Just wanted to add one more thing to my above post.....

Although rare there is condition called a "dark cutter" which can seriously affect beef quality.

Dark-cutting meat is characterized by a color range from dark red to nearly black and has both a sticky texture and a high water-holding capacity.
Dark cutting beef is most often associated with preslaughter stress. Environment factors such as extreme cold, rain or heat along with weather fluctuations can lead to temporary glycogen depletion. Cattle which become excitable during sorting, hauling, penning and overcrowding can be candidates for dark cutting. Holding cattle off feed for one to two days can also lead to dark cutting beef.

Heifers that have been showing estrus just prior to slaughter can have a high incidence of dark cutters.
Highly excitable cattle are more likely to produce dark cutter carcasses than calmer cattle.

The quality of dark-cutting beef is lower than normal. It has significantly shorter shelf-life than normal beef and greater water-holding capacity, which is more conducive to bacterial growth. The 2005 National Beef Quality Audit reported that 1.5 to 2.5 per cent of beef carcasses were dark cutters.