, but RUP intake and milk yield decreased. Genetic yield index did not affect CH4 production, yield, or intensity.

Including 8 hours of access to alfalfa in 1 or 2 grazing sessions in dairy cows fed a partial mixed ration: Effects on intake, behavior, digestion, and milk production and composition.

The aim of this study was to evaluate the inclusion of alfalfa grazing during 8 h continuous or partitioned in 2 separated sessions of 4 h after each milking, on nutrient intake, digestibility, ruminal fermentation, feeding behavior, milk production, milk composition, and milk fatty acid profile, in late-lactation cows fed a partial mixed ration (PMR). Twelve dairy cows (193 ± 83 d in milk, 584 ± 71 kg of body weight) were housed in individual outdoor pens and assigned to treatments according to a 3 × 3 Latin square design replicated 4 times. The treatments were as follows: (1) control (T0), cows were fed a total mixed ration (TMR) provided ad libitum 20.0% crude protein (CP), 32.2% neutral detergent fiber (NDF); (2) fed a diet combining a PMR which had the same ingredient composition as the TMR (60% of ad libitum intake) + 1 session of 8 h of pasture (T8), continuous grazing alfalfa (Medicago sativa; 20.6% CP, 35.8% NDF) after the p.m. milking; and (3) PMR (60% of ad libitum intake) + 2 daily sessions of 4 h of access to pasture after each milking (T4+4). The experiment lasted 57 d and was divided into 3 periods of 19 d each. The first 12 d of each period was used for diet adaptation, and the last 7 d was used for data collection. No differences among treatments were observed for any of the productive variables, feeding efficiency, or purine derivatives excretion. Cows in T0 had greater intake and apparent digestibility of dry matter, organic matter, and nonfibrous carbohydrates compared with T4+4 and T8. Compared with T0, alfalfa grazing increased the concentration of C18:1 trans-11 and decreased those of C16:0 and C17:0 in milk fat. Cows in T4+4 consumed 1.1 more kg DM/d of alfalfa and N provided by alfalfa in the diet was 3 percentage points higher compared with T8 cows (266 vs. 229 g/d, respectively). In addition, T4+4 cows had a greater daily range of ruminal pH than T8 (0.73 vs. 0.93), and the highest concentrations of NH3-N were recorded during the a.m. grazing session while in T8 cows it occurred during the night. In conclusion, including 8 h of alfalfa grazing in T8 and T4+4 treatments allowed the substitution between 35.8 and 38.7% of the total dry matter intake (DMI) of a PMR (with a similar CP concentration to alfalfa) for pasture, maintaining milk solids production and increasing the C18:1 trans-11 of milk fat compared with a TMR in mid late-lactation cows. In an herbage plus PMR diet, splitting the 1 continuous grazing session of 8 h into 2 sessions of 4 h increased the proportion of energy and N provided by alfalfa pasture and reduced PMR intake, without modifying the total nutrient intake or productive performance of cows.

Effects of guanidinoacetic acid supplementation on lactation performance, nutrient digestion and rumen fermentation in Holstein dairy cows.

BACKGROUND: Considering the high energy demand of lactation and the potential of guanidinoacetic acid (GAA) addition on the increase in creatine supply for cows, the present study investigated the effects of 0, 0.3, 0.6 and 0.9 g kg-1 dry matter (DM) of GAA supplementation on lactation performance, nutrient digestion and ruminal fermentation in dairy cows. The study used 40 mid-lactation multiparous Holstein cows and the study duration was 100 days. RESULTS: DM intake was not affected, but milk and milk component yields and feed efficiency increased linearly with increasing GAA addition. The total-tract digestibility of DM, organic matter, neutral detergent fibre, acid detergent fibre and non-fibre carbohydrates increased linearly and that of crude protein increased quadratically with increasing GAA addition. When the addition level of GAA increased, ruminal pH, molar percentages of butyrate, isobutyrate and isovalerate and the acetate-to-propionate ratio decreased linearly, and the total volatile fatty acids concentration and propionate molar percentage also increased linearly, whereas the acetate molar percentage and ammonia-N concentration were unaltered. The activities of fibrolytic enzymes, α-amylase and protease increased linearly. The populations of total bacteria, fungi, Ruminococcus albus, Fibrobacter succinogenes, Ruminococcus flavefaciens, Ruminobacter amylophilus and Prevotella ruminicola increased linearly, whereas protozoa and methanogens decreased linearly with increasing GAA addition. As for the blood metabolites, concentrations of glucose, urea nitrogen and methionine were unchanged, total protein, albumin, creatine and homocysteine increased linearly, and folate decreased linearly with increasing GAA supply. CONCLUSION: The results of the present study indicate that supplementation of GAA improved milk performance and rumen fermentation in lactating dairy cows. © 2022 Society of Chemical Industry.

