Effects of sodium bicarbonate with three ratios of hay crop silage to concentrate for dairy cows

Three ruminally cannulated Holstein cows were fed total mixed diets of hay crop silage and concentrate (30:70, 50:50, 70:30, 100:0) to evaluate effects of sodium bicarbonate supplements equivalent to 0, .4, and .7% of total ration dry matter (0, 68, and 114 g/d). Yields of milk, fat-corrected milk, fat, protein, and solids-not-fat, percentages of milk protein and solids-not-fat, and efficiency of production of fat-corrected milk declined with decreasing concentrate proportion. Buffer supplementation reduced milk fat percentage and milk yield was greater with 68 g/d sodium bicarbonate than with 114 g/d. Digestibilities of dry matter, organic matter, gross energy, cell solubles, and crude protein declined with decreasing proportion of concentrate while cellulose digestibility increased linearly. The proportion of dietary nitrogen transferred to milk decreased linearly with decreasing proportion of concentrate and sodium bicarbonate increased this transfer with the 70% concentrate diet. Sodium bicarbonate increased ruminal pH and acetate proportion while decreasing ammonia concentration. Acetate:propionate ratio was decreased by sodium bicarbonate addition to the 70% concentrate diet. High concentrate diets with hay crop silage may require higher amounts of buffers to influence production.     

Rumen volatile fatty acid production and nutrient utilization in steers fed a diet supplemented with sodium bicarbonate and monensin

Effects of feeding dietary supplements of monensin and sodium bicarbonate singly or in combination on production of rumen volatile fatty acids, nitrogen balance, and rumen water kinetics were studied. Four rumen fistulated steers were fed a diet (50% concentrate mix and 50% corn silage) ad libitum in a 4 X 4 Latin square design (21-day periods) with a 2 X 2 factorial arrangement of treatments. Sodium bicarbonate increased feed intake, water intake, rumen pH, fluid dilution rate, and decreased both molar proportion and production rate of propionate in the rumen. Alteration of the ratio of acetate to propionate reflects the large decrease in propionate production relative to the small increase in acetate production. In contrast, monensin did not alter significantly rumen fluid dilution rate or ruminal pH but did decrease the molar proportion of acetate and increase that of propionate. Monensin increased production of both acetate and propionate in the rumen; however, the large increase in propionate production appears to account for more of the increase in molar proportion of propionate in the rumen. Increases in total volatile fatty acid production per kilogram of dry matter consumed with monensin supplementation appears to result from decrease in feed intake, thereby increasing ruminal retention time of dry matter and potentially the extent of digestion. Efficiency of nitrogen utilization was not altered by either sodium bicarbonate or monensin.     

Urea synthesis by ruminal epithelial and duodenal mucosal cells from growing sheep

The objective was to determine whether ruminant gut tissues have the capability to synthesize urea in a short-term incubation. Mixed primary cell cultures containing ruminal epithelial (REC) or duodenal mucosal cells (DMC) were isolated from growing sheep (n = 4) fed a mixed forage-concentrate diet. Cells were incubated (90 min) in a Krebs salts-based buffer with either acetate (5 mM) or propionate (5 mM) plus a combination of substrate intermediates (5 mM) for urea synthesis: arginine, aspartate + citrulline (AspC), aspartate + ornithine + ammonia (AspON), or AspON + N-carbamoylglutamate (AspONG) in a 2 x 4 factorial arrangement of treatments. Volatile fatty acid, propionate vs. acetate, did not influence net urea synthesis. For REC, net urea synthesis (nmoles x (10(6) cells)(-1) x 90 min(-1)) was greatest with Arg (54.5 +/- 6.3) followed by AspC (4.6 +/- 1.1) and AspONG (3.6 +/- 1.4). For DMC, net urea synthesis for Arg (2.1 +/- 0.7) and AspONG (1.9 +/- 0.7) treatments was greater than for AspC (0.3 +/- 0.7) and AspON (-0.6 +/- 0.7) treatments. Thus, for both REC and DMC, arginase activity appeared to be sufficient for catabolism of arginine to urea. Furthermore, greater urea synthesis from ammonia, ornithine and aspartate in the presence of the N-acetylglutamate analogue suggests that carbamoyl phosphate synthetase is probably rate-limiting for urea synthesis and ammonia detoxification by ruminant gut tissues.     

