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PubMed2006

Effect of amount and ruminal degradability of soybean meal protein on performance of lactating dairy cows.

Twenty-eight Holstein cows (4 with ruminal cannulas) were blocked by days in milk into 7 groups and then randomly assigned to 1 of 7 balanced 4 x 4 Latin square diet sequences. The diets contained [dry matter (DM) basis] 20% alfalfa silage, 35% corn silage, and 45% concentrate mainly from high-moisture corn and soybean meal. Diets differed in crude protein (CP) content and source of protein supplement: diet A) 15.6% CP, 3.7% solvent-extracted soybean meal (SSBM), 4.5% expeller soybean meal (ESBM); diet B) 16.6% CP, 9.6% SSBM, 0% ESBM; diet C) 16.6% CP, 4.6% SSBM, 5.9% ESBM; and diet D) 17.6% CP, 11.7% SSBM, 0% ESBM. Each experimental period consisted of 14 d for adaptation plus 14 d for collection of production data. Sampling of ruminal digesta and spot sampling of blood, feces, and urine was done on d 26 and 27 of each period. Planned contrasts compared included diet A vs. diet B, diet B vs. diet C, and diet B vs. diet D. There were no effects of diet on most of the production traits measured. However, milk yield tended to be higher for diet B vs. A. Trends were also detected for higher DM intake and weight gain and lower milk yield/DM intake in cows fed diet D vs. diet B. Milk lactose content was higher on diets A and C than on B. Ruminal NH3 was higher on diet D vs. B, but other ruminal metabolites, apparent nutrient digestibility, and estimated bacterial CP synthesis did not differ across diets. Blood and milk urea-N were higher on diets C and D than on B; milk urea-N was higher on diet B than on A. Increasing dietary CP from 16.6% (diet B) to 17.6% (diet D) increased urinary N excretion by 54 g/d and reduced apparent N efficiency (milk N/N intake) by 2.5 percentage units, without altering yield. Under the conditions of this trial, milk production was not improved by feeding rumen-undegraded protein from ESBM or greater amounts of rumen-degraded protein from SSBM. Feeding more than 16.6% CP depressed N efficiency.

Allantoin↗
PubMed2006

Effect of dietary crude protein concentration on ruminal nitrogen metabolism in lactating dairy cows.

Ten lactating Holstein cows fitted with ruminal cannulas that were part of a larger feeding trial were blocked by days in milk into 2 groups and then randomly assigned to 1 of 2 incomplete 5 x 5 Latin squares. Diets contained [dry matter (DM) basis] 25% alfalfa silage, 25% corn silage, and 50% concentrate. Rolled high-moisture shelled corn was replaced with solvent-extracted soybean meal to increase crude protein (CP) from 13.5% to 15.0, 16.5, 17.9, and 19.4% of DM. Each of the 4 experimental periods lasted 28 d with data and sample collection performed during the last 8 d. Digesta samples were collected from the omasum to quantify the ruminal outflow of different N fractions. Intake of DM was not affected but showed a quadratic trend with maxima of 23.9 kg/d at 16.5% CP. Ruminal outflow of total bacterial nonammonia N (NAN) was not different among diets but a significant linear effect of dietary CP was detected for this variable. Bacterial efficiency (g of total bacterial NAN flow/kg of organic matter truly digested in the rumen) and omasal flows of dietary NAN and total NAN also showed positive linear responses to dietary CP. Total NAN flow increased from 574 g/d at 13.5% CP to 688 g/d at 16.5% CP but did not increase further with the feeding of more CP. Under the conditions of this study, 16.5% of dietary CP appeared to be sufficient for maximal ruminal outflow of total bacterial NAN and total NAN.

Animals↗
PubMed1980

Automated simultaneous determination of ammonia and total amino acids in ruminal fluid and in vitro media.

