Probabilistic assessment on the basis of interval data

Thacker, Ben H.,Huyse, Luc J. Techno-Press 2007 Structural Engineering and Mechanics, An Int'l Jou Vol.25 No.3

Uncertainties enter a complex analysis from a variety of sources: variability, lack of data, human errors, model simplification and lack of understanding of the underlying physics. However, for many important engineering applications insufficient data are available to justify the choice of a particular probability density function (PDF). Sometimes the only data available are in the form of interval estimates which represent, often conflicting, expert opinion. In this paper we demonstrate that Bayesian estimation techniques can successfully be used in applications where only vague interval measurements are available. The proposed approach is intended to fit within a probabilistic framework, which is established and widely accepted. To circumvent the problem of selecting a specific PDF when only little or vague data are available, a hierarchical model of a continuous family of PDF's is used. The classical Bayesian estimation methods are expanded to make use of imprecise interval data. Each of the expert opinions (interval data) are interpreted as random interval samples of a parent PDF. Consequently, a partial conflict between experts is automatically accounted for through the likelihood function.

Performance, Digestibility and Carcass Characteristics of Growing/Finishing Pigs Fed Barley-Based Diets Supplemented with an Extruded or Unextruded Blend of Peas and Canola Seed or Meal

Thacker, P.A.,Qiao, Shiyan Asian Australasian Association of Animal Productio 2002 Animal Bioscience Vol.15 No.1

Seventy-two crossbred pigs weighing an average of 41.5 kg were assigned on the basis of sex, weight and litter to one of four dietary treatments in a factorial (4 treatments${\times}$2 sexes) arrangement. The control diet was based on barley and soybean meal while the experimental treatments consisted of diets in which a portion of the dietary protein was supplied by 20% of a 50:50 blend of extruded ($130^{\circ}C$ for 20 to 25 sec) peas and full-fat canola seed, 20% of a 50:50 blend of unextruded peas and full-fat canola seed or a diet containing 10% peas, 6% canola meal and 4% canola oil (to equal the level of canola oil provided by 10% whole canola seed). Digestibility coefficients for dry matter, crude protein and gross energy were significantly higher (p<0.05) for the control diet than for the other three diets. Extrusion produced no beneficial effects (p>0.05) on nutrient digestibility and there were no differences in digestibility between the diet based on intact canola seed compared with the diet containing canola meal and oil. Choice of protein supplement had no significant effects on gain, feed intake or feed conversion during the grower or finisher phases and over the entire experimental period. Extrusion of the pea-canola blend produced no beneficial effects on pig performance as the performance of pigs fed either the extruded or unextruded blend of peas and canola seed was similar. In addition, the performance of pigs fed diets containing intact canola seed was similar to that of pigs fed canola meal and oil. Castrates gained faster and consumed more feed than gilts (p<0.05). However, their feed conversion was poorer than that of the gilts during the finisher period. There were no significant differences in carcass traits between pigs fed the control and any of the experimental treatments. Extrusion had no effect on carcass traits and the carcasses of pigs fed canola meal and oil did not differ from those of pigs fed whole canola seed. Castrates had a significantly lower dressing percentage, lower estimated lean yield but greater loin fat depth than gilts (p<0.05). The results of this experiment indicate that peas in combination with canola seed or canola meal are an acceptable alternative to soybean meal as a protein supplement for use in growing-finishing swine diets. Extrusion did not appear to have any beneficial effects on the nutritional value of the canola seed-pea blend as nutrient digestibility, growth performance and carcass traits were similar for pigs fed the unextruded blend of peas and canola seed compared with the extruded product. Since the process adds to the cost of the raw products, its use is unlikely to be economical.

Nutritional Evaluation of Canola Protein Concentrate for Broiler Chickens

Thacker, P.A.,Petri, D. Asian Australasian Association of Animal Productio 2011 Animal Bioscience Vol.24 No.11

This trial was conducted to determine the effects of including canola protein concentrate in diets fed to broiler chickens on nutrient digestibility and broiler performance (0-21 days). A total of 180, day-old, male broiler chicks weighing an average of 52.8${\pm}$0.6 g were assigned to one of six dietary treatments in a completely randomized design. The control diet was based on corn and soybean meal and contained 15% canola meal. The experimental diets contained 3, 6, 9, 12 or 15% canola protein concentrate added at the expense of canola meal. There were five birds per pen and six replicate pens per treatment. Feed and water were available ad libitum throughout the 21-day experiment. Chromic oxide (0.35%) was added to all diets as a digestibility marker and was fed throughout the experimental period. The digestibility of dry matter, energy and phosphorus increased linearly (p<0.01) with increasing levels of canola protein concentrate. Although nutrient digestibility was higher for birds fed diets containing canola protein concentrate, these improvements did not translate into improvements in broiler performance. Weight gain was unaffected (p = 0.24) by level of canola protein concentrate. Feed intake was significantly increased (p<0.01) with the result that feed conversion tended to be poorer (p = 0.07) for birds fed diets containing canola protein concentrate. Mortality was also unaffected (p = 0.56) by dietary treatment.

