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Like most agricultural production systems, effective decision making in turkey production systems requires the prediction of future status of the system and evaluation of alternative management policies. A simulation model of a turkey production system was developed to predict values of flock performance indicators of significant economic importance, namely body weight and feed consumption. Existing weather simulation models were combined and modified in order to develop a model that predicted daily dry-bulb temperature and humidity ratio outside the turkey house. The weather simulation model was validated using twenty years of daily observed weather data from Roanoke, Virginia. Thermal environment inside the turkey house was predicted from simulated outdoor weather using energy and mass balance equations. House environment prediction part of the model was validated using observed inside and outside temperature data collected at a turkey farm in Virginia. A discrete event simulation model was developed to simulate the effects of house thermal environment, feed energy, sex, and age on weight gain and feed consumption of growing turkeys. The model was validated using temperature, body weight, and feed consumption data collected at a turkey farm in Virginia. The observed average bird weights at marketing age were within 95% confidence intervals of the predicted values. However, the model underpredicted energy consumption values. The sensitivity of the model to variations in R-value, ventilation rate, and feed energy concentration was evaluated. The model was more sensitive to feed energy concentration. / Ph. D.

Two experiments were conducted to quantitate the effects of several parameters on the growth, carcass characteristics and fat deposition of the turkey. In the first experiment, 0, 5, 10 or 15% fat from three sources (Fat 1, Fat 2 or Fat 3) was added to low (18%), standard (21%) or high (24%) protein diets fed to Nicholas Large White male turkeys from 8 to 22 weeks of age. Carcass quality as measured by fat deposition, carcass yield and breast meat yield was determined. The addition of each 1% added fat up to 10% increased body weight gain .72%. Feed consumption decreased 1.3% and feed efficiency increased 2.3% for each 1% added fat up to 15%. Addition of Fat 2 to the diet resulted in significantly better feed efficiencies as compared with Fat 1 or Fat 3. The feeding of low protein diets as compared with standard protein diets decreased body weight gain, feed consumption and feed efficiency 13.2, 5.7 and 8.1%, respectively. Addition of fat to the diet increased 22-week body weight and the amount of breast meat produced per kg feed consumed. For each 1% added fat to low and standard protein diets, leaf and gizzard fat deposition increased 10.2 and 8.0%, respectively. Feeding low protein diets resulted in a 10.4% decrease in body weight and a 19.5% decrease in breast meat yield. The increase in leaf and gizzard fat deposition from each 5% increment of added fat up to 10% was counteracted by a 3% increase in dietary protein. In the second experiment, both sexes of the Nicholas Large White, Jaindl Large White and Jaindl Medium White strains were fed standard (21%) or high (24%) protein diets containing 0, 5 or 10% added dietary fat from 8 to 28 weeks of age. Carcass quality as measured by yield of carcass parts, fat deposition and the composition of breast meat was determined at 16, 20, 24 and 28 weeks of age. The Nicholas strain of turkey had a greater growth rate and consumed less feed to reach heavier weights than the Jaindl Large strain. Addition of 10% fat to the diet decreased feed consumption 12% and increased feed efficiency 17%. Fresh carcass and breast meat yield increased with age of the turkey, indicating that marketing at younger ages does not take full advantage of the meat producing capability of the turkey. The Jaindl Large and Medium White strains averaged 6.8 and 6.9% more breast meat yield than the Nicholas strain. The Nicholas strain deposited 4.36 times more leaf fat and 1.84 times more lipid within the breast meat as compared to the Jaindl Large strain. Added dietary fat decreased fresh carcass yield .41% and breast meat yield .65%. Feeding high protein diets increased fresh carcass yield and breast meat yield .25 and .47%, respectively. / Ph. D. / incomplete_metadata

A series of experiments was conducted to examine protein and energy utilization in growing and breeding turkeys, and to investigate the impact of body weight restriction on subsequent reproductive performance. In the first experiment, dietary self-selection of energy and protein and feed restriction were studied in growing turkeys. Body weight of males and females was significantly reduced by feed restriction. Protein efficiency was significantly lower in self-selecting males and females. Feed restriction significantly reduced the carcass yield of males, but not females. / Ph. D.

