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Biomedical subjects

W B Roush

Publications and source records attributed to W B Roush.

32 records · Page 2Linked to original sources
PubMed1994

A nonlinear dynamical (chaos) approach to the analysis of broiler growth.

Mathematical chaos has been observed in a number of biological areas, suggesting that order can be found in systems previously described as random. Nonlinear analyses were conducted to determine whether periodicity or chaos was evident in the growth responses of broiler chickens. Analyses of the absolute growth rate and growth rate acceleration were conducted for four lines of broilers selected at 14 or 42 d for high or low growth rates (Experiment 1) and for a commercial broiler strain (Experiment 2). Resulting Lyapunov exponents (LE) and correlation dimensions (CD) were statistically evaluated. Time series and return map graphics were analyzed. In both experiments, independence of day-to-day growth responses was indicated by low r2 values. In Experiment 1, there were significant differences between lines in growth rate (low, 9.1 +/- .3; high, 12.9 +/- .5 g/d) and the standard deviation of growth rate (low, 5.8 +/- .2; high 7.3 +/- .3 g/d). There were no significant differences for LE or CD values between lines or day of selection. In general, the positive LE, noninteger values of CD, and return map graphics in both experiments suggested the presence of chaotic dynamics. Evaluation of mathematical chaos in broiler growth may give insight into the dynamics and modeling of growth and diseases associated with growth.

Animals↗
PubMed1994

Laying hen production responses to least cost rations formulated with stochastic programming or linear programming with a margin of safety.

An experiment with 480 DeKalb DK laying hens was conducted to study the effect of rations formulated with stochastic programming (STCH) or linear programming with a margin of safety (LPMS) over 12, 28-d periods. Rations were formulated to guarantee the requirement of methionine and lysine > or = 69%, in all rations, and Ca and P > or = either 69 or 90%. The four rations were: LPMS69 with Ca and P > or = 69%, LPMS90 with Ca and P > or = 90%, STCH69 with Ca and P > or = 69%, and STCH90 with Ca and P > or = 90%. Rations formulated with STCH were lower in cost than LPMS rations for respective probability levels. Costs per metric ton for LPMS69, LPMS90, STCH69, and STCH90 were $155.70, $157.71, $155.00, and $156.30, respectively. Compared to STCH rations, LPMS rations were overformulated in nutrients. There was no difference (P > .05) in performance for hen-housed egg production, hen-day egg production, feed per dozen eggs, mortality, egg weight, or eggshell percentage.

Animals↗
PubMed1992

Broiler production under varying population densities.

The influence of population density on the growth performance and stress level of Hubbard x Hubbard chicks of equally mixed sex was studied. Six hundred and sixteen birds were housed under .05, .07, .09, or .11 m2 per bird (four replicates per density) from 0 to 7 wk. There were no treatment effects on feed conversion at 6 or 7 wk. Birds housed at .07, .09, and .11 m2 per bird had similar 7-wk BW and carcass weights, all significantly higher than birds housed at .05 m2 per bird. Under .05 m2 per bird, a higher percentage of breast blisters and ammonia burns (30%) was observed than at other densities. The 7-wk heterophil to lymphocyte ratios of birds raised at .09 and .11 m2 per bird (.42 and .45) were significantly higher than those at .05 and .07 m2 per bird (.28 and .30). Lowered BW and decreased carcass quality of birds raised at .05 m2 per bird suggested that these birds were stressed. However, decision analysis of economic potential indicated that the optimum profit potential per square meter was .05 m2 per bird for Maximax and Equally Likely decisions and .07 m2 per bird for the Maximin decision.

Animal Husbandry↗
PubMed1990

Evaluation of colony size and cage space for laying hens (Gallus domesticus) using fuzzy decision analysis.

A replicated experiment (two, 1-yr trials) was conducted to define colony size and cage space requirements of laying hens. DeKalb XL pullets, 19 wk of age, were randomly assigned to cages sized 1548, 3097, and 4645 cm2 at population densities of 2, 3, 4, or 5 hens. Membership values for fuzzy decision analysis were related to the performance of birds as measured by hen-day production and cumulative mortality. The decision analysis showed the crossover point between an uncrowded and a crowded condition was 3 birds in both trials for cage sizes of 1548 and 3097 cm2 based on maximin [corrected] decision values. The crossover point for the largest cage area (4645 cm2) differed between 3 and 4 birds for Trials 2 and 1, respectively. This suggested crowding pressure was not as great when more space was available to the birds.

Animals↗
PubMed1989

Methionine hydroxy analog (free acid) reduces avian kidney damage and urolithiasis induced by excess dietary calcium.