Catalyzed phenol-hypochlorite and ninhydrin colorimetric procedures were adapted to the Technicon AutoAnalyzer for simultaneous determination of ammonia and total amino acids in ruminal fluid or ruminal in vitro media. The manifold developed was compatible with a sampling rate of 40/h without significant sample-to-sample carryover. With proper storage, reagents for both the phenol-hypochlorite and the air-stable ninhydrin systems were stable for 8 mo or more. Response of individual amino acids in the phenol-hypochlorite system were generally 1% or less than equimolar amounts of ammonia. Certain amino acids inhibited ammonia color yield 10 to 15% when with equimolar amounts of ammonia; however, the inhibitory effect of casein amino acids was only 2 to 3%. Although ninhydrin response, relative to leucine, of individual alpha-amino acids ranged from 62 (valine) to 151% (histidine), recoveries of casein amino acids from ruminal fluid had coefficients of variation of 1% or less. Coefficients of variation for ammonia recoveries from ruminal fluid by the phenol-hypochlorite procedure were about half of those for the Conway microdiffusion technique. Intraclass correlations for the adapted procedures indicated high degrees of accuracy and precision for both ammonia and amino acid analyses.

Amino Acids↗
PubMed1983

Prospects for development and use of recombinant deoxyribonucleic acid techniques with ruminal bacteria.

Over the last decade, developments in recombinant deoxyribonucleic acid techniques and molecular biology have revolutionized bacterial genetics, creating vast, new potential uses of bacteria (as well as animal and plant cells) that were not even considered previously. Bacterial production of hormones is but one example. With bacterial species with well developed genetic systems, such as Escherichia coli, it is now possible genetically to "design" or "engineer" bacterial strains having specific characteristics. One reasonable future approach toward improvement of animal agriculture would be manipulation of the rumen ecosystem via the use of genetically modified ruminal bacteria, but significant obstacles exist with this approach. Genetic systems of ruminal and of anaerobic bacteria of the mammalian gastrointestinal tract, in general, have not been studied and are largely unknown. In this paper, the various criteria for possible establishment of recombinant deoxyribonucleic acid systems in ruminal bacteria are outlined. Secondly, applications for utilizing genetically engineered ruminal bacteria to control digestion of specific feedstuffs, to regulate specific fermentation products, and to control growth of specific bacterial species are discussed.

Anaerobiosis↗
PubMed1984

Toxicology of sulfur in ruminants: review.

This review deals with the toxicology of sulfur in ruminants including toxicity, neurotoxic effects, and mechanism of toxic action of hydrogen sulfide, clinical signs, and treatment. It will report effects of excessive intake of sulfur by ruminants on feed intake, animal performance, ruminal digestion and motility, rumination, and other physiological functions. Poisoning of animals with sulfur from industrial emissions (sulfur dioxide) also is discussed. Excessive quantities of dietary sulfur (above .3 to .4%) as sulfate or elemental sulfur may cause toxic effects and in extreme cases can be fatal. The means is discussed whereby consumption of excessive amounts of sulfur leads to toxic effects.

Animal Feed↗
PubMed1985

Lactogenic hormones: binding sites, mammary growth, secretory cell differentiation, and milk biosynthesis in ruminants.

Roles of the lactogenic hormones prolactin and placental lactogen in mammary development in ruminants were reviewed. In contrast with other ruminants, failure to detect lactogenic activity in the serum of pregnant cows (in excess of that attributed to prolactin) suggests that placental lactogen may have little direct effect on mammary growth or lactogenesis. However, replacement and ablation experiments using ergocryptine provide definitive evidence that increased periparturient secretion of prolactin is necessary for maximal milk production in cattle. Quantitative microscopy indicates a relative failure of mammary cells in cows with inhibited secretion of prolactin to differentiate structurally. Prolactin induces synthesis and secretion of alpha-lactalbumin in prepartum bovine mammary tissue. Temporary disruption of mammary microtubules immediately prepartum in pregnant heifers reduced subsequent milk production, biosynthetic capacity, and cellular differentiation. For maximal milk production, mammary secretory cells apparently must respond to lactogenic hormone stimulation during the immediate periparturient period. Colchicine may desensitize the mammary epithelium to prolactin action. Membrane binding of radiolabeled human growth hormone to ruminant mammary gland provides a measure of lactogenic hormone binding sites. Specific binding to 600 micrograms of mammary membrane protein was 296% greater in lactating, compared with nonlactating, pregnant (65 days of gestation) ewes. Binding capacity (fmol/mg membrane protein) averaged 275 +/- 57 in mammary membranes from nonlactating, pregnant ewes (100 days gestation, n = 2) and 2,325 +/- 521 in mammary membranes from lactating ewes (n = 6, 14 to 21 days postpartum). Greater understanding of hormonal regulation of the ruminant mammary gland likely will result in development of techniques to produce milk more efficiently and perhaps capability to evaluate production potential of young animals.

