RESUMO
This study aimed at assessing farmers' perceptions and acceptance of the proposed breeding strategy of Instituto Veterinario de Investigaciones Tropicales y de Altura (IVITA), located in the Central Andes of Peru. A total of 34 farmers, who had received guinea pigs from IVITA, were interviewed. The questionnaire was performed in Spanish language and covered topics about the guinea pig production, feeding, mating system, training, the main products, perception and acceptance of crossbred lines ("cuy RG"), and the farmers' comment about the terminal crossbred animal ("cuy G"). The preferred feeding strategy was a combination of forage and supplement. All farmers implemented a controlled mating system. Most farmers had received training on feeding, reproduction, management, equipment, and facilities. The main product is animals for slaughter. The 82.40% of farmers reported that they do not purchase guinea pigs from IVITA anymore, because they are highly susceptibility to lymphadenitis, which is a highly contagious disease and causes swollen lymph nodes and affects the meat quality. Most of the respondents classified the "cuy RG" and "cuy G" as suitable for meat production and were satisfied with the performance of the animals. Therefore, 58.80% of respondents already recommended "cuy RG" to other farmers. However, 17.70% of the respondents would not recommend these animals because they are susceptible to disease, especially lymphadenitis. Therefore, IVITA should engage in more structured dialogue with farmers and regularly include their opinion in future improvement of its breeding strategies. This could help to reach higher acceptance rates by farmers.
Assuntos
Meio Ambiente , Fazendeiros , Animais , Cobaias , Humanos , Peru , Inquéritos e Questionários , ReproduçãoRESUMO
This study aimed to estimate genetic parameters for four guinea pig lines of a crossbreeding scheme. Two paternal lines are selected for growth rate (P1) and feed conversion rate (P2), whereas two maternal lines are selected for growth rate of litter (M1) and litter size at birth (M2). The heritabilities and genetic correlations were estimated with animal linear models employing multivariate analyses with REML. The heritabilities for birth weight (BW) were 0.21±0.02 and 0.23±0.03 for P1 and P2, respectively, and for weaning weight (WW), the heritability was 0.28±0.03 for P2. The estimates for weight at 60 days of age (W60) were 0.34±0.01 and 0.47±0.04 for P1 and P2, respectively, and for partial feed conversion rate was 0.46±0.03 for P2. Heritabilities for litter weight at birth (LW) were 0.09±0.03 and 0.10±0.03 for P1 and M1, respectively. For litter weight at 10 days of age (LW10), the heritability was 0.15±0.03 for M1. Heritabilities for litter size (LS) were 0.17±0.03, 0.20±0.03 and 0.11±0.03, and for number of pups born alive (BA) were 0.09±0.03, 0.14±0.03 and 0.09±0.03 for P1, M1 and M2, respectively. Similarly, high genetic correlations were found between BW, WW and W60 and between LW, LS, LW10 and BA. The genetic correlation between BW direct and maternal was moderately negative (- 0.24 ± 0.10) for P1. These results show the genetic status for all four guinea pig lines, which is essential for the further improvement of the currently implemented breeding programme and also indicate an opportunity for genetic improvement.
Assuntos
Cobaias/genética , Hibridização Genética , Modelos Genéticos , Animais , Peso ao Nascer/genética , Peso Corporal/genética , Feminino , Modelos Lineares , Tamanho da Ninhada de Vivíparos , Masculino , Análise Multivariada , Peru , GravidezRESUMO
Cattle production is an essential livelihood strategy in south-western Burkina Faso. Although having a distinct cultural role and known to be resistant against African animal trypanosomosis, the Lobi taurine cattle breed is endangered due to its low market value. As the first step in preservation efforts, our study aimed to develop a typology of production systems at the farm level. We used a structured questionnaire and focus group discussions for collecting data on household characteristics, socioeconomic activities, livestock, and access to services. The sample comprised 169 households in three communities. The analytical strategy included factor analysis of mixed data and hierarchical clustering. We identified four distinct types of cattle production systems: (1) sedentary Lobi farms, (2) sedentary crossbreed farms, (3) semi-transhumant Fulani zebu farms, and (4) transhumant Fulani zebu farms. Significant factors in developing this typology were the farmers' ethnic group, crop diversity, cattle herd size, cattle herd composition, number of small ruminants, and livestock management strategies. Across all production systems, men were considered being primary decision-makers in cattle production, with women, herders, and children being responsible for specific tasks. All identified production systems are increasingly confronting disease pressure and scarcity of water and land. Future efforts in preservation and breeding will need to respond to these trends in the agroecosystem, integrate risk management measures, and resonate with the specific needs of the different household members involved in cattle rearing.
