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1.
Animal ; 11(4): 687-695, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27786142

RESUMO

Many local livestock breeds in developing countries are being replaced by exotic breeds, leading to a loss of genetic resources. In southern Mali, for the past two decades, a trend towards increasing crossbreeding between the trypanotolerant N'Dama cattle and the trypano-susceptible Fulani Zebu cattle has been taking place. A survey with 160 farmers owning a cattle herd was carried out in southern Mali to investigate their production objectives, as well as trait and breed preferences and correlated socio-economic determinants in order to understand farmers' breeding decisions and to identify comparative advantages of three breed groups (N'Dama, Fulani Zebu and crossbreds) raised in the study area. Data were analyzed using an exploded logit model. The reasons for raising cattle, as well as trait and breed preferences reflected the multiple objectives of the farmers. Draught power and savings were the most important production objectives. Productive traits were ranked highest; farmers reported large body size as the most preferred trait, followed by fertility, draught ability and milk yield. Crossbreds were the favored breed group. Breed preferences were mainly explained by 'resistance to disease' for N'Dama cattle and 'high market price' for Fulani Zebu and crossbred cattle. Production objectives, trait and breed preferences were mainly influenced by farmer group (local farmers and settled transhumants). Local farmers put comparatively more emphasis on livestock functions linked to crop production such as draught power. They had a higher preference for traction ability as a selection trait and preferred N'Dama over Fulani Zebu cattle. Settled transhumants emphasized milk yield as a selection trait and preferred Fulani Zebu over N'Dama. The results indicate that the trend towards more crossbreeding will continue putting the N'Dama breed under high risk of genetic dilution in southern Mali. The N'Dama cattle remain a valuable breed due to their adaptive traits such as disease and drought tolerance and their good traction ability, fulfilling the diverse objectives of local farmers. Crossbreeding was found to be a promising breeding strategy, which might contribute to the maintenance of the local breed, provided that breeding schemes are thoroughly planned and organized.


Assuntos
Bovinos/genética , Hibridização Genética , Animais , Bovinos/classificação , Fazendeiros , Feminino , Masculino , Mali , Fenótipo
2.
J Anim Breed Genet ; 132(2): 155-68, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25823840

RESUMO

Breeding programmes described as community-based (CBBP) typically relate to low-input systems with farmers having a common interest to improve and share their genetic resources. CBBPs are more frequent with keepers of small ruminants, in particular smallholders of local breeds, than with cattle, pigs or chickens with which farmers may have easier access to alternative programmes. Constraints that limit the adoption of conventional breeding technologies in low-input systems cover a range of organizational and technical aspects. The analysis of 8 CBBPs located in countries of Latin-America, Africa and Asia highlights the importance of bottom-up approaches and involvement of local institutions in the planning and implementation stages. The analysis also reveals a high dependence of these programmes on organizational, technical and financial support. Completely self-sustained CBBPs seem to be difficult to realize. There is a need to implement and document formal socio-economic evaluations of CBBPs to provide governments and other development agencies with the information necessary for creating sustainable CBBPs at larger scales.


Assuntos
Criação de Animais Domésticos , Cruzamento , Gado/genética , Agricultura/economia , Agricultura/métodos , Criação de Animais Domésticos/economia , Animais , Cruzamento/economia , Genética Populacional , Gado/crescimento & desenvolvimento
3.
J Anim Breed Genet ; 131(5): 341-9, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24943247

RESUMO

Village- and central nucleus-based schemes were simulated and evaluated for their relative bio-economic efficiencies, using Ethiopia's Menz sheep as example. The schemes were: village-based 2-tier (Scheme-1) and 1-tier (Scheme-2) cooperative village breeding schemes, dispersed village-based nuclei scheme (Scheme-3), conventional 2-tier central nucleus-based scheme (Scheme-4), and schemes linking a central nucleus and village multiplier nuclei with selection in central nucleus (Scheme-5) or in both central and village nuclei (Scheme-6). Among village-based schemes, Scheme-1 gave the highest genetic progress, while Scheme-2 was economically the most efficient with genetic gain in the breeding objective of Birr 5.6 and a profit of Birr 37.2/ewe/year. The central nucleus schemes were more efficient than the village schemes. Scheme-4 was the most efficient with genetic gain in the breeding objective of Birr 13.5 and a profit of Birr 71.2, but is operationally more difficult as it requires a very large central nucleus. The choice between village and central nucleus-based schemes would depend on local conditions (availability of infrastructure, logistics and technical knowhow and support). Linking central nucleus with village-based nuclei (Scheme-6) would be a feasible option to overcome the operational difficulties of the conventional central nucleus scheme. If a village-based breeding program is envisaged as should be the 1st step in most low-input systems, then Scheme-2 is the most efficient. To scale out to an entire Menz breed level, Scheme-3 would be recommended.


