Biological position of viruses: Viruses lack a cytoplasmic membrane and they do not have the basic component of a cell. They can only replicate inside the host cell. Outside the host cell, they are non-living.
The yearling program was, however, more variable with a maximum profit of $356 per head compared with $206 for calf fed, and a maximum loss of $171 per head compared with $152 for the calf fed program.
Weaning calves earlier cuts feed costs. A 1994 Penn State study that compared the cost of raising calves to 112 days of age estimated that weaning at 30 days instead of 60 days saved $32 per calf. Weaning at 45 days instead of 60 days saved $19. Weaning at 30 days saved $13 compared to weaning at 45 days. If we use 2007 milk replacer costs in this analysis, we see that weaning at 4 weeks may save as much as $55 per calf over 8-week weaning. Weaning at 45 days will save up to $30 per calf over 60 days.