Assessment of the Impact of Tsetse Challenge on Herd Composition, Milk Yield and Reproductive Performance of Cattle in Dawro Zone of Southern Nation, Nationality and People Regiona State, Ethiopia
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2007-06
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Abstract
This study was conducted in the Dawuro Zone of the Southern Nations, Nationalities and People Region. The specific study sites were Mareka and Tocha districts which were randomly selected from the Zone. The objective of the study were to determine the impacts of bovine trypanosomosis on cattle herd size and composition, milk yield and reproductive performances of cattle. Known tsetse infested areas, Tercha and Lala Kebeles were selected from Mareka and Tocha districts, respectively. As a control, known tsetse free area, Docha Kebele, was selected slected from Mareka District. A total of 52 households were selected randomly from each Kebele that made a total sample size of 156 households. A structured questionnaire was prepared and one visit interview was carried out to collect data about on socio-economic characteristics, farming system characteristics, cattle herd size and composition, milk yield and reproductive performances of cattle, major cattle health problems and mortalities. In addition, a total of 30 pre-partum cows were selected (10 from each Kebele) for a postpartum follow-up study, which lasted for about six months (October 2006-March 2007), to collect data on daily milk yield and the occurrence of first postpartum observable heat. Data collected were analyzed using descriptive statistics and independent t-test. The results showed that the most important cattle health problem identified were trypanosomosis and blackleg in tsetse challenged and free areas, respectively. Cattle herd size did not different significantly (p>0.05) between tsetse challenged and free areas. However, the average number of lactating pregnant (p<0.05) and dry pregnant cows (p<0.001) was significantly higher in tsetse free area than tsetse challenged areas. On the other hand the number of dry non-pregnant cows was significantly higher in tsetse challenged area than free area (p<0.01). The average daily milk yield was in general low in both tsetse challenged and free areas. The differences in milk yield at three stages of lactation in the two areas were significant (p<0.001). Cows in tsetse affected areas were able to give only 52.14, 47.73 and 29.63% of the daily milk yield of those in tsetse free area during the beginning, middle and end of lactation, respectively. In addition, cows in tsetse free areas had an average lactation length longer by 4.35 months than those in challenged areas. Cows in tsetse free areas gave their first calf earlier by an average of 5.64 months, had an average calving interval shorter by 2.41 months and required lesser number of services per conception by 0.35 (p<0.001). The results of the follow-up study showed that the average daily milk yield of cows in challenged areas was lower by 37 to 46.5%
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than those in free areas throughout the lactation period. Only 1 cow was detected in heat (5%) (on day 122 postpartum) in tsetse challenged area while 50% of the cows were in heat on day 107.8 on average in tsetse free area. The number of cattle died in one year time was significantly higher in tsetse challenged area (26.73 times) than tsetse free area (p<0.001). It can be concluded that tsetse infestation is seriously affecting the cattle herd composition and the performances of animals in the challenged area.
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cattle, herd composition, Ethiopia, milk yield, mortality