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PubMed1986

Effects of diet nitrogen and forage nitrogen insolubility on performance of cows in early lactation.

Thirty-six Holsteins were allotted at parturition to six treatments to measure effects of diet nitrogen and increased insolubility of silage nitrogen on performance and ruminal, plasma, and milk constituents during the first 100 d of lactation. Diets contained 40% concentrate and 60% silage in dry matter. The six silage treatments were untreated corn silage (low nitrogen); untreated corn silage and untreated alfalfa silage (1:1); untreated corn silage and formaldehyde and formic acid-treated alfalfa silage (1:1); ammonia-treated corn silage (low nitrogen); treated corn silage and untreated alfalfa silage (1:1); or treated corn silage and treated alfalfa silage (1:1). Diets containing ammonia-treated corn silage had higher hot water-insoluble nitrogen and diets containing formaldehyde and formic acid-treated alfalfa had higher autoclaved rumen fluid-insoluble and hot water-insoluble nitrogen that their respective untreated silage diets. Dry matter intake, daily yields of milk and its constituents, ruminal NH3 nitrogen, and plasma urea nitrogen were lower for cows consuming low nitrogen diets containing only corn silage compared with cows consuming high nitrogen diets containing alfalfa. Dry matter intake and milk protein yields were greater for cows consuming treated alfalfa compared with untreated alfalfa in the diet. Daily 4% fat-corrected milk yields tended to be higher for diets containing treated alfalfa than untreated alfalfa. Cows fed diets containing NH3-treated corn silage had similar milk, fat, and protein yields compared with diets containing untreated corn silage and urea in the concentrate.

Animal Feed↗
PubMed1990

Digesta kinetics in sheep and cattle fed diets with different forage to concentrate ratios at high and low intakes.

Effect of maintenance and ad libitum intakes on digesta kinetics was studied with six ruminally fistulated cows and six ruminally fistulated wethers to validate the use of sheep as a model of cattle. Complete diets were made up of ratios of alfalfa:cracked corn and soybean meal of 80:20, 55:45, and 30:70. The rate of passage of Cr-mordanted alfalfa and soybean meal in the reticulorumen was negatively related to percentage of concentrate in the diet in both species at low intakes. Passage values of particulate and liquid markers were faster at high than at low intakes in both species for all diets. Rumen liquid volume increased with intake only in the cows on the low and intermediate concentrate diets. No substantial differences were found in particulate passage values between sheep and cattle. However, liquid passage rates from the rumen and the differentials between liquid and particulate dilution rates were higher in cows than in sheep for all diets at both intakes. These results together with those for digestibility data reported in a previous communication suggest that caution should be exercised when extrapolating results from one species to the other.

Animal Feed↗
PubMed1993

Chewing activity and digestive responses of cows fed alfalfa forages.

Nonlactating Guernsey cows were fed alfalfa silage or coarsely chopped, coarsely chopped and reconstituted, or long alfalfa hays. A computer system was developed to monitor chewing activity. Effects of diets upon chewing activity, digestibility, and ruminal parameters were determined. Digestibilities of DM and N were lower for silage than for hays. Cows fed silage had lower ruminal ammonia concentrations that were caused, at least in part, by greater bound N. Digestibilities of DM, N, and fiber were not different among the hays. The computer system recorded 98% of chews; visual measurements of chewing activity agreed well with computer-logged data. Cows spent more time (463 vs. 348 min/d) eating long alfalfa hay than silage; time spent ruminating, total chewing time, and chewing rates were not different among diets. During eating, cows fed hay had more chews per unit of DM or NDF than when eating silage; during rumination, diets had no effect. Eating time of cows fed alfalfa silage was less than for those fed alfalfa hay. Coarsely chopped alfalfa hay was as effective as long alfalfa hay in eliciting chewing activity.

Animal Feed↗
PubMed1993

Mechanisms of movement of organochlorine pesticides from soils to cows via forages.

When cattle were allowed to graze land previously used as orchards, residues of DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene] were detectable in milk fat and adipose tissues. Concentrations of DDE exceeded .3 micrograms/g at times. Concentrations of DDE in adipose tissue were similar to those in milk fat at the beginning of lactation; residues in first lactation cows were approximately three times higher than in multiparous cows that were grazing similarly. Based on the equation [DDE, micrograms/g]milk fat = .28 (daily dose, mg).82, consumption of soil was likely not the sole source of residue when soil concentrations of DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane], DDE, and DDD [1,1-dichloro-2,2-bis(p-chlorophenyl)ethane] ranged from non-detected to 3.6, 2.1, and .655 micrograms/g, respectively. Grass appeared to be the likely source. Four plots were located on three orchard locations and one control location. Grasses in subplots were harvested at 2-, 4-, or 6-wk intervals during the 18-wk study. Grasses were extracted differentially to determine DDT and DDE residues adhering to the plant surface and those associated with plant tissue. Surface residue was not significant. The DDE averaged between .01 and .11 micrograms/g in dry grass tissues. Differences between residues in grasses among plots were associated with soil residue concentrations. Concentrations of DDE were not associated with air or soil temperature, relative humidity, solar radiation, or dry biomass harvested. Precipitation increased the volatilization of residues from soil and deposition in 2- and 4-wk grass samples.(ABSTRACT TRUNCATED AT 400 WORDS)

Adipose Tissue↗
PubMed1994

Effects of cobalt on in vitro fiber digestion of forages and by-products containing fiber.

