Researchers at Fort Valley State University (in Georgia) used 16 crossbred goats and wether sheep to investigate the effect of preslaughter diet management on physiological responses and microbial loads on skin and carcass.
Experimental animals were fed either a hay or concentrate diet for 4 days and then deprived of feed for either 12 or 24 hours prior to slaughter. Blood samples were collected to measure physiological responses. pH was measured in the Longisimuss dorsi muscle. Skin and carcass swabs were obtained to access microbial loads.
Skin swab samples collected from the sheep showed higher bacterial counts than goats. Behavior observations may have accounted for the difference, as sheep tended to spend more time lying down. Sheep fleece may also be responsible for picking up more fecal material in the holding pen. However, diet and feed deprivation did not influence skin contamination. Diet, species, and feed-deprivation also had no effect on E. coli and total coliform counts in carcass swabs.
Access full article from J. of Animal Science and Biotechnology
Other research regarding the effect of diet on bacterial loads has been contradictory. A 1998 Cornell University study demonstrated that cattle fed grain had much higher coliform and E. coli counts than cattle fed forage diets. The reverse was observed in a 1997 study at the University of Idaho, as artificially-innoculated sheep fed grass hay shed more E. coli and for a longer period of time than sheep fed a concentrate diet.
Skin swab samples collected from the sheep showed higher bacterial counts than goats. Behavior observations may have accounted for the difference, as sheep tended to spend more time lying down. Sheep fleece may also be responsible for picking up more fecal material in the holding pen. However, diet and feed deprivation did not influence skin contamination. Diet, species, and feed-deprivation also had no effect on E. coli and total coliform counts in carcass swabs.
Access full article from J. of Animal Science and Biotechnology
Other research regarding the effect of diet on bacterial loads has been contradictory. A 1998 Cornell University study demonstrated that cattle fed grain had much higher coliform and E. coli counts than cattle fed forage diets. The reverse was observed in a 1997 study at the University of Idaho, as artificially-innoculated sheep fed grass hay shed more E. coli and for a longer period of time than sheep fed a concentrate diet.
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