Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Foraging”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 631 records · Page 35Linked to original sources
PubMed1993

Effects of forage species and particle size on bacterial cellulolytic activity and colonization in situ.

Two ruminally cannulated Holstein heifers were used to evaluate effects of three forage species and two particle sizes in a 3 x 2 factorial arrangement on in situ fiber disappearance and carboxymethylcellulase activity (CMCase). A second objective was to compare CMCase and 15N as relative bacterial colonization markers. At time zero, 15N-enriched ammonium sulfate was dosed into the rumen. Residues in nylon bags incubated for 3, 6, 9, 12, 18, 24, 30, 36, 42, 48, 60, and 72 h were analyzed for NDF, ADF, CMCase, and 15N. Rates of NDF and ADF disappearance were faster (P < .05) for red clover (RC) than for gamagrass (GG) or orchardgrass (OG) and for forages ground to pass a 2-mm screen (P < .05) than for those ground to pass a 5-mm screen. Cumulative area under the curve (AUC) of CMCase activity was related to both NDF disappearance (r2 = .93) and 15N AUC (r2 = .99), indicating that CMCase can be used to estimate relative colonization of cellulolytic particle-associated bacteria (PAB). During the first 18 h of incubation, RC had greater (P < .05) CMCase and 15N enrichment of in situ residues than did OG or GG. The RC residues also had a greater (P < .05) ratio of CMCase activity:15N enrichment; this was presumed to indicate that, during this time, RC supported a greater total PAB population and had a greater proportion of cellulolytic PAB than did either GG or OG. Differences in the colonization rate of forage particles by cellulolytic PAB relative to total PAB may account for differences in rate of fiber digestion.

Animal Feed↗
PubMed1994

Influence of sugary-Brawn2 or dent corn at two forage levels on intake, digestion, and milk production by dairy cows.

Sugary-Brawn2 (su-Bn2) corn endosperm contains higher concentrations of watersoluble polysaccharides than dent corn. Eight multiparous Holstein cows averaging 48 d in milk and 667 kg BW at trial initiation were in a replicated 4 x 4 Latin square design with 28-d periods. Only cows in one square were ruminally cannulated. Treatments were su-Bn2 or dent corn and 45 or 60% of ration DM as alfalfa silage arranged as a 2 x 2 factorial within each square. Diets, formulated to contain 19% CP, were fed as total mixed rations twice daily. Intake of DM and milk yield averaged 26.8 and 39.9 kg/d, respectively, and were not affected by treatment (P > .10). Sugary-Brawn2 corn decreased milkfat percentage (3.27 vs 3.45%), particularly for the low-forage diet (3.15 vs 3.40%). Milk protein percentage was higher (3.15 vs 3.10%) for low-forage diets but was not affected (P > .10) by corn type. Ruminal pH was lower for low-forage diets. Feeding su-Bn2 corn decreased ruminal pH only at 4 h after feeding. Total VFA in ruminal fluid (millimolar) 6 h after feeding were higher, whereas acetate molar percentage and acetate:propionate ratio were lower for su-Bn2 corn. Ruminal in situ evaluation of su-Bn2 and dent corn revealed a larger soluble fraction, a faster rate of degradation, and higher availabilities of both DM and starch for su-Bn2 corn. Ruminal in situ rate of degradation and availability of alfalfa hay DM were reduced by su-Bn2 corn. Total tract apparent digestibilities of DM, CP, and starch were greater for su-Bn2 diets.(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗
PubMed1994

Influence of grazing cattle and sheep together and separately on animal performance and forage quality.

