scholarly journals APPARENT FEED PARTICLE SIZE PREFERENCE BY LAYING HENS

1988 ◽  
Vol 68 (3) ◽  
pp. 915-922 ◽  
Author(s):  
F. J. PORTELLA ◽  
L. J. CASTON ◽  
S. LEESON
Keyword(s):  
Particle Size ◽  
Chemical Analysis ◽  
Key Words ◽  
Feed Intake ◽  
Laying Hens ◽  
Adaptation Period ◽  
Disappearance Rate ◽  
Small Particles ◽  
Large Particles ◽  
Size Preference

Trials were designed to investigate the effect of feed particle size on apparent feed intake of laying hens. Feed was offered to five different groups of four birds each as either regular crumbles, mash, large crumbles (trained birds), large crumbles (untrained birds) or small crumbles, respectively. Except for the untrained birds, all birds were given a 15-d adaptation period. In each trial hens were offered 200 g of feed at 05:00 h and at each subsequent hour, until 20:00 h, feed was removed from the trough, sieved, weighed, remixed and returned to the feeders. Chemical analysis of the diet and various diet fractions was undertaken. There was marked disappearance of larger particles when birds were fed regular crumbles. However, smaller particles disappeared as the concentration of large ones decreased throughout the day. There was no marked disappearance of particles smaller than 0.60 mm. Feed intake was comparable when regular crumbles or mash rations were fed. Overall feed intake increased when small particles were offered, while intake decreased when the feed was changed abruptly to one of only large particles. It is concluded that particle size in regular crumbled layer feed is not uniform, and that particle size influences disappearance rate. Key words: Layer, particle preference, nutrient preference

APPARENT FEED PARTICLE SIZE PREFERENCE BY BROILERS

1988 ◽  
Vol 68 (3) ◽  
pp. 923-930 ◽  
Author(s):  
F. J. PORTELLA ◽  
L. J. CASTON ◽  
S. LEESON
Keyword(s):  
Particle Size ◽  
Chemical Analysis ◽  
Key Words ◽  
Feed Intake ◽  
Feed Consumption ◽  
Broiler Chicks ◽  
Disappearance Rate ◽  
Large Particles ◽  
Effect Of Particle Size ◽  
Size Preference

Broiler chicks of different ages were used to study particle size disappearance and the effect of particle size on feed intake. The disappearance of particles larger than 1.18 mm was obvious at all ages. However, it was noticed that at 8 and 16 d disappearance of particles between > 1.18 mm and < 2.36 mm was most pronounced. As birds became older, disappearance rate was greatest for particles > 2.36 mm. Throughout a 24-h period, particle breakdown was noted. Birds did eat these smaller particles at the end of a 24-h period, especially when the concentration of large particles was reduced. Chemical analysis revealed that birds selected material on the basis of particle size, since nutrient composition of the diet and of different diet fractions did not change throughout the day. Changing particle size abruptly from crumbles to pellets did not adversely affect overall feed consumption (P > 0.05) or bird performance. Key words: Broiler, particle size preference, crumbles, pellets

scholarly journals Effect of the levels of calcium and particle size of limestone on laying hens

2011 ◽  
Vol 40 (5) ◽  
pp. 997-1005 ◽  
Author(s):  
José Anchieta de Araujo ◽  
José Humberto Vilar da Silva ◽  
Fernando Guilherme Perazzo Costa ◽  
Janaína Maria Batista de Sousa ◽  
Patrícia Emília Naves Givisiez ◽  
...  
Keyword(s):  
Particle Size ◽  
Feed Intake ◽  
Laying Hens ◽  
Breaking Strength ◽  
Particle Sizes ◽  
Randomized Design ◽  
Mass Conversion ◽  
Completely Randomized Design ◽  
Thickness Shell ◽  
Haugh Unit

This experiment was conducted to evaluate the effect of levels of calcium (Ca) and particle size of limestone (LS) for laying hens. It was used 216 Dekalb White laying hens at 25 to 49 weeks of age in a completely randomized design in a 3 × 2 factorial arrangement, composed of three levels of calcium (3.92, 4.02 and 4.12%) and two particle sizes of limestone (thin - 0.60 mm; and thick - 1.00 mm), resulting in 6 treatments with six replicates of six birds. There was no significant effect of levels of calcium and limestone particle size neither of the interaction calcium × particle size for feed intake, egg weight, specific gravity, shell thickness, shell percentage, Haugh unit, calcium and phosphorus digestibility and percentage of digestive tract. Production, mass, conversion by mass and conversion by egg dozen had their best results with 4.12% of calcium in the diet. Percentage of gizzard and feed intake observed at 3:00 p.m. improved as limestone granulometry improved from 0.60 to 1.00 mm. There was an interaction effect among calcium level and limestone granulometry for breaking strength of tibia, bone density, length of the small intestine and feed intake at 6:00 a.m.; 9:00 a.m., 12:00 p.m., 6:00 p.m. and 9:00 p.m., respectively. It is recommended the addition of 4.12% of calcium and limestone in the thick granulometry (1.00 mm) for a better performance of commercial laying hens. More studies are needed to elucidate the mechanisms involved in the alteration of nutritional behavior of laying hens in response to changes in the levels of calcium and in the granulometry of limestone in the rations.

