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Biomedical subjects

R A Erdman

Publications and source records attributed to R A Erdman.

At least 109 records · Page 6Linked to original sources
PubMed1989

Effects of dietary and abomasally infused choline on milk production responses of lactating dairy cows.

Three experiments investigated the effects of exogenous choline on milk production responses of dairy cows. Ruminally fistulated Holstein cows were fed total mixed diets containing 30% corn silage and 70% corn/soybean meal-based concentrate in experiment 1, or 40% corn silage and 60% concentrate in experiments 2 and 3. In experiment 1, the effects of unsupplemented (control), dietary supplemented choline (50 g/d) and abomasally infused choline (50 g/d) were examined using three first-lactation cows in a 3 X 3 Latin square design. While dietary added choline had no effect, abomasally infused choline increased daily milk and 4% fat-corrected milk yield 3.2 and 3.8 kg/d respectively. In experiment 2, effect of daily abomasal infusion of 0, 30, 60 and 90 g choline were studied using four mature cows in a 4 X 4 Latin square design. Fat-corrected milk and milk fat percent were 2.6 kg/d and 0.59 percentage units higher for cows infused with 30 g/d choline than for unsupplemented controls, with 60 and 90 g/d choline infusions showing smaller effects. In experiment 3, daily abomasal infusion of 0 or 40 g choline were studied using four mature cows in a switchback design. Choline infusion (40 g/d) increased daily milk 1.6 kg/d over control while having no effect on milk composition or feed intake. Results of these experiments suggest a possible requirement for supplementing choline in lactating dairy cows.

Abomasum↗
PubMed1989

Probability of a return to work after either coronary balloon dilatation or coronary bypass surgery.

To examine whether coronary angioplasty has a different effect on work resumption than has coronary artery bypass surgery, we studied the work status of patients before and at least 1 year after either intervention. The population consisted of men aged less than 60 years, submitted to these procedures from September 1983 to July 1984. Of the 261 eligible patients, 219 (84%) participated, 94 after an angioplasty and 125 after a bypass procedure. 6 months preceding the intervention, 52% of the men were working. This had decreased to 47% at follow-up. Multiple logistic regression analysis showed that failure to resume work was correlated with bypass surgery vs balloon dilatation (rate ratio 1.8; 95% CI, 1.0-3.4), not working beforehand (rate ratio 6.5; 1.2-4.3), age greater than 55 years vs less than or equal to 50 years (rate ratio 2.6; 1.3-5.4) and with angina at follow-up (rate ratio 1.8; 1.0-3.3). Taking these additional risk factors into account permits a prediction of the probability of a return to work.

Angina Pectoris↗
PubMed1989

Prediction of physical indisposition with the help of a questionnaire for measuring denial and overcompensation.

A questionnaire for assessing feelings of 'weakness' (the feeling of resentment, dependency, anxiety and vital exhaustion) as well as aggression and activity was presented to two groups of healthy men (n = 202 and 178, respectively). One group underwent self-evaluation by means of questionnaires and an interview. In the other group self-evaluation and evaluation by the partner were measured using questionnaires during two assessments with an interval of 6 months. The construct validity of the scales corresponded to that of an earlier study on acute myocardial infarct (AMI) patients. The reliability (internal consistency) of the scales was less satisfactory compared to the study on AMI patients. The congruent validity of the scales measuring experience of weakness appeared to be good. The method of score comparison for assessing denial of weakness and overcompensation (by means of aggression and activity) turned out to be reasonably valid, at least for the scales measuring weakness. Analysis of the predictive value of the derived scores for denial and overcompensation led to the finding that the men who reported more physical complaints 6 months after completion of the defence list had a higher mean denial score than the men who reported fewer somatic complaints after 6 months. This confirms the hypothesis that denial of one's own emotional condition in the long run leads to an increase in (reporting) somatic complaints.

Adult↗
PubMed1989

In vitro degradation of choline from selected feedstuffs and choline supplements.