Cattle and sheep grazed together and separately from April to October during 3 yr. Initial forage composition was 29% Kentucky bluegrass (Poa pratensis L.), 11% white clover (Trifolium repens L.), and 60% weeds. There were six Angus cow-calf pairs or six ewes (1/2 Dorset x 1/4 Finn x 1/4 Rambouillet) with 11 lambs per each of three pasture replications for single animal species. Six cow-calf pairs plus six ewes and 11 lambs grazed in each of three replications of the mixed animal species treatment. There were approximately one cow and calf or five ewes with lambs per .44 ha. Lambs were weaned at 41 kg or by September 1. Calves were weaned approximately October 10. Lamb daily gain (.23 kg/d), total gain (23 kg), and weaning weights (43 kg) were greater (P < .01) and target weaning weights were reached 14 d earlier in the grazing season when both animal species grazed together than when lambs were in pastures with sheep alone (.18 kg/d, 19 and 38 kg, respectively). Calf gains were not influenced by treatment. Grazing pressure increased throughout the grazing season for cattle alone, peaked in midsummer, and then decreased by autumn for sheep alone, whereas grazing pressure initially increased then remained relatively constant with mixed-species grazing. Forage quality in pastures where sheep grazed alone was lower (P < .05) than in pastures where cattle grazed alone until lambs were weaned in late summer, whereas forage quality with mixed-species grazing was generally intermediate. Mixed grazing resulted in earlier weaning and increased lamb performance and BW of ewes, but not in increased animal production per hectare.

Animal Feed↗
PubMed1994

Relationships among ewe milk production and ewe and lamb forage intake in Targhee ewes nursing single or twin lambs.

Targhee ewes with single or twin lambs were used in four trials during early lactation through weaning to evaluate ewe milk production (MP), kilograms of lamb weaned, and forage intake by ewes and lambs. During Trial 1, ewes with lambs were individually penned, fed .45 kg of barley-ewe-1.d-1 and allowed ad libitum access to chopped alfalfa hay. Trials 2, 3, and 4 were conducted on three different types of Western range environments. Forage intake of ewes in Trials 2, 3, and 4 and of lambs in Trials 3 and 4 was estimated using chromic oxide. Estimates of milk production were obtained by hand-milking. Average lamb age was 4, 50, 78, and 106 d at the beginning of Trials 1, 2, 3, and 4, respectively. Milk production was greater (P = .01) for ewes nursing twins than for those nursing singles at d 4 and 14 in Trial 1. In Trials 2, 3, and 4, all ewes had similar (P > .18) milk production. Ewe DMI during Trials 1 and 2 was greater (P < .05) for ewes nursing twin lambs than for those nursing singles. There was no difference (P > .88) in DMI between ewes with single and those with twin lambs in Trials 3 and 4. Forage DMI by twin lambs, expressed as either kilograms.ewe-1.day-1 or percentage of lamb BW, was higher (P = .01) than intake by single lambs in Trials 3 and 4.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗
PubMed1994

Effect of frequency of supplementation and protein concentration in supplements on performance and digestion characteristics of beef cattle consuming low-quality forages.

Three experiments evaluated whether effects of altered frequency of supplementation on forage use and cow performance depended on supplement CP concentration and (or) grain type when fed to cattle eating low-quality forages. All experiments included supplementation frequency (daily = 7x; three times weekly = 3x) as one factor in a factorialized arrangement of treatments. In Exp. 1 and 2, the second factor was supplement CP concentration (10, 20, 30, and 40% CP), altered by changing the ratio of soybean meal to sorghum grain in supplements. Supplements were fed at 13.9 and 14.1 kg of DM/wk for Exp. 1 and 2, respectively. In Exp. 3, the second factor was supplement grain type (sorghum grain or corn) and supplements containing 21% CP were fed at 14.8 kg of DM/wk. In Exp. 1, eight ruminally fistulated steers (456 kg) consumed wheat straw ad libitum. Pregnant beef cows grazing dormant tallgrass prairie were used in Exp. 2 (475 kg; n = 128) and 3 (504 kg; n = 120). In Exp. 1, reducing supplementation frequency decreased (P < .01) straw intake but increased (P < or = .03) DM and NDF digestion. As CP concentration in supplements increased, straw DMI (P = .06) increased quadratically, whereas DM and NDF digestion increased linearly (P < .01). In Exp. 2, increasing CP concentration in supplements enhanced cows' ability to maintain BW and condition up to calving, with decreasing magnitude of difference between treatments at higher CP concentrations (P < .01). Increasing CP in supplements fed to the dams linearly (P = .05) increased calf weaning weight in Exp. 2. In Exp. 2 and 3, reducing supplementation frequency increased (P < or = .02) winter weight loss through calving. Grain type did not significantly affect most performance variables. In summary, response to supplementation frequency was not dependent on supplement CP concentration or grain type. Daily supplementation maximized forage intake and cow performance, although the magnitude of performance differences was not large.