Effects of raw and fermented rapeseed cake on ruminal fermentation, methane emission, and milk production in lactating dairy cows.

The objective of this study was to evaluate the effects of replacing raw rapeseed cake (RC) with fermented rapeseed cake (FRC) in the diet of dairy cows on methane (CH4) production, ruminal fermentation, and milk production, composition, and fatty acid composition. The Hohenheim gas test (exp. 1) was initially used to evaluate RC and FRC as substrates. Following batch fermentation, an in vitro study (exp. 2) was performed to assess the effects of replacing RC with FRC at 28.75, 57.5, 86.25, and 115 g/kg (FRC25, FRC50, FRC75, and FRC100) in the total mixed rations (TMR). Based on the in vitro results, the control TMR (115 g/kg dry matter (DM) of RC; CONRC) and experimental TMR (115 g/kg DM of FRC; FRC100) were chosen for an in vivo assessment. In exp. 3, four ruminally cannulated cows were used in a replicated 2 (group) × 2 (period) crossover design and fed the TMR ad libitum. In exp. 4, twenty multiparous Polish Holstein-Friesian cows in their mid-lactation (148 ± 26 d in milk) were used in a completely randomized design. The cows were fed a partial mixed ration without the RC and FRC, and the RC and FRC were supplied in a concentrate feeder at 2.65 kg/d/cow. The FRC100 markedly decreased CH4 production by 12% and archaeal population without adversely affecting nutrient digestibility. The molar proportion of propionate was increased, and the molar proportion of acetate and butyrate and acetate to propionate ratio were decreased by FRC100. No significant effects on milk production or composition, except an increase in milk urea concentration, were observed in cows fed FRC100. Milk C18:2 cis-9, trans-11 concentration was greater, and n-6 to n-3 fatty acid ratio was lower for FRC100 than CONRC. In-situ ruminal degradation of RC and FRC were explored using in-sacco techniques (exp. 5). The potential degradation and effective degradability of the DM, organic matter, and crude protein were significantly higher for FRC than RC. These results suggested that FRC could mitigate enteric CH4 production by decreasing archaeal abundances without adversely affecting milk production and ruminal fermentation in lactating cows.

The effect of excessive elemental sulfur addition on feed intake, digestibility, rumen characteristics, blood metabolites and nitrogen balance in Thai native beef cattle fed a diet containing high fresh cassava root.

This study aimed to study the effect of excessive elemental sulfur addition on intake, digestibility, rumen characteristics, blood metabolites and nitrogen balance in Thai native beef cattle fed diets containing high fresh cassava root (FCR) supplementation. Four Thai native beef cattle with an initial body weight (BW) of 100 ± 10.0 kg were used and randomly assigned to a 2 × 2 factorial in a 4 × 4 Latin square design. Two levels of FCR supplementation at 15 (FCR-1.5) and 20 g/kg of BW (FCR-2) and two levels of sulfur supplementation in concentrate at 10 (Sulfur-1) and 20 g/kg dry matter concentrate (Sulfur-2) were evaluated. This study showed that sulfur and FCR in combination (p < 0.05) increased dry matter and organic matter digestibility and bacterial population. Sulfur-2 resulted in higher (p < 0.05) sulfur intake and serum thiocyanate concentration than Sulfur-1. FCR-2 had a greater (p < 0.05) FCR intake, total volatile fatty acids and propionate concentration than FCR-1.5. In conclusion, excessive elemental sulfur addition with high FCR supplementation showed no negative effect in Thai native beef cattle.

Polyunsaturated fatty acids and rumen undegradable protein alter ruminal fermentation and milk fatty acid profiles in dairy cows.

