INVESTIGATIONS INTO TRADITIONALLY MANAGED DJALLONKE-SHEEP PRODUCTION IN THE HUMID AND SUBHUMID ZONES OF ASANTE, GHANA .4. LEVELS AND MAIN CAUSES OF LOSSES

The levels and causes of losses, in connection with weight groups from birth to natural weaning, have been discussed in detail. These includ e morality rates at neonatal (1-14 days), preweaning (14-60 days), and natural weaning (60-105 days) periods. The birth-weight group above 1 .5 kg showed no incidence of twin losses in the neonatal period. Durin g the preweaning period, the parity number of dam-related mortality ra te followed the expected course, particularly under the free-range sys tem with higher losses within the first-parity-group-born lambs, being lowest at the fifth parity, before increasing again thereafter. The s ituation under the semi-tethered system was, however, different, with lambs of more than the seventh-parity dam groups suffering the greates t preweaning losses. In both zones, lambs born during the dryspell-min or wet season (H = 12.5%; SH = 11.9%) had much higher losses than thos e born in the other seasons. In the post-preweaning to natural weaning period (60-105 days), slightly more losses to single (12.1%) than twi n (11.5%) lambs were recorded in the humid zone, while in the subhumid zone, the mortality incidence in twins (14.3%) was highly significant ly greater than in singles (7.7%). Although lambs' mortality rate vari ed seasonally, much higher losses occurred in the major-wet season (H = 19.1%; SH = 15.6%) at 105 days in both zones. The losses of weaned ( >105 days) to adult sheep (>365 days) over the study period from the f irst to the second year showed higher significant losses in males (H = 17.3%; SH = 30.4%) than in females (H = 16.0%; SH = 17.2%). Over the study period, weaned to yearling stock (>105-365 days) suffered signif icantly higher losses (H = 30.9%; SH = 32.5%) than the adults over 365 days old (H = 7.1%; SH = 9.6%). The distribution of the mortality rat es over the months was distinctly seasonal (bi-modal), rising steadily from May to June and July of the major-wet season and followed by a d rop in August (dryspell month), and then rising again September, peaki ng in October (months of the minor-wet season), with minimum values in February and April (in the transitional dry-wet season). A higher per centage of the classified main causes of losses was attributable to th e category endoparasite-diarrhoea-loss of weight complex among younger stock (H = 37.8%; SH = 35.7%) than among adult stock (H = 6.3%; SH = 3.7%). Losses in orphans, weak, and low-birth-weight lambs, and losses through drowning, ranked second (H = 21.0%; SH = 19.7%).