Ammonia↗
PubMed1995

Influence of moisture content of forage on ruminal functional specific gravity and passage of digesta.

Four crossbred beef steers (392 kg BW) fitted with ruminal cannulas were used in a 4 x 4 Latin square experiment with treatments arranged in a 2 x 2 factorial to evaluate effects of forage species (F) and reconstitution (R) on apparent digestibility, ruminal kinetics, and digesta functional specific gravity (FSG). Dietary treatments were alfalfa (Medicago sativa L.) and timothy (Phleum pratense L.) hays (90% DM) and the same hays reconstituted with water to 38% DM. Apparent DM digestibility was unaffected by R or F. Proportion of ruminal digesta with a FSG of .9 to 1.1 or 1.1 to 1.2 decreased linearly (P < .05) after feeding, whereas the proportion with FSG > 1.2 increased linearly (P < .01). Reconstitution decreased (P < .10) the proportion of ruminal digesta with FSG of 1.1 to 1.2 and increased (P < .10) the proportion with a FSG > 1.2 compared with the hay diets. Reconstitution decreased digesta passage rate for timothy forage; no influence on passage rate for alfalfa was detected (F x R, P < .10). Ruminal DM pool was increased by reconstitution (P < .10). Inert particles of 1-mm length passed from the rumen at a faster rate (P < .05) than 3-mm particles. Inert particles with SG of 1.32 passed from the rumen at a faster rate (P < .05) in the reconstituted alfalfa than in the dry alfalfa diet but at a slower rate in the reconstituted timothy than in the dry timothy diet. These results suggest that factors other than SG of the digesta can have a profound effect on passage of forage particles from the rumen.

Animal Feed↗
PubMed1996

Forage systems for beef production from conception to slaughter: III. Finishing systems.

Fall-weaned Angus calves grazed or were fed different forages during winter followed by 1) N-fertilized tall fescue (Festuca arundinacea Schreb.) grazed alone, 2) bluegrass (Poa pratensis L.)-white clover (Trifolium repens L.) sequence grazed with tall fescue-red clover (Trifolium pratense L.), or 3) bluegrass-white clover sequence grazed with alfalfa (Medicago sativa L.)-orchardgrass (Dactylis glomerata L.). Heifers were supplemented with grain at 1% of BW from April until slaughter in July. One-half of steers were supplemented with grain at 1% of BW from July until slaughter in October. Remaining steers were fed no grain but were finished on corn silage supplemented with .9 kg of soybean meal per steer daily, from October until slaughter in late January. Including alfalfa-orchardgrass in systems during the finishing phase resulted in higher daily and total gains during the grazing period, and carcasses had more marbling and higher USDA quality grades at slaughter compared with carcasses of cattle on systems using fescue-red clover. Correlation of final weight with carcass characteristics was low (r < .5). Performance and carcass characteristics were influenced as much or more by forage consumed during the previous wintering phase as by forage fed during the finishing phase. Wintering cattle on stockpiled fescue-alfalfa or alfalfa-orchardgrass hay generally resulted in higher BW at slaughter and more desirable carcass characteristics than systems using tall fescue alone or in combination with red clover. This was particularly notable in steers that grazed without grain until October and were finished on corn silage plus supplement. Final BW and carcass characteristics in all cattle were improved by full season grazing followed by feeding corn silage, compared with cattle finished with grain on pasture.

Animal Feed↗
PubMed1996

Application of nitrogen from swine lagoon effluent to bermudagrass pastures: seasonal changes in forage nitrogenous constituents and effects of energy and escape protein supplementation on beef cattle performance.