Assuntos
Criação de Animais Domésticos , Cruzamento , Fazendeiros , Gado , Animais , Burkina Faso , Bovinos , Características da Família , Fazendas , Feminino , Grupos Focais , Humanos , Masculino , Inquéritos e QuestionáriosRESUMO
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 & desenvolvimentoRESUMO
Based on the results of participatory approaches to define traits in the breeding objectives, four scenarios of ram selection and ram use were compared via deterministic modelling of breeding plans for community-based sheep breeding programmes in four diverse agro-ecological regions of Ethiopia. The regions (and production systems) were Afar (pastoral/agro-pastoral), Bonga and Horro (both mixed crop-livestock) and Menz (sheep-barley). The schemes or scenarios differed in terms of selection intensity and duration of ram use. The predicted genetic gains per year in yearling weight (kilograms) were comparable across the schemes but differed among the breeds and ranged from 0.399 to 0.440 in Afar, 0.813 to 0.894 in Bonga, 0.850 to 0.940 in Horro, and 0.616 to 0.699 in Menz. The genetic gains per year in number of lambs born per ewe bred ranged from 0.009 to 0.010 in both Bonga and Horro. The predicted genetic gain in the proportion of lambs weaned per ewe joined was nearly comparable in all breeds ranging from 0.008 to 0.011. The genetic gain per year in milk yield of Afar breed was in the order of 0.018 to 0.020 kg, while the genetic gain per generation for greasy fleece weight (kg) ranged from 0.016 to 0.024 in Menz. Generally, strong selection and shorter duration of ram use for breeding were the preferred options. The expected genetic gains are satisfactory but largely rely on accurate and continuous pedigree and performance recording.
Assuntos
Agricultura , Cruzamento/métodos , Fenômenos Ecológicos e Ambientais , Ovinos/classificação , Ovinos/genética , Animais , Etiópia , Feminino , Masculino , Modelos Genéticos , Ovinos/anatomia & histologiaRESUMO
High feed costs are major obstacles for resource-poor dairy sheep farmers in West Asia, along with large fluctuation in grain and straw prices. Farmers need low-cost diets using locally available feeds that can provide sufficient milk of good quality. Two experimental trials were conducted on Awassi milking ewes to evaluate nonconventional and balanced low-cost diets against the traditional unbalanced diet used by farmers (control) on the total yields (milk, fat, protein, and total solids) and milk composition (fat, protein, total solids, and lactose), an important indicator of milk quality. The first trial was conducted at the research station of the International Center for Agricultural Research in the Dry Areas (ICARDA, Aleppo, Syria) to test 6 low-cost balanced diets using locally available feeds and agro byproducts against the control diet. Each diet was tested on 8 ewes that were kept on pasture as a basal diet, but received different supplements, including barley, wheat bran and nonconventional feeds (urea-treated wheat straw, molasses, sugar beet pulp, and cotton seed cake). Five balanced diets enhanced the total yields of milk, fat, protein, and total solids, in 2 cases, significantly. These diets increased total milk yield by 17.7 to 50.2% and decreased supplement feeding costs by 43% compared with the control. However, milk composition remained unaffected. The second trial was conducted on 3 different farms in northern Syria to assess in each farm a low-cost balanced diet on milking ewes (n=15) in comparison to the farmer's control (n=15). The balanced diet was a modification requested by farmers of the best performing diet in the on-station trial. Confirming the first trial's research results, the balanced diet outperformed the control in total yields; for instance, it increased total milk yield by 28 to 40% and raised net income by 30%, without affecting milk composition. Both trials showed that using locally available nonconventional feedstuffs, such as molasses, integrated into balanced dairy sheep diets can decrease feed costs of resource-poor farmers, while enhancing total yields of milk and milk constituents without compromising milk quality components. This will greatly improve the profitability of dairy sheep production in dry areas.
