We review the global dynamics of livestock disease over the last two decades. Our imperfect ability to detect and report disease hinders assessment of trends, but we suggest that, although endemic diseases continue their historic decline in wealthy countries, poor countries experience static or deteriorating animal health and epidemic diseases show both regression and expansion. At a mesolevel, disease is changing in terms of space and host, which is illustrated by bluetongue, Lyme disease, and West Nile virus, and it is also emerging, as illustrated by highly pathogenic avian influenza and others. Major proximate drivers of change in disease dynamics include ecosystem change, ecosystem incursion, and movements of people and animals; underlying these are demographic change and an increasing demand for livestock products. We identify three trajectories of global disease dynamics: (i) the worried well in developed countries (demanding less risk while broadening the circle of moral concern), (ii) the intensifying and market-orientated systems of many developing countries, where highly complex disease patterns create hot spots for disease shifts, and (iii) the neglected cold spots in poor countries, where rapid change in disease dynamics is less likely but smallholders and pastoralists continue to struggle with largely preventable and curable livestock diseases.disease drivers | spatial and host dynamics | diversity of disease trajectories
Reproductive performance, mortality, growth, and culling and replacement rates based on 20000 calving records were evaluated for grade Boran beef cattle maintained with trypanocidal drugs in an area of high trypanosomiasis risk in Tanzania. Under ranching conditions, over a 10-year period in this area of high Olossina morsitans morsitans, O. pallidipes and O. brevipalpis challenge, a calving interval of 15-9 months, pre-weaning mortality of 8%, annual cow mortality of 5-8% and 8-month weaning weight of 133-5 kg resulted in a herd productivity of 96 kg of weaner calf per cow per year. The proportion of heifers required as replacements (45%) and the generation interval (6-9 years) indicated scope for implementation of selection programmes on growth traits. The level of productivity achieved compared favourably with major data sets recently analysed from pure Boran cattle under trypanosomiasis-free ranching conditions in Kenya, and from trypanotolerant N'Dama cattle in West Africa. These results indicate the possibility of improving livestock production in tsetse-infested areas by the rational use of chemoprophylaxis as an integral part of management.Year, season, cow age, calf sex and location on ranch had significant effects on practically all the traits of calving interval, pre-weaning mortality and growth, and cow productivity. Superior performance where bush clearance and tsetse fly control had taken place suggests that economic evaluation of these interventions should be attempted. The season of calving had a major effect on productivity. Cows of 5-8 years of age were the most productive, as were animals producing male calves, features well recognized in beef cattle production.An average of 4-4 treatments with Samorin, a prophylactic, and 0-6 treatments with Berenil, a therapeutic, were required per year. The number of treatments varied from year to year and by area, being greater in the south of the ranch where the tsetse challenge was considered higher. However, the age and season of calving had little effect on the number of treatments required. Despite such extensive use of trypanocidal drugs, there was no indication that drug resistance had developed or evidence that repeated inoculation of Samorin had affected productivity.Grading-up of small East African Zebu cattle to Boran over an 8-year period allowed annual comparison of birth weights, pre-weaning growth and weaning weights of two groups of calves, one having a higher level of Boran genes (varying from 12 to 6% higher annually) than the other. Those with the higher level of Boran genes performed better by 3-3% for all attributes studied, but as the percentage difference in Boran genes decreased, so did this difference. In an environment improved through bush clearance and tsetse fly control, the calves with higher levels of Boran genes were superior, but this superiority was not expressed in the unimproved environment.
The CABI African Soil Health Consortium (ASHC) aims to improve the livelihoods of smallholder farmers through better access to practical information about integrated soil fertility management. The next phase focuses on two types of intermediaries to reach smallholder farmers: agro-dealers and youth. This review reflects this focus and is therefore biased towards recent publications relevant to these intermediaries and also the impact of gender on provision of and access to agricultural information. There is a consistent demand for information on new varieties, pests and diseases, use of pesticides and fertilizer, as well as weather, credit and markets. The most frequently used sources of information are still the more traditional ones. Extension services, family, friends and neighbours, and agro-dealers are all important face-to-face sources of information. Radio dominates as the main mass media source. Local agro-dealers are often included by smallholder farmers among the most frequently used sources of information and they enjoy a degree of trust. There has been considerable investment by donors in extending and strengthening agro-dealer networks over recent years, including more emphasis on their roles as sources of information and advice. A new type of tech-savvy young entrepreneurial farmer is emerging who is more likely to wield a smartphone than a hoe. This is especially important against a background in which, despite the median age in African being just 19.7 years, the average age of farmers is estimated to be over 55. Family farming is receiving renewed emphasis. During its phase 2, which will run from 2015 to 2019, ASHC will share its experiences, successes and failures, and lessons learned in working with agro-dealers and youth intermediaries. In this way it aims to help others to communicate their key messages more effectively including via these intermediaries.
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