Assuntos
Criação de Animais Domésticos/métodos , Cruzamento , Ovinos/genética , Animais , Etiópia
4.
J Anim Breed Genet ; 131(5): 350-7, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24945868

RESUMO

A simulation study was conducted to optimize a cooperative village-based sheep breeding scheme for Menz sheep of Ethiopia. Genetic gains and profits were estimated under nine levels of farmers' participation and three scenarios of controlled breeding achieved in the breeding programme, as well as under three cooperative flock sizes, ewe to ram mating ratios and durations of ram use for breeding. Under fully controlled breeding, that is, when there is no gene flow between participating (P) and non-participating (NP) flocks, profits ranged from Birr 36.9 at 90% of participation to Birr 21.3 at 10% of participation. However, genetic progress was not affected adversely. When there was gene flow from the NP to P flocks, profits declined from Birr 28.6 to Birr -3.7 as participation declined from 90 to 10%. Under the two-way gene flow model (i.e. when P and NP flocks are herded mixed in communal grazing areas), NP flocks benefited from the genetic gain achieved in the P flocks, but the benefits declined sharply when participation declined beyond 60%. Our results indicate that a cooperative breeding group can be established with as low as 600 breeding ewes mated at a ratio of 45 ewes to one ram, and the rams being used for breeding for a period of two years. This study showed that farmer cooperation is crucial to effect genetic improvement under smallholder low-input sheep farming systems.


Assuntos
Criação de Animais Domésticos/métodos , Cruzamento , Ovinos/genética , Animais , Etiópia , Fluxo Gênico , Modelos Genéticos , Reprodução
5.
Animal ; 8(8): 1249-54, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24229847

RESUMO

We evaluated the efficiency of selection for body weight in a cooperative village breeding program for Menz sheep of Ethiopia under smallholder farming system. The design of the program involved organizing villagers in a cooperative breeding group to implement selective breeding of their sheep. The program was jump-started through a one-time provision of elite rams from a central nucleus flock, but subsequent replacement rams were selected from within the village flocks. We also evaluated body weight trends in a village where cooperative breeding was not implemented and individual farmers managed their flocks under traditional breeding practices. Under traditional breeding practices, genetic progress over 8 years either stagnated or declined in all the weights recorded. In the cooperative villages, selection differentials of 2.44 and 2.45 kg were achieved in 2010 and 2011 selection seasons, respectively. Birth weight, 3-month weight and 6-month weight increased, respectively, by 0.49, 2.29 and 2.46 kg in the third-generation lambs over the base generation. Improved rams supplied from the central nucleus flock gave an initial genetic lift of 14.4% in the 6-month weight. This was higher than the gain achieved from selection in the village flocks, which was 5.2%. Our results showed that village-based genetic improvement in body weights under smallholder conditions could be feasible if appropriate designs are adopted and that commencing with elite central nucleus rams help jump-start village-based programs.


Assuntos
Criação de Animais Domésticos/métodos , Peso Corporal/genética , Cruzamento , Ovinos/genética , Fenômenos Fisiológicos da Nutrição Animal , Animais , Peso ao Nascer , Meio Ambiente , Etiópia , Masculino , Estações do Ano , Ovinos/crescimento & desenvolvimento
6.
Trop Anim Health Prod ; 42(3): 327-40, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19711191

RESUMO

The objective of this study is to describe the present organisational structure of Boran cattle breeding and develop a model breeding programme using a deterministic approach under the current structure of the Boran Cattle Breeders Society. A breeding unit of 13,000 cows supplying bulls to a commercial population of 39,000 cows was assumed. Selection criteria used were growth and reproduction traits while breeding objective traits targeted were growth, carcass, reproduction, survival, milk yield and feed intake traits. Higher selection intensity was possible for breeding sires resulting in higher genetic gains compared to dams even though selection accuracies were generally low. Annual genetic gains were positive except for dressing percentage, cow survival rate, and age at first calving. However, a reduction of age at first calving by 9.5 days obtained a return of Ksh 49.76. The overall monetary genetic gain obtained was Ksh 84.89 with a profit per cow per year of Ksh 377.98. The basic breeding programme could be expanded to accommodate a larger population of Boran cattle. The implications of the results are also discussed.


