Effects of supplementation of limit-fed growing diets with either soybean meal or nonenzymatically browned soybean meal on steer performance

Seventy two individually fed Angus × Hereford steers (642 lb) were used to evaluate the effects of supplementing limit-fed, growing diets with either soybean meal (SBM) or nonenzymatically browned soybean meal (NSBM). Eight steers were allotted to a control diet composed of 39.1% high-moisture corn, 42% cottonseed hulls, 10.4% ground corn, 5% cane molasses 2.25% urea, and 1.5% vitamins and minerals (dry basis). The remaining steers were allotted to diets that derived 100, 80, 60, or 40% of their supplemental protein from SBM or 60, 45, 30, or 15% of their supplemental protein from NSBN. The balance of supplemental protein came from urea. All diets were formulated to contain 13.0% crude protein (dry basis). Steers were fed once daily for 80 days at 2.25% of BW. Average daily gain and efficiency did not differ (P>.05) between sources (ADG=1.932 + .103 × (% CP from SBM) + .097 × (% CP from NSBM); gain:feed=.140 + .0058 × (% CP from SBM) + .0051 × (% CP from NSBM)). The lack of response to NBSBM supplementation above that for SBM suggests that either degradable intake protein was limiting in the basal diet or a large proportion of the amino acids in the NSBM were unavailable due to overprocessing

Evidence of Final-State Suppression of High-p_T Hadrons in Au + Au Collisions Using d + Au Measurements at RHIC

Transverse momentum spectra of charged hadrons with ${p_{T} <}$ 6 GeV/c have been measured near mid-rapidity (0.2 $< \eta <$ 1.4) by the PHOBOS experiment at RHIC in Au + Au and d + Au collisions at ${\sqrt{s_{_{NN}}} = \rm {200 GeV}}$. The spectra for different collision centralities are compared to ${p + \bar{p}}$ collisions at the same energy. The resulting nuclear modification factor for central Au + Au collisions shows evidence of strong suppression of charged hadrons in the high-$p_{T}$ region (${>2}$ GeV/c). In contrast, the d + Au nuclear modification factor exhibits no suppression of the high-$p_{T}$ yields. These measurements suggest a large energy loss of the high-$p_{T}$ particles in the highly interacting medium created in the central Au + Au collisions. The lack of suppression in d + Au collisions suggests that it is unlikely that initial state effects can explain the suppression in the central Au + Au collisions.Comment: 3 pages, 4 figures, International Europhysics Conference on High Energy Physics EPS (July 17th-23rd 2003) in Aachen, German

Identified particles in Au+Au collisions at sqrt{s_NN} = 200 GeV

The yields of identified particles have been measured at RHIC for Au+Au collisions at sqrt{s_NN} = 200 GeV using the PHOBOS spectrometer. The ratios of antiparticle to particle yields near mid-rapidity are presented. The first measurements of the invariant yields of charged pions, kaons and protons at very low transverse momenta are also shown.Comment: 4 pages, 4 figures, Contribution to Quark Matter 2002, Nantes, France, July 200

Universal Behavior of Charged Particle Production in Heavy Ion Collisions

The PHOBOS experiment at RHIC has measured the multiplicity of primary charged particles as a function of centrality and pseudorapidity in Au+Au collisions at sqrt(s_NN) = 19.6, 130 and 200 GeV. Two kinds of universal behavior are observed in charged particle production in heavy ion collisions. The first is that forward particle production, over a range of energies, follows a universal limiting curve with a non-trivial centrality dependence. The second arises from comparisons with pp/pbar-p and e+e- data. N_tot/(N_part/2) in nuclear collisions at high energy scales with sqrt(s) in a similar way as N_tot in e+e- collisions and has a very weak centrality dependence. This feature may be related to a reduction in the leading particle effect due to the multiple collisions suffered per participant in heavy ion collisions.Comment: 4 Pages, 5 Figures, contributed to the Proceedings of Quark Matter 2002, Nantes, France, 18-24 July 200

Global Observations from PHOBOS

Particle production in Au+Au collisions has been measured in the PHOBOS experiment at RHIC for a range of collision energies. Three empirical observations have emerged from this dataset which require theoretical examination. First, there is clear evidence of limiting fragmentation. Namely, particle production in central Au+Au collisions, when expressed as $dN/d\eta'$ ($\eta' \equiv \eta-y_{beam}$), becomes energy independent at high energy for a broad region of $\eta'$ around $\eta'=0$. This energy-independent region grows with energy, allowing only a limited region (if any) of longitudinal boost-invariance. Second, there is a striking similarity between particle production in e+e- and Au+Au collisions (scaled by the number of participating nucleon pairs). Both the total number of produced particles and the longitudinal distribution of produced particles are approximately the same in e+e- and in scaled Au+Au. This observation was not predicted and has not been explained. Finally, particle production has been found to scale approximately with the number of participating nucleon pairs for $N_{part}>65$. This scaling occurs both for the total multiplicity and for high \pT particles (3 <\pT< 4.5 GeV/c).Comment: QM2002 plenary talk, 10 pages, 11 figure