Performance of Growing-finishing Pigs Fed Diets Containing Graded Levels of Biotite, an Alumninosilicate Clay

Thacker, P.A. Asian Australasian Association of Animal Productio 2003 Animal Bioscience Vol.16 No.11

The objective of this study was to evaluate the potential of an alumninosilicate clay, marketed under the trade name Biotite V, to improve growing-finishing pig performance and to determine its effects on nutrient digestibility and excretion. Sixty crossbred pigs (22.3${\pm}2.7kg$, Camborough 15 Line female${\times}$Canabred sire) were assigned on the basis of sex, weight and litter to one of four dietary treatments in a $2{\times}4$ (two sexes and four treatments) factorial design experiment. The experimental diets were based on barley and soybean meal and contained 0, 0.25, 0.5 or 0.75% biotite during the growing period (22.3-60.5 kg) and 0, 0.5, 1.0 or 1.5% biotite during the finishing period (60.5-110.3 kg). Each pig was allowed access to its own individual feeder for 30 min twice daily (07:00 and 15:00 h). Individual pig body weight, feed consumption and feed conversion were recorded weekly. The pigs were slaughtered at a commercial abattoir when they reached an average weight of 110.3 kg. Carcass weight was recorded and dressing percentage calculated. Carcass fat and lean measurements were obtained with a Destron PG 100 probe between the 3rd and 4th last ribs, 70 mm of the midline. Total tract digestibility coefficients for dry matter, energy, nitrogen and phosphorus were determined using three males and three females per treatment starting at an average weight of $52.2{\pm}3.8kg$. These pigs were housed under identical conditions as those used in the growing stage and were fed the same diets modified only by the addition of 0.5% chromic oxide as a digestibility marker. Over the entire experimental period (22.3-110.3 kg), daily gain was unaffected (p>0.05) by the inclusion of biotite in the diet. There was a cubic response for feed intake (p=0.06) and a quadratic response (p=0.07) for feed conversion due to biotite. Feeding biotite produced no significant (p>0.05) linear or quadratic effects on any of the carcass traits measured. Dry matter digestibility decreased linearly (p=0.02) with increasing levels of biotite in the diet. However, digestibility coefficients for energy, nitrogen and phosphorus were unaffected (p<0.05) by biotite inclusion. Lactobacilli and enterobacteria numbers were unaffected by inclusion of biotite while Salmonella was not detected in any of the fecal samples. The overall results of this experiment indicate that biotite inclusion did not reduce fecal excretion of nitrogen or phosphorus and failed to improve nutrient digestibility. Neither growth rate nor carcass quality was improved while a modest improvement in feed conversion was observed at lower levels of inclusion. Based on the results of this experiment, it would be difficult to justify the routine inclusion of biotite in diets fed to grower-finisher pigs. Whether or not a greater response would have been obtained with pigs of a lower health status is unknown.

Effects of Supplementary Threonine, Canola Oil or Enzyme on Nutrient Digestibility, Performance and Carcass Traits of Growing-finishing Pigs Fed Diets Containing Wheat Distillers Grains with Solubles

Thacker, P.A. Asian Australasian Association of Animal Productio 2009 Animal Bioscience Vol.22 No.12

This trial was conducted to determine the effects of various feed additives on nutrient digestibility, performance and carcass traits of growing-finishing pigs fed diets containing wheat distiller' grains with solubles (WDGS). Seventy-two, individually fed pigs (19.7${\pm}$2.6 kg), were assigned to one of six dietary treatments in a 6${\times}$2 (treatment${\times}$sex) factorial design (N = 12). The control diet was based on wheat and soybean meal while the five experimental diets contained 20% WDGS during the growing period and 12% WDGS during the finishing period. One 20% WDGS diet was unsupplemented while the remaining diets were supplemented with either 0.1% threonine, 5% canola oil, 0.2% enzyme (0.1% Endofeed W containing 1,250 units/g of xylanase and 385 units/g of $\beta$-glucanase and 0.1% Vegpro containing 7,700 HUT/g protease and 75 CMC/g cellulase), or a combination of the three additives at the same levels as those fed separately. The digestibility of dry matter, crude protein and energy were all significantly higher in the control diet than the unsupplemented diet containing 20% WDGS. None of the feed additives improved nutrient digestibility. In addition, none of the additives had any significant effect on gain or feed intake during the growing (19.7 to 43.6) or finishing (43.6 to 114.3 kg) periods or overall (19.7 to 114.3 kg). During the growing period, feed conversion was significantly improved for pigs fed the combination of additives compared with the unsupplemented WDGS diet. During the finishing period and overall, feed conversion was significantly improved for pigs fed 5% canola oil alone or in combination with the other additives. None of the supplements had any effect on carcass traits. These results indicate that WDGS can be successfully used as a partial replacement for soybean meal in diets fed to growingfinishing pigs. However, due to its low energy content, there may be some merit in including high energy ingredients such as canola oil when diets containing WDGS are fed.

