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结果 1081-1090 的 2,098
Genetic analyses of N’Dama cattle breed selection schemes
2009
Bosso, N.A. | Waaij, van der, E.H. | Kahi, A.K. | Arendonk, van, J.A.M.
Data from the nucleus herd at the International Trypanotolerance Centre (ITC) in The Gambia were used to evaluate the current N'Dama cattle breeding scheme implemented in a low input production system. Opportunities were investigated to further improve the breeding scheme through a comparison of alternatives to the current selection strategy. A deterministic simulation model was used to demonstrate the genetic and economic benefits of the different schemes. The breeding goal consisted of daily weight gain (from 15 to 36 months of age under high tsetse challenge conditions, DWG, g/day) and milk yield (milk off-take in the first 100 days of lactation, MY, kg). Substantial genetic response per year of 3.40 kg in MY and 0.25 g/day in DWG could be achieved. Simulation results showed that early selection of nucleus sires resulted in relatively higher genetic and economic responses compared to all other schemes investigated. For a practical breeding scheme (low input system), the scheme based on early selection of nucleus sires should be recommended since this leads to the best improvements in the overall breeding goal
显示更多 [+] 显示较少 [-]Characteristics of feeding and breeding practices for intensification of smallholder dairy systems in the Kenya highlands
2008
Bebe, B.O. | Udo, H.M.J. | Thorpe, W.
The use of cassava leaf silage as a feed supplemental in diets for ruminants and its introduction to smallholder farmers
2008
Marjuki, HE | Sulistyo, DW | Rini, I | Artharini, I | Soebarinoto | Howeler, Reinhardt H.
Introduction of cassava leaf silage making to smallholder farmers and its feeding to ruminants in cassava crop growing areas were investigated through laboratory and on-farm feeding trials, extension services and training. This with the aim to evaluate the response of the ruminants on cassava leaf silage feeding and the adoption of the technology by farmers. Fifteen male sheep aged 6-8 months with an initial body weight of 15.8 + 2.6 kg were used in a laboratory feeding trial and allotted to 3 treatments with 5 replications in a randomized block experiment design. The sheep were fed on chopped elephant grass and three different levels of cassava leaf silage as treatment. The three levels of supplementation of casava leaf silage (DM in % of body weight) were: 0, 0.75, and 1.5, which represented treatments A, B, and C, respectively, and the rest of the feed was elephant grass to reach a total DM intake in % of body weight of 5. The individual sheep was weighed every second week to measure their body weight changes. An on-farm feeding trial was conducted in collaboration with the farmers as target persons. The results showed that feeding increasing amounts of cassava leaf silage as a feed supplement for sheep significantly increased digestible crude protein (CP) intake and nitrogen retention, and this was also associated with an increase in average daily weight gain from 41.4 to 45.0 and 50.0 g/head/day, respectively, on treatments A, B and C. Cassava leaf has been commonly used as a feed for ruminant animals by smallholder farmers, but only during the cassava crop harvesting season, where the leaf was abundantly available. It was fed in fresh form, either as single or combined feed. Preservation of forages including cassava leaf in the form of hay or silage was not well known by the farmers in this study. The farmers showed good response on the introduced technology of cassava leaf silage making and feeding to their ruminant livestock. They noticed that cassava leaf silage showed higher palatability over the forages they have normally used to feed their livestock. The farmers have practiced the technology, but they lack equipments, especially chopping machine for a larger scale application of the technology.
显示更多 [+] 显示较少 [-]Participatory comparison of three pig fattening methods in the provinces of Sanguié and Boulkiemdé, Burkina Faso = Comparaison participatoire de trois méthodes d'engraissement des porcs dans les provinces du Sanguié et du Boulkiemdé au Burkina Faso
2004
Bosma, R.H. | Zongo, L.C. | Sané, A. | Zoungrana, C. | Soudré, A.
Is it worth to recuperate degraded pasturelands? An evaluation of profits and costs from the perspective of livestock producers and extension agents in Honduras
2004
Holmann, Federico J. | Argel M., Pedro J. | Rivas Ríos, Libardo | White, D. | Estrada, R.D. | Burgos, C. | Pérez, E. | Ramírez, G. | Medina, A.
