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PubMed2001

Responses to climatic factors by foragers of Plebeia pugnax Moure (in litt.) (Apidae, Meliponinae).

Flight activity of Plebeia pugnax Moure (in litt.) was studied in six colonies coming from Cunha, SP, from July to October 1994. Twice a week, from 8:00 a.m. to 6:00 p.m., for 5 minutes every half-hour, all the bees entering and leaving the hives were counted. Six hundred counts were made and the materials that foragers carried were recorded. Data were analysed in relation to temperature, relative humidity, light intensity and day time. Foragers' flight activity was relatively constant in a wide range of temperature, from 22 degrees C to 34 degrees C. The minimum temperature for the beginning of flight activity was 14 degrees C. Effective flight activity (when foragers of all colonies were leaving the hives) occurred at 15 degrees C. These bees also flew within a wide range of relative humidity, from 30% to 100%, decreasing slowly after 50%. Flight activity increased as light intensity rose and it has also increased as the hours passed by, reaching a peak around midday and decreasing gradually afterwards. Pollen was collected all day long, while resin collection was relatively constant and debris transportation was slightly higher after 10:00 h. From all known Plebeia species, this one flew on the lowest temperature ever registered for this genus.

Animals↗
PubMed2002

Prey foraging behavior, seasonality and time-budgets in black lion tamarins, Leontopithecus chrysopygus (Mikan 1823) (Mammalia, Callitrichidae).

Foraging behavior, seasonality and time-budgets in the Black Lion Tamarin (L. chrysopygus) was observed in the Caetetus Ecological Station, South-eastern Brazil, during 83 days between November 1988 to October 1990. For the full dry season we found that animal prey represented 11.2% of the black lion tamarin diet, while during the wet season they represented 1.9%. Foraging behavior made up 19.8% of their total activity in the dry season and only 12.8% in the wet season. These results point out that animal prey are relatively more important during the dry season, due to reduced availability of other resources, e.g. fruits, and that a greater foraging effort is required when a larger proportion of the diet is animal prey.

Animals↗
PubMed2005

Meals for two: foraging activity of the butterflyfish Chaetodon striatus (Perciformes) in southeast Brazil.

The banded butterflyfish (Chaetodon striatus) from the tropical and subtropical western Atlantic is a territorial, diurnal forager on benthic invertebrates. It is usually seen moving singly or in pairs, a few meters above the sea floor. We studied the foraging activity of C. striatus on rocky reefs in southeastern Brazil. This fish spent about 11 h and 30 min per day on feeding activities, and preferred colonies of non-scleratinian anthozoans over sandy and rocky substrata while foraging. The lowest feeding rates were recorded in the early morning and late afternoon, but we found no further differences between feeding rates throughout the day. We also found no differences between the feeding rates of paired and single individuals.

Animals↗
PubMed2000

Foraging resources of adult Mexican corn rootworm (Coleoptera: Chrysomelidae) in Bell County, Texas.

Pollen analyses were used to determine pollen foraging resources of adult Mexican corn rootworms, Diabrotica virgifera zeae Krysan & Smith, captured near Temple, Bell County, TX, in 1996 and 1997. In 1996, adult Mexican corn rootworms were captured in a corn, Zea mays L., field. In 1997, nine locations outside of cornfields were added. Overall, 92% of the beetles (n = 1,323) contained pollen. More than 142,000 pollen grains were counted, representing 45 families, 63 genera, and 27 species. Overall, in 1996, noncorn grass pollen (70%) occurred in the greatest percentage of total pollen followed by corn (17%), then nongrass pollen (13%). In 1997, noncorn grass pollen (76%) had the greatest percentage, then nongrass (18%), and finally corn pollen (6%). Corn pollen was found in 34% of the beetles in 1996 and 26% in 1997. Fifteen Asteraceae taxa were encountered including sunflower, Helianthus annuus L. Thirteen Fabaceae were found including soybean, Glycine max L. Mexican corn rootworm adults foraged mainly on noncorn grass pollen, but also foraged on pollen from a large diversity of plant species, indicating that noncorn pollen may play a role in the food habits of Mexican corn rootworm adults.