Assuntos
Ração Animal/economia , Indústria de Laticínios/métodos , Dieta/veterinária , Lactação/fisiologia , Leite/química , Ovinos/fisiologia , Fenômenos Fisiológicos da Nutrição Animal , Animais , Indústria de Laticínios/economia , Dieta/economia , Gorduras na Dieta/análise , Feminino , Lactose/análise , Leite/metabolismo , Proteínas do Leite/análise , SíriaRESUMO
Increased feed costs affect the livelihoods of dairy sheep farmers in the Middle East. Farmers endure high risks with large fluctuations in the price of grain used as animal feed, which is further affected by drought and declining range productivity. Using agricultural by-products and treated straw or vetch grazing for supplementing sheep diets would provide resource-poor dairy farmers with increased options to reduce feed costs, but the effects of such feeds on the quality of yogurt (the main product) need to be better understood. Two experiments were conducted to evaluate these effects. The first trial evaluated alternative diets using locally available feedstuffs, including agricultural by-products, compared with traditional diets used by dairy sheep farmers, and was conducted on-station at the International Center for Agricultural Research in Dry Areas (ICARDA, Tel Hadya, Aleppo, Syria). Milking Awassi ewes (n=56) were used to test 6 alternative diets against a traditional control diet containing barley, wheat bran, and barley straw. The 6 alternative diets contained 4 or more of the following ingredients: barley, sugar beet pulp, molasses, cotton seed cake, wheat bran, urea-treated wheat straw, and barley straw. Ewes on one of the alternative diets grazed vetch pasture, whereas ewes on the control diet and the 5 alternative diets grazed native range pasture. The milk fat content was higher in diets containing urea-treated straw. Yogurt firmness and adhesiveness were significantly lower in energy-rich diets (e.g., the control diet) and in the diets rich in soluble sugar (molasses). The effects of diet on yogurt color and on citric and succinic acid contents were significant. A yogurt produced from the milk of the group grazing on vetch was the most yellowish in color, which is appealing to Syrian consumers. The content of citric acid tended to be higher in yogurts produced from diets containing molasses. The second trial was conducted on 3 farms in northern Syria to assess an alternative diet (1 of the 6 tested in the first trial) on 15 milking ewes compared with the farmer's traditional diet (control). The alternative diet increased yogurt firmness and adhesiveness by 7 to 9% and 10 to 16%, respectively. The use of nonconventional feeds available in the region enhances yogurt quality, may reduce requirements for expensive grains, and thus, increase farmers' livelihoods by targeting expanding markets with better quality products.
Assuntos
Ração Animal , Suplementos Nutricionais , Leite/normas , Ovinos/metabolismo , Iogurte/normas , Animais , Indústria de Laticínios/métodos , Gorduras/análise , Feminino , Lactose/análise , Oriente Médio , Leite/química , Proteínas do Leite/análise , Iogurte/análiseRESUMO
Addressing the improvement of the textile characteristics is currently required in natural color production of alpaca fiber. This study analyses the possibility of implementing a genetic improvement program aiming to reduce the fiber diameter and the percentage of medullation in natural colors under the incomplete definition of the natural colors of alpaca fiber. The study considers color determination analysis in three separate steps. The first step aimed at finding the values of lightness (L*), red/green axis (a*), yellow/blue axis (b*) of three-dimensional space of color and chroma (C*ab), tone (h*ab) and color difference (ΔE) with mathematical models for the description of the coat color. The second analysis is aimed at estimating genetic parameters of color traits and their correlation with fiber traits (fiber diameter, standard deviations and percentage of medullation - PM). The third step was to determine the potential selection criteria of breeding animals based on the parameters provided by a three-dimensional space values regarding the coat color assignment in alpacas. The colorimetric data were taken using a Chroma meter device analyzing 3 008 records from Huacaya type alpacas, collected between 2018 and 2019. In the first objective of the study, the color traits were subjected to a principal component analysis. The analysis of variance components and the estimation of genetic parameters were carried out using a restricted maximum likelihood procedure. The discriminant analysis was used for the correct assignment of the coat color. The principal component analysis results showed that the L*, a*, b*, h*ab and ΔE values can be grouped into two Principal Components (PC) to describe the color, where the L* value is mainly distributed in PC2, b* is distributed in PC1, while a* is distributed in both components. The heritabilities found were 0.144, 0.128, 0.151, 0.104 and 0.152 for L*, a*, b*, PC1 and PC2. The relevant genetic correlations were between L*-PM (-0.557) and b*-PM (-0.622). The discriminant analysis showed a high percentage of correct assignment in white (99.15%) and black (99.19%) coat colors for Huacaya type alpacas, while for the intermediate colors, the accuracy was lower. The three analyses showed that there is no pure natural color, but a range of color variation. It is better to use the values of the three-dimensional space and within them, the values of L* and b* are potential selection criteria to be included in a genetic improvement program.
