CATTLE numbers dropped by almost half at the Warwick Cattle Sale yesterday.   The supply of stock almost halved from the previous week's level.   A fair panel of buyers was present however feeder buyers operated selectively.   Young cattle varied in price according to quality and most could not maintain the levels of the previous sale with the light weight lines and well-bred classes the least affected.   Vealer heifers lost 5c to 8c and medium weight yearling steers to feed averaged 3c/kg less.   Well-bred heavy weight yearling steers to feed experienced strong demand while the remainder were cheaper.   Medium weight yearling heifers to feed also sold to a cheaper trend to average 6c/kg less.   A handful of heavy grown steers averaged 2c dearer and cows sold to strong demand to be firm to 4c/kg better.   Steer calves returning to the paddock made to 379.2c, with most of the calves around 347c/kg.   Vealer heifers to feed averaged 311c and slaughter lines returned 309c, with some to local butchers reaching 329.2c/kg.   Light weight yearling steers mostly sold in the high 320c range with some to 338.2c/kg.   Medium weight yearling steers to feed made to 330c to average 316c/kg.   Well-bred heavy weights to feed averaged 320c and sold to 327.2c while the remainder averaged 293c/kg.   Medium weight yearling heifers to feed averaged 290c and made to 301.2c/kg.   Heavy grown steers made to 285c to average 282c/kg.   Medium weight 2 score cows averaged close to 211c and sold to 216.2c/kg.   Good heavy cows made to 238.2c to average 231c/kg.   Heavy bulls made to 260.2c/kg.