Effectof feed rations on livestock performance and impact of effective microorganisms on litter odour and other gases emissions.
Loading...
Date
2022
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of Zululand
Abstract
The increase in demand for animal protein has increased the demand for pork and beef by humans to supply this dietary protein. The short gestation period as well as the high number of piglets renders pig production relatively viable, hence increasing the number of farms. Feedlot farming has increased this production but not without high waste and odour emission which may be hazardous to animals, workers and the surrounding community members. Therefore, the aim of this study was to evaluate the effect of feed rations on livestock (cattle and swine) performance and the impact of effective microorganisms(EM) on litter type odour and other gaseous emissions. It was hypothesized that diet type and EM would not livestock litter odour and gaseous emissions. Experimental chapter one and two investigate the effect of feed type and effective microorganisms on performance and litter odour emission from feedlot cattle and swine, respectively. The EM was applied on litter at different treatment levels (10% EM, 20% EM, and 30% EM) to mitigate odour emissions. The results showed that different diets (starter, growerand finisher) fed to both cattle and swine improved (P<0.05) performance as the feed intake, weight gain and feed conversion ratio increased when animals changed from one diet to the other. However, it was also noted that the diet affected (P<0.05) odour emission from both beef cattle and swine manure. This was because the gaseous emission increased (P<0.05) as the beef animal’s diet changed from starter to grower while emissions from pig was also different (P<0.05) between starter and finisher. The gaseous compounds identified were classified into; Alcohols (4), aldehydes (6), volatile fatty acids (13), ketones (3), terpenoids (2), amides (3), phenolics (8), sulphur compounds(2) and nitrogen containing compounds (3) from beef litter. From pig litter, the gaseous compounds identified were classified into alcohols(5), aldehydes (5), volatile fatty acids(13), ketones (2), terpenoids (2), amides (1), phenolics (7), sulphur compounds (3) and nitrogen containing compounds (3). Among these gases, P-Cresol (4-methyl phenol) and phenol was assumed to have the highest potential hazardous effect in terms of air pollutants as listed by the US Environmental Protection Agency. Indole and skatole were also identified and have often been associated with acute bovine pulmonary edema and emphysema (ABPE) in cattle and boar taint in pigs. Effective microorganisms(EM) treatment showed no differences (P>0.05) among all litter treatment levels (10% EM, 20% EM, and 30% EM) but for the control. There were significant differences in the odour emitted between the different weeks (P<0.05) when compared to the control. P-Cresol, phenol, indole and skatole were reduced by EM to undetectable amounts in week 3 compared to the controls. However, dimethyl sulphide and dimethyltrisulphide were not mitigated by the use of EM hence further methods on how to mitigate these sulphurcompounds need to be explored. A 10% dose of EM for cattle litter treatment was preferred, sincethe effect of higher doses was minimal. However, for swine, a 30% EM dose treatment was recommended since most of the odorous compounds (Indole, skatole, phenol, and dimethylsulphide and dimethyl trisulphide) were reduced to undetectable amounts. It was also concluded that EM does not depend on concentrations to reduce odour from livestock manure, but time for the microbes to adapt, grow and multiply to mitigate odour. Keywords: Effective microorganisms, odour, volatile organic compounds, diet,P-Cresol, phenol, indole, skatole, dimethyl sulphide, dimethyl trisulphide, boar taint.
Description
A thesis submitted to the Faculty of Science and Agriculture in fulfilment of the requirements for the Degree of Master of Science in the department of Agriculture (Animal Science) at the University of Zululand, South Africa, 2022.
Keywords
effective microorganisms, dietary protein, odour, volatile organic compounds