A 2-yr study was conducted to evaluate 1) the effects of nitrogen level from swine lagoon effluent on forage composition and animal performance and 2) the effects of supplemental escape protein (EP) on performance by steers grazing pastures fertilized with swine lagoon effluent. Bermudagrass (Cynodon dactylon) pastures were fertilized via sprinkler irrigation with either 448 or 896 kg/ha of N from swine lagoon effluent (two pasture replications/treatment). Within each pasture, four supplement treatments were evaluated using electronic Calan gates (8 steers.pasture-1.yr-1). The treatments were 1) negative control (pasture only); 2) energy control, which supplied 79.9 g of EP.hd-1.d-1; 3) 159 g of EP.hd-1.d-1, and 4) 239 g of EP.hd-1.d-1. Gains were increased (P < .05) an average of .15 kg/d by supplementation, with no differences in gain among supplements. Forage samples representative of that grazed by steers (CONSUM) and representative of all available forage (AVAIL) were obtained at 14-d intervals. Total CP content of CONSUM and AVAIL samples were slightly higher (P < .20 and P < .15, respectively) from pastures fertilized with 896 compared with 448 kg/ha of N (20.8 vs 20.0% for CONSUM and 15.2 vs 14.2% for AVAIL). Concentrations of nonprotein N and soluble true protein (% of CP) in both AVAIL and CONSUM samples were higher (P < .06) from pastures fertilized with the higher N level. Total N uptake by the plant, based on CP content and animal grazing days/ha, was essentially the same for both N treatments.

Ammonia↗
PubMed1997

Neutral detergent fiber disappearance and gas and volatile fatty acid production during the in vitro fermentation of six forages.

Samples of unfractionated forage and isolated NDF from six forages were fermented in vitro, and NDF disappearance and gas and VFA production were measured over time. Rates based on each of these data sets were calculated using a one-pool logistic model. The rates of NDF disappearance and gas and VFA production did not differ within each forage. Gas and VFA production were linearly related to NDF digestion. Gas yield was .35 mL/mg (r2 = .92) of NDF digested for the isolated NDF. The amount of total VFA produced per milligram of NDF digested was more variable than gas (r2 = .72), with a slope of .01 mmol VFA/mg of NDF digested. The relationship between gas and VFA production was linear (mean slope of 1.43 mmol gas/mmol VFA, r2 = .69). The ratios of end products (gas and VFA) to NDF digestion and the ratio of acetate:propionate were variable during the first 8 h of fermentation but changed little after this time. Changes in the acetate: propionate ratio explained 23% of the variation in gas produced per millimole of total VFA detected.

Acetates↗
PubMed1997

Effect of increasing proportion of supplemental nitrogen from urea on intake and utilization of low-quality, tallgrass-prairie forage by beef steers.

Five Angus x Hereford steers with ruminal and duodenal fistulas were used in a 5 x 5 Latin square to determine effects of increasing the proportion of urea in supplemental degradable intake protein (DIP) on intake, fermentation, and digestion. Steers had ad libitum access to low-quality, tallgrass-prairie forage (2.4% CP, 76% NDF). Supplemental DIP (380 g/d) was from sodium caseinate and(or) urea and was balanced with cornstarch to provide a final supplement (approximately 939 g DM/d) that contained 40% CP. The percentages of supplemental DIP from urea were 0, 25, 50, 75, and 100%. Intake of forage OM was not affected (P > or = .30) by urea level. Ruminal and total tract digestibilities of OM and NDF generally responded in a quadratic manner (P < or = .09) to increasing urea, with the lowest values observed at the highest urea level. As a result, digestible OM intake (DOMI) declined (linear, P = .03) with increasing proportions of urea and tended (quadratic, P = .14) to exhibit the largest proportional decline at the highest urea level. The effects of increasing urea on duodenal N flow, microbial efficiency, ruminal contents, and fluid dilution rate were minimal. Ruminal ammonia N and molar percent acetate increased linearly (P < or = .02), whereas most other VFA (except propionate) decreased (P < or = .05) with increasing urea. In conclusion, although forage OM intake was not altered, OM digestion, NDF digestion, and DOMI were lowest when all supplemental DIP was supplied as urea. Changes in fermentation characteristics reflected the change in source of available nitrogen.