Animals↗
PubMed2000

Impact of Bemisia whiteflies (Homoptera: Aleyrodidae) on alfalfa growth, forage yield, and quality.

A 3-yr project was initiated in 1993 to examine the effects of insecticides and sustained whitefly, Bemisia argentifolii Bellows & Perring [aka. B tabaci Gennadius (Strain B)], feeding on alfalfa plant growth and vigor in greenhouse cage studies, and to determine the impact of natural Bemisia whitefly populations on alfalfa forage yields and quality in a large-plot field experiment. Alfalfa plant growth and vigor after exposure to imidacloprid and a mixture of fenpropathrin and acephate insecticides did not differ from untreated plants in the greenhouse. Consequently, foliar and soil applied insecticides were used to manipulate whitefly densities on alfalfa plants to measure whitefly feeding effects on plant growth and forage yield. Heavy whitefly densities on untreated alfalfa plants in the greenhouse resulted in significant reductions in relative growth rates and net assimilation rates as compared with imidacloprid-treated plants that were maintained relatively whitefly-free. Reductions in alfalfa plant growth measured between infested and treated plants were proportional to whitefly densities. Field plot results derived from three crop seasons were relatively consistent with our greenhouse trials. Both experimental approaches clearly showed that alfalfa plants exposed to high densities of whitefly immatures and adults grew at a significantly slower rate and produced less foliage. As a result of reduced growth rates, alfalfa maturity in the naturally infested plots was estimated to be approximately 7-10 d behind managed plots. Delays in maturity resulted in significant reductions in forage yields of 13-18% during August-September harvests when whitefly populations reached peak abundance. Whitefly feeding stresses also effected hay quality through the reduction of crude protein content and contamination of foliage with honeydew and sooty mold. The status of the Bemisia whiteflies as an economic pest to alfalfa is clearly evident from these studies, but the damage potential of whiteflies in the southwestern United States appears to be restricted to one or two harvest periods during the summer coinciding with peak adult populations and their dispersal from alternate host crops.

Animals↗
PubMedDate not supplied

Methane emissions of beef cattle on forages: efficiency of grazing management systems.

Fermentation in the rumen of cattle produces methane (CH4). Methane may play a role in global warming scenarios. The linking of grazing management strategies to more efficient beef production while reducing the CH4 emitted by beef cattle is important. The sulfur hexafluoride (SF6) tracer technique was used to determine the effects of best management practices (BMP) grazing compared with continuous grazing on CH4 production in several Louisiana forages during 1996-1998. Cows and heifers (Bos taurus) grazed common bermudagrass [Cynodon dactylon (L.) Pers.], bahiagrass (Paspalum notatum Flugge), and ryegrass (Lolium multiflorum Lam.) pastures and were wintered on bahiagrass hay with supplements of protein molasses blocks (PMB), cottonseed meal and corn (CSMC), urea and corn (URC), or limited ryegrass grazing (LRG). Daily CH4 emissions were between 89 and 180 g d(-1) for young growing heifers and 165 to 294 g d(-1) for mature Simbrah cows. Heifers on "ad lib" ryegrass in March and April produced only one-tenth the CH4 per kg of gain as heifers on LRG of 1 h. Using BMP significantly reduced the emission of CH4 per unit of animal weight gain. Management-intensive grazing (MIG) is a BMP that offers the potential for more efficient utilization of grazed forage crops via controlled rotational grazing and more efficient conversion of forage into meat and milk. Projected CH4 annual emissions in cows reflect a 22% reduction from BMP when compared with continuous grazing in this study. With the BMP application of MIG, less methane was produced per kilogram of beef gain.

Animal Husbandry↗
PubMedDate not supplied

Nitrogen removal and nitrate leaching for two perennial, sod-based forage systems receiving dairy effluent.