Urinary acidification previously was shown to be an effective treatment for calcium-induced urolithiasis in domestic fowl, but diuresis caused by the acidifying agent (ammonium chloride) was an undesirable side effect. Because supplemental dietary methionine reportedly acidifies mammalian urine, an experiment was conducted to evaluate the efficacy of the free acid form of methionine hydroxy analog (MHA) as an acidifying agent for treating avian urolithiasis. From 5 to 17 wk of age, immature Single Comb White Leghorns were fed diets containing normal calcium (1%) or high calcium (3.5%). Diets were supplemented with 0, 0.3 or 0.6% MHA. Relative to birds fed the normal calcium diets, birds fed the high calcium diet without added MHA were in a state of metabolic alkalosis and excreted more alkaline urine containing high levels of calcium. Birds fed the high calcium diet without MHA also had significantly higher kidney asymmetry ratios, a higher incidence of gross kidney damage, and a higher incidence of urolith formation when compared with birds fed normal calcium diets. When compared with the high calcium diet without MHA, the high calcium diet supplemented with 0.6% MHA significantly acidified the urine without causing detectable metabolic acidosis, significantly reduced kidney asymmetry and gross kidney damage, and reduced the incidence of urolith formation without increasing water consumption or urine flow. These data demonstrate that MHA effectively prevents calcium-induced kidney damage in domestic fowl without causing undesirable side effects. MHA did increase both fractional and absolute calcium excretion during calcium loading.

Acid-Base Equilibrium↗
PubMed1988

Strain differences in the number and size of glomeruli in domestic fowl.

1. An investigation was made into strain differences and the effect of the type of drinker on the number and size of glomeruli of Single Comb White Leghorn pullets. 2. The Dekalb XL strain had more glomeruli per kidney and per g of kidney than the Hyline W-36. The glomeruli of the Dekalb XL were smaller in circumference. There were no significant differences in the absolute or relative weights of the kidney. 3. The type of drinker, bell or trigger-cups, had no effect on the body weight or those kidney variables studied.

Animals↗
PubMed1987

Effect of watering devices on performance during pullet-rearing and cage-laying phases of single comb White Leghorn hens.

An experiment was conducted to examine the effect of watering devices used during pullet-rearing and cage-laying phases on subsequent biological and production responses of hens with 960 pullets reared in floor pens for an 18-wk period. During the pullet phase, birds were placed in one of three watering regimens: start/grow trigger-cups (SGTC), bell drinkers (BD), or a combination treatment consisting of 9 wk on BD and 9 wk on SGTC (BD/SGTC). During the laying phase, birds were placed in laying units with four birds per cage. Cages were equipped with mature bird trigger-cups (TC), fount-cups (FC), vertically activated nipple drinkers (VAND), or cone-shaped cups (CC). Cage waterers had significant influences on average hen-day egg production (HD) and feed conversion of the hens. For HD production, there was no difference between hens on CC and TC or between CC and FC. Birds drinking from VAND had significantly lower HD production and poorer feed conversion than birds on the other waterer treatments. There were no significant differences in body weight for birds raised on the different drinking devices. Cumulative mortality during the cage-laying phase was nonsignificantly higher for birds drinking from VAND than for birds drinking from CC. There was no effect of waterer type on egg weight or Haugh units. Specific gravity was poorer for eggs produced by hens drinking from FC as compared with eggs from hens on CC or VAND. Kidney weights and kidney as a percentage of body weight were affected by the interaction of the pullet-rearing and cage-laying phase waterers.

Animal Husbandry↗
PubMed1985

Urolithiasis in pullets and laying hens: role of dietary calcium and phosphorus.

A study was conducted to test the independent and combined effects of high dietary calcium and low available phosphorus on the incidence of urolithiasis in pullets and laying hens. One thousand Single Comb White Leghorn pullets were divided into four diet treatment groups beginning at 50 days of age. A normal calcium (1%), normal available phosphorus (.6%) diet (NCNP) was fed to control pullets. Other pullet groups were fed a high calcium (3.25%), normal available phosphorus (.6%) diet (HCNP), a normal calcium (1%), low available phosphorus (.4%) diet (NCLP), or a high calcium (3.25%), low available phosphorus (.4%) diet (HCLP). At 18 weeks of age, 368 pullets were necropsied. One percent of the HCNP group and 14% of the HCLP group developed urolithiasis. Urolithiasis was not found in pullets raised on the NCNP and NCLP diets. The remaining pullets were transferred to laying cages and were fed a commercial layer ration until they were 51 weeks old. None of the hens raised on the NCNP diet, 12% of the hens raised on the HCNP diet, 2% of the hens raised on the NCLP diet, and 14% of the hens raised on the HCLP diet had urolithiasis. Renal function studies were performed on 18-week-old pullets and 51-week-old hens. Pullets raised on the HCLP diet had significantly higher urine pH, significantly lower fractional inorganic phosphate excretion, and significantly higher fractional calcium excretion when compared with pullets raised on the other diet treatments. The profound effect of the HCLP diet on renal calcium and phosphorus excretion in pullets was not retained in the hens.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1984

Effect of increased bird population in a fixed cage area on production and economic responses of single comb white leghorn laying hens.