Studies of cattle and sheep eating leaf and stem fractions of grasses. 3. The retention time in the rumen of large feed particles

1981 ◽  
Vol 32 (1) ◽  
pp. 123 ◽  
Author(s):  
DP Poppi ◽  
DJ Minson ◽  
JH Ternouth
Keyword(s):  
Particle Size ◽  
Retention Time ◽  
Dry Matter ◽  
Simulation Studies ◽  
Small Particles ◽  
Dry Matter Distribution ◽  
Rhodes Grass ◽  
Large Particles ◽  
Voluntary Intake ◽  
Cattle And Sheep

Pangola grass (Digitavia decumbens) and Rhodes grass (Chlovis gayana) cut as 6 and 12 week regrowths were separated into leaf and stem fractions and fed ad libitum to four cattle and eight sheep fitted with ruminal fistulae to determine the importance of particle size in controlling the retention time of feed in the rumeno-reticulum (rumen). Particle size was determined by using a wet sieving technique, and based on the cumulative dry matter distribution on the sieves of faeces from cattle and sheep; all particles >1.18 mm were described as large particles. The proportion of large particles was measured in the chopped diet offered, the masticated diet, the ruminal contents and the faeces. Chopped leaf and stem fractions contained 0.85 and 0.86 g/g large particles respectively. Mastication by cattle reduced the proportion of large particles in leaf and stem to 0.58 and 0.76 (P < 0.01), and mastication by sheep to 0.56 and 0.67 (P < 0.01). The proportion of large particles in the rumen of sheep was 0.236 and 0.249 for leaf and stem respectively (P > 0.05) and in cattle 0.272 and 0.345 (P < 0.05). The faeces contained relatively few large feed particles (< 0.045 for cattle and <0.018 for sheep). Cattle eating leaf and stem produced faeces containing 0.027 and 0.040 (g/g) large particles (P <0.05), compared with only 0,008 and 0.013 (P < 0.05) in sheep. Most of the large particles entering the rumen in the masticated feed disappeared in the rumen by breakdown to smaller particles or by digestion. In cattle the proportions that disappeared were 0.978 and 0.976 (P > 0.05) for leaf and stem, and in sheep 0.993 and 0.991 (P > 0.05). Large particles in leaf and stem were retained in the rumen of the sheep for 11.0 and 11.7 h (P > 0.05). Cattle retained large particles in all diets for a longer time (P < 0.01); 16.1 h for leaf and 20,2 h for stem (P > 0.05). Differences in retention time of large particles in the rumen did not appear to be the only factor controlling the retention of dry matter in the rumen and voluntary intake. A model was developed to describe the flow of large and small particles through the rumen. Intake simulation studies indicated that the most important factor influencing dry matter retention time in the rumen was the retention time of small particles (> 1.18 mm). Changes in the rate of breakdown of large particles had a small effect on dry matter retention time.

Effects of ingredient particle size and feed form on the performance of Leghorn hens

1995 ◽  
Vol 75 (1) ◽  
pp. 109-114 ◽  
Author(s):  
R. M. G. Hamilton ◽  
F. G. Proudfoot
Keyword(s):  
Particle Size ◽  
Specific Gravity ◽  
Key Words ◽  
Feed Intake ◽  
Cereal Grains ◽  
Feed Conversion ◽  
Roller Mill ◽  
Body Weights ◽  
Feed Form ◽  
Genotype A

In each of two experiments, 1536 Leghorn pullets from two commercial genotypes (A and B) were given diets that were in the form of either mash, crumbles or pellets. The cereal grains used in these diets were either finely or coarsely ground using a hammer or roller mill. The particle size and form of the diets used were: FM, FMC, FMP, CM, CMC, and CMP. These diets were fed and data were collected when the birds were between 140 and 490 d of age.Pullets in exp. 2 were heavier at 140 d (P < 0.001) and lighter in weight at 490 d (P < 0.001), reached 50% EP 4.8 d earlier (P < 0.001), had 1.3% higher rate of EP (P < 0.05), and laid more large and small (P < 0.001) and fewer medium-sized (P < 0.01) eggs than those in exp. 1. Hens from genotype A had lower 140 and 490 d body weights (P < 0.001), 187 and 490 d egg weights and specific gravity (P < 0.001), better feed conversion (P < 0.001) and higher (P < 0.001) monetary returns than birds from genotype B. Birds receiving the FM and CM diets had higher EP (P < 0.05), feed intake (P < 0.001), monetary returns (P < 0.001), and numbers of medium-sized and small eggs (P < 0.05) than those fed the FMP and CMP diets. Specific gravity was higher (P < 0.001) for eggs laid at 187–188 d by the FMP and CMP-fed hens than for those given the FM or CM diets. In general, performance was better for the hens given the mash diets than for those fed the crumbled or pelleted diets. Key words: Particle size, feed form, hens