In northern Florida, year-round forage systems are used in dairy effluent sprayfields to reduce nitrate leaching. Our purpose was to quantify forage N removal and monitor nitrate N (NO3(-)-N) concentration below the rooting zone for two perennial, sod-based, triple-cropping systems over four 12-mo cycles (1996-2000). The soil is an excessively drained Kershaw sand (thermic, uncoated Typic Quartzip-samment). Effluent N rates were 500, 690, and 910 kg ha(-1) per cycle. Differences in N removal between a corn (Zea mays L.)-bermudagrass (Cynodon spp.)-rye (Secale cereale L.) system (CBR) and corn-perennial peanut (Arachis glabrata Benth.)-rye system (CPR) were primarily related to the performance of the perennial forages. Nitrogen removal of corn (125-170 kg ha(-1)) and rye (62-90 kg ha(-1)) was relatively stable between systems and among cycles. The greatest N removal was measured for CBR in the first cycle (408 kg ha(-1)), with the bermudagrass removing an average of 191 kg N ha(-1). In later cycles, N removal for bermudagrass declined because dry matter (DM) yield declined. Yield and N removal of perennial peanut increased over the four cycles. Nitrate N concentrations below the rooting zone were lower for CBR than CPR in the first two cycles, but differences were inconsistent in the latter two. The CBR system maintained low NO3(-)-N leaching in the first cycle when the bermudagrass was the most productive; however, it was not a sustainable system for long-term prevention of NO3(-)-N leaching due to declining bermudagrass yield in subsequent cycles. For CPR, effluent N rates > or = 500 kg ha(-1) yr(-1) have the potential to negatively affect ground water quality.

Biodegradation, Environmental↗
PubMed2006

Estimating yields of salt- and water-stressed forages with remote sensing in the visible and near infrared.

In arid irrigated regions, the proportion of crop production under deficit irrigation with poorer quality water is increasing as demand for fresh water soars and efforts to prevent saline water table development occur. Remote sensing technology to quantify salinity and water stress effects on forage yield can be an important tool to address yield loss potential when deficit irrigating with poor water quality. Two important forages, alfalfa (Medicago sativa L.) and tall wheatgrass (Agropyron elongatum L.), were grown in a volumetric lysimeter facility where rootzone salinity and water content were varied and monitored. Ground-based hyperspectral canopy reflectance in the visible and near infrared (NIR) were related to forage yields from a broad range of salinity and water stress conditions. Canopy reflectance spectra were obtained in the 350- to 1000-nm region from two viewing angles (nadir view, 45 degrees from nadir). Nadir view vegetation indices (VI) were not as strongly correlated with leaf area index changes attributed to water and salinity stress treatments for both alfalfa and wheatgrass. From a list of 71 VIs, two were selected for a multiple linear-regression model that estimated yield under varying salinity and water stress conditions. With data obtained during the second harvest of a three-harvest 100-d growing period, regression coefficients for each crop were developed and then used with the model to estimate fresh weights for preceding and succeeding harvests during the same 100-d interval. The model accounted for 72% of the variation in yields in wheatgrass and 94% in yields of alfalfa within the same salinity and water stress treatment period. The model successfully predicted yield in three out of four cases when applied to the first and third harvest yields. Correlations between indices and yield increased as canopy development progressed. Growth reductions attributed to simultaneous salinity and water stress were well characterized, but the corrections for effects of varying tissue nitrogen (N) and very low leaf area index (LAI) are necessary.

Agriculture↗
PubMed2002

Individual complexity and self-organization in foraging by leaf-cutting ants.

Leaf-cutting ants cut vegetation into small fragments that they transport to the nest, where a symbiotic fungus cultivated by the ants processes the material. Since the harvested leaf fragments are incorporated into the fungus garden and not directly consumed by the workers, it is expected that foraging workers select plants by responding to those physical or chemical traits that promote maximal fungal growth, irrespective of the potential direct effects of these leaf features on them. In this paper I summarize experimental work focusing on the decision-making processes that occur at the individual level, and discuss to what extent individual complexity contributes to the emergence of collective foraging patterns. Although some basic features of self-organizing systems, such as the existence of regulatory positive and negative feedback loops, are expected to be involved in the collective organization of leaf-cutting ant foraging, I contend that they are combined with complex individual responses that may result from the integration of local information during food collection with an assessment of colony conditions.

Animals↗
PubMed1990

Comparison of soybean meal/sorghum grain, alfalfa hay and dehydrated alfalfa pellets as supplemental protein sources for beef cattle consuming dormant tallgrass-prairie forage.