The present study evaluated the effects of incorporating polyunsaturated fatty acid (PUFA)- and rumen undegradable protein (RUP)-enriched feeds on ruminal fermentation, methane production, milk yield and milk FA profiles in dairy cows. Experiment 1 was carried out on 12 multiparous HF dairy cows in mid-lactation (106 ± 18.6 days in milk, 13.1 ± 1.67 kg/d of milk). Environmental conditions throughout the experiment were 34.5 ± 1.9 8°C, 58.0 ± 2.65% relative humidity and 85.7 ± 2.71 temperature-humidity index. Cows (n = 6/group) were randomly allocated to a control diet (Ctrl) consisting of corn silage and concentrate (F:C 60:40) containing 27.2% RUP in the crude protein (CP) or a treatment diet (Trt) consisting of 58.3% corn silage, 29.6% concentrate, 3.24% roasted soybean meal, 5.82% corn dried distiller grains with solubles and 3% added oil, which contained linseed, sunflower and tuna crude oil (1:1:1, wt/wt). The Trt diet contained 35.0% RUP in the CP. Experiment 2 was conducted in vitro using ruminal fluid collected from three Holstein Friesian dairy cows. The experimental design and diets were the same as in Exp. 1. Dry matter intake (DMI) tended to be lower (P = 0.06) in the Trt group. No difference in milk yield was detected, but the lower (P < 0.01) milk fat was measured in the Trt group (2.82% vs. 3.81%). Feed efficiency (milk/DMI) tended to be greater (P = 0.06) in the Trt cows (1.08 vs. 0.88). Lower 18:0 (5.73% vs. 8.29%), but greater concentrations of c9,t11 CLA (1.88% vs. 0.34%), c9,c12 18:2 (1.55% and 0.69%) 18:3n-3 (0.30% vs. 0.12%) and 22:6n-3 (0.17% vs. 0%) were detected in milk fat of cows fed Trt (P < 0.01). Atherogenicity and thrombogenic indices were lower (P < 0.01) with Trt. Concentrations of ruminal total volatile fatty acids and methane, which was assessed by production of volatile fatty acids, were 10.2% and 11.7% lower P < 0.01) in the Trt group. In conclusion, incorporating PUFA- and RUP-high feeds in lactating cow diets in the tropics causes a reduction in concentrations of ruminal VFA, methane production and milk fat while improving aspects of milk quality without affecting milk production.

The effect of dietary inclusion of Artemisia sieberi leaves on growth performance, feeding behaviors, ruminal fermentation, feed digestibility, and blood hemato-biochemical profile of growing male lambs.

The objective of this study was to investigate the impacts of replacing alfalfa hay with Artemisia sieberi leaves (ASL) on growth performance, feeding behaviors, total tract feed digestibility, ruminal fermentation as well as blood cells, and biochemical parameters. A total of 21 Kermani male lambs (average body weight (BW) of 25.2 ± 0.9 kg) were randomly divided into three groups and offered the following treatments: (1) basal diet (65% concentrate and 35% alfalfa hay as forage source), (2) ASL inclusion at 25% of forage source (8.75% of TMR, ASL25), and (3) ASL addition at 50% of forage source (17.5% of TMR, ASL50). The experiment lasted for 64 days, including 14 days of adaptation and 50 days of data collection. Dietary ASL inclusion decreased lambs' feed consumption (6.7 and 2.8% reduction in ASL25 and ASL50, respectively, p < 0.05) without affecting water intake, final BW, daily weight gain, and feed conversion ratio. Moreover, feeding behaviors, including time spent for eating, ruminating, and chewing activities, were uninfluenced by the dietary ASL addition on days 25 and 50 of the experiment. Based on the data provided, the substitution of alfalfa hay with ASL resulted in an increase in the digestibility of dry matter, organic matter, and neutral detergent fiber (p < 0.05). In addition, the ruminal fluid of ASL-fed lambs had a lower molar proportion of acetate and a higher proportion of propionate compared to that of the control animals (p < 0.05), whereas other volatile fatty acids (VFA) and total VFA were not different between the experimental groups. Blood hematocrit, hemoglobin, red cells, white cells, and their differentiation, platelets, glucose, total protein, albumin, globulin, triglyceride, calcium, phosphorus, aspartate aminotransferase, and alanine aminotransferase, urea, total antioxidant capacity, and malondialdehyde remained unchanged when ASL was included in the diet. Regardless of the slight decrease in dry matter intake, the lack of adverse effects of dietary ASL addition on growth performance, feeding behaviors, rumen fermentation, and blood hemato-biochemical parameters, along with positive impacts of ASL on propionate production and total tract feed digestibility, suggest that Artemisia sieberi leaves can be considered as a potential alternative feed resource for small ruminants.