Studies investigating the effects of feeding diets containing the yeast, Saccharomyces cerevisiae var. boulardii (SCB), and a yeast culture (YC) containing S. cerevisiae were conducted in market turkeys and Medium White turkey breeder hens. Increased utilization of dietary gross energy, N, Ca, P, B, K, Mg, and Mn were observed in poults fed a diet containing 1% YC when compared to the control and 1% inactivated YC diets at 4 weeks of age (WOA). It was concluded that the YC must be "biologically active" in order to affect nutrient retention in poults. Feeding day-old poults diets containing varying amounts of SCB resulted in increased body weights at 3 WOA. Greater body weights and a decrease in the number of mucous-secreting goblet cells per mm of villus height and a decreased crypt depth were observed in poults receiving .02% SCB from 3 to 5 WOA. No dietary differences were observed for either villus height or width. Results indicated that feeding SCB to poults increased body weight and altered gut morphology. Experiments conducted to evaluate the effects of .25% YC on market male turkey performance resulted in contradictory responses. Supplemental YC increased body weights of turkeys at 5, 8, 11, and 14 WOA in one trial, while no differences and depressed body weights from 2 through 17 WOA were observed in two subsequent trials, respectively. Similarly, feed to gain ratios were improved from day-old to 5 WOA in one trial, while no differences and a higher feed to gain ratio was observed from 2 to 5 WOA in the second and third trials, respectively. Results indicated that unelucidated factors may influence the response of market male turkeys fed dietary YC. Consistent results have been observed in two trials on the hatchability of fertile eggs (HFE) from hens of three genetic lines fed .5% dietary YC. Early embryonic mortality (0-10 d of incubation) was reduced when hens were supplemented with YC and the HFE was increased in eggs stored less than 9 days in select hen genotypes. Results indicated that the breeder hen's genotype and pre-incubation storage time are factors to be considered when evaluating a YC in turkey breeder hen diets. / Graduation date: 1994

An experiment was conducted to evaluate a breeder diet containing a yeast culture as a means of improving the reproductive performance of two genetically dissimilar lines of turkey hens (designated as L and H). Two hundred hens of lines L and H, 100 hens per line, were housed in a curtain sided breeder house (10 hens/line/pen). Starting at 31 weeks of age (WOA), the hens were fed either Corn-soy (CS) or Corn soy+yeast (CS+Y,.5% Diamond V Mills "XP" yeast culture, Saccharomyces cerevisiae) diets. Between 33 and 45 WOA, the hens were mated inter se and from 45 to 51 WOA reciprocal line matings were established. Hen reproductive parameters measured between 31 and 51 WOA were, body weight (BW) change, feed intake, feed per dozen eggs, egg production, egg size, fertility, embryonic mortality, and hatchability of fertilized eggs from 7 biweekly egg settings. No differences (P>.05) were observed with yeast culture supplementation of the diet for changes in BW, egg production, egg weight, embryonic mortality, and hatchability of fertilized eggs (n= 5 biweekly hatches) of either line. A significant time by diet interaction was evident only in feed intake. There was an improved (P<.05) hen fertility in line H as a result of feeding the dietary yeast culture. When reciprocal line crosses were established between 46 and 51 WOA, hatch of fertilized eggs (n= 2 biweekly hatches) was substantially improved (p<.05) from hens fed the yeast culture containing diet. The results of this study suggest that there is a genetic factor associated with the feeding of a diet containing a yeast culture to turkey breeder hens. / Graduation date: 1993

Two experiments were conducted with a total of 1,728 Large White turkeys to determine the relative potencies of four methionine compounds on an equimolar basis. A 28% protein basal diet composed primarily of ground yellow corn, dehulled soybean meal, and meat and bone meal was supplemented with DL-methionine (DL), sodium salt of DL-methionine (MENA), methionine hydroxy analogue calcium salt (MHAC), or methionine hydroxy analogue free acid (MHAA) at the .06, .12, .18, .24, or .3090 level of added methionine. Each of these 20 diets was fed to two pens of poults of each sex (9 birds per pen), and the basal diet was fed to eight pens of each sex from one day to sevenweeks of age in each experiment. From the combined six-week body weight data, MENA was 104.7 (86.1, 123.3), MHAC 101.8 (83.5, 120.1), and MHAA 92.590 (74.9, 110.1) as potent as DL (with 9590 fiducial limits) by the slope ratio procedure. No differences were detectable among the methionine products. The extra one degree of freedom associated with the nonlinear procedure accounted for 4.8 and 10. 7% of the residual variation in Experiments 1 and 2, respectively. Relative potencies were obtained for MENA of 110.3 and 115.6, MHAC of 100.4 and 88.1, and MHAA of 89.7 and 112.390 in Experiments 1 and 2, respectively. Two additional experiments were conducted using a total of 1,680 poults to study the relationships of methionine, choline, and sulfate in practical-type diets. A 6 x 2 x 2 factorial design was used involving increments of .0690 DL-methionine from 0 to .3090, 0 or .20% choline chloride, and 0 or . 10% potassium sulfate. The variables were added to a 21 90 protein basal diet containing 61% ground yellow corn and 32% dehulled soybean meal to which no supplemental choline or sulfate was added. Each of the 24 diets was fed to two pens of medium-type turkeys of each sex (9 birds per pen) from four to eight-weeks of age in the first experiment, and to two pens of Large White turkeys of each sex (9 and 8 birds per pen for males and females, respectively) from three to seven-weeks of age in the second experiment. From the addition of .06% and .12% DL-methionine, body weight gains were increased 11.0 and 16.5% in the first experiment, and 8.9 and 13.690 in the second experiment, respectively. In addition, methionine increased feed consumption about 1/3 these amounts, and feed efficiencies 1/2 these amounts. The addition of choline or sulfate failed to significantly increase these parameters, even in the absence of methionine. No significant interactions were observed among the dietary variables in either experiment. / M. S.