Supplementation of organic minerals and its effect on production performance and egg quality of laying hens

2020 ◽  
pp. 12-16
Keyword(s):  
Feed Intake ◽  
Egg Production ◽  
Laying Hens ◽  
Egg Quality ◽  
Production Performance ◽  
Control Group ◽  
Adaptation Period ◽  
Egg Shell ◽  
Organic Minerals

The present study was conducted to find the effect of different levels of organic minerals on egg production and egg quality of laying hens. A total of 45 laying hens were selected and divided into three groups with 3 replicates of 5 birds each. The control group was provided with commercial ration having inorganic minerals and the other two groups were supplemented with organic minerals at the rate of 7.5 (OM-50) and 15 mg/kg (OM-100). The experiment lasted for 5 weeks including 1 week of adaptation period. Overall feed intake was significantly higher (P<0.05) in the control. Significantly lower feed intake was recorded in group OM-100. Numerically lower (better) FCR was recorded in OM-100 at all recorded stages. Significantly (P<0.05) higher egg weight, egg shell weight and egg shell thickness was found in OM-100 compared to the control. Similarly, albumin height, Haugh unit and yolk weight were significantly (P<0.05) higher in M-100. It was concluded from the present results that organic minerals at the level of 50 and 100 mg/kg improved the performance and egg quality of laying hens. However, better results were found in OM-100.

The Infrared Analysis of Polyethylene Terephthalate Fibers and of Their Strength as Related to Sample Preparation and to Particle Size

1989 ◽  
Vol 43 (5) ◽  
pp. 791-794 ◽  
Author(s):  
R. O. Carter ◽  
K. R. Carduner ◽  
M. C. Paputa Peck ◽  
D. H. Motry
Keyword(s):  
Particle Size ◽  
Sample Preparation ◽  
Polyethylene Terephthalate ◽  
Infrared Analysis ◽  
Spectral Features ◽  
Band Broadening ◽  
Small Particles ◽  
Large Particles ◽  
Local Sample ◽  
Infrared Microscope

An explanation is presented for the broadening of intense spectral features observed in the infrared spectra of polyethylene terephthalate fibers prepared as KBr pellets. Since band broadening occurs in the spectra of stronger, undegraded fiber, it is proposed that, the stronger the fiber, the more the difficulty one has in pulverizing the sample. Larger particles result from undegraded polyester, which lead to broader bands for intense features. The local sample pathlength in the region of the large particles is greater than that for small particles, which can be more homogeneously mixed. Fiber samples can also be presented to an infrared microscope either “as is” or flattened. Striking differences exist between spectra for flattened and round fibers that were otherwise similar.

scholarly journals Stable solutions of a scalar conservation law for particle-size segregation in dense granular avalanches

2008 ◽  
Vol 19 (1) ◽  
pp. 61-86 ◽  
Author(s):  
M. SHEARER ◽  
J. M. N. T. GRAY ◽  
A. R. THORNTON
Keyword(s):  
Particle Size ◽  
Free Surface ◽  
Shear Flow ◽  
Free Surface Flows ◽  
Size Segregation ◽  
Small Particles ◽  
Surface Flows ◽  
Scalar Conservation Law ◽  
Large Particles ◽  
Scalar Conservation

Dense, dry granular avalanches are very efficient at sorting the larger particles towards the free surface of the flow, and finer grains towards the base, through the combined processes of kinetic sieving and squeeze expulsion. This generates an inversely graded particle-size distribution, which is fundamental to a variety of pattern formation mechanisms, as well as subtle size-mobility feedback effects, leading to the formation of coarse-grained lateral levees that create channels in geophysical flows, enhancing their run-out. In this paper we investigate some of the properties of a recent model [Gray, J. M. N. T. & Thornton, A. R. (2005) A theory for particle size segregation in shallow granular free-surface flows. Proc. R. Soc. 461, 1447–1473]; [Thornton, A. R., Gray, J. M. N. T. & Hogg, A. J. (2006) A three-phase mixture theory for particle size segregation in shallow granular free-surface flows. J. Fluid. Mech. 550, 1–25] for the segregation of particles of two sizes but the same density in a shear flow typical of shallow avalanches. The model is a scalar conservation law in space and time, for the volume fraction of smaller particles, with non-constant coefficients depending on depth within the avalanche. It is proved that for steady flow from an inlet, complete segregation occurs beyond a certain finite distance down the slope, no matter what the mixture at the inlet. In time-dependent flow, dynamic shock waves can develop; they are interfaces separating different mixes of particles. Shock waves are shown to be stable if and only if there is a greater concentration of large particles above the interface than below. Constructions with shocks and rarefaction waves are demonstrated on a pair of physically relevant initial boundary value problems, in which a region of all small particles is penetrated from the inlet by either a uniform mixture of particles or by a layer of small particles over a layer of large particles. In both cases, and under a linear shear flow, solutions are constructed for all time and shown to have similar structure for all choices of parameters.

