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Biomedical subjects

G C Fahey

Publications and source records attributed to G C Fahey.

At least 145 records · Page 8Linked to original sources
PubMed1985

Effects of dietary alfalfa:orchardgrass hay and lasalocid on nutrient utilization by gravid sows.

Twenty-four third- and fourth-parity crossbred gravid sows were housed in metabolism stalls and randomly allotted to four dietary treatments: corn-alfalfa:orchardgrass hay (46%; CH), CH plus lasalocid (CHL), corn-soybean meal (CS) or CS plus lasalocid (CSL). Daily feed intake was 2.36 kg for CH- and CHL-fed sows and 1.66 kg for CS- and CSL-fed sows. Lasalocid intake was 110 mg X sow-1 X d-1. Total feces and urine were collected during two 5-d collection periods, 40 and 80 d postcoitum. Digestible energy (DE), metabolizable energy (ME), nitrogen (N) retention, dry matter (DM), neutral detergent fiber (NDF) and acid detergent fiber (ADF) digestibilities, and retention of calcium (Ca), total phosphorus (P), magnesium (Mg), sodium (Na) and potassium (K) were determined. Percentage DE and ME were greater (P less than .0001) for CS- and CSL-fed sows (88.3 and 83.4%) than for CH- and CHL-fed sows (65.2 and 61.3%). Lasalocid did not influence (P greater than .05) DE and ME values but decreased (P less than .01) the ME:DE ratio. Percentage N digestibility was greater (P less than .0001) for CS- and CSL-fed sows (85.7%) than for CH- and CHL-fed sows (60.8%), but there was no significant difference in N retention, expressed as a percentage of N intake. Lasalocid increased (P less than .03) percentage N digestibility; however, the diet X additive interaction decreased (P less than .005) grams N retained X sow-1 X d-1 for CSL-fed sows. The CH- and CHL-fed sows digested more grams of DM, NDF and ADF but had lower percentage digestibilities of DM and fiber fractions than did CS- and CSL-fed sows. The diet X additive interaction decreased (P less than .05) percentages of Ca, P and K digested and decreased (P less than .05) grams mineral retained (Ca, P, Mg and K) and mineral retained expressed as a percentage of intake for CSL-fed sows. Results indicate that alfalfa:orchardgrass hay and lasalocid influenced energy, fiber, nitrogen and mineral utilization by gravid sows.

Animals↗
PubMed1985

Effects of roughage particle size on site of nutrient digestion and digesta flow through the gastrointestinal tract of sheep fed corncob-concentrate diets.

An experiment examining nutritional effects of dietary corncob particle size was conducted using ruminal-, duodenal- and ileal-cannulated sheep in a 4 X 4 Latin square design. Site of nutrient digestion and digesta flow were the principal criteria evaluated. Analyses of dry matter (DM), N, starch and neutral detergent fiber (NDF) were performed on feed, feces and digesta samples. Chromic oxide-impregnated paper was used as an external marker to estimate digestibilities at different sites along the gastrointestinal tract. Ruminal pH and volatile fatty acid molar proportions were also determined. All diets (74.9% concentrates: 25.1% corncobs) were pelleted and were similar in ingredient composition but varied in corncob particle size (corncob mean particle sizes were 6.5, 5.4, 1.4 or .8 mm). Dietary crude protein levels differed little among treatments. Starch concentration was higher in diets containing the larger corncob particles while NDF, acid detergent fiber (ADF), cellulose and hemicellulose concentrations were lower in diets containing larger particles, suggesting a reaction between starch and fiber moieties during the pelleting process. Starch flow past the duodenum decreased (P less than .05) as dietary corncob particle size decreased. Apparent NDF digestion before the duodenum was highest for sheep fed diets containing 1.4-mm corncobs (P less than .05). Apparent starch digestion in the small intestine decreased (P less than .05) as dietary corncob particle size decreased. A considerable amount of NDF was apparently digested in the small intestine of sheep consuming diets containing 5.4- and .8-mm corncobs. Likewise, a substantial amount of NDF was apparently digested in the large intestine. Few differences in apparent total tract digestibilities were noted.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Effect of roughage particle size on ruminal, digestive and metabolic characteristics of early-weaned lambs fed pelleted corncob-concentrate diets.