Animals↗
PubMed1986

Ruminal degradation of dried brewers grains, wet brewers grains, and soybean meal.

A series of trials was conducted to determine the ruminal degradation of nitrogenous compounds and dry matter of soybean meal, wet brewers grains, and dried brewers grains. In situ and in vitro estimates of degradation were positively correlated but yielded different absolute values for measures of ruminal degradation. Ruminal digestion of protein, predicted from in situ data, was 42, 73, and 83% for brewers dried grains, brewers wet grains, and soybean meal. Drying of wet grains at either 50 or 150 degrees C increased resistance to ruminal digestion equally. Measurements of flow of dry matter and nitrogen of feed origin to the duodenum were made in vivo for diets containing either brewers dried grains or soybean meal. Negative apparent digestibility of nitrogen in the rumen for a 13% crude protein, brewers dried grains ration indicates the potential for using a non-protein nitrogen supplement with this ration. Resistance to digestion of nitrogen from brewers dried grains occurred only in the rumen. Amino acid patterns delivered to the small intestine and digestion of duodenal contents were similar for diets containing brewers dried grains or soybean meal.

Animal Feed↗
PubMed1987

Effect of orally administered pilocarpine on ruminal characteristics and nutrient digestibility in cattle.

Four barren Holstein cows weighing 637 kg were fed a 45% concentrate diet plus the following amounts of pilocarpine: 1) 0 mg/kg; 2) 1 mg/kg; 3) 2 mg/kg; 4) 4 mg/kg body weight in a 4 X 4 Latin square design. Cows were administered the treatments for a 14-d adaptation period followed by an 8-d collection period. Digestibility of dry matter, crude protein, cellulose, and hemicellulose were determined during the first 3 d of the collection period. Ruminal liquid volume, volatile fatty acids, NH3N, bacterial mass production, viable bacteria, cellulolytic bacteria, liquid dilution rate, and particulate rate of passage were measured during the remainder of the collection period. As pilocarpine increased from 0 to 4 mg/kg body weight, digestibility of dry matter and cellulose increased by 8.5%. Digestibility of crude protein increased by 6.1%. Digestibility of hemicellulose was unchanged. Ruminal liquid volume was unchanged by treatment, whereas liquid dilution rate and particulate rate of passage increased 30% as pilocarpine increased. Ruminal volatile fatty acid concentrations and proportion were unchanged by treatment. Ruminal pH increased 4.2% and NH3N decreased by 37% as pilocarpine increased. Percent cellulolytic and bacterial mass production tended to increase as pilocarpine increased.

Animals↗
PubMed1987

Effects of feed intake and dietary urea concentration on ruminal dilution rate and efficiency of bacterial growth in steers.

Four multiple-fistulated steers (340 kg) were fed a diet containing 50% ground grass hay, 20% dry distillers grains, and 30% concentrate at two intakes (7.2 or 4.8 kg DM/d). Urea (.4 or 1.2% of the diet) was infused continuously into the steers' rumens. The experimental design was a 4 X 4 Latin square with a 2 X 2 factorial arrangement of treatments. Infusing urea at .4 or 1.2% of the diet resulted in ruminal NH3 N concentrations of 4.97 and 9.10 mg/dl, respectively. Feeding steers at high rather than low intake decreased ruminal and total tract digestibilities of organic matter, NDF, and ADF but did not increase ruminal escape of N. However, apparent N escape from the rumen calculated using purines, but not 15N, as a bacterial marker was higher when 1.2 vs. .4% urea was infused. Feeding at high rather than at low intake increased the total pool of viable bacteria per gram organic matter fermented in the rumen. Although ruminal fluid outflows and particulate dilution rates were greater when steers were fed at high than at low intakes, efficiencies of bacterial protein synthesis were unaffected by intake. The possibility of increased N recycling within the rumen with feeding at the higher intake is discussed.