Nutritional Requirements of Early Weaned Pigs - A Review -

Thacker, P.A. Asian Australasian Association of Animal Productio 1999 Animal Bioscience Vol.12 No.6

The process of weaning, no matter how carefully managed, results in changes in the gut of the pig that make it more susceptible to digestive upset, diarrhea and impaired appetite. The objective in developing feeding programs is to recognize these unique needs and facilitate a smooth transition to a dry feed. How well this is accomplished, has a significant impact on future performance. This paper provides a review of recent research on the nutrients required by early weaned pigs and examines what feedstuffs are available to provide those nutrients in a form that can be best utilized by the early weaned piglet.

Further Modifications to the Mobile Nylon Bag Technique to Determine Nutrient Digestibility for Swine

Thacker, P.A.,Qiao, S. Asian Australasian Association of Animal Productio 2001 Animal Bioscience Vol.14 No.8

Previous studies conducted with swine have reported that the mobile nylon bag technique (MNBT) does not always accurately predict in vivo nutrient digestibilities. Therefore, in this study, the MNBT was modified so that nutrient digestibilities would more closely resemble those from conventional (Con) digestibility studies obtained using the indicator method. A total of 19 feeds were tested including five cereal grains, five legumes, three high protein sources and six mixed diets. The principle changes to the MNBT included the use of a fecal collection harness which minimized the number of bags lost. In addition, previous protocols involved pooling of bags within pig while in the present experiment all bags were analyzed separately to increase the precision of the test. Finally, chemical analyses were done using the entire nylon bag plus residue rather than opening.the bags and scraping out the contents. With the exception of the barley sample (p=0.01), dry matter digestibility (DMD) coefficients obtained with the MNBT were not significantly different from those obtained with the indicator method. The linear regression equation relating the MNBT to the indicator method was Con DMD=-O.77+1.02 MNBT DMD ($r^2=0.93$: p<0.0001). There was no significant (p>0.05) difference in gross energy digestibility (GED) coefficients determined using the MNBT or the indicator method for any of the 19 feeds. The regression line equation relating the MNBT to the indicator method was Con GED=-5.68+1.06 MNBT GED ($r^2=0.94$: p<0.0001). The MNBT was less effective in predicting in vivo crude protein digestibility (CPD) than it was in predicting dry matter and energy digestibility. Differences greater than five percentage units were observed for two of the legumes, Kabuli chickpeas (p=0.02) and the extruded pea-canola seed mixture (p=0.01) as well as for three of the mixed diets including the unheated hulled barley-based diet (p=0.01), the unheated hulless-barley based diet (p=0.08) and the barley-soybean meal based diet (p=0.008). The regression equation relating the MNBT to the indicator method was Con CPD=5.75 + 0.90 MNBT CPO ($r^2=0.76$; p<0.0001). This study indicates that the modified MNBT can be used for the rapid determination of dry matter and energy digestibility in a wide variety of ingredients. For the measurement of crude protein digestibility, the technique produces results similar to conventional digestibility studies for cereal grains and high protein feeds but tends to overestimate protein digestibility for legumes and mixed diets.

Performance of Growing/Finishing Pigs Fed Hulled and Dehulled Peas With and Without Dietary Enzymes

Thacker, P.A.,Racz, V.J. Asian Australasian Association of Animal Productio 2001 Animal Bioscience Vol.14 No.10

Eighty crossbred pigs (Large White x Landrace) weighing 9.9 kg were assigned on the basis of sex, weight and Jitter to one of five dietary treatments in a factorial $(5\;treatments\;{\times}2\;sexes)$ arrangement to compare the nutritive value of hulled and dehulled peas fed with or without enzyme (0.25% Allzyme PF and 0.5% Biogal-S). A barley and soybean meal diet served as a control. Eight castrates and eight gilts were fed each diet. Digestibility coefficients for dry matter, crude protein and energy were higher for diets containing dehulled peas than hulled peas. In addition, enzyme supplementation modestly increased the digestibility of all three nutrients. Over the entire experimental period (9.9 to 103.3 kg), there were no performance differences (p>0.05) between pigs fed soybean meal based diets or diets based on any of the pea products. In addition, there were no differences in performance between pigs fed diets containing hulled or dehulled peas or between pigs fed diets with or without dietary enzyme. Castrates gained weight significantly faster, consumed more feed but had a poorer feed conversion than gilts (p<0.05). There were no differences in carcass traits between pigs fed diets based on soybean meal or any of the pea products. Carcass traits were similar for pigs fed hulled or dehulled peas while enzyme supplementation also had no effect on carcass data. Castrate pigs had a lower carcass value index, estimated lean yield and loin lean depth (p<0.05). Loin fat depth was greater for castrates than gilts (p<0.05). The overall results of this experiment provide little support for the need for enzyme supplementation of pea based diets fed to swine. In addition, dehulling did not appreciably improve the nutritive value of peas. Therefore, since the process adds to the cost of the raw product, its use is unlikely to be economical.