Cobalt glucoheptonate as a source of Co to enhance ruminal fiber digestion was evaluated in two in vitro digestibility experiments. In Experiment 1, Co supplementation (0, 5, and 10 ppm) of five substrates (leaf and stem fractions of alfalfa and orchardgrass hays and ground corn) was evaluated under two dietary conditions (ruminal fluid taken from steers fed alfalfa hay or a high concentrate diet) for 24 or 48 h of fermentation in a 3 x 5 x 2 x 2 factorial arrangement. In Experiment 2, four concentrations of Co (0, 10, 20, and 30 ppm) were added to five substrates (alfalfa hay, orchardgrass hay, corn cobs, recycled newsprint treated with HCl, and cellulose casings) and were incubated with ruminal fluid from steers fed alfalfa hay for 24 or 48 h of fermentation in a 4 x 5 x 2 factorial arrangement. No interactions among treatments were observed for digestibilities of DM, OM, or NDF in both experiments or for VFA concentrations in Experiment 1. Supplementation with Co did not increase digestibilities of DM, OM, or NDF in either experiment or concentrations of VFA in Experiment 1. In Experiment 1, in vitro digestibilities of DM, OM, and NDF were higher for inoculum from steers fed alfalfa versus concentrate. In Experiment 2, digestibilities of DM, OM, and NDF were highest for alfalfa hay and lowest for recycled newsprint treated with HCl. Cobalt concentrations that were above minimum requirements did not improve digestion of DM, OM, or fiber.

Animals↗
PubMed1995

Performance of lactating dairy cows fed either alfalfa silage or alfalfa hay as the sole forage.

Alfalfa was harvested from alternate windrows as 40% DM silage or hay in small rectangular bales and fed in two 12-wk 4 x 4 Latin square trials, each with 20 multiparous lactating cows (4 with ruminal cannulas). Diets contained (DM basis) 69 (trial 1) or 66% (trial 2) alfalfa, 26 to 33% high moisture corn, 1.3% minerals and vitamins, and about 1.6 Mcal of NEL/kg of DM. In trial 1, second-cutting silage (21.2% CP) and hay (19.7% CP) containing 35% NDF were fed in diets: 1) silage (17.3% CP), 2) hay (16.3% CP), 3) silage with 3% fish meal (19.1% CP), and 4) hay with 3% fish meal (18.1% CP). Cows had lower DMI and lost BW on diet 1. Yields of milk and milk components were similar on diets 1 and 2 and greater on diet 3 than on the other three diets, except that fat yield was greater on diets 1 and 3 than on diets 2 and 4. In trial 2, first-cutting silage and hay containing 19.9 and 16.5% CP and 40 and 41% NDF were fed in diets: 1) silage (16.8% CP), 2) hay (14.6% CP), 3) silage with 3% fish meal (18.2% CP), and 4) hay with 3% fish meal (16.0% CP). Cows had lower DMI and lost BW on diets 1 and 3.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1998

Proteolysis during ensilage of forages varying in soluble sugar content.

The effect of contrasting concentrations of water-soluble carbohydrates of herbage on silage fermentation and composition was examined using grass with high [250 g/kg of dry matter (DM)] concentrations of water-soluble carbohydrates and grass and clover with low (66 g/kg of DM) concentrations of water-soluble carbohydrates. Herbages were ensiled untreated, after inoculation with lactic acid bacteria, or after treatment with formic acid. Good quality silages were produced from herbage with high concentrations of water-soluble carbohydrates, regardless of treatment, and all pH values were below 3.7 after 90 d of ensilage. However, the silage formed from inoculated herbage had a significantly lower concentration of ammonia N and a significantly higher proportion of residual ribulose-1,5-bisphosphate carboxylase compared with the other two silages. Fast protein liquid chromatography (Pharmacia, Uppsala, Sweden) was used to measure ribulose-1,5-bisphosphate carboxylase, and measurement of true plant protein fractions in herbage and silage showed benefits over traditional measurements such as the measurement of N and ammonia N. Herbages with low concentrations of water-soluble carbohydrates produced inferior quality silages that had lower ribulose-1,5-bisphosphate carboxylase contents and higher ammonia N contents, regardless of treatment; few significant differences were observed among treatments. Under good ensiling conditions, when available water-soluble carbohydrate is adequate, the use of inoculants can improve fermentation characteristics and increase the ribulose-1,5-bisphosphate carboxylase content of silages. However, when the herbage has low concentrations of water-soluble carbohydrates, even in inoculated herbages, lactic acid bacteria may follow a heterofermentative pathway instead of a homofermentative pathway, which can result in a decrease in silage quality and a reduction in intact ribulose-1,5-bisphosphate carboxylase.

