Growth and carcass composition of female turkeys implanted with anabolic agents and fed high-protein and low-protein diets

This laboratory investigated the anabolic effect of the synthetic steroid trienbolone acetate (TA) and found it effective in male and female meat turkeys without any apparent gross abnormalities (Poultry Sci., 61: 1386, 1982). The present study was undertaken to characterize the response of female turkeys, fed equicaloric diets varying in dietary protein density to anabolic agents implanted at 13 wks. TA and zeranol (Z) were tested singly and in combination (TAZ). Body weight gain and feed conversion at 16 wks of age were improved (P less than 0.01) with TA and TAZ. The response to TA was enhanced as dietary protein density increased. Carcass fat, protein, ash, energy, potassium, and calcium were not altered by implant treatment. A trend existed toward increased carcass fat with zeranol implantation. Carcass moisture (P less than 0.01) and sodium (P less than 0.05) were increased in the TA treatment. Blood plasma electrolytes were not affected by implant treatments but plasma calcium was decreased (P less than 0.05) by TAZ. No synergism was noted between TA and Z with respect to growth, feed conversion, carcass composition, plasma electrolytes with the exception of plasma calcium. No interaction was observed between dietary protein density and implant treatment. Performance variables increased and carcass fat decreased with increasing dietary protein density. These results confirm our earlier finding with respect to TA and provide additional evidence that dietary protein density influences the response of meat turkeys to TA. The data show that zeranol lacks an anabolic effect in turkeys.     

Introduction to endoscopy

Endoscopy is an area of rapidly growing interest within veterinary medicine. This is understandable, because it is a relatively noninvasive procedure in which a tremendous amount of diagnostic data may be obtained. The purpose of this article is to introduce the novice to the equipment and potential uses of endoscopy.     

Rundschau

Ohne ZusammenfassungPflanzenschutzorganisation für Europa und die Mittelmeerländer     

Umweltorientierter Pflanzenschutz

Ohne Zusammenfassung     

Controlling growth and chemical composition of saplings by iteratively matching nutrient supply to demand: a bootstrap fertilization technique

We developed a fertilization technique that results in the control, and maintenance at defined rates and levels, of growth and tissue composition of plants of different sizes and developmental stages growing at exponential and nonexponential rates in solid media under naturally fluctuating light and temperature regimes. Clonal cottonwood (Populus deltoides Bartr.) saplings were grown in sand. Low concentrations of nutrient solution were added daily at different constant exponentially increasing rates for 20-30 days to produce plants with different growth rates and tissue nutrient composition. Matching nutrient supply to measured growth demand by bootstrapping, where bootstrapping is the use of an iterative equation that calculates demand from either actual or desired growth rates, maintained these differences for 20-40 days. Nutrient additions controlled growth of saplings with growth rates between 2.0 and 4.0% day(-1), heights between 13.9 and 37.5 cm, dry weights between 0.70 and 3.90 g, leaf nitrogen contents between 1.2 and 3.9%, and leaf carbon/nitrogen ratios between 42.1 and 12.5. The technique was reproducible in a greenhouse without temperature, humidity, or light control, and is easily modified to suit different plant species, plants of various sizes, and various growing conditions.