The sustainable mitigation of in vitro ruminal biogas emissions by ensiling date palm leaves and rice straw with lactic acid bacteria and Pleurotus ostreatus for cleaner livestock production.

AIMS: The sustainable utilization of date palm leaves (DPL) and rice straw (RS) as feed materials for ruminant was evaluated using an in vitro wireless gas production (GP) technique. METHODS AND RESULTS: DPL and RS were individually ensiled with lactic acid bacteria (LAB) for 45 days or used as substrates for the cultivation of Pleurotus ostreatus (PO) mushroom for 35 days. A total mixed ration was formulated as a control ration. In the other rations, berseem hay replaced DPL (ensiled without additives or ensiled with LAB or PO) at 25%, 50%, 75% and 100%. Ensiling with LAB did not affect the chemical composition of DPL or RS, while PO treatment reduced their fibre fraction contents. Ensiling without additives lowered (p < 0.05) the asymptotic production of total gas, methane (CH4 ) and carbon dioxide (CO2 ), and the rate of CH4 and CO2 while increasing (p < 0.05) the lag time of CH4 and CO2 production. Ensiling of materials with LAB and treatment with PO decreased (p < 0.05) the asymptotic production of total gas, CH4 and CO2 production and decreased the rate of CH4 and CO2 production. Ensiling without additives decreased (p < 0.05) total bacterial count, and increased (p < 0.05) fermentation pH and total volatile fatty acids (VFA), while LAB-ensiled DPL increased (p < 0.05) total VFA and propionate concentrations and decreased total protozoal count. The PO-treated DPL decreased (p < 0.05) bacterial count, protozoal count and fermentation pH and increased total VFA production. CONCLUSIONS: Replacing berseem hay with LAB or PO-treated DPL at 25% increased GP; however, increased CH4 and CO2 production, whereas the other replacement levels decreased total gas, CH4 and CO2 production. The treatment with LAB is more recommended than the PO treatment.

Evaluation of gallnut tannin and Lactobacillus plantarum as natural modifiers for alfalfa silage: Ensiling characteristics, in vitro ruminal methane production, fermentation profile and microbiota.

AIMS: The potential of gallnut tannin (GT) and Lactobacillus plantarum (LP) on fermentation characteristics, in vitro ruminal methane (CH4 ) production and microbiota of alfalfa silage was investigated. METHODS AND RESULTS: Alfalfa was ensiled with GT (20 and 50 g kg-1 dry matter [DM]) and LP (3 × 108  CFU per gram fresh matter) alone or in combination for 60 days. The GT and LP alone or in combination decreased DM losses, pH and non-protein nitrogen contents of alfalfa silage. All additive treatments decreased ruminal CH4 production, and increased propionic acid molar proportions and Fibrobacter succinogenes numbers. The LP treatment increased nutrient degradation, cellobiase, pectinase and protease activities, and Prevotella ruminicola abundance, whereas high-dose GT treatment inhibited these variables. Importantly, LP together with GT alleviated the adverse effects of high-dose GT supply alone by enhancing pectinase and protease activities as well as Rumincoccus flavefaciens and P. ruminicola growth. CONCLUSIONS: Combination of GT and LP can be used as an efficient additive to improve silage quality and utilization by ruminants. SIGNIFICANCE AND IMPACT OF THE STUDY: Using GT-LP combination has practical implications, particularly concerning effects of tannins on ruminal CH4 mitigation, which may alleviate inhibitory effects of tannins on feed digestion through modulating ruminal microbiota.

Effects of ruminal protozoa on methane emissions in ruminants-A meta-analysis.