Ammonia↗
PubMed1998

Splanchnic tissue energy use in ruminants that consume forage-based diets ad libitum.

The effects that characteristics of forage-based diets on gut and liver energy use in sheep with ad libitum consumption were discussed, and practical consequences of diet and animal effects on splanchnic energy use were projected. Explained variation in portal-drained viscera (PDV) and hepatic energy use by sheep in recent experiments increased when independent variables were included in regressions on DE intake (DEI) (PDV: R2=33 vs 22%; liver: R2=48 vs 25%). The regression equations used were the following: PDV energy use, Mcal/d=-.0194 + (.1207 x DEI, Mcal/d) + (1.1173 x fecal NDF excretion, kg/d) - (.2860 x DEI x fecal NDF excretion) and hepatic energy use, Mcal/d=.0014 + (.0266 x DEI, Mcal/d) + (.3325 x PDV energy use, Mcal/d) + (.0745 x urea N hepatic net flux, mol/d) + (.0016 x BW, kg). Thus, gut digesta, as implied by fecal NDF excretion, seemed to influence PDV energy use in addition to the effect of DEI, and energy consumption by the liver seemed affected by PDV energy use and hepatic ureagenesis. A regression equation (R2=49%) for splanchnic bed energy use, expressed as a percentage of DEI, was 43.61 - (9.531 x DEI, Mcal/d) + (15.914 x fecal NDF excretion, kg/d) + (6.057 x urea N hepatic net flux, mol/ d). If physiological control of feed intake with effect of efficiency of energy metabolism is assumed, and if whole-body efficiency of energy metabolism with ad libitum intake is constant, then efficiency of energy metabolism in extrasplanchnic tissues decreases as level of ad libitum intake and the ratio of splanchnic bed energy use to DEI decrease. Therefore, animal characteristics (e.g., maturity, body condition, and biological type) and grazing conditions (e.g., forage mass) may affect feed intake by influencing heat production by peripheral tissues. In conclusion, an increased understanding of dietary influences on efficiency of splanchnic tissue metabolism may lead to enhanced efficiency of forage utilization and ruminant production systems.

Animal Nutritional Physiological Phenomena↗
PubMed1998

Evaluation of wheat middlings as a supplement for beef cows grazing native winter range with differing forage availabilities.

We conducted two studies to compare wheat middlings as a low-protein, highly digestible fiber supplement to soybean meal and corn-soybean meal supplement for cows grazing winter range. In two 60-d winter grazing trials (December to February) cows (BW 500 kg) were allotted by age and weight to a 2 x 4 factorial with two forage availabilities and four supplements. Cows received either soybean meal (SBM), corn-soybean meal (CS), low wheat middlings (LWM), or high wheat middlings (HWM). The SBM and LWM supplements were formulated to provide the same daily CP, and CS and HWM provided the same daily CP and ME. In a 4 x 4 Latin square, four ruminally fistulated steers (BW 765 kg) received the same supplements and had free access to mature prairie hay. Cows grazing the high forage pasture gained more (P < .01) weight than cows grazing the low forage pasture. Cows supplemented with HWM gained less weight (P = .05) than cows supplemented with a similar amount of CP and ME from CS. Weight change of cows receiving SBM or LWM was similar. Increasing the amount of wheat middlings from LWM to HWM increased weight change (P = .04). In Exp. 2, SBM and LWM had similar total digestible DMI (DDMI). Steers supplemented with CS had higher total (P = .08) DDMI than HWM. Supplementation with HWM resulted in lower total (P = .02) DDMI than LWM. Response to SBM and LWM was similar. The CS and HWM resulted in beneficial performance responses as well as increasing the level of wheat middlings from low to high.

Animal Feed↗
PubMed1998

Ensiling effects of the ethanol fractionation of forages using gas production.

