Influence of virginiamycin on growth and efficiency of large white turkeys.

Efficacy of virginiamycin (22 mg/kg) in combination with no drug, amprolium, carbarsone, halofuginone, or monensin, was studied. Male and female turkeys were raised to market age in five experiments conducted from 1983 to 1987. Body weights and feed:gain responses to virginiamycin for males and females were positive and significant (P less than .05). Virginiamycin resulted in mean 5.2 and 6.3% body weight responses and 3.3 and 2.2% feed:gain responses for males at 19 or 20 wk of age and for females at 16 or 17 wk of age, respectively. Mortality rates were low in all studies, and were not influenced by virginiamycin. In a processing study, virginiamycin in combination with halofuginone did not affect shrinkage, yield, or market grade. Feed was utilized by males and females 3.9 and 3.0%, respectively, more efficiently than expected with dietary virginiamycin, compared with results predicted by a simulation modeling technique. Profitability was considerably greater with dietary virginiamycin using actual data than with simulated feed consumption data.

Effect of diet and population density on male turkeys under various environmental conditions. 2. Body composition and meat yield.

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 white lupine in diets of growing turkeys.

In Experiment 1, dehulling white lupine (WL) improved growth and feed efficiency of male Large White turkey poults fed 40% WL during 4 to 21 days of age. In Experiment 2, WL was included proportionally with soybean meal in corn-soy diets of female turkeys from 0 to 17 wk of age. Soybean meal: WL ratios (S:WL) were 1:0 (control), 2:1, 1:1, and 6:1. At 17 wk of age hens on S:WL diets of 2:1 had body weights that were similar to those of birds fed the corn-soy control diets. Growth of hens fed S:WL diets of 6:1 was depressed (P less than .05). Growth depressions were greatest earlier in the study; older birds made compensatory gains. Feed efficiency of hens fed S:WL diets of 1:1 was poorer than that of controls during 0 to 11 wk but better than that of controls after 11 wk of age. Feed efficiency values were similar during 0 to 17 wk for hens fed control and S:WL diets of 2:1 and 1:1. Sensory evaluation of roasted light and dark meat of market birds revealed no taste differences in relation to WL level in the diet.

Efficacy of halofuginone as a coccidiostat for turkeys.

Large White male turkeys were raised to 20 wk of age on diets with varying kinds and levels of coccidiosis drug protection. Dietary treatments included unmedicated control (UMC), amprolium (AMP, 125 mg/kg), and 3 levels of halofuginone hydrobromide (HAL, during 0 to 4 and 4 to 8 wk of age, in 3.3; 3.1.5; and 1.5,1.5 mg/kg, respectively). Turkeys on these five treatments were exposed to coccidial oocysts at 14 days of age and again at 61 days of age; turkeys in an identical five treatments were not exposed until 61 days of age. At 28 days, nonexposed turkeys gained well and similarly, whereas exposed UMC showed poor growth and high mortality. At 56 days, regardless of exposure, UMC were lightest, AMP birds were intermediate, and birds in all HAL treatments were heaviest. Similarities in results of exposed and nonexposed birds suggests that nonexposed birds became exposed through tracking of oocysts in the room. Lesion scores of those challenged with oocysts at 61 days showed that all treatments had adequate resistance to coccidiosis. At 20 weeks of age, combining both exposure methods, birds fed HAL (dosage 3.1.5 or 1.5, 1.5 mg/kg) were significantly heavier than UMC and AMP treatments.