The objectives of this study were to: (a) estimate milk and beef yields obtained from cows grazing pastures in different stages of degradation; (b) estimate income losses as a result of the degradation process; (c) estimate the proportion of pasture areas found in each stage of degradation within the six administrative regions of Honduras; and (d) identify different strategies and costs to recuperate degraded pastures. Data came from two surveys executed during a workshop carried out in March 2004. The subjective perceptions of 25 livestock producers and 8 extension agents of the 6 administrative regions of Honduras were obtained to estimate the losses of animal productivity within the farm, region, and country. A 4-level scoring of pasture degradation was defined - where 1 was for the best condition (i.e., non-apparent degradation) and 4 was for the worst (i.e., severe degradation). Regressions, explaining the animal productivity losses at each level of pasture degradation, were generated according to the subjective and descriptive information. Comparing the perception of degraded areas, producers considered that in Honduras the extent of pasture degradation is lower compared with extension agents. According to producers, 29% of the pasture area in the country is at Level 1 (i.e., no degradation) compared with only 19% of extension agents. Moreover, producers perceived a lower proportion of pastures in severe degradation (i.e., Level 4, 27%) in comparison with almost 31% perceived by extension agents. In the intermediate degradation levels (i.e., Levels 2 and 3), both groups were similar. The country is forgoing milk and beef production due to the process of pasture degradation. According to estimations from producers, Honduras is loosing 284,106 tonnes of fluid milk and 48,271 tonnes of beef (live weight) annually for having pasture areas in Level 4 (i.e., severe degradation), equivalent to 48% of the annual production of milk and to 37% of beef. In economic terms, these losses in milk and beef yields are worth US$63 and US$48 million annually, respectively. The perception of extension agents is even more alarming. Honduras could produce 66% more milk and 50% more beef annually if livestock producers renovated their pastures before they reached level 4, equivalent to US$94 million in less revenues from milk sales and US$66 million from less beef sales. Both groups perceive that pastures, in an early stage of degradation (i.e., Level 2), are more economical, practical and rapid to recuperate. Also, as the process of degradation advances (i.e., to Levels 3 and 4), both cost and time of recuperating such pastures increase significantly. According to producers, the recuperation of a pasture from Level 4 to Level 1 costs $140/ha and takes almost a half year (i.e., 5.6 months). Extension agents estimate this cost of recuperation 27% higher ($178/ha) with 5% more time (i.e., 5.9 months). Producers perceive that grasses spend proportionately less time in going from Level 1 to 2 (i.e., 2.9 years) and as the process of degradation continues, pastures remain longer at advanced degraded levels (i.e., 3.1 years in going from level 2 to 3, and around 4.0 years in going from level 3 to 4). Moreover, producers think that the average productive life of improved grasses is about 10 years, while extension agents think that grasses degrade faster, with an average productive life of 8.4 years, 16% less than producers. According to producers and extension agents, pastures degrade at an annual rate of 10% and 12%, respectively. With these rates, Honduras would maintain its current level of degradation between levels 2.48 and 2.65. However, the renovation of pastures at an annual rate of 10-12% does not solve the problem, but maintains it. Producers argued that the current financial situation does not allow the necessary cash flow to renovate their plots, and the option of credit is not viable since real interest rates are high (ie., 10%). After simulating this scenario, it was demonstrated that farmers are able to generate the additional income necessary to pay a credit, but only if this credit is taken with interest rates similar to those found in the international market (ie., 3%). In order to eliminate the degraded areas found in Level 4 at the country level, it is necessary a one-time investment of $57 million according to producers and $84 million according to extension agents. The benefit obtained from this investment would result in a daily increase of 156,000 liters of milk and 26,500 kilograms of beef, equivalent to $22 millions/yr. Therefore, there are significant economic and productive incentives for the private and public sectors to develop and execute a plan of action to recuperate pasturelands in advanced stages of degradation.
显示更多 [+] 显示较少 [-]Impact of the adoption of Brachiaria grasses: Central America and Mexico
2004
Holmann, Federico J. | Rivas Ríos, Libardo | Argel M., Pedro J. | Pérez, E.
