Research Results - (PDF, 101 mb) - USAID

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The second approach was to continue screening kids raised in confinement by challenge with 10,000 H.contortus larvae. Two groups (42 and 27 kids) have been screened. Two bucks and three does have been identified that had fewer than 500 EPG in challenge infections. These results are interesting because other kids had greater than 10,000 EPG. We plan to screen two additional groups of kids before January 1991 using the same design. In addition, we will expose kids with less than 500 EPG (in primary infections) to a secondary challenge for confirmation. Kids experiencing low EPG identified in these two approaches will be included in breeding challenge experiments planned for 1991. Project Achievements Goats have been identified that resist H. contortus larval challenge. Changes in Workplan We initially planned to compare two groups of at least 10 goats each-one group with low egg counts averaging less than 300 eggs per gram of feces (EPG), and the other group averaging more than 1000 EPG. Because of irsufficient kids available for the low EPG group, we have focused our efforts on obtaining additional kids that resist H. contortusinfections. We have used two approaches to identify these kids. In the first, four does from a low EPG group were bred to one buck from the same group. This produced five kids that were raised in confinement and challenged with 10,000 H. contortus. One doe had undetectable EPG on both the primary and secondary challenge infections. Additional kids will be available from this breeding stock for testing in the coming year. Activity No. 2. Identification of Antigens for the Diagnosis and Prevention of Heartwater in Goats. Objective Identify and evaluate Cowdria ruminantiumsurface proteins. Problem Statement and Approach Heartwater is caused by the rickettsia C. ruminantiumand infects goats, sheep, and cattle. In goats, the disease causes a very high mortality and can be devastating in susceptible populations. Ti;.nsmission is by ticks, primarily Amblyomma variegatum,which is widely distributed in Kenya. The approach is to identify C. ruminantiumsurface proteins in expression libraries made from genomic DNA. Justification The identification of recombinant surface proteins of the organism is the first step toward development of a subunit vaccine for the disease. Such a vaccine could be used to prevent the disease and eventually become part of a multivalent recombinant vaccine that would induce protection against the major goat diseases. Project Progress During the evaluation of the genomic DNA library for expression of surface proteins it became obvious that one or more of the cloned genes could be used to develop a diagnostic DNA probe. The DNA probe could be used to identify infected goats and ticks. This identification could be very important foy epidemiology studies to define areas where the disease occurs and to define conditions where goats are at risk of infection. Two DNA clones were identified: pCR9, which is derived from the Kiswani, Kenya, isolate of C. ruminantiumand pCS20, which is derived from the Crystal Springs, Zimbabwe, isolate. Initial specificity was determined by hybridization with labeled DNA from infected culture cells, but not to DNA from uninfected cells. Infurther studies, it was found that the labeled DNA insert from pCR9 bound to large amounts of some bacterial DNAs causing specificity problems. In contrast, the insert from pCS20 was more specific and did not bind to . ng of DNA isolated from several different rickettsia, bacteria and protozoa. Neither probe bound to DNA extracted from A.variegatum 89
nymphs and adults. However, a high number of DNA extracts of nymphs fed as larvae and adults fed as nymphs on heartwater-infected goats bound to the DNA probes. Based on the relative specificity, we are currently pursuing the use of pCS20 in epidemiological and other studies. In addition, the DNA sequence is being determined so that the probe can be widely used. For instance, investigators in other countries can make synthetic oligonucleotide probes from the DNA sequence and not have to obtain the DNA probe. Project Achievements 1. Development of a DNA probe for C. ruminantiumand detection of individual infected ticks. 2. Completion of Dr. Suryakant Waghela's Ph.D. program. Changes in Workplan The focus on identification of surface proteins was temporarily interrupted in order to characterize the DNA probes to detect organisms. The primary reason was to complete Dr. Waghela's Ph.D. program. Activity No. 3. Contagious Caprne Pleuropneumonia (CCPP) Vaccine. Objective Immunize goats with expressed F38 surfce einie tats with etra 3proteins g surface protein that reacts with neutralizing monoclonal antibody. Problem Statement and Approach CCPP is the most serious disease of goats in Kenya, causing high mortality and great economic loss. The disease occurs in epidemics in all areas of the country, including western Kenya. The SR-CRSP project and KARI developed an inactivated vaccine for CCPP. This vaccine is very effective and one dose induces protection for at least one year. All the SR-CRSP 90 goats and the KARI goats are routinely vaccinated. In addition, several hundred thousand doses of vaccine have been distributed to farmers in Kenya. There is a high demand for the vaccine by farmers and several million doses are needed. We continue to work with government and commercial sources to get more vaccine made. Since we have considerable experience with the CCPP system, it is a logical target for initial inclusion in a multivalent recombinant vaccine for goats. To this end, we are identifying F38 proteins expressed by recombinant organisms. Justification Delivery of individual monovalent vaccines, several of which are required to protect against the important goat diseases, is not possible in the case of farmers with a small number of goats and limited resources. Therefore, multivalent