Influence of Oxide Particle Size on the Erosion of the Control Stage Nozzle in a Supercritical Steam Turbine

2013 ◽  
Author(s):  
Liu-xi Cai ◽  
Shun-sen Wang ◽  
Lei Zhang ◽  
Jing-ru Mao ◽  
Zhen-ping Feng ◽  
...  
Keyword(s):  
Particle Size ◽  
Steam Turbine ◽  
Erosion Resistance ◽  
Size Range ◽  
Small Particles ◽  
Suction Surface ◽  
Erosion Damage ◽  
Pressure Surface ◽  
Control Stage ◽  
Large Particles

Reducing the solid particle erosion (SPE) of blades is one of the most important problems for high-parameter steam turbine. Based on the erosion rate models and the particle rebound models of blade materials obtained through the accelerated erosion test under high temperature, a lot of three dimension numerical simulations were conducted in this paper. The influence of particle size on the impingement point distribution on the nozzle surface and the erosion characteristics of control stage nozzle in a supercritical steam turbine were analyzed quantitatively. The size range of the oxide scale particles participating in the erosion damage were extended to 500μm, and some special anti-erosion measures corresponding to different size particles were proposed to reduce the erosion of nozzle. Results show that the erosion of pressure surface in the trailing edge of nozzle is mainly from the high-intensity impingement of particles smaller than 160μm, especially those with the size range from 20μm to 60μm. For the impingement of these small particles, optimizing the profile and cascade structure as well as coating the hard coating on the surface of nozzle can improve the erosion resistance of nozzle. However, these small particles do not impinge the nozzle trailing edge suction surface. The severe erosion damage of suction surface of nozzle was from the impingement again of the particles with the size range from 200μm to 500μm after rebounding from nozzle pressure surface. It is very difficult to resist the erosion damage of these large particles for the hard coating, and separating large particles from main steam before entering the nozzle chamber should be a good choice for improving the erosion resistance of turbine. These studies will provide a technical basis for selecting anti-erosion measures of control stage nozzle.

scholarly journals RESPONSE OF WHITE LEGHORNS TO DIETS CONTAINING GROUND OR WHOLE TRITICALE

1987 ◽  
Vol 67 (2) ◽  
pp. 583-585 ◽  
Author(s):  
S. LEESON ◽  
J. D. SUMMERS
Keyword(s):  
Body Weight ◽  
Key Words ◽  
Feed Intake ◽  
Egg Production ◽  
Laying Hens ◽  
Energy Value ◽  
White Leghorns

Growing leghorn pullets and laying hens were fed diets containing triticale as the sole cereal source. Body weight of pullets was not affected (P > 0.05) by up to 70% dietary inclusion of triticale. When layer diets contained 70% whole or ground triticale in place of corn, egg production was depressed (P < 0.05) while birds consumed more feed (P < 0.05). The feed intake effect is discussed in relation to the energy value of triticale. Key words: Triticale, pullets

Inkjet printable silver dispersions: Effect of bimodal particle-size distribution on film formation and electrical conductivity

2010 ◽  
Vol 25 (5) ◽  
pp. 821-827 ◽  
Author(s):  
Krishna Balantrapu ◽  
Meaghan McMurran ◽  
Dan V. Goia
Keyword(s):  
Electrical Conductivity ◽  
Particle Size ◽  
Size Distribution ◽  
Film Formation ◽  
Small Particles ◽  
Silver Films ◽  
On Demand ◽  
Drop On Demand ◽  
Large Particles ◽  
Effect Of Particle Size

Inks containing silver nanoparticles of 12 nm, 80 nm, and a 15%/85% mixture of the two sizes were used to evaluate the effect of particle size and size distribution on the electrical properties of sintered films. The silver layers deposited with a “drop-on-demand” inkjet printer were heated at temperatures ranging from 125 to 200 °C. The small particles formed less resistive films at 125 °C, while the larger ones provided better electrical conductivity above 150 °C. The inks containing mixed small and large particles yielded the most conductive silver films over the entire investigated temperature range. A mechanism explaining these results is proposed based on the evolution of film microstructure with temperature.

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