Effect of Diet and Population Density on Male Turkeys Under Various Environmental Conditions.

Abstract

Large White Nicholas male turkeys were reared at two stocking densities (.21 or .46 m2 per bird) and fed one of four diets: 1) control corn and soybean (mash) with 1% fat (CSM); 2) as Diet 1, pelleted (CSP); 3) as Diet 1 with supplemental fat increasing from 1 through 8% with age (CSF); and 4) as Diet 1 with barley at 0, 20, 35, 50, and 65% during successive 4-wk periods (CSB). The turkeys were reared in four environments: (A) intermittent light schedule [4(2 h light (L):4 h dark D))] with temperature at 7 or 21 C during light and dark photoperiod, respectively; (B) and (D) with intermittent light (2L:4D) with a constant 21 and 7 C temperatures, respectively; (C) continuous light cycle (18L:6D) with temperatures as in Environment A. At 20 wk of age, two turkeys per replicate pen, were killed for determination of body composition and meat yield. Compared with turkeys fed CSM diet, those on CSF and CSP diet had increased percentage carcass fat. Meat yield per bird and percentage carcass fat were greater for turkeys reared at .46 m2 per bird compared with rearing at .21 m2 per bird. Pelleting and fat supplementation resulted in significantly increased amounts of breast meat and leg compared with CSM. Breast meat yield (percentage) and amount were greater at 7 C (Environment D) than at 21 C (Environment B) and the cycling regimen (Environment A). Percentage abdominal fat was greatest at 7 C. Interactions of environment and diet were detected for breast meat yield percentage (P less than .023) and weight (P less than .036). Diet type had no effect on percentage breast meat or weight in Environment C. An increased amount of breast meat was obtained by feeding CSP in Environments A, B, and D, and dietary fat supplementation increased breast meat yield in Environments A and D over CSM treatment.

Effects of Three Different Lighting Programs on Live Weight Change of Bronze Turkeys under Semi-Intensive Conditions

“…It is important to note that the highest weight gain occurred in the 18L:6D group, whereas the lowest weight gain was observed in the 12L:12D group in both the first 10 and the last 6 weeks of the study. The results of the feed intake of turkeys are similar to those of other studies in the literature (HALVORSOR et al, 1991;NOLL et al, 1991;CLARKE et al, 1993;SENGUL et al, 2000). On the other hand, maximum live weight difference among three lighting programs throughout first 10 weeks (3473.5 g) was notably higher than the weight gain (2208 g) observed throughout last 6 weeks.…”

Searching for Significance: The Perils of Excluding Pseudo-Outliers

“…The techniques reported by Ajuyah et al (1991), Halvorson et al (1991), and Izat et al (1991) were selected solely because they were recent papers using commonly reported methods of selecting data. The purpose of this work was not to criticize these authors' works or to question the validity of their data or conclusions, but rather to use their techniques to illustrate potential shortcomings of such practices.…”

“…Experiments 1 and 2 essentially duplicate the form of sample truncation used in Ajuyah et al (1991) and Halvorson et al (1991), that of choosing birds closest to the pen means. A third experiment was conducted attempting to duplicate the procedure in Izat et al (1991) as closely as possible.…”

“…Several recent studies published in Poultry Science (Ajuyah el ah, 1991;Halvorson et al, 1991;Izat et al, 1991; among numerous others dated back several years) have employed sampling strategies designed to include only birds near the pen mean to statistically test hypotheses concerning the effect of a specified treatment on some characteristic of interest (e.g., parts yield). The identification of outliers can be a valuable procedure for achieving accurate test results; a large literature exists on methods of detecting outliers (Rousseeuw and van Zomeren, 1990).…”

Effects of Beak Trimming, Stocking Density and Sex on Carcass Yield, Carcass Components, Plasma Glucose and Triglyceride Levels in Large White Turkeys

“…That means sex of the birds had difference response in different density. Halvorson et al (1991) reported that the carcass percentage and carcass fat were affected by stocking density. Interaction of B × D × S in thighs indicating that thighs of birds were affected differently in different sex, density and trimmed or untrimmed condition.…”