Two experiments were conducted to determine effects of feeding corncobs of various mean particle size (MPS) on ruminal, digestive and metabolic characteristics of early-weaned lambs fed pelleted 74.9% concentrate:25.1% corncob diets. The MPS of corncobs in diets was 6.5, 5.4, 1.4 and .8 mm, respectively. As particle size decreased, percentage starch decreased and percentage neutral detergent fiber (NDF), acid detergent fiber (ADF) and cellulose increased. In Exp. 1, 28 crossbred rams (seven/treatment, avg initial wt, 15.3 kg) were used in a randomized complete-block design. In Exp. 2, lambs from Exp. 1 were re-weighed (avg initial wt, 16.8 kg) and fed the same diets as in Exp. 1. In Exp. 1 and 2, lambs ingested dry matter (DM) equal to 2.68 and 3.74% of body weight, respectively. In Exp. 1, apparent DM digestibility was unaffected by corncob MPS; however, in Exp. 2, DM digestibility was highest (68.8%) for lambs fed the 6.5-mm diet and lowest (63.8%) for those fed the .8-mm diet. Apparent starch digestibility was high (greater than 98.8%) in both experiments. Neutral detergent fiber and ADF digestibilities were highest for lambs fed the 1.4-mm diet (50.5 and 43.6%, Exp. 1; 39.6 and 28.9%, Exp. 2). A dramatic increase (6.8 to 39.1%) in acid detergent lignin (ADL) digestibility was observed in Exp. 1 as corncob MPS decreased. In Exp. 2, ADL digestibilities were similar for lambs fed the 6.5-, 5.4- or 1.4-mm diets (avg value, 5.9%) and highest for those fed the .8-mm diet (29.7%). Nitrogen metabolism was unaffected by corncob MPS. In Exp. 1, digestible energy intake, corrected for urinary losses, did not differ among treatments but in Exp. 2, lambs consuming the 6.5-mm diet had higher corrected digestibility energy intakes (1,926.6 kcal/d) than did those fed other diets (avg, 1,832.4 kcal/d). Ruminal pH sampled 4 h post-feeding was highest for lambs consuming the 6.5-mm diet (6.25) in Exp. 1 and the 1.4-mm diet (5.89) in Exp. 2. Lowest ruminal pH (5.30 and 5.36, respectively) was for lambs consuming the .8-mm diet in Exp. 1 and the 5.4-mm diet in Exp. 2. Ruminal lactate concentrations were variable within and among treatments. Total ruminal volatile fatty acid (VFA) concentrations were similar across treatments but in Exp. 2, there was a shift in molar proportions from acetate to propionate as corncob MPS decreased.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1985

Biological activity of phenolic compounds. Hepatic cytochrome P-450, cytochrome b5, and NADPH cytochrome c reductase in chicks and rats fed phenolic monomers, polymers, and glycosides.

Eight experiments were conducted to determine effects of a phenolic polymer (Kraft wood lignin, Indulin), phenolic glycosides (cane molasses and wood molasses), and phenolic monomers (vanillin, vanillic acid, ferulic acid, and p-coumaric acid) on liver cytochromes P-450, cytochrome b5, and NADPH cytochrome c reductase in chicks and rats. Chicks fed 6.0% lignin had a higher (P less than 0.01) cytochromes P-450 content than did chicks fed 0% fiber, 6.0% wood cellulose (Solka Floc), or 6.0% arenaceous flour. NADPH cytochrome c reductase activity was not affected by treatment. Chicks fed 12.0% wood molasses had a higher (P less than 0.06) cytochromes P-450 level than did chicks fed 0% fiber or 6.0% wood molasses. Cane molasses incorporated at both 6.0 and 12.0% of the diet induced (P less than 0.05) cytochromes P-450 content over those of control-fed birds. Chicks fed 6.0% lignin, with or without antibiotic (bacitracin:neomycin sulfate, 2:1), had a higher (P less than 0.01) cytochromes P-450 level than did chicks fed control diets, with or without antibiotic. Additionally, chicks fed 6.0% lignin had lower (P less than 0.01) intestinal diaminopimelic acid (DAP) levels than did chicks fed 0% fiber. Rats fed 0% fiber, 6.0% wood cellulose, 6.0% arenaceous flour, or 6.0% lignin exhibited no difference in cytochrome level or activity among treatments. Chicks fed 0.5% vanillin, 0.5% vanillic acid, 0.5% ferulic acid, or 0.5% p-coumaric acid had comparable cytochromes level and activity compared with chicks fed no phenolics. Chicks fed 0.5% p-coumaric acid had lower (P less than 0.05) rates of gain than did chicks fed control or other phenolic-containing diets. Rats fed these phenolics had similar cytochromes P-450 content among treatments.