We studied the use of gas curve subtraction to distinguish between two fractions soluble in neutral detergent solution. Samples of unfractionated (whole) forage, residue insoluble in 90% ethanol, and isolated NDF were fermented in vitro, and gas production was monitored. The gas volume associated with the ethanol solubles (A fraction) was determined as the difference between the gas from the whole forage and from the ethanol residue. The gas yield associated with the fraction insoluble in 90% ethanol but soluble in neutral detergent solution (B fraction) was determined by subtracting the isolated NDF gas curve from the corresponding ethanol residue curve. This experiment included three forages (alfalfa, bromegrass, and orchardgrass) harvested at two maturities and preserved by freeze-drying or ensiling to form a 3 x 2 x 2 factorial arrangement. Ensiling reduced the rate of gas formation from the A fraction by approximately 30% (P < .01). Ensiling increased (P < .05) the size of the A fraction (2 to 10% of DM) but did not change the volume of gas produced (P > .05). The gas yield from the B1 fraction was reduced 40% (P < .05) by ensiling with no significant change in rate. Curve subtraction of gas production profiles may be used to obtain rate estimates for multiple neutral detergent soluble pools. The separation of the neutral detergent solubles into two pools clarified the effects caused by ensiling. Changes due to ensiling on the rate of gas produced were associated with the A fraction, and the effects on final gas volume were associated with the B1 fraction.

Animals↗
PubMed1999

In situ neutral detergent insoluble nitrogen as a method for measuring forage protein degradability.

A method of estimating the undegraded intake protein (UIP) concentration of forages was developed and validated with a series of in situ experiments. The hypothesis was that UIP calculated from in situ neutral detergent insoluble N (NDIN) is equal to total in situ N minus the microbial N that is estimated from purines (MN). The in situ disappearance rates of total in situ N (TN), MN, and NDIN were measured for six hay samples and two range masticate samples. Hypothetical rates of passage (2 or 5%/h) were used to calculate UIP (% of DM) for each N pool. Estimates of UIP from TN were higher (P = .0001) than those from either MN or NDIN, and MN estimates of UIP were similar (P = .48) to NDIN estimates. A low-N fiber source (solka floc) was incubated in situ for 8 h. Analysis of the residue detected purines before, but not after, neutral detergent extraction. Several in situ incubation (i.e., Dacron bag size and number of Dacron bags in a mesh bag) and neutral detergent extraction conditions were tested. None of the factors tested affected in situ NDIN disappearance (P > .05). The hypothesis that NDIN is completely digestible in the rumen was tested. Estimates of the extent of NDIN digestion were made using 96-h in situ incubations, and UIP was recalculated for the test samples. Mean in situ UIP concentration decreased upon recalculation (P = .05). In situ NDIN provides estimates of forage UIP that are equal to estimates from MN. Forage UIP estimates are less when extent of N degradation is estimated and included in the calculation.

Animal Feed↗
PubMed2001

Tasco-Forage: I. Influence of a seaweed extract on antioxidant activity in tall fescue and in ruminants.

Seaweed (Ascophyllum nodosum) is a known source of plant growth regulators, and application to turfgrasses has increased activity of the antioxidant superoxide dismutase (SOD) and specific vitamin precursors. Increased antioxidant activity in both plants and animals diminishes oxidative stress. Two pasture experiments investigated effects of Tasco-Forage (a proprietary seaweed-based product) applied to tall fescue (Festuca arundinacea) on antioxidant activity in plants and in ruminants that grazed the forage. In Exp. 1, fescue was 70 to 100% infected with the endophyte fungus Neotyphodium coenophialum ([Morgan-Jones and Gams] Glenn, Bacon, and Hanlin). Twenty-four wether lambs (initial BW 41 kg; SD = 5) grazed fescue treated with 0, 1.7, or 3.4 kg Tasco/ha applied in April and July, 1994, with four replications per treatment. Grazing occurred for 26 d beginning April 21 and for 22 d beginning July 19. In July, there was a linear increase in daily gains (P < 0.05), and serum vitamin A (P < 0.13) and whole-blood Se (P < 0.10) tended to increase in lambs grazing Tasco-treated fescue. In Exp. 2,48 Angus and Angus x Hereford steers (initial BW 245 kg; SD = 20) grazed infected or uninfected tall fescue in Virginia that was treated (3.4 kg/ ha) or untreated with Tasco in April and July, 1995. Steers that grazed infected tall fescue had lower (P < 0.02) serum vitamin A and E and tended (P < 0.07) to have lower whole-blood Se in September compared with steers that grazed uninfected tall fescue. Tasco decreased (P < 0.06) serum vitamin E but tended to increase whole-blood Se (P < 0.10) in September and serum vitamin A in July (P < 0.12). During 1996 and 1997, the experiment was repeated in Virginia with Angus steers and was replicated at Prairie, MS, where 1/4 Brahman x 3/4 Angus steers were used. Forty-eight steers were included at each location in each year (n = 192 total steers for 1996 and 1997). Steers that grazed infected tall fescue in Mississippi had lower (P < 0.05) serum vitamin E by the end of the grazing season. At both locations Tasco increased (P < 0.05) activity of superoxide dismutase in both infected and uninfected fescue. The endophyte in tall fescue seemed to decrease antioxidant activity in grazing steers, whereas Tasco seemed to increase antioxidant activity in both the forage and the grazing ruminant. Tasco may provide opportunities to reduce oxidative stress in plants and animals.

