Cattle slaughter finished the holiday shortened week at 419,000 head, down 12 percent from a year ago and down 36 percent relative to the week prior. Slaughter is forecast to move higher over the next six weeks. This week, slaughter is projected out at 500,000 head, down 9 percent from last year. Over the next six weeks, slaughter is forecast at an average of 605,000 head, even with the prior six week…