SPECIFICATION OF PEN RAIL SPACING AND TROUGH HEIGHTS TO PREVENT ESCAPE AND ENABLE GOOD ACCESS TO FEED BY SHEEP DURING SEA SHIPMENTS FROM NEW-ZEALAND

A trial was carried out to determine the optimal height of feeding tro ughs above floor level and the spacing between pen railings which woul d enable sheep to access feed troughs but prevent them from getting ou t of pens during sea voyages. The trial involved a group of 16 large ( 79 kg) wether sheep and 24 small (30 kg) wether lambs which were held in pens and trained to eat lucerne pellets. Feed troughs similar to th ose used on ships were constructed 260 mm deep and 220 mm wide. A syst em of adjustable railings were used to alter the trough height and to determine the optimal spacing to allow the large sheep to get their he ads through, but to prevent small sheep from escaping. In order that s heep of various sizes can access feed from the bottom of feed troughs, the height of the top edge of the trough should not exceed 360 mm abo ve floor level for 30 kg sheep or 460 mm for mature sheep. This range is due to differences between the groups in their shoulder height, and variation between individuals within each group. Shoulder heights of the small sheep used in this trial ranged from 505 to 590 mm, and for the 16 mature animals the range was 610-715 mm. It is important that t he feed troughs are low enough for all animals to access the feed on o ffer. Mature sheep were able to pass their heads between rails spaced at 200 mm without difficulty, but some difficulty was experienced when the space was reduced to 180 mm. The maximum rail spacing which preve nted the escape of 30 kg lambs could not be determined with certainty because they could pass through a space of only 180 mm when laid on th eir side, but the smallest space through which they passed voluntarily was 220 mm. Hence the optimal spacing between railings which would al low all sheep good access to feed and would prevent almost all small s heep from escaping is about 190-210 mm.