Two experiments were conducted to determine the effect of dietary self-selection of protein and energy on the reproductive performance of Large White turkey hens. The first study examined the effect of self-selection on reproductive performance during a production cycle that started in July and ended in December. Hens were maintained on one of two dietary regimes for a 20-week production cycle. Control birds were fed a conventional diet (18% crude protein, 2700 kcal/kg) which contained nutrients at levels recommended by the National Research Council (NRC, 1984). The remaining hens were allowed to select their diet from two feed sources: one relatively high in protein and low in energy (35% crude protein, 1850 kcal/kg) and the other relatively low in protein and high in energy (8% crude protein, 3220 kcal/kg). Hens fed the split diet produced an equal number of eggs as control hens but consumed significantly less feed (p≤.05). The diet that was selected contained approximately 40% less protein than the control diet (p≤.001) which resulted in significantly increased efficiency of protein utilization (eggs/kg protein) for hens fed the split-diet (p≤.001). In addition, the incidence of broodiness was significantly reduced in the split-diet treatment (p≤.10). Egg weight, fertility, hatchability and hatch of fertile eggs were not significantly effected by the dietary regimes. There was significantly greater body weight loss in hens fed the split-diet (p≤.05). Increasing trends in feed, energy, and protein consumptions were noted over the course of production. For this reason a second experiment was conducted to determine if these trends were the result of seasonal affects, due to changing ambient temperatures, or the result of changes in nutrient requirements of the turkey hen occurring with different stages of production. The second experiment was similar to Experiment 1 except that the production period started in March and ended in July. As in the first experiment, egg production was equal for hens in the two treatment groups. Feed intake and energy intake were not significantly different for hens fed the split and complete diets. However, as in the previous experiment, protein intake was significantly reduced in the split-diet treatment (p≤.001). The incidence of broodiness was again attenuated among split-fed birds (p≤.10). Average daily feed and energy intake appeared to decrease over the course of production which was presumed to be related to increasing ambient temperatures. As in the previous experiment, protein intake increased over the course of production despite increasing environmental temperatures. Therefore, the increased protein selection noted in these two experiments does not seem to be related to hot weather and may indicate an increased protein requirement in the later stages of egg production. Based on the finding that the incidence of broodiness was reduced among hens fed the split-diet, blood sera from hens in both experiments were analyzed for luteinizing hormone (LH) and prolactin (PRL). Although the incidence of broodiness was significantly reduced among birds fed the split-diet, there was no significant difference in serum LH and PRL concentrations. Therefore, the reduction in the incidence of broodiness that was noted in these experiments was not correlated with changes in the blood concentration of these hormones. / Master of Science

Four experiments were conducted on hens of turkey and Japanese quail. In Experiment I, turkey hens were fed diets containing either 0% added fat, 3.5% animal-vegetable fat blend (AV) or 3.5% dry fat product (DF). In Experiment II with turkey hens, 2 holding diets and 4 breeder diets were investigated. The holding diets contained either 0% added fat or 5% of AV. The breeder diets contained 0% added fat of 5% of one of the following: AV, corn oil (CO) or olive oil (OO). In Experiment III with Japanese quail, 3 pre-breeder (PB) and 3 breeder diets (BD) were studied. They contained either 0, 3.5 or 7% added AV. In Experiment IV with Japanese quail, all diets contained 97% of a semi-purified basal diet and 3% of one of the following: corn starch (CS), corn oil (CO), palmitic acid (PA), oleic acid (OA), linoleic acid (LA) or linolenic acid (LN). The fatty acid composition of plasma and yolk lipids of both turkeys and quail was influenced by the fatty acid composition of the diets. Quail fed a CO diet deposited more linoleic acid in the egg than did those on a LA diet. (Abstract shortened by UMI.)