Plasma alpha-tocopherol profiles in sheep after oral administration of dl-alpha-tocopheryl acetate and d-alpha-tocopheryl succinate

The purpose of this study was to compare the bioavailability of dl-alpha-tocopheryl acetate and d-alpha-tocopheryl succinate when administered to sheep in a single oral dose weekly. The sheep, five per treatment, were given a basal diet without vitamin E supplement (control) or basal diet with weekly administration of 2225 IU of dl-alpha-tocopheryl acetate, 2225 IU of d-alpha-tocopheryl succinate, or 6675 IU of d-alpha-tocopheryl succinate. Increases in plasma alpha-tocopherol concentration levels over the 3-wk period of study were determined and compared. The greater availability of dl-alpha-tocopheryl acetate was indicated by the significantly higher peak plasma alpha-tocopherol concentrations and the greater area under the curve produced by administration of the acetate than the succinate esters at the same dosage. Reported data on plasma alpha-tocopherol concentrations suggest that bioavailability in sheep of d-alpha-tocopheryl succinate versus dl-alpha-tocopheryl acetate is 3:1.     

Sodium bicarbonate and alfalfa hay additions to wheat silage diets fed to lactating dairy cows

Two experiments were conducted to examine dietary effects of .8% sodium bicarbonate and 1.4 kg/d of alfalfa hay on performance and rumen metabolism of lactating dairy cows fed 50% wheat silage and 50% concentrate (dry basis). In Experiment 1 with 12 midlactation Holsteins in a 4 X 4 Latin square design, intake, milk production, and milk composition were not affected by treatment. Dietary sodium bicarbonate and alfalfa hay did not alter blood, rumen, or fecal pH. Rumen volatile fatty acid pattern was not affected by sodium bicarbonate, but addition of hay resulted in higher molar percentage propionate and lower acetate: propionate ratios. In Experiment 2 with 32 early lactation cows (20 Holsteins and 12 Jerseys) in a complete randomized block design, supplementation of sodium bicarbonate, alfalfa hay, or both did not affect intake, milk production, or milk composition in the first 8 wk of lactation. Blood, rumen, and fecal pH were not affected by treatment. Dietary sodium bicarbonate did not alter ruminal volatile fatty acid profile, whereas addition of hay increased molar proportion acetate and decreased molar proportion butyrate. A shift in rumen fermentation was observed across treatments from wk 1 through 8 postpartum with molar proportions of acetate and butyrate increasing and molar proportion of propionate decreasing.     

双乙酸钠对鲜湿米粉条保鲜和品质的影响

研究山梨酸钾、脱氢乙酸钠、双乙酸钠以及丙酸钙对鲜湿米粉条的保鲜效果,结果显示,双乙酸钠保鲜效果最优,添加量为0.2g/kg,残留量未检出。探讨了双乙酸钠对鲜湿米粉条感官要求、理化指标及微生物指标的影响,结果表明,添加双乙酸钠后,显著降低了霉菌总数,鲜湿米粉条外观、色泽、气味、口味等感官要求均有明显改善,水分、酸度等理化指标变化很小。     

Effects of feeding monensin sodium to lactating goats: milk composition and ruminal volatile fatty acids

When diets containing 33 and 18 ppm monensin sodium were fed for ad libitum intake to dairy goats, milk fat content was reduced by 15 and 5%. Milk protein content was increased 10% when 33 ppm sodium monensin was fed with diet at restricted intake. Milk yield was not affected. Both ad libitum and restricted consumption of diet containing 33 ppm monensin sodium reduced ratios of ruminal acetate:propionate. These resulted from increased propionate concentration with ad libitum consumption and from reduced acetate with restricted feeding. Diets containing 18 ppm monensin sodium resulted in slightly higher concentrations of both propionate and acetate. Monensin sodium did not reduce feed intake significantly.     