Livestock production plays a key role in tropical Latin America in a changing economic environment. This study focuses on documenting the transformations of extensive production systems by using superior forage germplasm supplied by regional research systems. The adoption of improved Brachiaria grasses was evaluated from 1990 to 2003 to estimate its impact in terms of animal productivity and income in Central America and Mexico. Information on seed sales in the local market made it possible to estimate the areas planted and the value of additional milk and beef production attributable to adoption. Mexico presents the highest volume of marketed seed and of area established with improved pastures. Among Central America countries, Costa Rica was outstanding in terms of the high volume of seed sold and the area planted, followed by Honduras, Nicaragua, and Panama. The annual growth rate of seed sales was very high during the study period, reaching 32% in Mexico, 62% in Honduras, 45% in Nicaragua, 39% in Costa Rica, and 54% in Panama. The area planted with Brachiaria species during this period totaled 6.5% of the total surface of permanent grasses in Mexico, 12.5% in Honduras, 1.0% in Nicaragua, 18.7% in Costa Rica, and 0.1% in Panama. Excluding Nicaragua and Panama, where adoption is low, Brachiaria grasses account for 24%-55% of total annual milk production and for 5%-18% that of beef. These figures clearly demonstrate that those adopting new Brachiaria cultivars are farmers mainly oriented toward milk production and, to a lesser extent, beef. In monetary terms, the value of additional production attributable to the adoption of Brachiaria grasses in the selected study countries was estimated at US$1084 million per year, 78% corresponding to milk and 22% to beef. Due to the magnitude of the livestock sector in Mexico, adoption generates slightly more than 80% of production profits. Study results indicate that the investment of public funds in Central America and Mexico to support the International Network for Evaluation Tropical Pastures (RIEPT, its acronym in Spanish) paid off in terms of adoption of improved grasses and significant increases in the supply of milk and beef, fundamental items in the diet of consumers from all income levels in the region.
显示更多 [+] 显示较少 [-]Evolution of milk production systems in Tropical Latin America and its interrelationship with markets : An analysis of the Colombian case
2003
Holmann, Federico J. | Rivas Ríos, Libardo | Carulla, Juan E. | Rivera, B. | Giraldo, Luis Alfonso | Guzmán Pérez, Silvio | Martínez, M. | Medina, A. | Farrow, Andrew
The objectives were to: (1) identify and quantify the effect of technological change on productivity, profitability, and competitiveness in different milk production systems and regions of the country; (2) analyze the relationship between productivity, technological change, profitability, and competitiveness; (3) analyze the evolution of milk production systems in Colombia; and (4) discuss the market concentration and its impact on the formation of milk price. Data came from a survey to 545 farms during the year 2000 in five regions: Caribbean and Piedmont in the lowlands, Coffee Growing, Antioquia, and the Cundiboyacense altiplanicie in the highlands. The survey was designed to quantify inputs and products in order to determine costs and prices at the farm level in order to calculate (a) variable costs for feed supplementation, labor, health, reproduction, fertilization, and irrigation; (b) gross income from the sale of milk and beef, and (c) to characterize farms according to productivity level and management practices. The statistical analysis of multiple correspondence and general linear models were used to explain the variability observed between productivity and profitability as a function of technological change. Independent of the production system or the region where farms were located, the increase in competitiveness was in direct relationship with herd size. Thus, as herd size increased, production costs per unit of milk and beef decreased, net incomes per cow increased, and the return to capital investment improved. However, when this increase in competitiveness was associated with increases in productivity, this trend was not observed, which suggested that highly productive farms were not necessarily competitive. The dual-purpose system was the most profitable one in the Piedmont, Caribbean, and Coffee growing regions while in Antioquia and in the Cundiboyacense altiplanicie the most profitable was the specialized dairy system. With regards to technological change, the adoption of improved pastures and the investment in pasture divisions for a more efficient rotation generated higher productivity and income in all regions and production systems, as well as increased competitiveness through a reduction in production costs per unit of milk and beef. The use of strategic feed supplementation to the basal diet of forage had mixed effects. The best economic response to this supplementation in lowland regions (i.e., Piedmont and Caribbean) was with low quantities (i.e., < 0.5 kg DM/cow/day) of feed supplements while in highland regions (i.e., Coffee Growing area, Antioquia and the Cundiboyacense altiplanicie) was with moderate quantities (i.e., between 0.5 and 2 kg DM/cow/day). The use of fertilization and irrigation increased productivity, but reduced net income and increased production costs, except in the Cundiboyacense altiplanicie. The practice of milking twice a day increased