The effects of different ruminal protozoa (RP) on CH4 emissions from ruminants were evaluated in a meta-analysis, using 64 publications reporting data from 79 in vivo experiments. Experiments included in the database reported CH4 emissions (g/d) and total RP (TRP, log10 cells/mL) from the same group of animals. The relationship between CH4 emissions and RP (TRP, entodiniomorphids, and isotrichids), and TRP-, entodiniomorphid-, and isotrichid-based CH4 emission prediction models, were evaluated as mixed models with experiment as a random effect and weighted by the reciprocal of the standard error of the mean and centered around one. Positive associations existed between TRP and isotrichids with CH4 emissions but not between entodiniomorphids and CH4 emissions. A reduction in CH4 emissions was observed, averaging 7.96 and 4.25 g/d, per log unit reduction in TRP and isotrichid concentrations, respectively. Total RP and isotrichids were important variables in predicting CH4 emissions from ruminants. Isotrichid CH4 prediction model was more robust than the TRP, evidenciated by lower predicted sigma hat study (%), and error (%), and with higher concordance correlation coefficient. Both TRP and isotrichid models can accurately predict CH4 emissions across different ruminant types, as shown by the low square root of the mean square prediction error, with 6.59 and 4.08% of the mean of root of the mean square prediction error in the TRP and isotrichid models, respectively. Our results confirm that isotrichids are more important than entodiniomorphids in methanogenesis. Distinguishing these 2 populations yielded a more robust CH4 prediction model than combining them as total protozoa.

Effects of replacing magnesium oxide with calcium-magnesium carbonate with or without sodium bicarbonate on ruminal fermentation and nutrient flow in vitro.

The objective of this study was to evaluate the effects of replacing magnesium oxide (MgO) with calcium-magnesium carbonate [CaMg(CO3)2] on ruminal fermentation with or without the addition of sodium bicarbonate (NaHCO3). Eight fermentors of a dual-flow continuous-culture system were distributed in a replicated (2) 4 × 4 Latin square design in a 2 × 2 factorial arrangement of treatments (magnesium sources × NaHCO3). The treatments tested were 0.21% MgO [MgO; dry matter (DM) basis; 144.8 mEq of dietary cation-anion difference (DCAD)]; 0.21% MgO + 0.50% NaHCO3 (MgO+NaHCO3; DM basis; 205.6 mEq of DCAD); 1.00% CaMg(CO3)2 [CaMg(CO3)2; DM basis; 144.8 mEq of DCAD]; and 1.00% CaMg(CO3)2 + 0.50% NaHCO3 [CaMg(CO3)2+NaHCO3; DM basis; 205.6 mEq of DCAD]. Diets were formulated to have a total of 0.28% of Mg (DM basis). The experiment consisted of 40 d, which was divided into 4 periods of 10 d each, where 7 d were used for adaptation and 3 d for sampling to determine pH, volatile fatty acids (VFA), ammonia (NH3-N), lactate, mineral solubility, N metabolism, and nutrient digestibility. The effects of Mg source [MgO vs. CaMg(CO3)2], NaHCO3 (with vs. without), and the interaction were tested with the MIXED procedure of SAS version 9.4 (SAS Institute). There was no Mg source × NaHCO3 interaction in the pH variables and mineral solubility, and Mg sources evaluated did not affect the variables related to ruminal pH and solubility of Mg. On the other hand, the inclusion of NaHCO3 increased the pH daily average, independent of Mg source, which led to a reduced time that pH was below 5.8 and decreased area under the curve. Total VFA and lactate concentration were similar among treatments regardless of NaHCO3 and Mg source; however, the molar proportion of isobutyrate and NH3-N concentration were lower in diets with CaMg(CO3)2 compared with MgO. Moreover, NaHCO3 inclusion increased NH3-N, total daily NH3-N flow, isobutyrate concentration, and acid detergent fiber digestibility. Our results showed that CaMg(CO3)2 leads to a lower NH3-N concentration and isobutyrate proportion. Therefore, because most of the tested variables were not significantly different between MgO and CaMg(CO3)2 when combined or not with NaHCO3, CaMg(CO3)2 can be a viable alternative source to replace MgO in dairy cow diets without affecting mineral solubility, ruminal pH, nutrient digestibility, total VFA, and the main ruminal VFA. Although Mg sources are known to have an alkalizing effect, NaHCO3 inclusion in diets with Mg supplementation allowed an increase in ruminal pH, as well as an increase in isobutyrate and NH3-N flow.

Growth performance, nutrient digestibility, and ruminal fermentation of dairy calves fed starter diets with alfalfa hay versus corn silage as forage and soybean oil versus palm fatty acids as fat source.

