Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 16, 1997
Publication Date: N/A
Interpretive Summary: Waste management systems are complex and operate under great variability. Each step of a waste management system has the potential for nutrient loss associated with environmental risks. Nutrient flow can be predicted using modeling methods to estimate contamination risk, recognizing that actual conditions may vary substantially from predicted levels. Variability at specific sites occurs as a result of nutrient concentrations, site vulnerability, and/or handling methods. Soil coring and analysis provide measures of contaminant levels but are expensive and time consuming for general surveys of waste handling sites. Less expensive, quicker, but adequate methods are needed for evaluating the relative level of contaminant movement beneath waste management sites. Electromagnetic methods have the potential to fulfill that need and have been assessed near liquid storage ponds. For livestock production systems, such as cattle feedlots, most of the manure is handled in solid rather than liquid form. Therefore, electromagnetic methods need to be evaluated for solids handling areas as well. This report presents survey results from a compost site and a waste storage pond. The methodology shows good potential as a waste site diagnostic tool indicating concentrations of nutrients exceeding thresholds, thereby signaling a need for remedial action.
Technical Abstract: The effects of heat stress (HS) are well documented: reduced intakes, reduced growth, and occasionally reduced feed efficiency. In recent years, producers and researchers alike have noted the increased susceptibility of high-lean growth swine to heat stress. A study was developed to look at the effects of heat stress induced feed restriction versus a similar feed restriction in thermoneutral (TN) conditions on growth performance in finishing high-lean growth barrows. Sixty Large White X Landrace finishing pigs (65.2 +/-0.5 kg) were randomly assigned to one of five treatments (two replications). The five treatments included: control (ad-lib feeding, thermoneutral temperature, 18C; 13% HS (13% feed restriction induced by an increased temperature, fed a diet with 13% more ideal protein); 13% TN (fed the same amount of the same diet as the 13% HS, eaten in two separate meals, but housed in TN); 26% HS (26% feed restriction induced by an increased temperature, fed a diet with 26% more ideal protein); and 26% TN (fed the same amount of the same diet as the 26% HS, eaten in two separate meals, but housed in TN). Ten additional animals were slaughtered at the onset of the experiment to measure initial composition. Animals were slaughtered when the average treatment weight reached 107.5 kg. Actual feed restrictions were 18.7% and 25.4% reduced from controls. Daily feed intake (FI), weekly weights (WT), and bi-monthly backfats (BF) were taken. Neither FI nor WT were different between the respective HS and TN trts (P>0.01). Backfats taken at the 10th rib by ultrasound revealed significant differences in both the 13% HS vs 13% TN and the 26% HS vs 26% TN (P<0.05). It was concluded that compared to feed restriction at TN, heat stress did not affect growth rate but may have affected carcass composition.