Animal Feed↗
PubMed1988

Effects of niacin and whole cottonseed on ruminal fermentation, protein degradability, and nutrient digestibility.

Four mature nonlactating Holstein heifers fitted with ruminal and duodenal cannulae were used to investigate in vivo effects of niacin and whole cottonseed. Each heifer was assigned randomly to a treatment in a 2 X 2 factorial arrangement of treatment sequences within a 4 X 4 Latin square design. Heifers were fed isonitrogenous complete mixed rations individually twice daily. Diets contained corn-soybean meal concentrate, corn silage, chopped coastal bermudagrass hay, plus 1) 0% niacin and 0% whole cottonseed, 2) 0% niacin and 15% whole cottonseed, 3) .07% niacin and 0% whole cottonseed, or 4) .07% niacin and 15% whole cottonseed. Dry matter consumption, ruminal pH, ruminal ammonia and VFA concentrations, microbial N production, and DM and ADF digestion were not affected by treatment. Numbers of ruminal protozoa and RNA concentrations were reduced with whole cottonseed feeding and increased by addition of niacin. Whole cottonseed increased molar percentages of acetate while depressing propionate. Niacin supplementation resulted in greater digestion of both CP and NDF. Ether extract digestibility was highest in heifers fed whole cottonseed. Fiber digestion was not affected by whole cottonseed feeding.

Animals↗
PubMed1988

Effects of a new multielement buffer on production, ruminal environment, and blood minerals of lactating dairy cows.

Twelve multiparous Holstein cows were used to evaluate the capacity of a multielement compound consisting mainly of northupite and sylvite to alleviate low milk fat percent. Possible mechanisms of action were assessed. Cows were arranged in a 4 X 4 Latin square design replicated three times. Basal diet was 55% concentrate:45% forage fed ad libitum. Dietary treatments were control, NaHCO3 at 1% of diet DM, and multielement buffer at 1 and 3% of diet DM. Feed intake and milk production were similar for all treatments. Milk fat percentages for the four treatments were 2.97, 3.21, 3.43, and 3.67%, respectively. A shift toward a higher molar percent of ruminal acetate and a lower molar percent of valerate appeared to coincide with changes in milk fat percentage. Milk protein percentage also was increased by supplemental multielement buffer. Ruminal fluid acidity was reduced by NaHCO3 and multielement buffer. Extent of in situ digestion of forage DM and cellulose was improved when cows consumed a buffering agent. Rate of corn silage digestion tended toward improvement. As mineral buffer was consumed, concentrations of Mg and K increased in ruminal fluid and blood. As dietary Na intake increased, ruminal and plasma Cl concentrations were depressed and plasma S and Ca were elevated.

Animals↗
PubMed1989

Effect of particle size of alfalfa hay on intake, digestibility, milk yield, and ruminal cell wall of dairy cattle.

Alfalfa hay was chopped in a tubgrinder containing screens with apertures of 31, 63, or 100 mm. The hays were fed with concentrate to lactating cows (Experiment 1) and without concentrate to nonlactating, fistulated cows (Experiment 2). The objective was to find effects of forage particle size upon intake, digestibility, milk yield, and ruminal cell wall. In Experiment 1, there were no significant effects of forage particle size upon forage or total DM intake, digestibility of NDF, cellulose, nitrogen retained, milk yield, or milk fat percent. Digestibility of DM, ADF, and protein increased as particle size decreased. In Experiment 2, forage DM intake was greater for the 63 than the 100-mm forage but digestibility of cell wall and DM were not different among treatments. Ruminal volume for the 31 and 63-mm forages was greater than the 100-mm forage. Ruminal DM and ruminal cell wall were greater for the 63-mm forage than the 100-mm forage, with the 31-mm forage in between. Increased volume, DM, and cell wall probably account for increased intake of the 63-mm forage. Chopping alfalfa to these three sizes had no particularly positive or negative effects on animal productivity.

Animal Feed↗
PubMed1990

Effects of feeding fungal culture extract and animal-vegetable fat on degradation of hemicellulose and on ruminal bacterial growth in heifers.