Animal Feed↗
PubMed2001

Tasco-Forage: III. Influence of a seaweed extract on performance, monocyte immune cell response, and carcass characteristics in feedlot-finished steers.

Tall fescue (Festuca arundinacea Schreb.) infected with the endophyte Neotyphodium coenophialum ([Morgan-Jones and Gams] Glenn, Bacon, and Hanlin) causes fescue toxicosis in cattle grazing the forage, but effects of the endophyte were considered to be abated soon after removal of the animals from pastures. Tasco-Forage, a proprietary extract from the brown seaweed Ascophyllum nodosum, is a known source of cytokinins and has increased antioxidant activity in both plants and the animals that graze the forage. Tasco was applied at 0 and 3.4 kg/ha to infected and uninfected tall fescue pastures in Virginia and Mississippi. Forty-eight steers grazed the pastures at each location during each of 2 yr (n = 192) before being transported to Texas for feedlot finishing. On arrival at the feedlot, steers from Tasco-treated pastures had higher (P < 0.01) monocyte phagocytic activity and tended (P < 0.07) to have higher major histocompatibility complex class II expression than steers that grazed the untreated pastures. A depression (P < 0.05) in monocyte immune cell function due to grazing infected fescue was detected throughout the feedlot finishing period but was reversed by Tasco. Rectal temperatures were elevated (P < 0.07) in steers that had grazed the infected tall fescue when they arrived in Texas, but by d 14 no difference was detected. However, by d 28 the temperature effects of infected tall fescue were reversed. Steers that had grazed infected fescue had lower (P < 0.01) rectal temperatures on d 112 of the feedlot period, demonstrating a much longer-lasting effect of the endophyte on thermoregulatory mechanisms than previously thought. Steers that had grazed Tasco-treated pastures had higher (P < 0.01) rectal temperatures on d 56 than steers that had grazed untreated fescue. Steers that had grazed the Tasco-treated pastures had higher marbling scores (P < 0.05) regardless of the endophyte, but no effect of Tasco or endophyte on gain was measured. Our data suggest that Tasco application to tall fescue pastures alleviated some of the negative effects of tall fescue toxicity.

Animal Feed↗
PubMed2001

Effects of supplement type on animal performance, forage intake, digestion, and ruminal measurements of growing beef cattle.