both productivity and profitability and reduced production costs, except in the Caribbeanregion. Farms that de-wormed milking cows with low frequency against internal and external parasites obtained higher incomes and lower production costs in comparison with farms that de-wormed cows with higher frequency although there were no differences in productivity. The amount of years of experience of farmers at producing milk was a key factor to increase profits, although not productivity. Farms located in sites where the commercial value of land was high (>US$6,000/ha) and near market centers had higher productivity that those with commercial value of land medium ($3,000 to $6,000/ha) and low (<$3,000/ha) but were less profitable in all regions. Box 1: Recommendations to researchers and extensionists Identify profitable technologies. Technologies that increase productivity are not necessarily profitable, which suggest the need to determine appropriate ways to evaluate them economically. This was the case of fertilization and irrigation. It is necessary to determine the best economic response to various levels of N2 and H2O to different species of improved grasses under various soil types and conditions. The most competitive and profitable breed group in the dual-purpose system was the crossbred with low (24% European-76% Zebu genes) and medium levels of dairy genes (55% European-45% Zebu genes) but had lower productivity than the purebred group (98% European genes). In the specialized dairy system, the purebred group was slightly more profitable, productive and competitive than the crossbred group with medium level of dairy genes, but this difference was not significant. The Colombian dairy sector has become more productive and competitive, but less profitable. Comparing the evolution of dairy farms with studies 12 years ago, milk production per hectare increased by 44% in dual-purpose herds and 14% in specialized dairies. This increase in productivity reduced the milk production cost by 16% and 10% in dual-purpose and specialized dairies, respectively, due to an increase in stocking rate by 15% and 17% in dual-purpose and specialized dairies as well as to an increase in investment in infrastructure and equipment by 258% and 37% in dual-purpose and specialized dairies, respectively. However, the net income per hectare during this period decreased by 27% and 69% in dual-purpose and specialized dairies due to a reduction in the producer's price of milk and beef of 22% and 20% in dual-purpose systems, and of 41% and 27% in specialized dairies. Nevertheless, this reduction in price to producers was never translated in lower prices to consumers, but remained in the hands of supermarkets and milk processing plants which expanded and modernized with long-life technology. Development agencies must internalize the fact that policies oriented to markets will be increasingly "oriented to supermarkets". If one adds that in Colombia exists 3 or 4 supermarket chains that control the food retail market, the conclusion is that sectoral policies will need to learn how to deal with a handful of giant companies. This in a huge challenge, and demands an urgent review of ideas and strategies. Box 2: Recommendations to decision makers Regionalize research. Due to the fact that the most profitable production systems are region-specific, Colombia should have different strategies for research and technology transfer in order to exploit more efficiently the comparative advantages of each region and production system. Promote collective action. It is necessary to promote cooperatives and associations to help small producers to adapt to new patterns with higher levels of competition. Otherwise, the new rules of the game could induce a massive exodus of producers in the short term and in a relatively brief period of time. It is possible, in the short run, to adopt technologies that increase milk productivity and reduce production costs while profits are reduced as a result of falling real prices as occurred in Colombia during the 90's. However, in the long run, this situation is simply unsustainable. The proposals and challenges presented in this case study have illustrated the problems and opportunities of the dairy sector in Colombia. However, these systems could represent similar situations in other countries of Latin America. Given the phenomenon of globalization and higher degree of efficiency that these systems are being exposed to, the issues of productivity, technological change, competitiveness, and markets, are critical and of enormous relevance for the performance and survival of the livestock sector in the next decades. Box 3: Recommendations to producers Without research there is no future. Efficiency goes hand in hand with technology and this depends on research and technology transfer. However, public funds allocated to agricultural research are being reduced. The challenge consists that producers in Colombia take greater control of livestock research by building alliances with local, regional and international organizations leaders in forage and livestock research. For this it is necessary that producers define and fund their own research agenda. Production-to-consumption participation. In the coming years, producers cannot limit themselves to participate only in the primary phase of production, but to expand their scope of action to other phases of the market chain to have a higher participation in the formation of milk prices and to capture a greater piece of the final price.
