R. N. Brewer

Broiler Growth Data: 1986-1991

Growth data from weekly weighing of 50 bird samples of broilers grown on litter in commercial-style broiler houses in 22 trials over a five-year period are presented. Broilers were found to be 23% heavier at 21 days of age and 10% heavier at 49 days of age than was reported in the literature in 1987. Three-week weights averaged 711 g and seven-week weights averaged 2437 g. Equations were developed and parameters estimated to describe weight as a function of age for two time periods. The time periods selected nominally coincide with (1) the time that starter rations are fed (from hatch to between three and four weeks of age), and (2) the time that growing and finishing rations are fed (from three to four weeks of age until birds are marketed). A second-degree polynomial was used to describe growth during starting (bird age = 28 days). A straight line was used to describe growth during growing (28 days = bird age = 49 days). Parameters are provided for mixed males and females during starting. They are provided for mixed sexes and for males and females separately during growing. Parameter estimates are provided which represent the five years of data in this study and also for estimates of July 1991 growth.

Physical and Chemical Characteristics of Pine Shavings Poultry Litter

Pine shavings poultry litter from four growouts was analyzed for particle size distribution and chemical composition. Little change in the particle size distribution was observed after the first growout. The majority of the nutrient mass was associated with the larger size particles [those failing to pass a size 50 (0.297 mm) sieve] while the nutrient density increased with the smaller size fractions. Crude fiber decreased while ash and crude protein increased as particle size decreased.

Equilibrium Moisture Relations for Pine Shavings Poultry Litter Material

ABSTRACT EQUILIBRIUM moisture measurements were made for clean pine shavings poultry litter material at 20 and 26 °C for a wet basis moisture content range of 1.3 to 30.7%. Parameters were estimated for the Chung and Modified Henderson equations for predicting both equilibrium moisture content and equilibrium relative humidity. Temperature was not included as a variable due to data scatter. There was little difference in the ability of each equation to represent the data. Attempts at measurements on shavings-manure mixture were unsuccessful.

Changes in Physical And Chemical Characteristics of Poultry Litter Due to Rotary Tilling

Pine shavings poultry litter from four growouts were analyzed for particle size distribution and chemical composition for untilled litter and litter that had been tilled three times following each growout. Little change in the particle size distribution was observed after the first growout for either treatment. The majority of the nutrient mass was associated with the larger size particles (those failing to pass a No. 50 screen) while the percent element analysis increased with the smaller size fractions for both treatments. Little change in nutrient content was observed between treatments, but the tilled litter had an increase in percent ash content and a decrease in percent crude fiber. No difference was observed in the crude protein percentage in the two treatments.

PARTITIONED VENTILATION CONTROL FOR BROILERS

ABSTRACT A partitioned ventilation control strategy was developed for broiler house environmental control. In the strategy, ventilation to remove moisture produced by broilers is partitioned into two daily time periods. The protocol calls for 50 to 60% of the moisture to be removed by ventilation at a high rate during the warmest seven to nine hours of the day. The remaining moisture is removed by ventilating at a lower rate during the remainder of the 24-hour period. The strategy was implemented in a small-scale, commercial-style broiler house using a low-cost microcomputer and associated input/output components. Over five growouts, a brooding gas savings of approximately 19% was realized compared to an identical house using a conventional control strategy and electromechanical controls. House temperature and bird performance were essentially the same for the two control schemes.

Daily Mean Dew Point Temperature Prediction for Ventilation Control in Humid Climates

ABSTRACT MICROCOMPUTER control systems allow real-time decision making to be incorporated into livestock production facilities. Air moisture content is a necessary input for computer based ventilation control. Suitable sensors for air moisture measurement are lacking for many applications. Methods for its estimation are needed to be effectively integrate these improved control systems into the livestock industry. Two methods of predicting daily mean dew point temperature under humid weather conditions are presented. Method one is based on the measurement of early morning dry-bulb temperature. Method two is based on an equation for hourly dry-bulb which uses forecasts of daily high-low dry-bulb temperature. Results are compared to weather data for Montgomery, AL and the deviations are discussed. Method one over-estimates the daily mean dew point temperature by approximately 2 °C for Montgomery, AL and method two underestimates early morning dry-bulb temperature by approximately 2 °C.

Energy savings with use of double sidewall curtains on broiler houses

Results are presented from four cold weather trials involving a poultry house with double sidewall curtains and a house with single curtains. Total gas used for heating when double sidewall curtains were used was 21.2% less than for single curtains. Gas usage during the first three weeks was reduced by 15.8%.