Four Holstein heifers cannulated in the rumen and proximal duodenum were used to analyze effects of Aspergillus oryzae fermentation extract and yeast culture (Amaferm Micro-Mix. Biozyme Enterprises, Inc., St. Joseph, MO) and 5% animal-vegetable fat on ruminal and total tract digestibilities of nutrients. Heifers were assigned treatments in a 4 x 4 Latin square design with a 2 x 2 factorial arrangement of treatments. Few interactions between main effects were noted. Feeding fat decreased ruminal molar ratio of acetate:propionate. Rate of disappearance of potentially digestible NDF from orchardgrass hay was higher when heifers were fed fat. Thus, the lack of differences in digestibilities of NDF, ADF, or in the major hemicellulosic sugars is interpreted to suggest that 5% animal-vegetable fat had few toxic effects on ruminal microbes under the conditions of this study. Amaferm Micro-Mix tended to increase acetate:propionate in the rumen, but had little effect on site or extent of digestion of any of the fiber components measured. Efficiency of bacterial protein synthesis was not affected by treatment. Ruminal and total tract digestibilities of total hemicellulosic sugars were highly correlated (r = .82 and .72) with respective digestibilities of hemicellulose measured as NDF minus ADF.

Animal Feed↗
PubMed1990

Effects of feeding frequency on ruminal parameters, plasma insulin, milk yield, and milk composition in Holstein cows.

Two experiments were conducted to determine the effects of frequency of feeding on ruminal fermentation, blood parameters, milk yield, and milk composition in cows fed a 60% pelleted concentrate and 40% chopped alfalfa hay (DM basis) diet. In Experiment 1, four ruminally cannulated cows were fed concentrates in 12 equal portions at 2-h intervals or in two equal portions at 0500 and 1500 h in a crossover design. In Experiment 2, treatments were as in Experiment 1 plus an additional treatment consisting of a total mixed diet fed at 2-h intervals in a 3 x 3 Latin square design. All treatment periods were 2 wk. In Experiment 1, increased frequency of concentrate feeding tended to result in elevated ruminal pH and increased acetate to propionate ratio. Plasma insulin concentration tended to be higher (1.54 vs. 1.04 ng/ml) and milk fat percentage increased from 2.21 to 2.60% for 2 and 12 times daily feeding, respectively. In Experiment 2, frequency of feeding concentrate or total mixed diet did not affect ruminal and blood parameters or milk yield. In both experiments, milk protein and lactose concentrations were not influenced by feeding frequency. Results suggest that where intake is kept constant, increased feeding frequency will not influence milk yield but could result in elevated milk fat percent in animals fed fat-depressing diets.

Animals↗
PubMed1990

Nutrient digestion, ruminal fermentation and plasma lipids in steers fed combinations of hydrogenated fat and lecithin.

Commercial soybean lecithin replaced hydrogenated fat in steer diets to determine if phospholipids enhance fatty acid digestion and microbial fermentation in ruminants. Four diets were fed in a 4 x 4 Latin square to four Angus steers with ruminal cannula. One diet contained no added fat (control) and three contained hydrogenated fat and lecithin in weight ratios of 100:0, 86:14, and 72:28. All diets with added fat had lower fatty acid digestibilities compared with the control diet with no difference due to level of lecithin. Ruminal acetate and acetate:propionate ratios were reduced by all fat supplements but reduced less for the supplements containing lecithin. Plasma triglyceride and cholesterol concentrations were increased from dietary fat but not increased as much if lecithin were present in the diet. Feeding lecithin to ruminants does not improve digestibility of hydrogenated fats that are highly saturated.

Animals↗
PubMed1990

Effects of source and amount of protein on ruminal fermentation and passage of nutrients to the small intestine of lactating cows.