Quantitative relationships between the cage area allotted per hen and parameters associated with egg production were examined by regression analysis. Hens were placed 3, 4, and 5 birds per cage (30.5 x 50.8 cm) with 516, 387, and 310 cm2 of floor area per hen, respectively. Egg production declined as the area per hen was reduced. There was no numerical difference for feed consumption per dozen eggs between 516 or 387 cm2 per hen. Feed conversion was less efficient when the area was reduced to 310 cm2 per hen. Feed conversion when adjusted to 20 dozen eggs accentuated the decline in efficiency as previously noted. Mortality was significantly related to a reduction in cage area per hen. Egg weight tended to increase as the allotted area per bird decreased. Eggs produced and feed consumed per cage were highly correlated to bird numbers per cage area. An economic analysis based on dozens of eggs produced, feed consumption, egg and feed prices, grower payment, and pullet cost showed that profitability associated with increased bird numbers in a fixed cage area is sensitive to changes in egg and feed prices.

Animal Feed↗
PubMed1984

Changes in serum corticosterone concentration of laying hens as a response to increased population density.

The response of adrenal glands of Single Comb White Leghorn laying hens housed under different population densities was studied. The birds were reared in floor pens until they were 19 weeks of age, after which they were housed in cages. Cage size was 30.5 X 50.8 cm. Three, four, or five birds were housed per cage. Corticosterone concentrations were measured in all birds 48 and 96 hr following housing in cages and weekly thereafter for 6 weeks. Corticosterone concentrations were consistently higher in the serum of birds housed five per cage than in birds housed three or four per cage. It was concluded that in order to minimize physiological stress in cage layers, more than 387 cm2 per bird should be considered.

Adrenal Glands↗
PubMed1984

Effect of watering systems for floor-reared pullets on subsequent caged laying hen performance.

Two watering system trials were conducted with floor-reared pullets. Trial 1 showed that pullets raised on trigger cups (STC) compared to pullets raised on dome waterers (DW) had significantly better feed conversion and lower mortality. A significant difference was shown between 4 and 5 hens per cage for hen-day egg production and feed per dozen eggs. There were no differences in production responses according to cage waterer availability or for main effect interactions. Trial 2 showed that raising pullets on STC, DW, or a DW to STC change during the rearing phase had no effect on cage laying performance. Mortality trends were shown according to waterer system. Trial differences were hypothesized to be associated with the laying cage waterer type used in each trial; fount cups were used in Trial 1 and TC in Trial 2.

Animals↗
PubMed1981

True metabolizable energy values of corn and different varieties of wheat and barley using normal and dwarf single comb White Leghorn Roosters.

An experiment with four trials was conducted to measure the true metabolizable energy value of corn and different varieties of wheat and barley using normal and dwarf Single Comb White Leghorn (SCWL) roosters. Maxigene, Purple, Red, and Yamhill wheats and corn were assayed for TME using normal sized and dwarf roosters in Trials 1 and 2, respectively. Hannchen, No. 2 Western, Lady Godiva, and Hiproly barleys were assayed using normal sized and dwarf SCWL roosters in Trials 3 and 4, respectively. The pooled results indicated that normal sized roosters gave (P less than .01) significantly higher TME values than dwarf roosters. There was no significant difference in TME found between wheat and barley cultivars, although both types of grain were significantly (P less than .01) lower in TME than the value found for corn. Average dry matter TME values for corn, wheat, and barley were 4.17, 3.70, and 3.54, respectively. A bird x grain interaction was found to be significant (P less than .05).

Animal Feed↗
PubMed1979

An application of response surface methodology to research in poultry nutrition.

Response Surface Methodology (RSM) is an experimental procedure for exploring and examining the nature of responses obtained from the simultaneous variation of quantitative factors. The method has been used only to a limited extent in poultry research. Statistical procedures were discussed for fitting a response surface to experimental data. An outline was made of the mathematical process for finding the stationary point, yield at the stationary point and nature of the response surface. A poultry example was given which involved the investigation of the protein and energy requirements of Japanese quail. The advantage of RSM was shown when it was determined by RSM procedures that the optimum response for body weight was out of the exploratory region covered in the first trial. A second trial was then conducted based on the levels of protein and energy predicted to give an optimum body weight. Optimum responses were shown for both body weight and feed conversion. Examination of the responses by three dimensional figures and computer plotting of contours was shown. The RSM procedure appears to offer an efficient method for examining the requirements and relationships of nutrients for poultry.

Analysis of Variance↗