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Articles by P. W. Waldroup
Total Records ( 18 ) for P. W. Waldroup
  A.M.H. Subuh , M.A. Motl , C.A. Fritts and P. W. Waldroup
  A study was conducted in which whole unextracted soybeans were processed by passing the beans through a roller mill and then extruding without steam. The processed beans were then included into nutritionally adequate broiler diets, replacing solvent extracted soybean meal in ratios of 0/100, 25/75, 50/50, and 0/100 % with dietary energy levels of 3200, 3300, and 3400 ME kcal/kg. This resulted in a 3 x 4 factorial arrangement of treatments. Each treatment was fed to six replicate pens of 60 male chicks of a commercial broiler strain from 1 to 42 days of age. The results of the study demonstrate that the inclusion of extruded fullfat soybean in a pelleted broiler diet supported chick performance equal or superior to that of dehulled solvent extracted soybean meal, and that extruded soybeans could partially or completely replace soybean meal without any adverse effects on body weight, feed conversion, mortality, dressing percentage, or abdominal fat content provided the diets are nutritionally balanced.
  P. W. Waldroup , S. E. Watkins , J. T. Skinner and A. D. Desai
  A study was conducted with broiler feed medicated with bacitracin methylene disalicylate (BMD) to determine if the addition of lignin sulfonate pellet-binding agents affects the assay of active concentration of BMD in pelleted feed. This study also examined the stability of BMD in the presence of these pellet-binding agents in pelleted feed over extended storage. Diets were mixed that contained 27.5 mg/kg of BMD. Diet 1 did not contain a pellet binder. Diet 2 contained 1.25% Ameri-Bond 2x, and Diet 3 contained 0.6% Pel-Stik. Mash and pelleted samples of each diet were assayed for loss on drying (LOD) and BMD level during week 0. Pelleted samples were stored at ambient temperature (25 oC) and ambient humidity, or elevated temperature (37 oC) and ambient humidity. Samples stored at 25 oC were assayed during weeks 2, 4, 7, 10, and 13, and those stored at 37 oC were assayed during weeks 1, 2, 3, and 4 for LOD and BMD levels. Assay results from week 0 in both mash and pelleted feeds demonstrated the non-interference of the pellet binders with the assay of BMD. The BMD assay results of feeds stored at 25 and 37 oC demonstrated that these pellet binders do not affect the stability of BMD in feed.
  C. P. Ojano-Dirain and P. W. Waldroup
  Information on amino acid requirements of broilers raised under warm environments is very limited. Two studies of identical design were conducted to evaluate Lys, Met and Thr needs of 3 to 6 week-old male broilers held in battery pens at 26.7 oC. A basal diet was supplemented with amino acids in a 4 x 3 x 2 factorial arrangement with Lys levels of 1.03, 1.08, 1.12, and 1.16%, Met levels of 0.38, 0.44, and 0.50%, and Thr levels of 0.78 and 0.87%. Feed consumption, body weight (BW) gain and carcass yield were determined. Lys levels had no significant effect on 21 to 42 d BW gain, feed conversion ratio (FCR), or dressing percentage (DP). Increasing Lys levels from 1.03 to 1.12% significantly (P < 0.05) improved breast yield (BY) and reduced abdominal fat. Increasing Met to 0.44% resulted in significant improvements in BW gain, FCR, DP, BY, and a numerical (P=0.08) reduction in AF. Threonine levels used in this study had no significant effect on any parameter. There was a significant interaction of Lys and Thr on breast yield; however it followed no consistent trend. These results suggest that under moderate heat stress, the present levels of Lys and Met suggested by NRC may be inadequate for maximum live performance or breast meat yield; however, suggested levels of Thr appear to be adequate for this age period.
  C. P. Ojano-Dirain and P. W. Waldroup
  Broiler production has increased rapidly in tropical and subtropical countries in the past decade and is predicted to sustain strong growth in the future. One of the greatest challenges to efficient production in these areas is the reduction in performance associated with warm and hot weather conditions. Various dietary approaches have been taken to enhance broiler performance under these conditions. Numerous management strategies have been employed to alleviate the adverse effects of heat distress with varying degrees of success. Nutritional means of alleviating heat distress have focused largely on manipulation of energy and protein or amino acid content of the diet. Although the tendency has been to increase protein/amino acid levels to account for reduced intake, research indicates that such an action is not sufficient to overcome adverse effects. Improving overall balance of the diet by amino acid supplementation appears to be more effective than increasing total protein intake. More research is needed to quantify amino acid needs under warm weather conditions.