Ammonia↗
PubMed1998

Feed intake relative to stage of lactation for dairy cows consuming total mixed diets with a high or low ratio of concentrate to forage.

This experiment examined the effect of feed quality on the relationship between intake and stage of lactation in dairy cows. Two total mixed diets composed of grass silage and concentrate were formulated. The high concentrate total mixed diet was designed to meet energy requirements, and the low concentrate total mixed diet was designed to limit intake. Twenty-four Holstein-Friesian cows were offered the total mixed diets in a full 2 x 2 change-over design with control treatments. The changeover was at 153 d in milk (DIM). For the statistical analyses, two periods of 13 wk, one period before and one period after the changeover, were used. Dry matter intake (DMI), milk yield, body weight, and body condition score were significantly greater for cows fed the high concentrate total mixed diet than for cows fed the low concentrate total mixed diet. Significant interactions between total mixed diet and period were observed for DMI and milk yield. However, no significant residual effects of changing from one total mixed diet to the other were observed. The interactions were due to substantially different slopes of DMI and milk yield relative to DIM for cows fed the two different total mixed diets. For cows fed the low concentrate total mixed diet, there was no effect of stage of lactation on DMI; the slope was 0. For cows fed the high concentrate total mixed diet, there was a significant decline in DMI as lactation progressed.

Animal Feed↗
PubMed2005

Trace elements analysis in forage samples from a US Navy bombing range (Vieques, Puerto Rico).

Plants are good environmental sensors of the soil conditions in which they are growing. They also respond directly to the state of air. The tops of plants are collectors of air pollutants, and their chemical composition may be a good indicator for contaminated-areas when it is assessed against background values obtained for unpolluted vegetation. Both, aquatic and terrestrial plants are known to bioaccumulate heavy metals and therefore represent a potential source of these contaminants to the human food chain. An evaluation of heavy metals was conducted from vegetation samples collected at the Atlantic Fleet Weapons Training Facilities (AFWTF) in Vieques, Puerto Rico. In order to understand the potential risks associated to heavy metal mobilization through biological systems, it is first necessary to establish background values obtained from reference locations. This information allows a better interpretation of the significance of anthropogenic factors in changing trace elements status in soil and plants. Since Guánica State Forest is located at a similar geoclimatic zone as the AFWTF, samples at this site were used as a standard reference material and as experimental controls. Both sampling and analysis were conducted as previously described in standardized protocols using acid digestion of dry ashes. Then, levels of heavy metals were obtained by air-acetylene flame detection in an atomic absorption spectrophotometer. Our results from the samples taken at the AFWTF indicate mobilization of undesirable trace elements through the marine and terrestrial food web. Since plants naturally remove heavy metals from soils, they could be employed for the restoration of this and similarly contaminated sites.

Environmental Monitoring↗
PubMed2001

[Effects of volatiles from different trophic level on foraging behavior of Aphidius avenae].

The responses of female Aphidius avenae to volatiles from undamaged wheat plant, Sitobion avenae and Rhopalosiphum padi, aphids-plant complexes and aphids damaged plant were investigated in wind tunnel and Y-tube olfactometer. The volatiles from undamaged wheat plant, S. avenae and R. padi were much less attractive to A. avenae than those from aphids-plant complexes and aphids-damaged plant. Although the parasitic rate was much lower, the R. padi-plant complexes and R. padi damaged plant were also attractive to A. avenae. Identification of volatiles by GC-MS showed that the main volatiles induced by aphids feeding were 2-camphene, 6-methyl-5-hepten-2-one, 6-methyl-5-hepten-2-ol, Z-3-hexenyl-acetate, and methyl salicylate, among which, 6-methyl-5-hepten-2-one and 6-methyl-5-hepten-2-ol were more attractive to A. avenae, while methyl salicylate was not attractive.

Animals↗
PubMed2000

[Application of Quantitative Theory I in commenting the relationship of forage species and weed species].

Quantitative Theory I was applied to evaluate the influence of managing measures on the relationship of pasture grass and weeds on two typical grasslands of south China. Grazing intensity and fertilizer dosage were the key factors affecting the dominance of pasture grass. The main weed species were E. odoratum, E. rubiginosum, H. perforata, I. anlindrica and E. annua. The suitable density of cattle was 1-4 cattle.hm-2, and the dosage of fertilizer application was 500-1000 kg.hm-2 for superphoshate, and 150-250 kg.hm-2 for KCl.

Ecosystem↗