Assuntos
Agricultura/economia , Cruzamento/economia , Bovinos/genética , Criação de Animais Domésticos/economia , Animais , Feminino , Quênia , Masculino , Seleção Genética
7.
Zoonoses Public Health ; 57(5): 367-74, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19309482

RESUMO

The prevalence of mastitis and brucellosis in urban and peri-urban settings was studied in Awassa and two smaller nearby towns in southern Ethiopia, because milk-born diseases are causing a risk for human health, besides direct impacts on animal production. Mastitis was investigated by examining 80 cows (320 udder quarters) using California mastitis test (CMT) and somatic cell count (SCC). The prevalence of brucellosis was assessed by sampling 177 cattle in Awassa and its peri-urban areas using serological methods. Logistic regression was used to analyse risk factors associated with mastitis. Prevalence of clinical mastitis on quarter level was 0.9%, and 1.9% of quarters were non-functional or blocked. Prevalence of sub-clinical mastitis at quarter level in urban and peri-urban areas was significantly different (P < 0.05). Cows in large herds and at advanced lactation number were associated with higher risk of infection. The percentage of quarters positive on CMT (42.5%) was close to the percentage-positive detected by SCC (41.2%). Prevalence of brucellosis was 3.9% in the peri-urban area, while no brucellosis cases were detected in Awassa. More frequent use of artificial insemination in the urban than in peri-urban area might have contributed to the absence of brucellosis in the urban location. The extent of mastitis is, however, a threat to the dairy enterprise in and around Awassa. Pasteurization of milk and milk products is indicated in some parts of the area because of the danger of brucellosis.


Assuntos
Brucelose Bovina/epidemiologia , Mastite Bovina/epidemiologia , Animais , Anticorpos Antibacterianos/sangue , Brucella/imunologia , Bovinos , Contagem de Células , Etiópia/epidemiologia , Feminino , Leite/citologia , Leite/microbiologia , Prevalência , Fatores de Risco
8.
Trop Anim Health Prod ; 42(1): 79-87, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19544004

RESUMO

The llama claims the largest population of the domestic South American camelids, most of which are raised in Bolivia. More than 53,000 rural families are dedicated to llama husbandry as part of their livelihood strategy. Contemporary Andean societies deliberately select animals for specific traits and employ substantial livestock management to secure subsistence. This study presents traditional llama husbandry and breeding management activities in the Ayopaya region, Bolivia. Traditional selection traits for male and female llamas are documented and assessed by a ranking and a ratio-scaled evaluation. Husbandry and management parameters are in concordance with other studies conducted in the region, but show a high variation. Average llama herd sizes are rather small (mu = 45.6). In some herds, breeding males are utilized for a long time and mix with other herds, causing concerns about inbreeding. Preferred trait groups for llama males according to farmers' responses were body conformation, fibre, testicle conformation, fleece colour and height at withers. Traditional selection criteria generally relate to the phenotype, but also include the commercially interesting fibre trait. The presented results should be considered in breeding and management programmes for the respective llama population to ensure sustainable use of this genetically and culturally valuable resource.


Assuntos
Criação de Animais Domésticos/métodos , Cruzamento/métodos , Camelídeos Americanos/crescimento & desenvolvimento , Animais , Bolívia , Feminino , Masculino , Fenótipo , População Rural , Inquéritos e Questionários
9.
Trop Anim Health Prod ; 38(4): 305-22, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-17137133

RESUMO

Livestock diversity contributes in many ways to human survival and well-being, while its loss reduces options for attaining sustainable agriculture and universal food security. The current rapid rate of loss of this diversity is the result of a number of underlying factors. While in some cases changes in production systems and consumer preferences reflect the natural evolution of developing economies and markets, in other cases production systems, breed choice and consumer preferences have been distorted by local, national and international policy. In the context of a widespread threat to local pig breeds in Vietnam, this paper identifies and quantifies the level of agricultural subsidies that are currently contributing to this process of breed substitution. Producer subsidies-which tend to improve the competitiveness of imported breeds and their crosses over local breeds--are shown to be considerable, and mitigating measures are now urgently needed to avoid an irreversible loss of livestock diversity.


Assuntos
Criação de Animais Domésticos/economia , Cruzamento , Financiamento Governamental , Variação Genética , Suínos/genética , Animais , Cruzamento/economia , Conservação dos Recursos Naturais , Cruzamentos Genéticos , Feminino , Abastecimento de Alimentos , Masculino , Vietnã
10.
Anim Genet ; 31(3): 159-65, 2000 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10895305

RESUMO

The genetic variability of various local chicken populations derived from Bolivia, India, Nigeria and Tanzania was evaluated with 22 microsatellites. Between two and 11 alleles per locus were detected. All populations showed high levels of heterozygosity with the lowest value of 45% for the population named Aseel from India and the highest value of 67% for Arusha from Tanzania. A dendrogram was constructed based on CHORD distance by upgMa analysis. Within this tree the populations were assorted according to their geographical origin. Bootstrapping values within the dendrogram were between 37 and 99%. The contribution of the determination of genetic variability with genetic markers to the decision on conservation and/or further use of the populations in crossbreeding programs designed to create genetic stocks with improved adaptability and productivity in tropical countries is discussed.