  S. E. Watkins , E. A. Saleh and P. W. Waldroup
  This trial was conducted to determine if the reduction in weight gains and feed intake observed for broilers fed 30% cottonseed meal diets was associated with the high fat level of the diets necessary to maintain the diets isocaloric compared to corn-soybean meal control diets. Three series of energy levels were formulated to contain 2950/3000, 3000/3050, 3050/3100 ME Kcal/kg with values representing the starter/grower (S/G) dietary energy values, respectively. Within each energy series, diets were formulated to contain either soybean meal as the primary protein source (0% CSM) or 30 % cottonseed meal (30 % CSM). Male broilers were fed starter diets 0 to 21 days followed by grower diets to 42 days. At the end of the trial, six birds per pen were processed to determine carcass and parts yield. Results showed that 21 and 42 days body weights, feed consumption and mortality of the birds receiving the 30 % CSM diets were comparable to the performance of birds receiving the 0% CSM diet for the similar energy series. There was an interaction effect for 21 days feed conversion with the feed conversion of the 0% CSM 3000/3050 series significantly lower than all of the other conversion rates. Feed conversion rates at 21 and 42 days were significantly depressed for the birds receiving the 30 % CSM diets. Although the dressing percentage was lower for the 30 % CSM birds, abdominal fat was also lower and breast meat yield equaled the 0 % CSM birds. Increasing the dietary energy level increased abdominal fat. The results indicated that the high dietary fat levels used in previous experiments could to be interfering with optimum usage of a 30 % CSM diet for growth but not for feed conversion.
  P. W. Waldroup and J. A. England
  The increased growth rate of Large White turkeys has prompted producers to change feeds at more frequent intervals than previously. However, nutrient recommendations by established agencies such as the National Research Council (1994) have not adjusted to this change. Using regression analysis of published amino acid recommendations, modified amino acid recommendations were calculated for feeding on three week intervals. Male Large White turkeys were fed diets formulated to provide from 90 to 115% of the modified recommendations from day-old to 18 weeks of age; samples of the birds were processed to determine carcass characteristics. Based upon the results of the present study, the amino acid recommendations derived from regression analysis of NRC recommendations appear to be a good basis for use when changing diets at intervals of 3 week for male Large White turkeys. To insure maximum breast meat yield, these should be increased by approximately 5%.
  P. W. Waldroup , J. H. Kersey and M. T. Kidd
  An experiment was conducted to estimate the Thr needs of male Large White turkeys from 8 to 12 week of age and to evaluate the effects of dietary CP on Thr needs. The dietary treatments consisted of a 2 x 6 factorial arrangement with two levels of CP (16.0 and 19.8%), each containing 0.50% total Thr by analysis. Aliquots of each CP basal diet were supplemented with L-Thr to provide total Thr levels of 0.50, 0.57, 0.64, 0.71, 0.78, and 0.85%. Initial and final bird weights were taken to determine BW gain; feed conversion ratios were calculated with adjustment for weight of birds that died during the study. Nonlinear and quadratic regression analyses were used to estimate a Thr requirement to optimize BW gain and feed conversion. For both BW gain and feed conversion, significant interactions were observed between dietary CP and Thr levels. Performance was superior for poults fed the low CP diet series, noted primarily at the lower levels of Thr. As levels of Thr reached a surfeit, no significant differences in performance were noted between poults fed the two CP levels. Using nonlinear regression analysis, dietary Thr levels of 0.68 (16.0% CP) and 0.76% (19.8%) were adequate for maximum BW gain while Thr levels of 0.61 (16.0% CP) and 0.70% (19.8%) were adequate for optimum feed conversion. However, when estimates were based on fitting a quadratic regression, dietary Thr levels of 0.83 (16.0% CP) and 0.98% (19.8%) were adequate for maximum BW gain, while Thr levels of 0.77 (16.0% CP) and 0.82% (19.8%) were adequate for optimum feed conversion. While the interactions between dietary CP and Thr may be interpreted to suggest that dietary CP levels influence amino acid requirements, the two basal diets were composed of protein sources that differ in digestibility of Thr. It is possible that the reduced BW gains and impaired feed conversion observed at the lowest level of Thr supplementation on the high CP diets were the result of a lower level of digestible Thr, rather than a direct influence of CP level per se.