Two experiments were conducted to determine the effects of supplement type on the rate of gain by heifers grazing bermudagrass and on the intake, apparent total-tract OM digestibility, ruminal fermentation, digesta kinetics, in situ DM digestibility, and forage protein degradation by steers fed prairie hay. In Exp. 1, 45 heifers (284+/-24 kg) grazed a bermudagrass pasture for 91 d in the late summer to determine the effects of no supplement (CON), or one of four individually fed monensin-containing (150 mg/[heifer x d]) supplements (MINCS; 0.1 kg of mineral mix with 0.2 kg [DM] of cottonseed hulls as a carrier/[heifer x d]), a pelleted protein supplement (PROT; 1 kg of DM, 242 g of degradable intake protein [DIP]/[heifer x d]), or high-fiber (HF) and high-grain (HG) (2 kg of DM, 243 and 257 g of DIP, respectively/[heifer x d]) pelleted energy supplements. In Exp. 2, four ruminally cannulated steers (311+/-22 kg) with ad libitum access to low-quality (4% DIP, 73% NDF, 40% ADF) prairie hay were individually fed monensin-containing (200 mg/[steer x d]) treatments consisting of 1) mineral mix + corn (MINCR; 0.1 kg of mineral and 0.4 kg of cracked corn [DM] as a carrier, 19 g of DIP/[steer x d]), 2) PROT (1.4 kg of DM, 335 g of DIP/[steer x d]), 3) HF, or 4) HG (2.9 kg of DM, 340 and 360 g of DIP, respectively/[steer x d]) in a 4 x 4 Latin square with 14-d adaptation and 6-d sampling periods. In Exp. 1, the HF-, HG-, and PROT-supplemented heifers had greater (P < 0.01) rates of gain than CON heifers, and the HF- and HG-supplemented heifers tended (P < 0.11) to gain more weight than those fed PROT. In Exp. 2, steers fed PROT consumed more (P < 0.05) hay OM than HF and HG, or MINCR. Total OM intake was greater (P < 0.01) by supplemented steers than MINCR-fed cattle. Hay OM digestibility was not affected (P = 0.19) by treatment, but total diet OM digestibility was greater (P < 0.01) for HF- and HG- than for MINCR- or PROT-fed steers. The rate of in situ DM digestibility was greater (P < 0.01) for HF, HG, and PROT than for MINCR. Results from these studies indicate that feeding milo- vs fiber-based energy supplements formulated to provide adequate DIP did not result in different forage intake, OM digestibility, or in situ DM digestibility, whereas both increased ADG in heifers consuming low-quality forages compared with unsupplemented or mineral- or protein-supplemented cattle. An adequate DIP:TDN balance decreased the negative associative effects often observed when large quantities of high-starch supplements are fed with low-quality hay.

Animal Feed↗
PubMed2002

Influence of rumen protein degradability and supplementation frequency on steers consuming low-quality forage: I. Site of digestion and microbial efficiency.

Seven cannulated (rumen and duodenal) Angus x Hereford steers (264 +/- 8 kg BW) consuming low-quality forage (5% CP; 61% NDF; 31% ADF) were used to determine the influence of CP degradability and supplementation frequency (SF) on DMI and nutrient digestion. Treatments included an unsupplemented control and degradable intake protein (DIP) or undegradable intake protein (UIP) provided daily, every 3 d, or every 6 d. The DIP treatments (18% UIP) were calculated to provide 100% of the DIP requirement, while the UIP treatments (60% UIP) were provided on an isonitrogenous basis compared with DIP. Forage DMI was not affected by treatment. Total DM and N intake, duodenal N flow, and intestinal N disappearance increased (P < 0.01) with supplementation. Dry matter intake and duodenal N flow responded quadratically (P < 0.04; greatest values on the every-third-day treatments) as SF decreased. However, no differences in N intake or intestinal N disappearance were observed because of CP degradability or SF. Duodenal bacterial N flow and true bacterial N synthesis (g bacterial N/kg of OM truly digested in the rumen) were increased (P < 0.05) with supplementation. Also, duodenal bacterial N flow was greater (P < 0.05) for DIP compared with UIP. Duodenal nonbacterial N flow was increased (P = 0.02) with CP supplementation and for UIP compared with DIP (P < 0.01). Supplemental CP increased (P < 0.01) total tract DM and N digestibility with no difference due to CP degradability or SF. Results suggest CP supplements consisting of 20 to 60% UIP can be effectively used by steers consuming low-quality forage without adversely affecting DMI, nutrient digestibility, or bacterial CP synthesis, even when provided as infrequently as once every 6 d.

Animal Feed↗