Effects of intraruminal infusions of mineral salts on volatile fatty acid production in steers fed high-grain and high-roughage diets

Four rumen fistulated Holstein steers were used to assess the effects of intraruminal salt infusions on various rumen characteristics including volatile fatty acid production rates. In the first experiment, the basal diet consisted of 75% concentrate and 25% corn silage (high-grain diet). The experimental design was a 4 X 4 Latin square in which the four treatments were: 1) intraruminal infusion of 8 liters of water (control) or 8 liters of water plus 2) 288 g sodium bicarbonate, 3) 200 g sodium chloride, or 4) 600 g sodium chloride. In the second experiment, procedures were the same except the basal diet consisted of 64% alfalfa hay and 18% each of corn silage and concentrate (high-roughage diet). When the high-grain basal diet was fed, intraruminal infusions of mineral salts increased dilution rate of rumen fluid. Total fluid flow from the rumen also was increased by salt infusions with sodium bicarbonate and the most sodium chloride from (600 g/day) exerting greatest effects for both dietary regimens. Salt infusions reduced the molar percentage of rumen propionate and increased the molar percentage of acetate when the high-grain diet was fed. These same treatments were without effect on molar percentages of rumen acids when the high-roughage diet was fed. The change in the molar percentages of acetate and propionate on the high-grain ration was solely from reduction in propionate production. The lower production of propionate, from salt infusions, may have occurred because of the washout of readily fermentable materials. Dry matter disappearance from feeds placed in dacron bags and suspended in the rumen was unaffected by infusion of mineral salts.     

Effects of potassium carbonate and sodium bicarbonate on rumen function in lactating Holstein cows

Twelve multiparous lactating Holstein cows were used to compare effects of 1) no buffer, 2) 1.5% sodium bicarbonate, 3) 1.25% potassium carbonate, or 4) 1.85% potassium carbonate in total diet on rumen environment and liquid turnover, dry matter intake and digestibility, milk yield and composition, and blood acid-base balance. Cows fed buffered diets had greater dry matter intake and greater digestibility of dry matter, acid detergent fiber, and neutral detergent fiber than controls. Rumen pH was higher in cows fed buffers than in controls 2 to 4 h postfeeding, but buffered diets were not different. Rumen volume, osmolality, and liquid turnover were unaffected by dietary treatment. Molar percentage of rumen acetate was greater, propionate was less, and acetate:propionate ratio was greater in cows fed 1.85% potassium carbonate compared with other treatments. There were no treatment effects on milk yield, although milk fat percentage tended to be greater in buffered diets. Blood acid-base balance was not altered. Cows fed diets containing potassium carbonate performed similarly to those fed sodium bicarbonate. No adverse effects of potassium carbonate on rumen function or environment were observed. Potassium carbonate is an acceptable buffer and serves as a potassium supplement.     

Volatile fatty acid metabolism by rumen mucosa from cattle fed hay or grain.

Effects of an all-grain versus an all-hay diet on metabolic activity of rumen mucosa of cattle were investigated. After diets had been fed for 3 to 4 mo, rumen papillae were collected at slaughter from the dorsal rumen sac and incubated with one of various volatile fatty acids. Rates of substrate utilization were in the order: n-butyrate greater than n-valerate approximately propionate greater than iso-butyrate approximately iso-valerate. Over-all, papillae from hay-fed steers utilized greater amounts of volatile fatty acids. Dietary treatment did not significantly affect extent of conversion of volatile fatty acids to lactate and to ketone bodies. Lactate was the major metabolite from propionate and n-valerate. Ketone body formation accounted for more than 90% of n-butyrate uptake by papillae. Ketone formation from n-valerate was restricted to beta-hydroxybutyrate while that from iso-valerate was essentially acetoacetate plus acetone. Metabolic systems in rumen mucosa of physiologically mature ruminants seem to adapt little to varying individual volatile fatty acids available for absorption in vivo.     

Tolerance of acetate,propionate and sorbate by Saccharomyces cerevisiae and Torulopsis holmii

Several strains of Saccharomyces cerevisiae and one of Torulopsis holmii were investigated with regard to their tolerance of acetate, propionate and sorbate. The S. cerevisiae strains had poor acetic acid tolerance in sour dough pH 4·3, the dough raising power decreasing on average by 67% in the presence of 0·34% sodium acetate, while T. holmii was not affected by this concentration. Propionate (0·16%) and sorbate (0·08%) were more inhibitory than acetate, inhibiting the dough raising power even in normal dough at pH 5·9. Torulopsis holmii also had a good tolerance of propionate and sorbate and seems suitable for raising sour doughs.     