Three experiments were conducted to compare soybean meal/sorghum grain (SBM/SG), alfalfa hay or dehydrated alfalfa pellets (DEHY) as supplemental protein sources for beef cattle grazing dormant range forage. In Exp. 1 (35-d digestion study), 16 ruminally cannulated steers were stratified by weight (average BW 259 kg) and assigned randomly within stratification to: 1) control, no supplement; 2) SBM/SG (25% CP) fed at .48% BW; 3) alfalfa hay (17% CP) fed at .70% BW; or 4) DEHY (17.4% CP) fed at .67% BW. Steers receiving protein supplements displayed at least a twofold increase in forage intake (P less than .10). In addition, steers supplemented with DEHY consumed approximately 15% more forage (P less than .10) than SBM/SG- or alfalfa hay-supplemented steers. Digestible DM intake (kg/d), however, was similar between alfalfa hay- and DEHY-supplemented steers and 20% greater (P less than .10) than for SBM/SG-supplemented steers. In Exp. 2, 82 mature, nonlactating Hereford x Angus cows (average BW 489 kg) were assigned randomly to SBM/SG, alfalfa hay or DEHY supplement treatments, which were replicated in three pastures. Cows supplemented with DEHY gained more weight (P less than .05) during the first 84 d of supplementation and displayed the least amount of weight loss at calving (d 127; P less than .05) and just prior to breeding (P less than .10). In contrast, calving interval (361 d) and pregnancy rate (94%) were unaffected (P greater than .10) by dam's previous supplemental treatment. In Exp. 3, one block (pasture) of cows from Exp. 2 was selected at random and grazing behavior was monitored during week-long periods in January and February. A treatment X time interaction (P less than .05) occurred for total time spent grazing; treatments did not differ in January, but cows supplemented with alfalfa hay spent less time grazing in the February grazing period. In conclusion, DEHY and alfalfa hay appear to be at least as effective as SBM/SG as a supplemental protein source for pregnant grazing cows when supplements are fed on an equal CP and ME basis.

Animal Feed↗
PubMed1990

Differential passage rates and digestion of neutral detergent fiber from grain and forages in 30, 60 and 90% concentrate diets fed to steers.

Six ruminally cannulated steers were used to determine the effects of altering dietary concentrates on fiber digestion. Diets contained 30, 60 or 90% of a concentrate based on flaked sorghum grain plus a 50:50 mixture of wheat straw and alfalfa hay. Total tract digestibility of NDF was not altered, but digestibility of potentially digested NDF (PDF) decreased (P less than .05) from 92 to 48% as concentrates increased from 30 to 90% of diet DM. Ruminal passage rate for straw (3.4 and 3.0%/h) and for hay (4.6 and 4.7%/h) was unchanged when concentrate was increased from 30 to 60%, but it decreased by 28 (2.2%/h) and 13% (4.1%/h), respectively (P less than .05), when concentrates were increased to 90%. Passage rate for grain (5.3, 5.1 and 4.4%/h) and fluid (9.3, 10.0 and 8.2%/h) was not influenced by concentrate percentage. Calculated ruminal digestibilities of NDF in individual ingredients did not differ between 30 and 60% concentrates, but they decreased (P less than .05) by 72, 57 and 34% for straw, hay and grain when concentrate was increased to 90%. Because of their relative contribution to total diet NDF, straw, hay and grain accounted for 28, 18 and 54% of the total decrease in estimated fiber digestion. It is concluded that PDF as well as NDF should be evaluated in studies of concentrate effects on fiber digestion, and that dietary concentrate level has more influence on passage rate of low-quality forage than on passage rate of grain or high-quality forage. In 90% concentrate diets, although fiber digestibility was depressed more for forage than for grain, grain accounted for most of the depression in fiber digestion because grain was the primary source of dietary fiber.

Animal Feed↗
PubMed1991

Extent and site of mineral release from six forage species incubated in mobile dacron bags.

