Meat Science Commons^™

1992 Beef Cattle Report, Darrell W. Nelson

Nebraska Beef Cattle Reports

Economic efficiency of beef production to weaning and to slaughter was estimated in three groups, different in milk available (low, medium, and high) to the calves but the same in growth potential. Efficiency was the ratio of income to expenses. Income was derived from cull cows and calves at weaning or carcasses of calves fed to slaughter. Feed and non-feed expenses for the cowherd and for calves to weaning or to slaughter were included. Efficiencies were estimated assuming observed reproductive rates and energy requirements for maintenance, as well as for equal reproductive rates and equal requirements for maintenance in the …

Control Of Salmonella On Beef Tissue Surfaces In A Model System By Pre- And Post-Evisceration Washing And Sanitizing, With And Without Spray Chilling, James S. Dickson, Maynard E. Anderson

James S. Dickson

Beef tissue was inoculated with a nalidixic acid resistant strain of Salmonella California and processed under conditions simulating pre- and post-evisceration carcass washing and sanitizing. These treatments, using distilled water to wash and 2% acetic acid to sanitize, reduced the population of salmonellae by as much as 2-log10 cycles when compared to samples which were washed only in distilled water. Increasing the acid temperature to 55°C reduced the bacterial populations further. Spray chilling, when used in series with the pre- and post-evisceration treatments, apparently resulted in recovery of some injured Salmonella.

Contamination Of Beef Tissue Surfaces By Cattle Manure Inoculated With Salmonella Typhimurium And Listeria Monocytogenes, James S. Dickson

James S. Dickson

Contamination of beef lean and fat tissue surfaces by Salmonella typhimurium and Listeria monocytogenes was evaluated using phosphate buffer or sterilized manure as an inoculation menstruum. Immersion in inoculated phosphate buffer resulted in an increase in numbers of attached cells during the 120 min inoculation for both bacterial species. Tissue immersed in inoculated manure generally showed an increase in cell numbers up to 10 min of immersion with only slight increases in cell numbers from lOto 120 min. Fewer cells attached to either tissue type from the manure inoculum (P<0.05), although actual numerical differences were small.

The Wokalup Beef Cattle Selection Experiment, Alan Lymbery, Mick Carrick, Patrick Donnelly

Journal of the Department of Agriculture, Western Australia, Series 4

The aim of the Department of Agriculture's long-term beef cattle selection experiment at Wokalup is to examine the effects of selection for faster-growing cattle on biological traits that may influence the productivity of a commercial beef herd. Selection lines were established from Hereford and multibreed cattle in 1977. Twelve years of selection have produced an increase in growth rate to weaning of about 120 g per day in both lines. About 40 per cent of this increase is the result of permanent genetic improvement.

We plan to compare these characteristics in cattle from the selection lines with cattle that have …

Attachment Of Salmonella Typhimurium And Listeria Monocytogenes To Glass As Affected By Surface Film Thickness, Cell Density, And Bacterial Motility, James S. Dickson, E. K. Daniels

James S. Dickson

With equal cell densities, surface film thickness did not influence the numbers &Salmonella typhimurium and Listeria monocytogenes cells which attached to glass. Motile L. monocytogenes cells had a greater cell surface charge and generally attached in higher numbers than non-motile cells.

Control Of Salmonella Typhimurium, Listeria Monocytogenes, And Escherichia Coli 0157:H7 On Beef In A Model Spray Chilling System, James S. Dickson

James S. Dickson

Simulated water spray chilling cycles were modified to include acetic acid as a sanitizer. The modified cycles were tested for effectiveness in reducing levels of S. typhimutium, L. monocyfogenes, and E. coli 0157:H7 on beef lean and fat tissue. Reductions of up to 3 log cycles were obtained for all three bacterial species on fat tissue. Reduction was less on lean tissue with the same treatments, although the modified cycles reduced populations when compared to the control cycle.

Storage And Bacterial Contamination Effects On Myofibrillar Proteins And Shear Force Of Beef, James S. Dickson, John D. Crouse, M. Koohmaraie

James S. Dickson

Thirty-two steaks from the longissimus muscle, fifth rib to third lumbar vertebra, were obtained from youthful carcass beef. Half were sterilized by ultraviolet light and all vacuum packaged and stored for 1, 14, 28 or 57 days at 2°C. After storage, steaks were examined for microbial populations, myofibril fragmentation index (MFI), cooking characteristics and shear force (SF). Aerobic and anaerobic counts decreased during storage. Psychrotrophic counts were low throughout. Sterilization had no effect on SF or MFI. Cooking loss tended (P < 0.09) to increase with time of storage. SF values decreased and MFI values increased through day 14, but remained relatively constant after that. Results of SDS-PAGE, SF and MFI indicate major changes in proteolysis of myofibrils and tenderness were completed by day 14.

Attachment Of Salmonella Typhimurium And Listeria Monocytogenes To Beef Tissue: Effects Of Inoculum Level, Growth Temperature And Bacterial Culture Age, James S. Dickson

James S. Dickson

The effects of inoculum level, growth temperature and culture age on the attachment of Salmonella typhimurium and Listeria monocytogenes to beef tissue surfaces were evaluated. An increase in inoculum level resulted in an increase in the number of attached cells for both bacteria which was proportional to the increase in inoculum. Bacteria grown at 23°C attached in higher numbers flVO5) to fat tissue than bacteria grown at 37°C or at 37°C followed by 24 h at 5°C. Growth temperature did not affect attachment to lean tissue for either bacterium. Overnight cultures of both bacteria attached in greater numbers 0VO.05) to …

Veterinary Consultancy Boosts Piggery Profits, Ashley Mercy

Journal of the Department of Agriculture, Western Australia, Series 4

A pilot Pig Herd Health Management Scheme co-ordinated by the Department of Agriculture has stimulated much increased involvement of veterinarians in the Western Australian pig industry. Co-ordinated by Ashley Mercy, principal veterinary officer (epidemiology) horn 1985 to 1989, the scheme demonstrated the value of having regular visits from veterinary consultants and in implementing programs to prevent disease and production problems occurring in herds.