Assuntos
Camelídeos Americanos , Colorimetria , Animais , Cor , Colorimetria/veterinária , Fibras na Dieta , FenótipoRESUMO
Community-based breeding programs (CBBPs) for small ruminants have been suggested as alternatives to centralised, government-controlled breeding schemes which have been implemented in many developing countries. An innovative methodological framework on how to design, implement and sustain CBBPs was tested in three sites in Ethiopia: Bonga, Horro and Menz. In these CBBPs, the main selection trait identified through participatory approaches was 6-month weight in all three sites. In Horro and Bonga, where resources such as feed and water permitted larger litter sizes, twinning rate was included. Ten-year (2009 to 2018) performance data from the breeding programs were analysed using Average Information Restricted Maximum Likelihood method (AI-REML). Additionally, the socioeconomic impact of CBBPs was assessed. Results indicated that 6-month weight increased over the years in all breeds. In Bonga, the average increase was 0.21 ± 0.018 kg/year, followed by 0.18 ± 0.007 and 0.11 ± 0.003 kg/year in Horro and Menz, respectively. This was quite substantial in an on-farm situation. The birth weight of lambs did not improve over the years in Bonga and Horro sheep but significant increases occurred in Menz. Considering that there was no direct selection on birth weight in the community flock, the increased weights observed in Menz could be due to correlated responses, but this was not the case in Bonga and Horro. The genetic trend for prolificacy over the years in both Bonga and Horro flocks was positive and significant (P < 0.01). This increase in litter size, combined with the increased 6-month body weight, increased income by 20% and farm-level meat consumption from slaughter of one sheep per year to three. The results show that CBBPs are technically feasible, result in measurable genetic gains in performance traits and impact the livelihoods of farmers.
Assuntos
Cruzamento , Ovinos , Animais , Peso Corporal , Etiópia , Feminino , Tamanho da Ninhada de Vivíparos/genética , Masculino , Fenótipo , Gravidez , Ovinos/genética , Fatores SocioeconômicosRESUMO
A comprehensive dynamic simulation model was developed to describe a community-based breeding program for the Menz sheep population of Ethiopia. Selection of male and female animals based on their own and maternal performance was simulated. The breeding goal traits were 6-mo weight, preweaning survival, and fertility rate. The model input data were obtained from the flock book, questionnaires, and references. The simulation model used a mix of deterministic and stochastic procedures to model the complex system. In the baseline scenario, the proportion of selected male and female animals varied between 20 and 30% and between 70 and 80%, respectively. A reasonable annual genetic gain was predicted for the breeding goal traits at the village level. For 6-mo weight and preweaning survival rate, the annual genetic gain varied from 0.213 to 0.214 kg and 0.255 to 0.256%, respectively. For fertility rate, an annual genetic gain of 0.063% was obtained. The predicted rate of inbreeding per year was between 0.094 and 0.116%. Furthermore, a scenario analysis was conducted by varying the proportions of selected animals. Annual genetic gains of 0.230 kg, 0.277%, and 0.069% were obtained for 6-mo weight, preweaning survival rate, and fertility rate, respectively, when the proportion of selected male and female animals decreased by 10%. The annual genetic gains decreased to 0.198 kg, 0.236%, and 0.059%, respectively, when the selection proportion of male and female animals increased by 10%. The lowest rate of inbreeding per year, ranging from 0.065 to 0.079%, was achieved when the selection proportion of selected male and female animals increased. The model is relevant for the step-by-step evaluation of more than one round of selection. It is flexible and usage driven. The model is a valuable tool to design different population structures and can be easily expanded to adopt different breeding strategies. Hence, the system dynamics modeling approach is a potential tool to describe complex breeding programs.