A study was conducted to measure the extent of DM disappearance and mineral release from six forage species within the rumen, abomasum and intestines of the adult bovine using the mobile bag technique. Three nonlactating Holstein cows, fitted with ruminal and duodenal cannulas, were given ad libitum access to alfalfa hay. One gram (DM) of alfalfa, rhizoma peanut, dwarf elephantgrass, bahiagrass, bermudagrass, and limpograss was individually weighed into 8-cm x 3-cm dacron bags. After ruminal incubation for 24 h, bags were incubated in an acid-pepsin solution (a simulated abomasal environment) for 1 h, inserted into the duodenum via cannula, and collected in the feces upon excretion. Ruminal incubation accounted for 86% to 100% of total DM disappearance. Release of Ca from all forages was at least 65%, with the majority having extents of release of over 70%. Most Ca was released in the rumen, but acid-pepsin incubation and washing increased Ca release an additional 17 to 272%. Forages with the highest NDF concentration (bermuda, bahia, and limpograss) sequestered Ca in the intestines. Total tract P release ranged from 84 to 98%, with an average of 7.5 percentage units occurring postabomasally. Grasses released more P in the intestines than legumes. Eighty-eight to 98% of total Mg was released in the rumen. Acid-pepsin incubation increased Mg release only slightly, with some Mg being sequestered in the intestines. Potassium release was complete in the rumen. Ranking of minerals based on maximal extent of release was K greater than Mg greater than P greater than Ca. With the exception of K, legumes released more of their minerals than grasses.

Abomasum↗
PubMed1991

Forage mineral concentration, animal performance, and mineral status of heifers grazing cereal pastures fertilized with sulfur.

Thirty yearling Santa Gertrudis-sired heifers (average initial weight 238 kg) were continuously grazed (five heifers/pasture) on six 2-ha oat-wheat small grain pastures for 112 d to determine the effect of fertilization of pastures with urea (U) vs ammonium sulfate (AS) on mineral status and performance of heifers. Pastures were fertilized with either U, at 200 kg/ha, or AS, at 438 kg/ha, to provide 92 kg of N/ha in November 1987 and March 1988. Ammonium sulfate provided 107 kg of S/ha. Forage samples were collected during each month. Heifers were initially weighed following an overnight fast and at the end of four consecutive 28-d intervals (Periods 1 to 4). Serum and ruminal fluid were collected on d 56 and 112. Pastures fertilized with AS had a greater (P less than .10) in vitro dry matter disappearance during Periods 2 and 3. Ammonium sulfate-fertilized pastures had greater than (P less than .05) S concentrations from January 29 through termination of the trial. There were no differences in ADG (P less than .28) or gain/ha (GPH; P less than .43) over 112 d; however, heifer ADG was greater (P less than .08) in Period 3 and tended to be greater (P less than .16) in Period 2 for those animals grazing U-fertilized pastures. Pastures receiving AS produced less (P less than .04) GPH during Period 2. Ammonium sulfate fertilization in this trial had no effect on forage K, Ca, P, Mg, Cu, or Mo mineral concentrations or on serum mineral and ruminal VFA concentrations, but it did result in an increase in IVDMD and a trend for decreased ADG apparently associated with a decrease in forage intake.

Ammonium Sulfate↗
PubMed1992

Forage systems for beef production from conception to slaughter: I. Cow-calf production.

Six year-round, all-forage, three-paddock systems for beef cow-calf production were used to produce five calf crops during a 6-yr period. Forages grazed by cows during spring, summer, and early fall consisted of one paddock of 1) tall fescue (Festuca arundinacea Schreb.)-ladino clover (Trifolium repens L.) or 2) Kentucky blue-grass (Poa pratensis L.)-white clover (Trifolium repens L.). Each of these forage mixtures was combined in a factorial arrangement with two paddocks of either 1) fescue-red clover (Trifolium pratense L.), 2) orchardgrass (Dactylis glomerata L.)-red clover, or 3) orchardgrass-alfalfa (Medicago sativa L.), which were used for hay, creep grazing by calves, and stockpiling for grazing by cows in late fall and winter. Each of the six systems included two replications; each replicate contained 5.8 ha and was grazed by eight Angus cow-calf pairs for a total of 480 cow-calf pairs. Fescue was less than 5% infected with Acremonium coenophialum. Pregnancy rate was 94%. Cows grazing fescue-ladino clover maintained greater (P less than .05) BW than those grazing bluegrass-white clover, and their calves tended (P less than .09) to have slightly greater weaning weights (250 vs 243 kg, respectively). Stockpiled fescue-red clover provided more (P less than .05) grazing days and required less (P less than .05) hay fed to cows than stockpiled orchardgrass plus either red clover or alfalfa. Digestibilities of DM, CP, and ADF, determined with steers, were greater (P less than .05) for the orchardgrass-legume hays than for the fescue-red clover hay. All systems produced satisfactory cattle performance, but fescue-ladino clover combined with fescue-red clover required minimum inputs of harvested feed and maintained excellent stands during 6 yr.