  C. A. Fritts , J. H. Kersey and P. W. Waldroup
  Protein supplements produced by rendering of whole hens at the end of their production cycle (spent hen meal) was used to provide a portion of the diets of laying hens in an 84 d feeding trial. Diets were formulated to provide 0, 5, 10, or 15% spent hen meal (SHM) from three different locations using conventional rendering procedures. The diets were formulated to provide digestible amino acids at a minimum of 95% of recommended (NRC, 1994) total amino acids for laying hens consuming 100 g of feed per day. Results of the study indicate that nutritionally valuable high-protein meals can be produced from whole spent hens using conventional rendering procedures. Such meals may be safely used at levels up to 10% in diets for laying hens provided good analytical procedures are followed to determine nutritional content. Due to the high level of residual fat and the highly unsaturated nature of this fat, it will be necessary to insure that adequate amounts of a suitable antioxidant is used during manufacturing to prevent rancidity development.
  P. W. Waldroup and E. O. Oviedo-Rondon
  Computerized growth models can be a useful tool to determine more profitable and accurate concentrations and balance of dietary amino acids and other nutrients for broiler chickens. The methodology of mathematical modeling can be rapidly accepted in poultry nutrition and research due to the complexity of nutrient requirement estimations in practical and economical terms, and the necessity to have some quantitative margin of safety in the prediction of broiler performance for decision-making applications in the poultry industry. This paper reviews the current problems related to the methodologies for amino acid requirement estimation for growing chickens, the development of mathematical modeling of growth and their applications in poultry nutrition, and a short chronological review of the evolution of computer growth models.
  E. O. Oviedo-Rondon , C. A. Fritts and P. W. Waldroup
  Estimation of amino acid requirements is a complex problem where many factors such as experimental conditions, genetic strain, gender, growth rate, protein quality and level of other dietary nutrients may interfere with the response. Due to the difficulties of using empirical research to resolve these problems, several mathematical growth models have been developed which could be useful for this purpose. Among the models proposed, the OmniPro® II growth model was chosen to evaluate its accuracy to estimate protein and amino acid requirements for broilers under a commercial feeding program. Diets formulated based on levels of protein and amino acids estimated by OmniPro® II were compared with diets based on NRC (1994) recommendations. Significant differences between sexes were observed for all variables evaluated. Broilers fed diets formulated with 100% of OmniPro® II estimations had BW that was similar to those fed diets based on NRC or 110% OmniPro, and were significantly heavier than those fed the 90% OmniPro diets. The feed conversion of male broilers fed diets based on OmniPro recommendations was significantly better than that of chicks fed diets based on NRC recommendations. Females fed with diets according to OmniPro or NRC had the highest dressing percentage, and differed only from those fed the 90% OmniPro diets. These data suggest that nutrient estimations generated by the OmniPro® II support performance equal to or better than that of broilers fed diets based on NRC nutrient recommendations.
  P. W. Waldroup , J. H. Kersey and C. A. Fritts
  Two experiments were conducted to evaluate the influence of balance among the branched-chain amino acids Leu, Ile, and Val in broiler diets when levels of these amino acids were deemed adequate. High levels of Leu were obtained by either increasing the quantity of corn gluten meal (disproportionately high in Leu relative to Ile and Val) or by supplementing a corn-soybean meal diet with crystalline Leu. Supplements of Ile and Val were added to aliquots of the high Leu diets to maintain Ile:Leu:Val ratios similar to those observed in diets at the lowest level of Leu. Live performance and organ weights of chicks grown to 21 d on these diets were evaluated. The results of the present studies suggest that an antagonism among or between Leu, Ile, and Val is not likely to result in depressed performance of broilers fed practical type diets when levels of these amino acids are above their minimum requirements. The primary effect noted in these studies was a reduction in feed intake as the level of corn gluten meal increased, attributed primarily to changes in texture of the diet. Further research is needed to evaluate the potential impact of an imbalance in diets with reduced levels of crude protein where one or more of the branched-chain amino acids may be at minimal dietary levels with high levels of Leu from corn protein.