Age Factors↗
PubMed1984

Blood metabolite profiles of broodmares and foals.

Serum amino acid profiles and other serum characteristics of broodmares and their foals wee studied. Compared with mares, foals had significantly higher concentrations of serum leucine, threonine, aspartic acid, asparagine, glutamic acid, glutamine, proline and tyrosine, glucose, cholesterol, creatinine and phosphorus. Foals had significantly less serum histidine, glycine, cystine, taurine, protein and urea nitrogen. Lysine and/or methionine supplementation of pregnant and lactating broodmare diets were conducted. Changes in serum amino acid profiles caused by dietary amino acid supplemented were then quantified. Changes in concentrations of 19 amino acids as well as of ammonia occurred from the first bleeding period (12 weeks prepartum) to the second bleeding period (seven weeks prepartum) in mares supplemented with methionine. When blood samples were collected at 2 h intervals post feeding, after a preliminary rise, a large decrease in serum amino acid levels occurred over a 19 h pot feeding period.

Amino Acids↗
PubMed1984

Effects of lasalocid and monensin on nutrient digestion, metabolism and rumen characteristics of sheep.

Two experiments were conducted to evaluate metabolism and rumen fermentation responses of lambs fed either monensin or lasalocid (33 mg/kg level) in an alfalfa-corn diet. Experiment 1 was a lamb metabolism trial where rumen samples were taken at the end of each excreta collection period. In Exp. 2, ruminally cannulated sheep were used and cotton thread cellulose and soybean nitrogen (N) disappearance were measured by the in situ dacron bag technique. Rumen turnover rates and volatile fatty acid (VFA) and ammonia pool sizes were determined. In Exp. 1, dry matter and fiber (neutral detergent fiber, NDF; acid detergent fiber, ADF and hemicellulose) digestibilities were not influenced by treatment. Absorbed N was increased (P less than .05) with lasalocid, but not with monensin. No direct or adaptive rumen effects on in situ cellulose or N disappearance were noted in Exp. 2 for either additive. In Exp. 1, at 6 h postfeeding, both additives increased (P less than .05) propionate concentration and lowered (P less than .05) the acetate: propionate (A:P) ratio, while only monensin decreased (P less than .05) rumen ammonia levels. However, no differences in ammonia or VFA concentrations were noted at 2 and 4 h postfeeding. In Exp. 2, where pool size was considered, monensin-fed sheep had lower (P less than .05) total quantities of rumen ammonia at 8 and 12 h postfeeding. Both additives decreased A:P ratios at 6 and 12 h. Lasalocid increased (P less than .05) acetate, propionate and total VFA pool size at 12 h.

Ammonia↗
PubMed1984

Effects of intake of a mixed dairy steers on digestion events.

Ruminally cannulated steers were in a 4 X 4 Latin square to determine the effect of amount of feed ingested on fiber digestion and other digestion events. Alfalfa haylage, corn silage, and a corn-soybean meal mix were incorporated in a ratio 45:20:35 (dry matter) and fed at either 100, 85, 70, or 55% of ad libitum intake. Acid-insoluble ash, lanthanum, and chromium-ethylenediaminetetraacetic acid were digestion, particulate, and liquid markers. Apparent digestibility of dry matter, neutral detergent fiber, and cell solubles decreased linearly as feed intake increased. The fiber fraction digested was a larger percentage of the dry matter digested at low than at high intakes of feed. A more rapid rate of cellulose disappearance and a slow rate of passage of particulate matter through the rumen and total digestive tract with decreasing feed intake were key factors responsible for bringing about changes of digestion coefficients. A consistently lower rumen pH of steers at high intakes of feed was thought to account for the slower rate of ruminal fiber disappearance. The lower tract accounted for 11 to 17% of dry matter disappearance, and tended to play a greater role during periods of high feed intake. Rumen and fecal sampling techniques provided similar ruminal rates of solids passage.

