Factors affecting morbidity and mortality on-farm and on-station in the Ethiopian highland sheep.

Factors affecting morbidity and mortality of the Ethiopian highland sheep were studied both on-farm and on-station at Debre Berhan between 1989 and 1990. Primary causes of infectious origin resulted in high proportional morbidity (88.4% on-farm) and mortality (72.9% on-farm and 71.8% on-station) rates. Nutritional and managemental factors were also responsible for mortalities in lambs. The most frequent secondary causes of morbidity and/or mortality were ectoparasites and nasal myiasis. Health management interventions on-station were not high enough to produce performance improvements above the on-farm levels. However, the occurrence of gastrointestinal parasites significantly (P < 0.05) differed between the two management systems. The frequency of some of the major causes of morbidity and mortality such as pneumonia, fasciolasis and enteritis were significantly (P < 0.01) affected by season and age of an animal. In order to alleviate the major health constraints identified in this study, a proper health management intervention involving vaccination, strategic anthelmintic treatment and feeding management are suggested.

Causes of lamb morbidity and mortality in the Ethiopian highlands.

A study was conducted to investigate causes of lamb morbidity and mortality on farms and on-station at Debre Berhan during 1989 and 1990. It showed pneumonia (bacterial and/or verminous), starvation-mismothering exposure (SME) complex, gastrointestinal parasites, enteritis, abomasal impaction and physical injuries to be important health constraints on productivity. Neonatal mortalities were 51.5% and 46.3% on farms and on-station respectively and occurred owing to management problems such as SME, abomasal impaction and physical injuries. On the farms the lamb birth weight was 2.56 +/- 0.25 kg and was significantly (p < 0.05) affected by the dam's age, lambing weight, litter size, sex of lamb and year of lambing, but not by the season of lambing. Birth weight significantly (p < 0.05) influenced lamb mortality. Lambs with a low birth weight tended to die from SME. Morbidities and mortalities due to infectious causes increased in older lambs, suggesting that infections were acquired with age when resistance was lowered owing to inadequate nutrition and poor management. Heavy loss of lambs could be overcome by such health management interventions as foster mothering, warming lambs during the cold season and vaccination with polyvalent vaccines against pasteurellosis, clostridial infection and Dictyocaulus filaria.