The objective of this experiment was to determine the extent of in vitro degradation of choline from barley, corn, corn gluten meal, cottonseed meal, fish meal, soybean meal, alfalfa hay, timothy hay, choline chloride, and choline stearate. During four individual fermentation runs, samples were incubated in vitro for .25, 1, 3, 6, 12, 18, 24, 36, and 48 h with an inoculum mixture containing rumen fluid obtained from a rumen-fistulated dairy cow fed 17.5% corn silage and 28.7% grass silage and 53.8% concentrate diet. Because of their low choline content (less than .68 mg/g) corn, corn gluten meal, alfalfa hay, and timothy hay gave erratic values for choline disappearance for different fermentation runs and times of incubation although disappearance tended to increase with time. Data for the rest of the feeds and choline supplements were analyzed using nonlinear regression procedure to obtain estimates of potentially degradable choline, rapidly degradable choline, and the rate of choline degradation in vitro. The mean estimates of rumen degradable choline (%) were 79.4, 84.7, 82.9, 83.8, 98.0, and 98.6 for barley, cottonseed meal, fish meal, soybean meal, choline stearate, and choline chloride, respectively. The results suggest that incorporating choline-rich feedstuffs in diets can only marginally increase the postruminal flow of choline in dairy cows.

Animal Feed↗
PubMed1988

Dietary choline effects on milk yield and duodenal choline flow in dairy cattle.

In Experiment 1, the effect, in early lactation, of 0 or 3 g of supplemental choline/kg of total diet DM on milk yield and composition was tested in 20 first lactation and older Holstein cows. In Experiment 2, 30 first lactation and older Holstein cows between 45 and 200 d postpartum were assigned to treatments of 0, 2.5, and 5.0 g of supplemental choline/kg of total diet DM to test the effect of dietary choline with diets based on corn and soybean meal. In Experiments 1 and 2, added choline had no effect on either milk yield or fat-corrected milk yield. In both experiments, fat yield and fat percentage tended to increase with choline supplementation, but protein yield and protein percentage were unaffected. In Experiment 1, choline had no effect on serum lipids. Ruminal dosing of steers with 27 g/d supplemental choline in Experiment 3 increased duodenal choline flow by only 3 g/d. The apparent rumen degradability of choline tended to be higher (77.1 vs. 70.6%) in the supplemented steers. Choline concentration in rumen fluid and duodenal chyme were higher in the supplemented steers. Choline supplementation in Experiments 1 and 3 had no effect on rumen VFA or rumen pH. Dietary choline supplementation apparently is ineffective because of rapid degradation of choline in the rumen.

Animals↗
PubMed1988

Effects of limestone on starch digestion in Holstein steers.

Eight calcitic and three dolomitic limestones were examined for particle size and reactivity with hydrochloric acid at pH 3.5 and 5.5. Reactivity was higher in calcitic than dolomitic limestone. Within calcitic limestones, reactivity was highly related to particle size. A highly reactive limestone was selected for use in two digestion trials with Holstein steers. In Trial 1, 4 steers (approximately 300 kg) were fed diets consisting of 40% corn silage and 60% concentrate (DM basis) with .62 or 2.34% limestone in a single reversal trial with 3-wk experimental periods. Added limestone affected only starch digestibility, which increased from 91.3 to 93.2%. Fecal pH increased from 5.7 to 6.4 by limestone addition. In trial 2, four rumen and duodenally cannulated steers (approximately 475 kg) were fed the same diets in the same design. Limestone addition increased fecal pH from 5.7 to 6.5. There were no effects of limestone on rumen or total tract digestion of starch or other nutrients. Limestone addition had no effect on rumen pH, buffering capacity, or VFA concentrations. Addition of a highly reactive limestone to diets containing high amounts of starch had little effect on starch digestion in either the rumen or lower gastrointestinal tract.

Animals↗
PubMed1987

Denial and overcompensation in male patients with myocardial infarction. An explorative study of the measurement of defense mechanisms by interpersonal comparison.

In psychoanalytic literature it is asserted that in patients with acute myocardial infarction (AMI) the period prior to the infarction is characterized by denial of resentment, dependency, anxiety and vital exhaustion. AMI patients overcompensate these characteristics by means of aggressive and active behavior. In the present study an instrument was constructed to measure these defense mechanisms. 122 male AMI patients and their partners completed a questionnaire for the purpose of judging the afore-mentioned characteristics in the AMI patients. The judgement related to the 3 months prior to the infarction. The study showed that the questionnaire was internally consistent (reliable) and valid. It was found that AMI patients saw themselves as having been less resentful, dependent, anxious and exhausted than their partners judged them to have been. The AMI patients did not judge themselves to have been more aggressive or active than their partners judged them to have been. The results indicate the potential usefulness of the method of comparing scores (patients vs. partners) in measuring defense mechanisms. Methodological problems and problems regarding the interpretation of scores are critically discussed.