Microbiological, Sensory and Chemical Characteristics of Vacuum-Packaged Ground Beef Patties Treated with Salts of Organic Acids

Vacuum-packaged ground beef patties containing sodium lactate (NaL), sodium propionate (NaP), sodium acetate (NaA) and sodium citrate (NaC) at various levels and combinations were stored up to 28 days at 4°C. Addition of sodium lactate alone or in combination with sodium propionate increased shelf life of the patties by decreasing microbiological growth and decreasing negative flavor notes associated with lipid oxidation. Lean color also was improved by addition of sodium lactate alone or in combination with sodium propionate. Lipid oxidation by TBA was only slightly affected by treatment addition or storage.     

Rumen volatile fatty acid molar proportions,rumen epithelial gene expression,and blood metabolite concentration responses to ruminally degradable starch and fiber supplies

The objective of this work was to characterize rumen volatile fatty acid (VFA) concentrations, rumen epithelial gene expression, and blood metabolite responses to diets with different starch and fiber sources. Six ruminally cannulated yearling Holstein heifers (body weight = 330 ± 11.3 kg) were arranged in a partially replicated Latin square experiment with 4 treatments consisting of different starch [barley (BAR) or corn (CRN)] and fiber [timothy hay (TH) or beet pulp (BP)] sources. Treatments were arranged as a 2 × 2 factorial. Beet pulp and TH were used to create relative changes in apparent ruminal fiber disappearance, whereas CRN and BAR were used to create relative changes in apparent ruminal starch disappearance. Each period consisted of 3 d of diet adaptation and 15 d of dietary treatment. In situ disappearance of fiber and starch were estimated from bags incubated in the rumen from d 10 to 14. From d 15 to 17, rumen fluid was collected every hour from 0500 to 2300 h. Rumen fluid samples were pooled by animal/period and analyzed for pH and VFA concentrations. On d 18, 60 to 80 papillae were biopsied from the epithelium and preserved for gene expression analysis. On d 18, one blood sample per heifer was collected from the coccygeal vessel. In situ ruminal starch disappearance rate (7.30 to 8.72%/h for BAR vs. 7.61 to 10.5%/h for CRN) and the extent of fiber disappearance (22.2 to 33.4% of DM for TH vs. 34.4 to 38.7% of DM for BP) were affected by starch and fiber source, respectively. Analysis of VFA molar proportions showed a shift from propionate to acetate, and valerate to isovalerate on TH diets compared with BP. Corn diets favored propionate over butyrate in comparison to BAR diets. Corn diets also had higher molar proportions of valerate. Expression of 1 gene (SLC9A3) were increased in BP diets and 2 genes (BDH1 and SLC16A4) tended to be increased in TH diets. Plasma acetate demonstrated a tendency for a starch by fiber interaction with BAR-BP diets having the highest plasma acetate, but other metabolites measured were not significant. These results suggest that TH has the greatest effect on shifts in VFA molar proportions and epithelial transporters, but does not demonstrate shifts in blood metabolite concentrations.     

Effects of sodium bicarbonate and sodium sesquicarbonate on animal performance, ruminal metabolism, and systemic acid-base status

Six rumen-fistulated lactating Holstein cows were arranged in a replicated 3 x 3 latin square design with 3-wk periods and offered diets containing concentrate and corn silage in a 60:40 ratio (DM basis). Treatments were: 1) basal diet, 2) basal diet with 1% NaHCO3, and 3) basal diet with 1% sodium sesquicarbonate. There were no differences among treatments in milk production, milk protein, or 3.5% FCM, but sodium sesquicarbonate increased milk fat percentage (3.89, 3.94, 4.06%) compared with that of the control. Rumen pH was higher for cows fed buffered diets than for control cows. Urine pH was higher for cows fed NaHCO3 diet than for those fed sodium sesquicarbonate and control diets. No differences were detected among treatment means for molar percentage of isobutyrate, isovalerate, or total VFA, Dietary sesquicarbonate addition increased molar percentage of acetate, decreased propionate, and resulted in a higher acetate:propionate ratio compared with the cows fed NaHCO3. However, molar percentage of butyrate and valerate decreased in cows fed sodium sesquicarbonate when compared with those fed the control diet. No differences among treatment means were detected for blood pH, pCO2, or HCO3.     