Four Holstein cows fitted with ruminal and duodenal cannulas were used in a 4 x 4 Latin square to investigate the effects of source (corn gluten meal or soybean meal) and amount (14.5 or 11.0%) of CP on ruminal fermentation, passage of nutrients to the small intestine, and animal performance. Cows wee fed for ad libitum intake a diet of 60% corn silage and 40% concentrate on a DM basis. The treatments, arranged in a 2 x 2 (source x amount of CP) factorial, were 1) 14.5% CP, soybean meal; 2) 11.0% CP, soybean meal; 3) 14.5% CP, corn gluten meal; and 4) 11.0% CP, corn gluten meal. Digestion in the rumen of OM, starch, ADF, and NDF was not affected by source or amount of CP in the diet. Total VFA and NH3 concentrations in ruminal fluid were increased by feeding diets that contained 14.5% CP or soybean meal. FLows of non-NH3 N and amino acids to the duodenum were greater in cows fed the 14.5% CP diets because of a greater flow of non-NH3 nonmicrobial N to the duodenum. Larger amounts of lysine passed to the duodenum when cows were fed soybean meal compared with corn gluten meal. Microbial N flow to the duodenum and efficiency of microbial growth were not affected by treatments, suggesting that ruminal NH3 concentration was not limiting for maximal microbial protein synthesis. Feeding 14.5% CP diets increased the production of milk (29.5 vs. 26.8 kg/d) and milk protein compared with 11.0% CP diets, possibly because of greater passage of amino acids to the small intestine. Feeding soybean meal to cows increased production of milk protein compared with feeding corn gluten meal, possibly because more lysine passed to the small intestine.

Amino Acids↗
PubMed1990

Effects of feed processing and frequency of feeding on ruminal fermentation, milk production, and milk composition.

Twenty Holstein cows, averaging 108 d postpartum, were used in five replicated 4 x 4 Latin squares to investigate the effects of feed processing and frequency of feeding on ruminal fermentation, milk production, and milk composition. Four rumen-fistulated cows were used in one of the replicates to monitor ruminal fermentation. Each cow was fed for ad libitum intake a diet of 55% alfalfa and 45% concentrate on a DM basis. Treatments were 1) noncubed diet fed two times daily, 2) noncubed diet fed four times daily, 3) cubed diet fed two times daily, and 4) cubed diet fed four times daily. Alfalfa was fed as long hay in the noncubed diet and chopped and pressed into a cube in the cubed diet. Dry matter intake by cows was not different between treatment comparisons. However, cows fed the noncubed diet consumed 5% more concentrate and 5% less alfalfa than did cows fed the cubed diet. Milk production was greater (1.4 kg/d) when the cubed diet was fed to cows, but the percentage and yield of milk fat were depressed (.43 percentage units and .09 kg/d), causing a decreased production of 4% FCM (.9 kg/d). The depression in milk fat percentage and yield may have been attributed to lowered ruminal fluid pH and a decreased ratio of acetate to propionate in cows consuming the cubed diet. Even though ruminal fluid pH and the ratio of ratio of acetate to propionate tended to be lower when cows were fed four times rather than two times per day, production and composition of milk were not affected by frequency of feeding the diets.

Animal Feed↗
PubMed1991

Ruminal digestion and microbial utilization of diets varying in type of carbohydrate and protein.

Three ruminally and duodenally cannulated, lactating Holstein cows were used in a 3 x 3 Latin square experiment to study the effects of differing levels of nonstructural carbohydrate and degradable intake protein on ruminal digestibility and microbial protein production. Three diets were formulated to contain 1) 38 and 13.2%, 2) 31 and 11.8%, and 3) 24 and 9% nonstructural carbohydrate and degradable intake protein as percentages of the DM, respectively. Dry matter intakes were similar for all diets (21.9, 21.1, and 18.3 kg/d for diets 1, 2, and 3, respectively). Likewise, microbial efficiency, as estimated from purine analysis, was unaffected by diet and averaged 24 g of microbial N/kg of OM digested for all treatments. Ruminal digestion of OM averaged 66.6, 65.1, and 55.7% for diets 1, 2, and 3, respectively, resulting in lower microbial N flow per day for diet 3 (317, 333, and 202 g, respectively). Digestion of nonstructural carbohydrate and CP followed similar trends as did OM digestion, whereas NDF digestion remained similar across all diets. These results indicate that nonstructural carbohydrate greater than 24% and ruminally degradable protein greater than 9% of DM will enhance microbial protein flow from the rumen.

Animal Feed↗