For arbitrary placement of labels, instead of using the "tickInterval" option, provide an array of tick positions to "tickArray". Only those items in the array will be displayed. The option also works with the "tickLabels" feature. The slider below has the following setup:
$('#slider1').labeledslider({ min: 4, max: 40, tickArray: [4, 8, 12, 27, 33, 38, 40], tickLabels: { 12:'cat', 38:'dog', } });