Adult↗
PubMed1987

Simultaneous measures of rates of ruminal digestion and passage of feeds for prediction of ruminal nitrogen and dry matter digestion in lactating dairy cows.

Three ruminal-cannulated Holstein cows in early lactation were fed three diets, each containing different energy and protein supplements in two consecutive 3 X 3 Latin squares. Each supplement contained a combination of three different feedstuffs (ground corn, soybean meal and wheat mids; corn gluten feed, rolled oats and distiller's dried grains; ground barley, brewer's grains and cottonseed meal). Diets consisted of 30% corn silage, 10% alfalfa hay, 10% alfalfa haylage, 17.7% ground corn plus minerals and vitamins, with the remainder as supplemental feedstuffs individually marked for measurement of ruminal turnover and in situ digestion rates. An extra period at the end of each Latin square was used to measure ruminal turnover and in situ digestion of individual forages. Diet had no effect on dry matter intake or milk yield. Mean fractional turnover (per hour) rate, measured by labeling feedstuffs with cerium, samarium or lanthanum was .044, .048, .049, .043, .047, .046, .050, .047, .049, .037, .046 and .045 for corn, soybean meal, wheat mids, corn gluten feed, oats, distiller's dried grains with solubles, barley, brewer's dried grains, cottonseed meal, alfalfa hay, corn silage and alfalfa haylage (P greater than .1), respectively. In situ-predicted ruminal degradation of N weighted for rate of passage was 61.4, 67.0, 81.5, 74.8, 86.3, 71.0, 75.7, 52.1, 54.2, 60.8, 71.7 and 70.9% for respective feedstuffs (P less than .05). In comparison with mean literature values for in vivo-measured N degradability, mean literature value = 1.172 (in situ predicted) -9.73 (P less than .05, R2 = .51). Results are interpreted to indicate a tendency for overestimating ruminal N degradability by in situ methods in feedstuffs of low degradability, while underestimating degradability in more highly degraded feedstuffs. Estimates were 11 to 17 percentage units lower than literature values for alfalfa hay and haylage and 17 units lower than literature values for distiller's dried grains.

Animal Feed↗
PubMed1986

Effect of rumen ammonia concentration on in situ rate and extent of digestion of feedstuffs.

Three dry Holstein cows fitted with rumen fistula were fed a 7.4% crude protein diet consisting of 47.4% corn, 50% cottonseed hulls, and 2.6% minerals and vitamins during a 44-d experiment. Treatments consisted of rumen infusion, 0, 33, 67, and 100 g/d of urea nitrogen applied in a four period Youden Square design. Increasing urea infusion increased rumen fluid ammonia nitrogen from 4.3 to 25.0 mg/dl. Estimated effective dry matter degradation based on in situ rates of digestion were increased from 67.9 to 74.4% for corn and 77.5 to 80.3% for soybean meal with maximums at 100 g/d infused urea nitrogen. Up to 67 g/d infused nitrogen increased dry matter degradation of corn gluten feed from 67.0 to 71.4% and cottonseed meal dry matter degradation from 56.7 to 60.1%. Alfalfa hay dry matter and neutral detergent fiber degradation were not increased by urea infusion. Minimum rumen ammonia required in feeds in this trial were pooled with literature data and suggest that lowest ammonia concentrations required for maximal digestion was a function of the rumen fermentability of the diet or feed. The equation: minimum ammonia concentration (mg/dl) = .452 fermentability % - 15.71, accounted for 50% of the variation in minimum ammonia requirements. We conclude that rumen ammonia concentrations required for maximum digestion are not constant but rather are a function of fermentability of the diet.

Ammonia↗
PubMed1984

Dietary choline for the lactating cow: possible effects on milk fat synthesis.

Two experiments with low forage diets tested effects of added dietary choline on milk fat synthesis. In Experiment 1, 18 Holstein cows were in a 12-wk trial. Choline (0, 1.5, and 3 g/kg) was added to the concentrate portion of a 70% concentrate, 30% corn silage diet (dry matter). Treatments were applied in a switchback design with 4-wk experimental periods. Highest choline increased milk fat by .34 percentage units and fat-corrected milk by 2 kg per day over controls. Rumen pH and volatile fatty acids were similar among treatments. Free fatty acids of blood serum were reduced 3.0 mg/100 ml by 3 g/kg choline. In Experiment 2 with four mature Holsteins, choline was added (0, 2, 4, and 6 g/kg concentrate) in 25% corn silage and 75% concentrate diets. Treatments were applied in a 4 x 4 Latin square design. Addition of 4 g/kg choline resulted in 3.7 kg/day and .77 percentage unit increases of fat-corrected milk and milk fat percent, respectively, whereas fat-corrected milk and milk fat percent at 6 g/kg were only slightly higher than controls. We hypothesized that choline aided transport of mobilized free fatty acids from adipose tissue through the liver to the mammary gland.