  S. E. Madrigal , S.E. Watkins , N. B. Anthony , C. E. Wall , C. A. Fritts and P. W. Waldroup
  Two studies were conducted in environmental chambers to evaluate different dietary modifications on the incidence or severity of ascites, leg disorders, and sudden death syndrome in males of two commercial broiler strains and their reciprocal crosses. A high energy-high nutrient density diet (HE) series served as the positive control. Two other diet series consisted of a high fiber (HF) diet fed 7 to 21 days of age, followed by the HE series, and a low energy-low nutrient density diet during the early growth phase, as suggested by a major breeder. All diets were pelleted. In one study, a low ventilation model was used while in the second study a low temperature model was used. However, due to limitations of the system we were unable to attain the desired low temperatures. In both studies, however, atmospheric levels of CO2 and ammonia were greatly elevated. There were no differences in incidence or severity of ascites, leg disorders, or sudden death syndrome among broilers fed the different dietary regimes to 49 days of age. Broilers fed diets designed to reduce early growth rate were significantly lighter than those fed the HE diets at 21 days of age. At 49 days of age body weights were not always significantly different but quantitative weight differences were equal or greater than those observed at 21 days of age. It is possible that under environmental conditions more favorable to the development of ascites that dietary modification may prove beneficial. In these studies, however, live performance was reduced by the dietary modifications with no beneficial effects on reduction of ascites.
  P. W. Waldroup , C.A. Fritts , J. H. Kersey , E. A. Saleh , B. J. Kerr and M.T. Kidd
  A study was conducted to determine the minimum crude protein content of finisher diets based on corn and soybean meal supplemented with commercially available amino acids for male Large White turkeys. Diets were formulated to contain a minimum of 105% of NRC (1994) recommended levels of Met, Lys, TSAA, Thr, and Trp for diets fed 16 to 20 wk of age; no other essential amino acids were specified. The crude protein content of the diets ranged from 75 to 100% of the recommended level of 16.5%. When diets were formulated to contain at least the minimum recommended levels of Met, TSAA, Lys, Thr, reducing the crude protein content of the diet to less than 85% resulted in a significant reduction in weight at 20 wk or body weight gain from 16 to 20 wk. Addition of Ile and Val to diets formulated to contain 80 or 85% of the recommended crude protein level had no significant effect on body weight or weight gain, indicating that a deficiency of these amino acids per se was not responsible for the reduction in performance on diets with low levels of crude protein. Feed conversion was more variable and was not significantly influenced by dietary crude protein.
  C. A. Fritts and P. W. Waldroup
  A study was conducted to evaluate the use of Bio-Mos®, a mannan oligosaccharide derived from the cell wall of yeast, as a potential replacement for growth promoting antibiotics in the diet of growing turkeys. Bio-Mos® was added to nutritionally complete turkey diets at the rate of 0.05 and 0.10%. The growth-promoting antibiotics bambermycins and bacitracin methylene disalicylate (BMD) were added at 2.2 and 55 mg/kg, respectively. One group was fed the diet with no supplements and served as the negative control. Male turkeys of a commercial Large White strain were fed the test diets from day old to 20 wk of age. Birds were weighed at intervals through the trial and samples of birds processed at 20 wk for parts yield and determination of intestinal breaking strength. Body weight, mortality, breast meat yield, and intestinal breaking strength were not significantly (P < 0.05) influenced by dietary treatments. Feed conversion from 0 to 20 wk of age was significantly improved by both BMD and 0.10% Bio-Mos®. The addition of BMD significantly reduced the percentage of abdominal fat in the carcass. These results suggest that Bio-Mos® might be considered as a part of an overall feeding and management program to aid in overcoming potential loss of growth-promoting antibiotics.
  P. W. Waldroup , Edgar O. Oviedo-Rondon and C. A. Fritts
  A study was conducted to evaluate the response of broilers to diets containing a mannan oligosaccharide, antibiotics, or a combination of antibiotics and mannan oligosaccharide. All diets were supplemented with copper sulfate to provide 250 mg/kg Cu in diets fed to 42 d and 62.5 mg/kg Cu in diets from 42 to 56 d, in addition to the 10 mg/kg provided in the trace mineral mix. Bio-Mos®, a mannan oligosaccharide derived from the cell wall of the yeast Saccharomyces cerevisiae, was added at 1 g/kg in diets fed to 42 d and at 0.75 g/kg in diets fed 42 to 56 d. The antibiotic program consisted of 55 mg/kg of bacitracin methylene disalicylate to 42 d of age followed by 16.5 mg/kg virginiamycin to 56 d of age. When the Bio-Mos® and antibiotics were fed in combination, half the levels indicated above were fed. Twelve pens of 50 male broilers were fed each of the dietary treatments. Results of the study indicate that body weight of broilers was not significantly influenced by the antibiotic treatment, addition of Bio-Mos®, or the combination of antibiotics and Bio-Mos®. Feed conversion at 42 d was significantly improved by both the antibiotic treatment and by the addition of Bio-Mos®. At 56 d the feed conversion of birds fed the antibiotics or the combination of antibiotics and Bio-Mos® was improved compared to that of birds fed the negative control (P = 0.10). No significant effects on mortality, dressing percentage, or parts yield were observed. Possible interference of copper sulfate with the activity of the antibiotics and Bio-Mos® is discussed.