Animal Feed↗
PubMed1992

Performance, forage utilization, and ergovaline consumption by beef cows grazing endophyte fungus-infected tall fescue, endophyte fungus-free tall fescue, or orchardgrass pastures.

Two 120-d trials (May to September, 1988 and 1989) determined the effects of grazing tall fescue (two varieties) or orchardgrass on forage intake and performance by beef cows. Each summer, 48 cow-calf pairs grazed endophyte-infected Kentucky-31 tall fescue (KY-31), endophyte-free Mozark tall fescue (MOZARK), or Hallmark orchardgrass (OG) pastures (16 pairs/treatment). Forage OM intakes and digestibilities were determined during June and August each year. Cow and calf BW and milk production were determined every 28 d. During June of both years, OM intakes did not differ (P greater than .10) among treatments. During August of 1988, intakes were 18% lower (P less than .05) by KY-31 cows (1.6% of BW) than by MOZARK or OG cows (average 1.95% of BW); however, no differences (P greater than .10) were measured in August of 1989. Estimates of ergovaline consumption during June from KY-31 were between 4.2 (1988) and 6.0 mg/d (1989), whereas August estimates were between 1.1 (1988) and 2.8 mg/d (1989). Ergovaline in MOZARK estrusa was below detection limits, except in August of 1989. Cows that grazed KY-31 lost three times (P less than .01) more BW than cows that grazed MOZARK or OG (42 vs 9 and 13 kg, respectively). Milk production by KY-31 cows was 25% lower (P less than .01) than that by cows that grazed MOZARK or OG (6.0 vs average of 8.0 kg/d). Similarly, slower (P less than .01) calf gains were noted for KY-31 than for MOZARK or OG (.72 vs .89 and .88 kg/d, respectively). Cows grazing KY-31 experienced accelerated BW loss and reduced milk production and weaned lighter calves than did cows grazing MOZARK or OG. Decreased performance was not explained by consistently reduced forage intakes; hence, altered nutrient utilization was suspected.

Acremonium↗
PubMed1993

Feed intake, digestibility, and live weight gain by cattle consuming forage supplemented with rice bran and(or) corn.

Effects of supplementing cattle consuming forage with rice bran and(or) corn on feed intake, digestibility, and live weight gain were determined. Holstein steer calves (176 +/- 4.3 kg average trial BW), in two simultaneous 4 x 4 Latin squares, had ad libitum access to bermudagrass or ryegrass-wheat hay without supplementation (Control) or with (DM basis) .5% of BW of ground corn (C), .64% of BW of rice bran (R), or .25% of BW of corn plus .32% of BW of rice bran (CR). Total OM intake with bermudagrass diets was less for R than for C, but values for R and C were not different with ryegrass-wheat (forage source x supplement type interaction; P < .05). An interaction (P < .06) between supplement type and forage source also occurred in digestible OM intake (3.33, 3.66, 2.93, 3.37, 3.77, 4.04, 3.73, and 3.94 kg/d for Control, C, R, and CR with bermudagrass and ryegrass-wheat, respectively). Mature beef cows (504 +/- 25.5 kg BW), in a 6 x 6 Latin square, were limit-fed ryegrass-wheat and alfalfa hay (3:1; air-dry basis) without supplementation (Control) or with (DM basis) .2 or .4% of BW of ground corn (L-C and H-C), .26 or .52% of BW of rice bran (L-R and H-R), or .2% of BW of corn plus .26% of BW of rice bran (H-CR). Duodenal flows of total (125, 122, 123, 137, 136, and 129 g/d) and microbial N (63.3, 64.7, 64.8, 70.3, 73.1, and 65.1 g/d for Control, L-C, H-C, H-R, and H-CR, respectively) were greater (P < .05 and .06, respectively) for rice bran than for corn supplements. Crossbred beef steers (96; 235 +/- 3.2 kg initial BW) of two frame sizes, with half treated with an estrogenic growth promotant, grazed fescue-clover and received Control, L-C, H-C, L-R, H-R, and H-CR supplements for 84 d. Supplement amounts were 50% greater relative to BW than in the preceding experiment. Overall ADG was increased (P < .05) by supplementation and was affected (P < .05) by a supplement type x level interaction (.71, .76, .97, .85, .76, and .94 kg/d for Control, L-C, H-C, L-R, H-R, and H-CR, respectively). Neither frame size nor growth implant modified effects of supplement treatments on ADG.