Ammonia↗
PubMed1984

Milk production and nitrogen utilization by dairy cows infused postruminally with sodium caseinate, soybean meal, or cottonseed meal.

Four Holstein cows with fistulated rumens were in a 4 X 4 Latin square design for us to determine effects of administering different sources of protein postruminally on milk production, milk composition, and efficiency of nitrogen utilization. Treatments consisted of postruminal infusion of 1) water, 2) sodium caseinate, 3) soybean meal, or 4) cottonseed meal. Milk yield (kg/day) and milk protein production (g/day) for the four treatments were: 1) 30.6, 1043; 2) 32.7, 1146; 3) 32.1, 1102; and 4) 31.1, 1087. Synthesis of milk protein increased during postruminal infusions of protein as indicated by the increased casein nitrogen fraction in milk. All protein infusions improved efficiency of use of absorbed nitrogen for synthesis of milk protein. Milk fat percentage and daily production of milk fat were not affected by treatments.

Abomasum↗
PubMed1983

Effects of ruminant digestion and metabolism on phenolic monomers of forages.

Immature and mature lucerne (Medicago sativa) and tall fescue (Festuca arundinacea) hays were analysed for their lignin and phenolic monomer (hydroxybenzoic and hydroxycinnamic acid derivatives) contents. These hays were given to four sheep with rumen, duodenal and ileal cannulas, and to a steer with rumen and abomasal cannulas, to investigate the extent and sites of digestion of lignin and phenolic monomers. The hays and digesta samples were analysed for alkali and nitrobenzene-extractable phenolic monomers. Lanthanum oxide was used as an external marker in the digestion studies. Urine was also collected for estimates of total phenolic balance. Grass hays contained greater concentrations of alkali-labile phenolic monomers than did legume hays, whereas legume hays had higher levels of nitrobenzene oxidation products. Mature tall fescue hay had greater concentrations of phenolic monomers than did immature tall fescue hay, but corresponding differences with maturity were not observed with lucerne hays. There were quantitative differences between diets in the digestibilities and in the sites of digestion of phenolic monomers. Digestibilities ranged from 0.191 to 1.004 for alkali-labile compounds and from -1.137 to 0.868 for nitrobenzene oxidation products. Composition of lignin was altered during its passage through the digestive tract. The proportion of phenolic monomers not recovered in urine and faeces varied from -1.014 to 0.871 for individual compounds and differed between diets. Soluble phenolic monomers decreased in concentration as digesta passed from the rumen to the abomasum and duodenum, but increased again in the ileum; levels varied with diet. Phenolics were rapidly solubilized in the rumen after feeding. Results indicate that forages differ in their phenolic monomer content and in the digestibility of these compounds. Therefore, lignin is not an inert compound in the digestive tract of ruminants as has been previously reported.

Animals↗
PubMed1983

Effects of phenolic monomers on rat performance and metabolism.

Phenolic monomers identified in common roughages were included in diets fed to rats both as mixtures, to mimic phenolic composition of roughages, and individually at various levels. Three performance and digestion/metabolism trials were conducted. Dry matter, protein, total carbohydrate, cellulose, and soluble carbohydrate (dextrose plus starch) digestibilities were measured. Urine and fecal samples were analyzed for phenolic monomers in trial 1. Inclusion of phenolic monomers (p-coumaric, ferulic, protocatechuic and salicylic acids, and vanillin) in rat diets resulted in reduced feed intake with a linear trend toward decreased intake with increasing dietary phenolic (p-coumaric and ferulic acids) concentrations. Average daily gain also exhibited a similar negative linear relationship. p-Coumaric and ferulic acids did not differ from one another in their effects, whereas salicylic acid had greater negative effects and vanillin was not different from the phenolic-free control. Some differences in digestibility of individual nutrients were observed, but were small in magnitude and did not correlate well with the altered growth responses. Analysis of urine and feces revealed low recoveries of phenolic monomers, suggesting extensive metabolism of phenolics by rats after intestinal absorption. Potential exists for phenolic monomers to be intake- and growth-depressing agents in both animal and human diets.