  P. W. Waldroup , C. A. Fritts and Fenglan Yan
A study was conducted to evaluate the effects of combinations of antibiotics, mannan oligosaccharides, and organic forms of copper in the diet of broilers. Male broilers in litter floor pens were fed nutritionally complete diets with a 2 x 2 x 3 arrangement of treatments including two antibiotic programs (none; 55 mg/kg bacitracin methylene disalicylate from 0 to 42 d followed by 16.5 mg/kg virginiamycin to 63 d), two levels of mannan oligosaccharide (none; 1 g/kg Bio-Mos® from 0 to 42 d followed by 0.75 g/kg to 63 d) and three copper programs (none; copper sulfate to provide 250 mg/kg from 0 to 42 d followed by 62.5 mg/kg to 63 d; Bioplex® Cu to provide 55 mg/kg from 0 to 42 d followed by 27.5 mg/kg to 63 d). This resulted in a total of 12 experimental treatments, each fed to eight pens of 50 male chicks. Birds and feed were weighed at intervals during the study and samples of birds processed at 63 d to determine dressing percentage and parts yield. Body weight and feed conversion at 21 d was significantly improved by addition of the antibiotics but did not prove to be significantly improved at later ages. Addition of copper from either copper sulfate or Bioplex® Cu had no significant effect on any parameter tested. Addition of Bio-Mos® at the levels tested had no significant effect on any parameter but did interact with some of the other factors. Carcass characteristics were not improved by any of the factors tested. It is possible that the level of Bio-Mos® used in this study was not sufficient to elicit a positive response.
  F. Yan , C. A. Fritts , P. W. Waldroup , H. L. Stilborn , D. Rice , R. C. Crum , Jr. and V. Raboy
  Large White turkeys were fed diets containing either normal yellow dent corn (YDC) or a corn mutation containing low phytate phosphorus and high available phosphate corn (HAPC). Diets were considered nutritionally adequate in all respects with various degrees of reduction in available phosphorus content ( - 0.0, - 0.05, - 0.10 or - 0.15% of NRC (1994) recommendations for different feeding periods). These diets were fed with or without the addition of 1000 U/kg of phytase enzyme (Natuphos®, BASF), resulting in a total of 16 dietary treatments. Each treatment was assigned to three pens of 20 male turkeys from day-old to 20 wk of age. Body weight, feed consumption, and tibia ash were determined at 28 d intervals during the study. Male turkeys fed diets with HAPC did not differ significantly in BW or feed conversion (FC) from those fed diets with YDC, and had significantly higher tibia ash at 4, 8, and 12 wk of age. Addition of 1000 U/kg of phytase resulted in significantly higher BW at 4, 8, 12, and 16 wk of age as compared to unsupplemented controls with no significant differences in FC. The addition of phytase significantly improved tibia ash at every age. Dietary phosphorus content had no effect on BW or FC at any age. Reduction of phosphorus generally did not impair tibia ash until reduction of 0.15% below NRC (1994) recommendations. Addition of phytase aided in overcoming the reduction in phosphorus content. The combination of HAPC, addition of phytase, and reduction in dietary phosphorus content should aid in reducing phosphorus excretion without impairing performance.
  E. O. Oviedo-Rondon , C. A. Fritts and P. W. Waldroup
  The use of computerized mathematical growth models to estimate accurate and profitable dietary amino acid needs for broilers is a promising alternative to use of fixed requirements. Estimation of crude protein needs by the OmniPro® II growth model is higher than minimum CP levels known to support maximum broiler performance. In this experiment, male broilers were fed either a series of diets formulated using OmniPro® estimations for total amino acids and CP, or a series of diets formulated to provide from 90 to 105% of amino acids estimations made by OmniPro without a CP minimum. Results indicated that diets formulated based on OmniPro total amino acid estimations, with or without minimum crude protein constraints, supported the best live performance and carcass traits.
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