Assuntos
Galinhas/genética , Variação Genética , África , Alelos , Criação de Animais Domésticos , Animais , Ásia , Genética Populacional , Heterozigoto , Repetições de Microssatélites , América do Sul , Clima Tropical
11.
Br Poult Sci ; 39(1): 62-9, 1998 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9568301

RESUMO

1. DNA fingerprints of chickens from 2 commercial lines were used to identify oligonucleotide probes providing informative DNA fingerprints. 2. The oligonucleotides [CA]8, [CAC]5, [GGAT]4 and [GACA]4, producing a high number of bands of sufficient intensity and regular distribution, were chosen for further analysis out of 10 tested. 3. Analyses of banding patterns within families revealed Mendelian inheritance of the fragments detected. The DNA fingerprints obtained with the 4 chosen oligonucleotide probes showed about 40 scorable bands in total. 4. Comparison of banding patterns within and between the chicken lines for all 4 oligonucleotide probes revealed levels of bandsharing which did not differ significantly. The number of loci detected by these probes ranged from 25 to 30 each. 5. The probes [CA]8, [CAC]5, [GGAT]4 and [GACA]4 can be used to produce informative DNA fingerprints of chicken. These probes provide estimates of the genetic similarity/variability of individuals or of populations and provide a valid measure of the actual degree of genetic similarity/variability.


Assuntos
Galinhas/genética , Impressões Digitais de DNA/veterinária , Sequências Repetitivas de Ácido Nucleico , Animais , Sequência de Bases , Bandeamento Cromossômico , Impressões Digitais de DNA/métodos , Sondas de Oligonucleotídeos , Linhagem
12.
J Anim Breed Genet ; 114(1-6): 55-68, 1997 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-21395803

RESUMO

SUMMARY: Starting with the second crossbred generation, parental genomic-proportion lines in individuals deviate considerably from expectation. These individual variations offer the potential to increase the efficiency of crossbreeding programmes. DNA fingerprinting was established as an approach, to quantify the genomic contribution of the parental lines in individuals of two crossbred generations. For this purpose, line-specific bands were identified in representative banding patterns of pooled DNA from purebreds. The representative banding patterns obtained with eight combinations of restriction enzymes HinfI and AluI, and oligonucleotide probes [CA]8, [CAC]5, [GGAT]4, and [GACA]4, contained between nine and 14 line-specific bands. The estimation of the proportion was based on the relative proportion of line-specific bands of one parental line in banding patterns of crossbreds. This was first done in F1 individuals with a definite 50% genomic proportion of each parental line, to determine the accuracy of the approach. The mean value, 51.0 ± 0.34%, observed in 45 F1s using all eight combinations of enzymes and probes, of genomic contribution of one parental line, was close to the theoretical value of 50%. In 24 animals of the BC1, considerable shifting of the parental genomic proportion was observed. ZUSAMMENFASSUNG: Schätzung der Genomanteile bei Hühnern verschiedener Kreuzungsstufen durch DNA-Fingerprinting Von der ersten Rückkreuzungsgeneration an treten erhebliche, individuelle Verscheibungen in der Verteilung der Genomanteile der parentalen Ausganslinien vom Durchschnitt auf. Diese individuelle Variation stellt ein Potential zur Steigerung der Effektivität von Kreuzungszuchtprogrammen dar. Mit der vorliegenden Arbeit wird eine Untersuchungsmethode zur direkten Quantifizierung der Genombeiträge der parentalen Ausganslinien bei Individuen verschiedener Kreuzungsstufen durch DNA fingerprints vor gestellt. Dazu wurden in für die Ausgangslinien repräsentativen Bandenmustern aus DNA-Gemischen linienspezifische Banden identifiziert. Die repräsentativen Bandenmuster wurden mit den Restriktionsenzymen HinfI and AluI sowie den Oligonukleotidsonen [CA](8) , [CAC](5) , [GGAT](4) , und [GACA](4) erzeugt und enthielten 9-14 linienspezifische Banden. Die Bestimmung der parentalen Genomanteile beruhte auf der Identifizierung linienspezifischer Banden in den Bandmustern von Kreuzungsindividuen und der anschließenden Berechnung des relativen Anteils an für eine parentale Linie spezifischen Banden. Um die Genauigkeit der Untersuchungsmethode zu evaluieren, wurde sie zunächst bei F(1) Tieren angewandt, die einen Anteil von jeweils 50% der elterlichen Linien aufweisen müssen. Der Durchschnittswert berechnet über alle 45 F(1) Individuen und alle acht Kombinationen von Enzymen und Sonden betrug 51,0 ± 0,34% Genomanteil der einen parentalen Linie und lag somit nahe dem theoretischen Wert von 50%. Bei 24 Tieren der R1 konnte eine beachtliche Verschiebung der Genombeiträge der parentalen Ausgangslinien gezeigt werden.

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