显示更多 [+] 显示较少 [-]Normal haematological values of Galla goats in Kenya
1989
Wesonga, H.O. | Nandokha, E.
Haematological values of healthy Galla goats have been determined. These values have been found to differ from those reported by other authors in different breeds of goats from various countries. Those values found to be of highly significant difference (P
显示更多 [+] 显示较少 [-]Optimisation of breeding schemes for litter size, lambing interval, body weight and parasite resistance for sheep in Kenya
2011
Verbeek, E. | Kanis, E. | Bett, R.C. | Kosgey, I.S.
The current study optimised breeding schemes for litter size (LS), lambing interval (LI), body weight (BW) and gastrointestinal parasite resistance for sheep in Kenya. Selection for the breeding goal traits was performed in a conventional way using information on phenotypes only. For gastrointestinal parasite resistance, information on genetic makers was used, with faecal egg count (FEC) as an indicator trait. Selection for parasite resistance was partly based on field measurements and the possibilities for marker-assisted selection (MAS) were explored. Several selection schemes were defined based on whether a classical selection only was used (Latin number 1), a quantitative trait loci (QTL) for FEC was assumed to be available (2), that the correlation between FEC and BW was assumed to be positive (unfavourable-Roman I) or negative (favourable- II) and finally how FEC was included in the index (i.e., no inclusion (A), with FEC (B) or with FEC QTL (C-F)). The schemes with overlapping generations were evaluated using the computer program SelAction. Rams, ewes and total selection responses in US dollars ($) per animal, and rams' and ewes' accuracies for each scheme with a favourable or unfavourable correlation were estimated. The differences in total selection responses between schemes that did not include FEC in the selection index resulted in a response of $0.16 in scheme 1AI and $0.20 in scheme 1AII. In schemes 1BI and 1BII, FEC was included in the index. The responses in scheme 1BI and 1BII were $0.165 and $0.217, respectively. The increase in response in schemes II compared with schemes I was due to a favourable correlation between BW and FEC. The different FEC index traits had a different effect on economic response. It should be noted that increased emphasis on selection for FEC will reduce the relative responses to the breeding goal traits BW, LS and LI. Consequently, the goal of selection for FEC should be to maintain acceptable levels of gastro-intestinal parasite resistance as well as sufficient improvement of LS and BW.
显示更多 [+] 显示较少 [-]Role of traditional enclosures on the diversity of herbaceous vegetation in a semi-arid rangeland, southern Ethiopia
2010
Angassa, A. | Oba, G. | Treydte, A.C. | Weladji, R.B.
Grazing management and seasonality strongly influence the recovery potential of herbaceous vegetation in semi-arid rangelands of southern Ethiopia after history of heavy grazing. We investigated effects of management (enclosures versus grazed landscapes), age of enclosures and seasonality related to rainfall (i.e., independent variables) on herbaceous biomass, grass basal cover, herbaceous species abundance, species richness and diversity in a savanna rangeland of southern Ethiopia. We further assessed the relationship between the herbaceous biomass and species richness. Management significantly affected most of the herbaceous response variables (i.e., comparing enclosures and open grazed). Herbaceous biomass, grass basal cover, herbaceous species richness and diversity were greater in enclosures than in grazed areas. Rainfall was also influential on herbaceous biomass, grass basal cover, abundance of herbaceous species, herbaceous species richness and diversity. Herbaceous biomass, abundance and diversity did not however vary with the age of enclosures, while herbaceous species richness appeared to decrease as the age of enclosures advanced. Grass basal cover initially decreased and later on increased with the age of enclosures, so that the older enclosures disclosed improvement of grass basal cover.
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