Animal Feed↗
PubMed1993

Influence of Aspergillus oryzae fermentation extract on forage intake, site of digestion, in situ degradability, and duodenal amino acid flow in steers grazing cool-season pasture.

Ten ruminally and duodenally cannulated (326 +/- 28 kg) and four esophageally fistulated (394 +/- 23 kg) steers grazing cool-season pasture throughout the growing season were used to evaluate the influence of Aspergillus oryzae fermentation extract (AO) supplementation on intake, forage nutrient utilization, and duodenal amino acid flow. Steers grazed a predominantly smooth brome (Bromus inermis L.) pasture, and measurements were taken in three periods (June, July, and August). Steers were dosed daily at 0700 via the ruminal cannula with AO (2 g of AO per steer daily; DM basis) or not supplemented with AO. Each period consisted of 18 d for adaption to AO and 7 d for collection. Forage N was greater, and ADF was lower (P < .10), in June than in July and August. Ruminal pH, ammonia, total VFA concentration, and VFA proportions were not affected (P > .10) by AO supplementation. In vitro DM digestibility (percentage) and forage OM intake (grams/kilogram of BW) were greater (P < .10) for steers supplemented with AO. Ruminal and total tract NDF and ADF digestibilities were lower in June and greater during July (P < .10) in steers supplemented with AO. Total tract percentage of N disappearance was lesser during June and greater (P < .10) during July for steers receiving AO. Total, essential, and nonessential amino acid flows were increased (P < .10) by both AO supplementation and advancing season. In situ rate of ruminal CP degradation was not affected (P < .10) by treatment during any period.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1993

Determinants of forage quality in Pensacola bahiagrass and Mott elephantgrass.

Our objective was to determine animal responses and forage characteristics that could explain the greater forage quality of 'Mott' dwarf elephantgrass (Pennisetum purpureum Schum.) than that of 'Pensacola' bahiagrass (Paspalum notatum Flugge). Both grasses were harvested after 5 wk of regrowth in June and September. Sheep fed Mott hays had greater (P = .001) voluntary intake of digestible OM (DOM) than did those fed Pensacola, but voluntary intake of ash-free NDF (NDFa) did not differ (P = .21) between grasses. When hays were fed at equal NDFa intakes, sheep fed Mott chewed at a greater (P = .002) rate during eating, spent less (P = .028) time ruminating per unit OM intake, and had smaller (P = .006) prefeeding digesta pools of total and indigestible NDFa. Mott hays had greater N and K and smaller NDFa concentrations. Mott had greater (P = .001) epidermis and smaller (P = .001) sclerenchyma proportions in leaf blades, and leaf epidermis of Mott was more digestible (P = .011) in vitro. For both grasses, hays harvested in June had greater (P = .011) voluntary intake of DOM and shorter (P = .082) mean retention time of small ruminal digesta particles (< 1.18 mm) than did those harvested in September. Within grasses, there were no seasonal differences in NDFa concentration in hay, or in leaf anatomy. A less fibrous leaf structure and a more readily digested leaf epidermis may have accounted for the greater DOM intake of Mott than of Pensacola, but the greater DOM intake of hays harvested in June than of those harvested in September was not explained by measured forage characteristics.

Animal Feed↗