Animals↗
PubMed1983

Effects of dietary fibers on mineral status of chicks.

We investigated the effects of replacing dietary starch with dietary fibers of various types and particle sizes on utilization of bivalent cations by chicks. Inclusion of polyethylene powder, alfalfa cell walls, corn bran, oat bran and wheat bran into diets resulted in lower serum and tibia Zn levels. However, addition of pectin, cellulose and a xylose:gum arabic (50:50) mixture did not affect tissue Zn levels, whereas addition of 4% lignin increased serum Zn level from 2.50 to 3.44 micrograms/ml. Ingestion of fibers with particle sizes less than 300 micrometers resulted in higher serum Zn levels compared with those of particle sizes greater than 300 micrometers. Incorporation of 4 and 8% pectin decreased (P less than 0.05) serum and tibia Mg levels. When brans were fed, kidney Mg levels were lower due to fiber additions. Inclusion of lignin, the xylose:gum arabic mixture and alfalfa cell walls resulted in lower liver Cu levels; polyethylene and solka floc had no effect on liver Cu status. Fiber did not affect tissue Ca or Fe status. Each mineral influenced by fiber type, level or particle size appeared to be affected through different mechanisms.

Animals↗
PubMed1982

Effects of energy level and monensin on reproductive performance and lactation of beef cows.

This experiment consisted of a 2 year drylot study involving 80 multiparous, suckled beef cows (40 Angus and 40 Herefords). Experimental treatments (breed, monensin and year) were arranged in 2(3) factorial to evaluate the effect of breed and monensin on reproductive performance and lactation. Cows received 85% of the NRC total digestible nutrient (TDN) requirement for the first 56 days of the 140 day trial. Cows were synchronized with Synchro-Mate B and artificially inseminated 30 days into each trial with blood samples collected for luteinizing hormone (LH) analysis from one-half of each treatment group from 24 to 36 hours after implant removal. Progesterone determinations were made on plasma samples collected at day 9 and 16 after implant removal. On day 56, milk yield estimates were obtained by the weigh-suckle-weight technique. Following these collections, energy levels were increased by allowing ad lib consumption of forage. Calves, which were removed from the cows during feeding, were given access to a 75% TDN creep ration after day 56. Milk estimates were again evaluated at 140 days. Monensin supplementation did not result in a difference in cow weight change through the restricted energy period (first 56 days) or throughout the entire 140 day period. Milk yield estimates at 56 and 140 days and calf gains throught the trial, were unaffected by monensin supplementation. Monensin resulted in no effect on conception rate or services per conception. The time of the LH peak was shifted slightly forward by monensin although not significantly. Progesterone levels were not consistently affected by monensin supplementation.

Journal Article↗
PubMed1982

Effects of creep feeding and monensin on reproductive performance and lactation of beef heifers.

A 23 factorial arrangement of treatments was utilized to determine the effect of breed, creep feeding and monensin on subsequent reproductive performance and lactation of 32 primiparous heifers. One-half of each breed (Angus and Hereford) group had access to creep feed (2.67 Mcal metabolizable energy/kg) while nursing their dams. Approximately 40 d before breeding through 120 d of lactation, all heifers were fed a suboptimal energy diet and 50% of each breed and creep group received 200 mg monensin/head daily. Estrus was synchronized with a progestogen. Volatile fatty acids (VFA) were determined periodically throughout the monensin-feeding portion of the experiment. Twenty-four hour milk production, percentage butterfat and percentage solids-not-fat were determined at 60 and 120 d postpartum. Weaning weights (adjusted to 205 d and for age of dam) of the original heifers were heavier (P less than .05) for those that were creep fed compared with those not creep fed (219 vs 202 kg). Monensin-supplemented females gained significantly more weight from the initiation of treatment to immediately postcalving and gave birth to heavier calves (P less than .05) even though they received comparable amounts of dietary energy as those that did not receive monensin. The energy stressed, monensin-supplemented first-calf heifers exhibited a shorter postpartum interval (P less than .05) to first estrus than did those that did not receive monensin (55.7 vs 69.1 d, respectively). First-calf heifers that had been creep fed while nursing their dams had a lower (P less than .05) daily milk yield at 120 d post-partum than those that did not have access to creep feed. No detrimental effects were observed due to long-term monensin supplementation.