Effects of acetate,propionate, and pH on volatile fatty acid thermodynamics in continuous cultures of ruminal contents

To investigate the effects of acetate, propionate, and pH on thermodynamics of volatile fatty acids (VFA) in the rumen, a dual-flow continuous culture study was conducted to quantify production of major VFA, interconversions among the VFA, and H₂ and CH₄ emissions in a 4 × 4 Latin square design. The 4 treatments were (1) control: pH buffered to an average of 6.75; (2) control plus 20 mmol/d of infused acetate (InfAc); (3) control plus 7 mmol/d of infused propionate (InfPr); and (4) a 0.5-unit decline in pH elicited by adjustment of the buffer (LowpH). All fermentors were fed 40 g of a pelleted diet containing whole alfalfa pellets and concentrate mix pellets (50:50) once daily. After 7 d of treatment, sequential, continuous infusions of [2-¹³C] sodium acetate (3.5 mmol/d), [U-¹³C] sodium propionate (2.9 mmol/d), and [1-¹³C] sodium butyrate (0.22 mmol/d) were carried out from 12 h before feeding for 36 h. Filtered liquid effluent (4 mL) was sampled at 0, 2, 4, 6, 8, 12, 16, and 22 h after feeding, and assessed for VFA concentrations, with another filtered sample (20 mL) used to quantify aqueous concentrations of CH₄ and H₂. Headspace CH₄ and H₂ gases were monitored continuously. Ruminal microbes were isolated from the mixed effluent samples, and the microbial community structure was analyzed using the 16S rRNA amplicon sequencing technique. The digestibility of neutral detergent fiber, acid detergent fiber, and starch and microbial C sequestrated from VFA were not affected by treatments. The LowpH treatment increased net propionate production and decreased H₂ and CH₄ headspace emissions, primarily due to shifts in metabolic pathways of VFA formation, likely due to the observed changes in bacterial community structure. Significant interconversions occurred between acetate and butyrate, whereas interconversions of other VFA with propionate were relatively small. The InfAc and InfPr treatments increased net acetate and propionate production, respectively; however, interconversions among VFA were not affected by pH, acetate, or propionate treatments, suggesting that thermodynamics might not be a primary influencer of metabolic pathways used for VFA formation.     

Interactions of alfalfa hay and sodium propionate on dairy calf performance and rumen development

The objective of this experiment was to investigate the effects of different levels of alfalfa hay (AH) and sodium propionate (Pro) added to starter diets of Holstein calves on growth performance, rumen fermentation characteristics, and rumen development. Forty-two male Holstein calves (40 ± 2 kg of birth weight) were used in a complete randomized design with a 3 × 2 factorial arrangement of treatments. Dietary treatments were as follows: (1) control = concentrate only; (2) Pro = concentrate with 5% sodium propionate [dry matter (DM) basis]; (3) 5% AH = concentrate + 5% alfalfa hay (DM basis); (4) 5% AH + Pro = concentrate + 5% alfalfa hay + 5% sodium propionate (DM basis); (5) 10% AH = concentrate + 10% alfalfa hay (DM basis); and (6) 10% AH + Pro = concentrate + 10% alfalfa hay + 5% sodium propionate (DM basis). All calves were housed in individual pens bedded with sawdust until 10 wk of age. They were given ad libitum access to water and starter throughout the experiment and were fed 2 L of milk twice daily. Dry matter intake was recorded daily and body weight weekly. Calves from the control, 10% AH, and 10% AH + Pro treatments were euthanized after wk 10, and rumen wall samples were collected. Feeding of forage was found to increase overall dry matter intake, average daily gain, and final weight; supplementing sodium propionate had no effect on these parameters. Calves consuming forage had lower feed efficiency than those on the Pro diet. Rumen fluid in calves consuming forage had higher pH and greater concentrations of total volatile fatty acids and molar acetate. Morphometric parameters of the rumen wall substantiated the effect of AH supplementation, as plaque formation decreased macroscopically. Overall, the interaction between forage and sodium propionate did not affect calf performance parameters measured at the end of the experiment. Furthermore, inclusion of AH in starter diets positively enhanced the growth performance of male Holstein calves and influenced both the macroscopic and microscopic appearances of the rumen wall. These benefits, however, were small when only sodium propionate was offered.     