The present study was intended to evaluate the effect of forage source (alfalfa hay; ALF vs. corn silage; CS) along with a supplemental fat source (soybean oil; SO vs. rumen-inert palm fatty acids; PF) on growth performance, nutrient digestibility, and ruminal fermentation in dairy calves. Forty-eight new-born Holstein female calves (3 d old) were assigned to one of 4 treatments: (1) alfalfa hay with soybean oil (ALF-SO); (2) alfalfa hay with palm fatty acids (ALF-PF); (3) corn silage with soybean oil (CS-SO); (4) corn silage with palm fatty acids (CS-PF). Starter diets had equal amounts of forage (100 g/kg dry matter; DM) and fat source (30 g/kg DM). Calves were fed a constant amount of milk (d 1 to 63) and had ad libitum access to water and starters (d 1 to 83). The lowest and greatest starter intakes during the preweaning period occurred in ALF-SO and CS-PF, respectively. This coincided with forage × fat source interaction for average daily gain (ADG) during preweaning. The forage source affected total DM intake and ADG over the entire period, body weight (BW) at weaning, and final BW with greater values in calves that received CS compared with ALF. The concentrations of total short-chain fatty acids and butyrate were increased, whereas concentration of acetate and acetate:propionate ratio were decreased in the rumen of calves fed CS compared with ALF. Feeding CS increased urinary excretion of allantoin and, as a trend, total purine derivatives (PD) and estimated microbial protein synthesis in comparison with ALF. The fat source affected starter intake, ADG, and BW postweaning with the highest values in PF. The digestibility of neutral detergent fiber, crude protein and, as a trend, organic matter were higher in calves fed PF compared with SO. Calves fed PF had lower ruminal ammonia-N concentration and urinary N excretion and greater urinary excretion of allantoin and total PD. Calves receiving SO had a lower ruminal protozoa population. In conclusion, supplementing starter diets with CS and PF is superior to ALF and SO. Interaction of the positive effects of CS and PF on performance underlines that concurrent supplementation of CS with PF is especially recommendable in young calves before weaning.

Effect of Paulownia Leaves Extract Levels on In Vitro Ruminal Fermentation, Microbial Population, Methane Production, and Fatty Acid Biohydrogenation.

Paulownia is a fast-growing tree that produces a huge mass of leaves as waste that can be used as a feed source for ruminants. The previous study showed that phenolic compounds were the most active biological substances in Paulownia leaves, which affected the ruminal parameters and methane concentration. However, there are no scientific reports on the Paulownia leaves extract (PLE) containing phenolic compounds for their mode of action in the rumen. Phenolics constituted the main group of bioactive compounds in PLE (84.4 mg/g dry matter). PLE lowered the concentration of ammonia, modulated the VFA profile in the ruminal fluid, and decreased methane production. The PLE caused a significant reduction of in vitro dry matter degradability, reduced the number of methanogens and protozoa, and affected selected bacteria populations. PLE had a promising effect on the fatty acid profile in the ruminal fluid. Paulownia as a new dietary component or its extract as a feed additive may be used to mitigate ruminal methanogenesis, resulting in environmental protection and reducing ruminal biohydrogenation, improving milk and meat quality.

Llama and sheep ruminal fluid digestive capacity by in vitro gas production technique.

BACKGROUND: The in vitro gas production technique has been used to evaluate forage fermentation kinetics. However, individual and animal species variation can change fermentation patterns due to differences in ruminal environment and microbiota. The aim was to verify whether rumen inoculum (RI) of llama had superior intrinsic digestion capacity and reduced methane (CH4 ) production compared to sheep RI using fescue and paspalum hay as substrates. RESULTS: Dry and organic matter (OM) digestibility produced with llama RI tended to exceed that of sheep (P = 0.099 and 0.074, respectively) at 24 h of incubation. However, at 48 h, the sheep RI presented higher substrate digestibility and asymptotic value of gas production than that of llama (P < 0.010). CH4 production showed no differences between RI or substrates (P > 0.050). The NH3 -N and total volatile fatty acid concentrations were greater in the RI of llamas compared to those of sheep (P < 0.050). Acetate and butyrate proportions and acetate-to-propionate ratio were greater in the RI of llamas compared to those of sheep (P < 0.001) at 24 and 48 h. However, propionate proportion was greater in sheep compared with llama (P < 0.001). CONCLUSION: Llama RI tended to surpass that of sheep in dry and OM digestibility at 24 h of incubation, but sheep RI at 48 h presented a higher digestibility and gas production value than llama RI. No differences between the two species were detected for CH4 production. This study showed that llama RI did not perform better than sheep RI in digesting low-quality forages. © 2022 Society of Chemical Industry.