Assuntos
Cruzamento/métodos , Simulação por Computador , Modelos Biológicos , Ovinos/fisiologia , Animais , Peso Corporal , Etiópia , Feminino , Endogamia , Masculino , Fenótipo , Ovinos/genética , Inquéritos e QuestionáriosRESUMO
Crossbreeding of indigenous tropical and improved western dairy cattle breeds as tool to improve dairy cattle performance on smallholder farms has been widely advocated, criticised and yet applied. The government of Ethiopia supported this technology for decades but adoption rate is low. Constraints are documented but there is little information about farm level introduction and development of crossbreeding. A total 122 smallholders with mixed crop livestock farms and at least 8 years of successful crossbreeding were interviewed using a pre-tested questionnaire in two contexts in Amhara Regional state in north-western Ethiopia. Crossbreeding initiator was either uncoordinated government extension or a coordinated development project, also implemented with governmental support. Qualitative and quantitative data on farmers' motivations, crossbreeding introduction, initiator support, breeding adaptation and impacts at farm level were analysed. Results show that even though motives vary between contexts the underlying reason to introduce crossbreeding was economic profit. To be able to introduce crossbreeding support of initiators (e.g. extension) and other farmers was essential. The crossbreeding introduction context had some influence. Governmental actors were the main source of support and supplier of exotic genetics but the farmer network acted as safety net filling gaps of government support. Breeding strategies focused on performance increase. A lack of basic understanding of crossbreeding has been identified. A surprising, probably biased, result was general satisfaction with initiator support and with breeding services. It was challenged by the high proportion of farmers unable to follow a breeding strategy due to insufficient bull and/or semen supply. Crossbreeding changed the smallholder production system to a high input - high output system. Except for crossbred adaptation problems, challenges were ranked context specific and influenced by the initiator. Farmers perceived crossbreeding as success and recommended it. We conclude that farmers can realize income increase with crossbreeding. The complexity of this technology, high initial investment and the need for support services and external production inputs are probable reasons why crossbreeding uptake is low. Improving the availability of semen and/or bulls must be the top priority for breeding service providers to enable farmers to follow a breeding strategy and reach a suitable and sustainable herd performance. Access to investment capital, input supply, strong technical support and market linkages are crucial for successful crossbreeding.
Assuntos
Criação de Animais Domésticos/métodos , Bovinos/fisiologia , Hibridização Genética , Clima Tropical , Animais , Etiópia , Feminino , Gado , Masculino , Inquéritos e QuestionáriosRESUMO
Identification of breeding objective traits pertinent to specific production environments with the involvement of target beneficiaries is crucial to the success of a breed improvement program. A choice experiment was conducted in four locations representing different production systems and agro-ecologies that are habitat to four indigenous sheep breeds (Afar, Bonga, Horro and Menz) of Ethiopia with the objective of identifying farmers'/pastoralists' preferences for sheep breeding traits. Following a synthesis of secondary information and diagnostic surveys, two communities per location consisting of 60 households each having at least four breeding ewes were identified. Producers' priority attributes used in the choice sets were identified through in-depth production system studies conducted from December 2007 to March 2008. On the basis of prior information, four to seven attributes were used to design choice sets with different profiles in order to capture results that mimic real life of the different communities. The attributes and levels chosen for the sheep profile were as follows: body size (large/small), coat color (brown/white/black), tail type (good/bad) for both rams and ewes; horn (polled/horned) and libido (active/poor) for rams; and lambing interval (three lambings in 2 years/two lambings in 2 years time), mothering ability (good mother/bad mother), twinning rate (twin bearer/single bearer) and milk yield (two cups per milking/one cup per milking) for ewes. A fractional factorial design was implemented to construct the alternatives included in the choice sets. The design resulted in a randomized selection of 48 sheep profiles (24 sets) for both sexes, which were grouped into four blocks with six choice sets each. An individual respondent was presented with one of the four blocks to make his/her choices. Results indicate that producers' trait preferences were heterogeneous except for body size in rams and mothering ability in ewes where nearly homogeneous preferences were investigated. In the pastoral production system, attention was given to coat color of both breeding rams and ewes, favoring brown and white colors over black. Ram libido influenced producers' decisions in Bonga, Horro and Menz areas. The influence of milk yield and twinning on respondents' decision making was high in Afar and Horro, respectively. Breeders in all areas attempt to combine production and reproduction traits as well as they can in order to maximize benefits from their sheep. The elicited measurable objective traits were used to design alternative community-based sheep breeding plans for the four indigenous sheep breeds in their production environments that have been implemented since.