Animals↗
PubMed1984

Effects of silage pH on voluntary intake of corn silage.

We evaluated effects of silage pH on corn silage intake. Sixteen Holstein heifers (292 kg) were fed control corn silage during a 2-wk preliminary period. This was followed by an 8-wk experimental period in which animals were fed silage neutralized with 0, 2, 4, or 6% sodium bicarbonate (dry matter) added prior to feeding with corresponding pH's 3.72, 4.46, 5.62, and 8.05. Organic matter intake was increased 1.0 and 1.2 kg/day by addition of 2 and 4% sodium bicarbonate versus controls whereas 6% sodium bicarbonate reduced intake .7 kg/day. An equation developed to predict organic matter intake from silage pH was: Y = 3.20 + 3.92 (pH) -.35 (pH)2 with coefficient of determination .66. This equation predicted maximum organic matter intake at pH 5.6. It appears that silage pH is a factor that affects voluntary consumption of corn silage and that pH 5 to 6 is optimum, whereas silage pH above and below may reduce intake.

Animal Feed↗
PubMed1983

Effect of rumen protein degradability on milk yield of dairy cows in early lactation.

Twenty-four mature Holstein cows were fed diets of 40% corn silage and 60% concentrate (dry matter) beginning at parturition through wk 16 of lactation. A control concentrate (corn, soybean meal, and barley) was fed through wk 4 followed by assignment of cows to either a concentrate of low or high rumen protein degradability. In situ trials with two fistulated cows fed similar diets yielded rumen protein degradabilities of 78.5, 70.3, 69.9, 67.3, 49.1, and 36.5% for barley, corn, corn gluten feed, soybean meal, brewer's grains, and cottonseed meal. The low degradability concentrate (corn, cottonseed meal, brewer's grains, and corn gluten feed) had an estimated rumen protein degradation of 52.9% and a total ration crude protein of 14.3%. The high degradability concentrate containing corn, barley, and soybean meal was 72.8% rumen degradable, and total ration protein for this treatment was 14.5%. Dry matter intakes were 21.0 and 22.0 kg/day for the low and high degradability diets. Milk yield, fat percent, and fat-corrected milk were not affected by treatment. Milk protein percent and protein yield decreased from 3.00 to 2.84% and 1.07 to .99 kg/day in the high and low degradability diets. Efficacy of use of degradability as a criterion for feed formulation is questioned until understanding of both feed protein breakdown and microbial synthesis is greater.

Animals↗
PubMed1982

Dietary sodium bicarbonate and magnesium oxide for early postpartum lactating dairy cows: effects on production, acid-base metabolism, and digestion.

In two experiments with cows in early lactation fed 40% corn silage and 60% concentrate diets (dry basis), we examined effects of 1.0% dietary sodium bicarbonate and .8% magnesium oxide in a 2 x 2 factorial arrangement on performance, acid-base metabolism, and digestion. In Experiment 1 with 20 Holstein and 4 Jersey cows, intake and milk production were not affected by treatment through 12 wk postpartum. In digestion trials at 3, 6, 9, and 12 wk postpartum, addition of magnesium oxide increased digestibility of dry matter 1.8% units by sodium bicarbonate whereas acid detergent fiber digestion increased 9 to 12% units with addition of either buffer. In Experiment 2, with four fistulated Holstein cows in a Latin square design, intake per unit body weight was increased .18% units by dietary sodium bicarbonate while milk production was unaffected. Dry matter and acid detergent fiber digestion were increased slightly by sodium bicarbonate plus magnesium oxide addition whereas nitrogen balance increased 23 g/day in cows fed magnesium oxide alone. Because of the low fiber content of the ration, milk fat percent increased .5 to .9% by addition of either buffer in both experiments and resulted in corresponding increased in fat-corrected milk. Sodium bicarbonate and magnesium oxide prevented rapid declines in rumen pH associated with feeding in Experiment 2, which related to changes in acid detergent fiber digestion. Blood acid-base metabolites were relatively unchanged by treatment in either experiment. Urinary bicarbonate and net acid excretion rates were changed on the average by +41 and +43 meq/h by sodium bicarbonate or magnesium oxide but could not be related to changes in intake and production.