Recent Results from PHOBOS at RHIC

The PHOBOS experiment at RHIC has recorded measurements for Au-Au collisions spanning nucleon-nucleon center-of-mass energies from 19.6 GeV to 200 GeV. Global observables such as elliptic flow and charged particle multiplicity provide important constraints on model predictions that characterize the state of matter produced in these collisions. The nearly 4 pi acceptance of the PHOBOS experiment provides excellent coverage for complete flow and multiplicity measurements. Results including beam energy and centrality dependencies are presented and compared to elementary systems.Comment: 4 pages, 4 figures, proceedings from PANIC02 in Osaka, Japa

Charged hadron transverse momentum distributions in Au+Au collisions at sqrt(s_NN) = 200 GeV

We present transverse momentum distributions of charged hadrons produced in Au+Au collisions at sqrt(s_NN) = 200 GeV. The spectra were measured for transverse momenta p_T from 0.25 to 4.5 GeV/c in a rapidity range of 0.2 < y_pi < 1.4. The evolution of the spectra is studied as a function of collision centrality, from 65 to 344 participating nucleons. The results are compared to data from proton-antiproton collisions and Au+Au collisions at lower RHIC energies. We find a significant change of the spectral shape between proton-antiproton and peripheral Au+Au collisions. Comparing peripheral to central Au+Au collisions, we find that the yields at high p_T exhibit approximate scaling with the number of participating nucleons, rather than scaling with the number of binary collisions.Comment: 5 pages, 4 figures, submitted to Phys.Lett.

Effects of ruminally protected choline and dietary fat on performance of finishing heifers

A 120-day finishing study utilizing 318 heifers (753 lb initial body weight) examined the effects of ruminally protected choline in diets with no tallow or 2 or 4% of supplemental tallow. Heifers were fed a finishing diet based on a mix of steam-flaked and dry- rolled corn; encapsulated choline (20, 40, or 60 g/head/day, supplying 5, 10 or 15 g choline/head/day) was top-dressed to the diet or not added. Dry matter intake decreased linearly with inclusion of fat (P<.05) but was not affected significantly by addition of choline. Daily gains also decreased linearly (P<.05) with fat addition. Choline supplementation increased gain (linear, P<.1; qua dratic, P<.05), with the greatest increase occurring for the first 20 g increment encapsulated choline/day. Likewise, feed efficiency improved (P<.1) with supplemental choline. Again, the greatest response occurred for the first 20 g/day. Kidney, pelvic, and heart fat and yield grade both increased linearly (P<.1) with fat supplementation. The percentage of carcasses grading USDA Choice decreased (linear, P<.05; quadratic, P<.1) when choline was added at 60 g/day. Hot carcass weight, marbling, dressing percent, and 12th rib fat thickness were not affected significantly by either fat or choline. Ruminally protected choline can improve average daily gain and feed efficiency of finishing cattle

Performance of growing heifers fed prairie hay and supplemented with alfalfa and(or) cooked molasses blocks of different protein concentrations

Crossbred heifers (683 lb; n = 175; 30 pens) were used to evaluate alfalfa and cooked molasses block supplementation to prairie hay. Treatments were arranged in a 2×3 factorial with the factors being 0 or 5 lbs of alfalfa supplementation, and supplementation with no block or with low or high protein blocks (analyzed to contain 14.4 and 27.5% crude protein, respectively). Heifers had ad libitum access to prairie hay and salt. The experiment was 89 days, with heifers fed blocks for 84 days. During days 5 to 19, heifers had ad libitum access to blocks. Thereafter, access was restricted to 4 hours daily. No significant interactions occurred between alfalfa and blocks for intake or gain. Supplementation with alfalfa increased total forage intake by 49% (18.4 vs. 12.3 lb/day), and gains from –.39 lb/day to +.95 lb/day. Intake of the blocks was lower when alfalfa was supplemented (.76 vs. .98 lb/day). Heifers fed the high-protein block gained more weight (.46 lb/day) than those fed the lowprotein block (.25 lb/day) or no block (.12 lb/day). Heifers fed the high-protein block ate more forage (16.1 lb/day) than those fed the low-protein block (14.8 lb/day), with heifers fed no block (15.3 lb/day) being intermediate. Intake of block was greater for the high-protein (.93 lb/day) than for the low-protein block (.81 lb/day). Differences in forage intake accounted for much of the differences in performance among treatments

Effects of virginiamycin or monensin plus tylosin on ruminal fermentation characteristics in steers fed dry-rolled corn with or without wet corn gluten feed

A study was conducted to evaluate effects of virginiamycin and monensin plus tylosin on ruminal fermentation characteristics in steers fed dry rolled corn-based finishing diets with or without wet corn gluten feed. Ruminal pH was higher, concentrations of volatile fatty acids were lower, and ciliated protozoal numbers were higher in steers fed diets with wet corn gluten feed. Including virginiamycin or monensin plus tylosin had few effects on the ruminal fermentation characteristics we measured. Including wet corn gluten feed appeared to stabilize the ruminal fermentation