The Effects of Phytase Supplementation on Performance and Phosphorus Excretion from Broiler Chickens Fed Low Phosphorus-Containing Diets Based on Normal or Low-phytic Acid Barley

Thacker, P.A.,Haq, Inam,Willing, B.P.,Leytem, A.B. Asian Australasian Association of Animal Productio 2009 Animal Bioscience Vol.22 No.3

A total of 240 day-old broiler chicks were used to study the effects of phytase on performance and phosphorus (P) excretion from birds fed diets containing low phytate barleys formulated without inorganic P. A positive control based on Harrington barley (HB) was formulated to meet requirements for total P. Three experimental diets, based on either HB (0.39% total P with 0.28% phytate P) or the low phytate varieties LP 422 (0.36% total P with 0.14% phytate P) and LP 955 (0.40% total P with 0.01% phytate P), were formulated to be below requirements for total P by removing all the inorganic P from the diet. The four diets were fed with and without 1,000 FTU/kg phytase. Apparent P digestibility was significantly higher (p<0.01) for birds fed the low phytate barleys than for birds fed HB either supplemented or un-supplemented with inorganic P. P excretion was significantly lower (p<0.01) for birds fed HB without inorganic P than with inorganic P. P excretion was further reduced by the use of the low phytate barleys LP 422 and LP 455 (p<0.01). Phytase supplementation did not affect P excretion (p = 0.39). Body weight gain and feed intake were highest for birds fed the HB diet with inorganic P and lowest for birds fed the HB diet without inorganic P (p<0.01). Among the three low P diets, body weight gain and feed intake of broilers increased as the level of phytate in the barley declined (p<0.01). Phytase modestly increased body weight gain (p = 0.08) and feed intake (p = 0.04). The overall results of this study indicate that it may be possible to reduce the amount of inorganic P used when formulating diets with low phytate barley compared with the levels needed when formulating diets with normal phytate barley. However, it is not possible to completely replace the inorganic P in diets containing low phytate barley without impairing poultry performance. Feeding diets devoid of supplementary inorganic P in combination with low phytate barley resulted in a significant reduction in P excretion by poultry.

The Effects of Canola or Mustard Biodiesel Press Cake on Nutrient Digestibility and Performance of Broiler Chickens

Thacker, P.A.,Petri, D. Asian Australasian Association of Animal Productio 2009 Animal Bioscience Vol.22 No.11

This study compared the nutritional value of canola (B. napa) and mustard (B. hirta) press cakes obtained from the biodiesel industry as ingredients for use in diets fed to broiler chickens. A total of 210, one-day old, male broiler chicks were randomly assigned to one of seven dietary treatments. The control diet was based on wheat and soybean meal and contained 15% canola meal. For the experimental diets, 5, 10 or 15% of the canola meal was replaced with an equal amount of either canola or mustard biodiesel press cake. Dry matter and neutral detergent fiber digestibility were significantly higher for birds fed diets containing either canola or mustard biodiesel press cake compared with canola meal. Dry matter and neutral detergent fiber digestibility of the canola biodiesel press cakes was higher than the mustard biodiesel press cakes. Ether extract digestibility and nitrogen retention were significantly higher for birds fed canola biodiesel press cake compared with canola meal and mustard biodiesel press cake. Body weight gain and feed intake did not differ between birds fed canola or mustard biodiesel press cake and canola meal. In addition, there was no significant difference in body weight gain or feed intake between birds fed diets containing canola or mustard biodiesel press cake. Feed conversion was significantly improved for birds fed either canola or mustard biodiesel press cake compared with canola meal. Mortality was unaffected by treatment. Since the performance of broilers fed canola biodiesel press cakes was essentially the same as that of broilers fed canola meal, it is difficult to justify a premium to be paid for canola biodiesel press cake over that paid for canola meal. In addition, there was no difference in the performance of broilers fed biodiesel press cake obtained from canola or mustard seed. As mustard seeds are generally available at a lower price than canola seed, there may be some incentive to use mustard rather than canola seed for producing biodiesel press cake for use in poultry production.