Factors affecting mortality in free ranging Small East African goats. MSc thesis, University of Nairobi

Abstract

The causes, levels and factors affecting mortality of the Small East African goat on a semi- arid thornbush savannah, at Isiolo, were determined. A total of 40 deaths of immatures and adults were were used to determine causes of death and factors affecting cause of death. Factors affecting mortality of kids and adults were analysed using ordinary and weighted least squares. The mortality levels for 156 kids aged 1-13 days was 16%, for 104 kids aged 14-160 days was 18%, for weaners (161-365 days) was 4% and adults was 12%. The causes of death in immatures and adult animals were emaciation - 30%, miscellaneous causes - 20%, unexplained loss- 17.5%, pneumonia - 17.5% and predation - 15%. In immatures and adults, forage condition 4 weeks prior to death, the weight of the animal before death and the weight change over 4 weeks before death, affected the cause of death (P<0.05). Sex, lactation, time period, and age did not affect cause of death (P>0.05). Low forage scores were associated with death due to emaciation while high forage scores were associated with death due to infectious conditions. Deaths from emaciation and non-specific causes were ♦ (V) associated with animals with low body weights and loosing weight while those from pneumonia were associated with high body weights and those which lost little or gained weight. In kids of 1-13 days, birth weight (P<0.001), sex (P<0.05) and milk intake (PCO.OOl), significantly affected mortality. Forage score, type of birth, age of dam at kidding and weight of dam at kidding were not significant (P>0.05). The probability of survival was higher for kids with high birthweight, females, and kids with higher milk intake. In kids of 14-160 days of age type of birth (P<0.05) and average weight gain (P<0.001), affected mortality. Birth weight, sex, dam weight and dam age at kidding were not significant (P>0.05). Twins and kids gaining weight faster had higher probability of survival. In adults weight, the reproductive status and weight change affected mortality during the dry season (P<0.001) both linearly and curvilinearly. The age of the animal was non significant linearly (P>0.05) but was significant curvilinearly (P<0.05). Animals with a lower reproductive stress (neither lactating nor pregnant), higher body weight at start of dry season and gaining weight during the dry season had higher probability of survival.