Animals↗
PubMed1981

Alkali treatment of cereal grains. II. Digestion, ruminal measurements and feedlot performance.

Two trials were conducted to determine the effects of feeding alkali-treated corn on various metabolic and performance characteristics of cattle. In the first trial, four ruminally-fistulated cows were fed high moisture corn (HMC) in the following forms: whole, rolled, sodium hydroxide (NaOH)-treated and ammonium hydroxide-treated. The corn was fed as 75% of the diet (dry matter basis) in four 15-day feeding periods in a 4 x 4 Latin square design. NaOH-treated HMC produced the highest dry matter digestibility (P less than .05), the highest rumen pH (P less than .05), the highest ruminal fiber digestion (P less than .05) and the highest fecal pH (P less than .05). Rolled HMC produced the lowest rumen pH (P less than .05) and lowest fiber digestion (P less than .05). Ammonium hydroxide-treated HMC produced no response in comparison to whole HMC and had the lowest rate of passage (P less than .05). Fecal starch, fecal water content, rumen fill and rumen ammonia were unaffected by treatments. In the second trial, 90 yearling steers were randomly allotted to five groups of 18 (six steers per pen). Steers were fed ad libitum a diet of 20% corn silage, 5% supplement and 75% corn as dry shelled corn, whole HMC, rolled HMC, NaOH-treated dry shelled corn or NaOH-treated HMC. There were no treatment effects on daily dry matter intake. Cattle fed either of the NaOH-treated corns had lower (P less than .05) average daily gains and poorer (P less than .05) feed efficiencies. No treatment effect was apparent for any carcass characteristic measured except yield grade, which was lower (P less than .05) for steers fed NaOH-treated HMC. Whole HMC produced the highest (P less than .05) fecal pH values while both NaOH treatments produced lower (P less than .05) fecal pH values than the other treatments.

Animal Feed↗
PubMed1981

Comparison of two forms and two levels of lasalocid with monensin on feedlot cattle performance.

One growth and two finishing trials were conducted with beef steers to compare lasalocid sodium and monensin sodium. Pure lasalocid, mycelia-cake lasalocid and monensin, each added individually to commercial protein supplement blocks at 880 mg/kg, depressed (P greater than .05) block intake so that approximately 100 mg of each additive were consumed daily by each animal. Daily gain, feed intake and feed efficiency for steers receiving blocks containing additives did not differ from the corresponding measures for steers receiving control blocks. No differences were observed in diet dry matter digestibility, as determined with acid-insoluble ash as an internal marker. Both forms of lasalocid and monensin reduced (P greater than .05) the incidence and concentration of coccidia oocysts. By day 40, only one steer on each of the additive treatments was shedding oocysts (4.2% of additive-supplemented animals), compared with 41.5% of the control steers. During trial 2, steers fed pure lasalocid gained faster and more efficiently (P greater than .05) than those fed the mycelia-cake lasalocid, monensin or control diets. The improvement in feed efficiency over the control value was 10.0, 3.4 and 4.0% with pure lasalocid, mycelia-cake lasalocid and monensin, respectively (P greater than .05). Steers fed mycelia-cake lasalocid had higher (P greater than .05) dressing percentages than those fed pure lasalocid or monensin. Dressing percentage was the only carcass measurement affected. In trial 3, lasalocid at 30 and 45 g/ton and monensin at 30 g/ton improved (P greater than .05) feed efficiency by 7.5, 11.0 and 8.2%, respectively. No significant differences in incidence or concentration of oocysts were observed between treatment groups in trial 3, probably because steers were in slatted floor pens.

Animal Feed↗