RESUMO
The current study evaluated the effect of glutamate supply on the onset of puberty and possible links to changes in serum concentrations of insulin [INS], glucose [GLU] and triiodothyronine [T(3)]. The study was conducted from June to November in prepuberal female goats (n=18; 3 mo. old, 7/8 Saanen-Alpine, 1/8 Criollo, 26° north) randomly assigned to two experimental groups: (i) excitatory amino acids group (group AA, n=10; 16.52±1.04 kg LW, 3.4±0.12 body condition score [BCS], receiving an intravenous infusion of 7 mg kg(-1) live weight [LW] of l-glutamate, twice a week, and (ii) control group (group CC, n=8; 16.1±1.04 kg LW, 3.1±0.12 BCS) receiving saline. Blood samples were obtained twice a week, for assessing progesterone [P(4)], as well as in a monthly basis to evaluate INS and T(3) by RIA. Mean final LW and BCS were 23.2±0.72 kg, 3.53±0.10 units, without differences between groups. The AA group depicted an earlier onset of puberty (6.9±0.3 compared to 7.5±0.4 mo.; P<0.05) and an increased ovarian activity (70±0.28% compared to 25±0.26%; P<0.05). Neither serum INS concentrations nor serum glucose concentrations differed between treatments (1.2±0.06 ng mL(-1) and 89.6±1.8 mg 100 mL(-1); P>0.05, respectively). Serum T(3) concentrations, however, were greater in AA goats (1.55±0.03 compared to 1.39±0.04 ng mL(-1)). In addition, a treatment x time interaction occurred (P<0.05) across the experimental period for both T(3) and INS, with increases by the last third of the experimental period, time at which the onset of puberty occurred in both experimental groups. No differences (P>0.05) for glucose concentrations across time occurred between treatments. Results indicate that, in prepuberal goats, glutamate acts as a cue for sexual maturation in a glucose-independent pathway, while both T(3) and INS seem to act as metabolic modulators for the establishment of puberty in goats. Actions of INS and T(3) are mediated directly on hypothalamic centers regulating the pulsatile release of GnRH or indirectly by peripheral cues reflecting INS-T(3) actions on somatic development remains to be determined.
Assuntos
Ácido Glutâmico/farmacologia , Cabras/sangue , Cabras/crescimento & desenvolvimento , Insulina/sangue , Progesterona/sangue , Maturidade Sexual/fisiologia , Tri-Iodotironina/sangue , Animais , Peso Corporal/fisiologia , Feminino , Distribuição Aleatória , Maturidade Sexual/efeitos dos fármacos , Fatores de TempoRESUMO
No national breeding programme for llamas is in place in Bolivia. Initiatives for genetic improvement are rarely found and are usually carried out by NGOs working in rural development or improvement of livestock production or research stations. Farmers in the Province of Ayopaya in the District of Cochabamba have formed a breeders' organization with the aim of improving fibre production. In this study, a detailed outline of a breeding programme with a focus on organizational and technical details is described. Facing constraints like illiteracy of farmers, bad infrastructure and lack of finances, a simple breeding programme is set up. The breeding goal is a higher fleece weight while keeping the fleece quality at the current high level. Greasy fleece weight and fibre diameter are identified as main selection criteria. Mass selection of males is carried out. Selected males are either exchanged between farmers and used in the herds or are kept during the mating season in a central mating station owned by the breeders' organization. Model calculations were carried out with the program zplan, which is based on a deterministic approach. zplan evaluates the genetic and economic efficiency of breeding strategies considering one cycle of selection. Scenarios with only intra-herd use, using only the central mating station or combinations of those were compared in terms of expected genetic gain and expected increase of inbreeding. Fastest genetic progress is achieved when the males are kept in a central mating station as the selection intensity is on a high level. Rates of inbreeding vary between 0.08 and 0.32% per generation.
Assuntos
Cruzamento/métodos , Camelídeos Americanos/genética , Seleção Genética , Agricultura/métodos , Animais , Bolívia , Cruzamento/normas , Feminino , Nível de Saúde , Humanos , Masculino , Densidade DemográficaRESUMO
A survey in Burundi, Rwanda, Tanzania and Uganda was conducted in order to determine the different production systems under which Ankole cattle are currently kept. Additionally, selection criteria of livestock keepers were documented. In Burundi, Rwanda and parts of Uganda, livestock keepers are sedentary and herds are small, whereas in the other areas Ankole cattle are kept in large herds, some of them still under a (semi-)nomadic system. Milk is the main product in all areas, and is partly for home consumption and partly for sale. Although the production systems vary in many aspects, the selection criteria for cows are similar. Productive traits such as milk yield, fertility and body size were ranked highly. For bulls, the trait 'growth' was ranked highly in all study areas. Phenotypic features (coat colour, horn shape and size) and ancestral information are more important in bulls than in cows. The only adaptive trait mentioned by livestock keepers was disease resistance. In areas of land scarcity (Burundi, Rwanda, western Uganda), a clear trend from pure Ankole cattle towards cross-bred animals can be observed.