vaccines are needed and to incorporate CCPP antigens into a multivalent format, we are using recombinant DNA to obtain F38 surface proteins. Project Progress The plan was to use a monoclonal antibody developed by SR-CRSP that causes growth-inhibition of F38 to identify an F38 surface protein expressed in a genomic DNA library. Initial experiments were done to verify that the monoclonal antibody bound to a protein epitope, providing a rationale for screening expressed by recombinant E.coli that are not glycosylated. The carbohydrate antigen that is used in the latex agglutination test was found to block the growth-inhibition caused by the monoclonal antibody. This indicated that the monoclonal antibody recognized a carbohydrate epitope and could not be used to screen the E.coli recombinants expressing F38 proteins. An antibody was needed that reacted with F38 surface proteins and could be used for immunoscreening. To obtain this antibody, large numbers of F38 organisms were grown, isolated, and reacted with complement inacti
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198 199-... Annu..a Repo.. "" >' ''
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Small Ruminant Collaborative Resear
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41 Breeding More Prolific Strains o
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Foreword This 1989-90 Annual Report
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Maps Maps of the countries with whi
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Kenya ix
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Lima Peru xi
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Breeding a Genetically Improved Dua
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Toggenburg x 1/4 Anglo Nubian x 1/4
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HSA12 BOVINE MOUSE GAPD 13 TPI 1 12
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Over one-third of the phenotypic va
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example, the EAG does may have been
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years of age resulted in upward tre
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Figure 5. Fingerprinted with the M1
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not significant. This could imply t
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Table 9. Least squares constants &
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Blackburn, H.D., and J.F. Taylor. 1
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milk on a regular basis, only a sma
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Training Progress and Institutional
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Economic Analysis of Small Ruminant
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With the DPG, farmers have acquired
Page 43 and 44: IDRC, and ILCA. The best performers
Page 45 and 46: kidded at the tasseling stage of th
Page 47 and 48: workshop held in Nairobi. Each pres
Page 49 and 50: * University of California, Davis B
Page 51 and 52: U.S. Institution Department of Anim
Page 53 and 54: and F2 sheep at the Tadla Farm and
Page 55 and 56: component of the US. participation
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Page 59 and 60: Java. Working Paper, SR-CRSP, Bogor
Page 61 and 62: Summary In Morocco cereal stubble r
Page 63 and 64: of cottonseed meal/day between week
Page 65 and 66: the last month of pregnancy on ewe
Page 67 and 68: By-Product and Crop Residue Utiliza
Page 69 and 70: Research Results Objectives 1. To c
Page 71 and 72: weights, lambs born, lamb birth wei
Page 73 and 74: Asystasia was the best, especially
Page 75 and 76: * Colorado State University Animal
Page 77 and 78: viral proteins are required for fur
Page 79 and 80: vitro propagation of its causative
Page 81 and 82: ined had variable levels of CPA ent
Page 83 and 84: flock has been verified. Although t
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Page 89 and 90: Myers, F.J., B.R. Madewell, P.H. Gu
Page 91 and 92: Bazalar, H. and C. McCorkle (eds.)
Page 93: can be devastating in susceptible p
Page 97 and 98: Other Contributions Contributions T
Page 99 and 100: * Montana State University Agropast
Page 101 and 102: the low or control lines. These res
Page 103 and 104: currently in press. In addition, a
Page 105 and 106: Range Research for Increasing Small
Page 107 and 108: Grazing and Animal Nutrition Studie
Page 109 and 110: Table 3. Results from the supplemen
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Page 115 and 116: Training Progress and Institutional
Page 117 and 118: Productivity of Artemisia herba-alb
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Page 121 and 122: Greater efficiency of digestion in
Page 123 and 124: Table 5. Dry matter consumption (kg
Page 125 and 126: Alpaca. Data is scare about alpacas
Page 127 and 128: Internatl. Stockman's School Handbo
Page 129 and 130: * University of Missouri Socioecono
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Page 133 and 134: Publications The following publicat
Page 135 and 136: Research Results Objectives Project
Page 137 and 138: Publications Thesis and Dissertatio
Page 139 and 140: Training Progress and Institutional
Page 141 and 142: Fernadez, M.E., and N. Canales. 198
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1. Introduce selected farmers to pr
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Study in Cigudeg Subdistrict, Distr
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Economic Analysis of Small Ruminant
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* Expenditures by Program Project E
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SMALL RUMINANT CRSP USAID GRANT NO.
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Summary of Host Country Contributio
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I! t, 199 I ---. III JaeHeso CarlMe
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