Effect on Feed Intake of Infusing Sodium Propionate or Sodium Acetate into a Mesenteric Vein of Cattle

Solutions containing sodium propionate or sodium acetate were infused into a mesenteric vein of eight steers in order to examine the effect of increasing the entry rate of these metabolites on feed intake. Infusion of propionate inhibited feed intake to varying degrees, but acetate infused at equivalent rates had no effect. Rate of entry of propionate into the visceral circulation may be a physiological mechanism for controlling feed intake in cattle, but it is mainly effective when the animal has eaten close to its voluntary maximum intake.     

Effects of intraruminal administration of polyol to sheep

In-vitro incubations were used to study the effect of intraruminal administration of a mixture of the polyhydric alcohols, arabinitol, xylitol, galactitiol, mannitol and sorbitol, on fermentation pattern and the fate of the polyhydric alcohols. Incubations were carried out with rumen fluid taken from sheep before receiving polyol and after 2 and 3 weeks of intraruminal administration of 2.12 g polyol DM/kg live wt.^0.75 per day to observe effects of adaptation. Inclusion of polyol in incubations with unadapted rumen fluid had little effect on the volatile fatty acid pattern. However, with adaptation there was a shift in the fermentation pattern in the presence of polyol towards a higher acetate: propionate ratio. The hexitols rapidly disappeared in all the incubations, while the pentitols were more resistant to fermentation. Significantly faster fermentation of arabinitol by rumen fluid from sheep which had received polyol indicated that adaptation had taken place. In the incubations with adapted microbes, xylitol was significantly more resistant to fermentation than arabinitol; after 6 h incubation, approximately half the xylitol and only one fifth of the arabinitol remained unfermented. Analysis of duodenal digesta from adapted sheep which were receiving polyol showed that most of the small amount of pentitol which entered the small intestine did so within 2–3 h of dosing. Despite the apparent resistance of pentitols to rumen fermentation, only 1.0% of the arabinitol and 1.8% of the xylitol in the daily dose entered the small intestine.     

Influence of sodium bicarbonate on growth and health of young calves

Fifty-four Holstein and Jersey calves were assigned at 4 days of age within breed and sex to one of four treatments: control consisting of colostrum, milk replacer, and starter; buffered colostrum and replacer (.6% sodium bicarbonate) and starter (2% sodium bicarbonate); acidified colostrum (1% propionic), untreated replacer, and starter; and acidified, buffered colostrum (1% propionic, .6% sodium bicarbonate), buffered replacer (.6% sodium bicarbonate), and starter (2% sodium bicarbonate). The feeding regimen was colostrum once daily, day 4 to 14; milk replacer once daily, day 15 to 28; and calf starter ad libitum, day 4 to 84. Bull calves were fed for 42 days and heifers for 84 days. Calves fed acidified colostrum refused more feed and were less efficient from day 4 to 14 than calves fed buffered colostrum. Bulls were more sensitive to acidified colostrum than heifers. Starter intake, total dry matter intake, and average daily gains were similar for all calves during days 4 to 84. Rumen fluid from calves fed diets with sodium bicarbonate was higher in acetate and lower in propionate and lactate than that from calves fed diets without sodium bicarbonate. Sodium bicarbonate improved intake of acidified colostrum during the first 2 or 3 days of feeding but had no other effect on gain or feed intake.     

Counteractive effects of propionate or 1,2-propanediol against hypoglycemia and ketonemia of tributyrin-treated cows

We administered tributyrin (500 ml), tributyrin (500 ml) plus magnesium propionate (400 g), tributyrin (500 ml) plus sodium propionate (400 g), or tributyrin (500 ml) plus 1,2-propanediol (400 ml) as a single dose into rumens of lactating cows and then measured in blood the plasma concentrations of glucose, acetoacetate, 3-hydroxybutyrate, free fatty acids, and insulin as a function of time. Tributyrin administration caused hypoglycemia and hyperketonemia similar to the ketotic condition in less than 3 h and was a negative correlation of --.88 between glucose and ketone concentrations in blood plasma. Administration of either magnesium propionate, sodium propionate, or 1,2-propanediol could counteract the hypoglycemia and hyperketonemia induced by tributyrin administration without significantly changing the insulin response. Of the two propionate compounds, magnesium propionate was more effective than sodium propionate for alleviating hypoglycemia and hyperketonemia.