Acid-Base Equilibrium↗
PubMed1981

Dietary fermented ammoniated condensed whey and postprandial effects on blood and urine acid-base metabolites in lactating cows.

Effects of a fermented whey product containing 38% lactic acid, time post-feeding, and temperature on acid-base metabolism were studied with four lactating Jersey cows in a 4 X 4 Latin square. Treatments included 0, 33, 66, and 100% replacement in soybean meal with fermented whey in a 60% corn silage, 40% concentrate diet (dry basis). Increasing fermented whey to 100% reduced intake and mild production, 27 and 32% compared to animals fed 0 and 33% fermented whey diets. Fermented whey had no effect on blood pH, carbon dioxide tension, bicarbonate, and potassium whereas increasing fermented whey about 33% replacement reduced glucose and sodium in plasma 15 and 40 mg/100 ml from controls. Increasing consumption of fermented whey to 100% replacement increased urinary ammonium excretion 1365/meq per day and slightly decreased urine pH, which suggested changes in acid excretion. Effects of time postfeeding on blood traits were measured from samples taken at 0, 1, 2, 3, 4, 6, and 8 h. Blood pH was higher at 1 to 3 h as compared with 4 to 8 h postfeeding, whereas carbon dioxide tension and bicarbonate increased 10.6 mm mercury and 6.3 meq/liter at 1 h and declined afterward. Period effects for blood acid-based characteristics showed decreasing blood carbon dioxide tension with increasing ambient temperature.

Acid-Base Equilibrium↗
PubMed1980

Effect of dietary calcium and sodium on potassium requirement for lactating dairy cows.

In two experiments we studied the effect of dietary calcium and sodium on the potassium allowance of .7 to .8% for lactating cows. In Experiment 1, 12 first-lactation cows in midlactation were fed three diets containing .52, .77, and 1.04% potassium with four dietary calcium concentrations .50, .69, .87, and 1.03%. Increasing dietary potassium from .52 to 1.04 increased intake of dry feed as a function of body weight. With rations containing 17% coarsely ground fiber, increasing dietary calcium up to 1.03% increased intake and milk production 1.3 kg per day and 1.6 kg per day linearly. In Experiment 2, 16 cows in midlactation were fed rations with two potassium (.42 and .84%) and with two sodium concentrations (.31 and .52%). Increasing dietary potassium increased dry matter intake 1.2 kg per day while dietary sodium had no effect on intake. Potassium had no effect, but increasing sodium decreased fat-corrected milk 1.7 kg per day. Of potassium, sodium, magnesium, and calcium in serum, potassium was the element most consistently affected in both experiments. Increasing dietary potassium to .77 and .84% increased serum potassium. Dietary calcium and sodium had little effect on potassium required for lactating cows.

Animals↗
PubMed1980

Effect of dietary sodium bicarbonate and magnesium oxide on production and physiology in early lactation.

Twenty cows were in an experiment to measure effects of dietary buffers, sodium bicarbonate and magnesium oxide, on ration adjustment and incidence of metabolic problems in the first 8 wk postpartum. Cows were fed 2.7 kg grain per day and alfalfa ad libitum prepartum and switched immediately to a complete ration of 40% corn silage and 60% concentrate (dry matter) postpartum. Treatments included 1.5% sodium bicarbonate and .8% magnesium oxide (total ration dry matter) fed in a 2 x 2 factorial arrangement. Cows receiving bicarbonate peaked 2 to 3 wk earlier in intake and averaged 2.1 kg per day greater intake than those fed the control diet. Actual milk production was increased by sodium bicarbonate with greatest differences for cows receiving both buffers averaging 3.8 kg per day more milk than control cows. Increases over co ntrols were 2.6 and 5.6 kg fat-corrected milk per day for cows receiving sodium bicarbonate alone or in combination with magnesium oxide, respectively. Sodium bicarbonate increased acetate to propionate molar ratios in rumen samples taken at 1 and 2 wk postpartum whereas neither buffer had any effect on rumen pH. Blood hematocrit and urine pH were not affected by treament. Magnesium oxide increased fecal pH .8 units and slightly decreased fecal starch, but sodium bicarbonate had no effect.

Animals↗