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Viability of smallholder dairying in Wedza, Zimbabwe 总被引：1，自引：1，他引：0
Plaxedis Ivy Zvinorova Tinyiko Edward Halimani Renneth T. Mano Nobbert Takarwirwa Ngongoni 《Tropical animal health and production》2013,45(4):1007-1015
Viability differences in smallholder dairy farming are a result of differences in access to markets and services. It is hypothesized that innovations that improve productivity and market linkages also improve returns and viability. The viability of smallholder dairying in Wedza was characterised by interviewing 52 households using semi-structured questionnaires. Information on demographics, production, marketing, livestock numbers, assets and constraints was obtained. Farmers were resource-constrained with differences in access to resources. The highly resourced farmers had higher milk output and numbers of livestock. Almost 40 % of the households were female-headed, and these dominated the poor category. Household sizes ranged from 4 to 13 persons. Milk off-take was low (3.7?±?0.53 l/cow/day), due to various constraints. Only rich farmers had viable enterprises in purely financial terms. Per litre cost of milk was more than selling price (US$0.96) for most farmers except the relatively rich. Operating ratios were 1.7, 0.6, 1.4 and 1.1 for the poor, rich, sub-centre and milk collection centre farmers, respectively. This means incomes from the dairy activities did not cover costs. Sensitivity analysis indicated that increases in total variable costs and labour reduced returns. Milk production and viability were influenced by access to resources and markets. 相似文献
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Ivy Drafor 《Journal Of Agricultural & Food Information》2013,14(4):230-245
Radio is an important medium for conveying agricultural information among farmers in remote areas. This study assessed the channels of information available to four farming communities in Ghana and analyzed stakeholder networks in information generation and dissemination. About 50% of the farmers expressed a willingness to pay for relevant information, though they think general farm information should be free to all. Farmers ranked other farmers as their most important and least expensive sources. Farm-level decision-making requires timely, adequate, and appropriate information, which can bring smallholder farmers closer to their world competitors through increased production, effective marketing, and increased incomes. 相似文献
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Pituitary porcine growth hormone (pGH) and a recombinant pGH analog stimulate pig growth performance in a similar manner 总被引：5，自引：0，他引：5
This study was conducted to establish the extent to which different doses of pituitary porcine growth hormone (ppGH) increase pig growth performance. Pigs were treated daily for 11 wk with 0, 35 or 70 micrograms ppGH/kg BW. In addition, these effects were compared with those produced by treating pigs with 0, 35, 70 or 140 micrograms.kg BW-1.d-1 of a recombinantly derived analog of porcine growth hormone (rpGH). This analog lacks the first seven amino acids at the NH2 terminus. Growth rate was increased similarly by ppGH and rpGH (the maximal increase was 19%). Feed efficiency was improved by ppGH and rpGH (the maximal response was 25%). This improvement in feed efficiency was associated with a decrease in feed intake (17% with the largest dose of rpGH). Both ppGH and rpGH decreased adipose tissue growth and increased muscle mass. Carcass lipid was decreased by 68% in pigs treated with the largest dose of rpGH. The recombinant pGH analog appeared to be less potent than ppGH in decreasing adipose tissue growth rate. All other parameters measured, however, indicated that rpGH mimicked the biological effects of ppGH (including binding to pig liver membranes and induction of insulin-like growth factor I production). Sensory panel evaluations indicated that neither ppGH nor rpGH affected pork palatability. Larger doses of pGH (greater than 70 micrograms/kg BW) adversely affected pig mobility. This impairment in mobility appears to be due to osteochondrosis. Our findings establish that the rpGH analog is equipotent to ppGH in stimulating growth performance and that pigs can be treated without any significant adverse effects when they are treated with less than 70 micrograms of pGH.kg BW-1.d-1. 相似文献
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Ivy Stone Jean-Pierre Ouellet Luc Sirois Marie-Josée Arseneau Martin-Hugues St-Laurent 《Forest Ecology and Management》2008
We investigated immediate, medium and long-term effects of logging on arboreal lichen biomass in old-growth balsam fir forests (Abiesbalsamea (L.) Mill.) in the highlands of Québec's Gaspé Peninsula using three complementary approaches. Firstly, we estimated the immediate loss of lichen biomass following logging and the annual lichen litterfall from remnant trees over 2 post-logging years. Treatments included selection cutting at three intensities (25, 30, 35%), diameter-limit cutting and cutting with protection of regeneration and soils (CPRS). Among studied treatments, we found that CPRS and diameter-limit cutting removed almost all the standing lichen biomass, while selection and partial cut allowed an immediate retention of ∼40–60% of the initial lichen biomass. Our results also suggested that the impact of logging on lichen litterfall rates were higher in silvicultural treatments (3–8.5%) compared to controls (1–2%); litterfall rates did not differ after 1 or 2 years post-treatment. Secondly, we evaluated medium-term effects by comparing pre-harvest fruticose lichen biomass data with data collected at the same site 4 years after experimental thinning operations. Mean fruticose lichen biomass did not change 4 years post-harvest. However, Bryoria spp. biomass did increase relative to Alectoriasarmentosa while Usnea spp. remained unchanged. Finally, the long-term logging effects were assessed by evaluating fruticose lichen biomass along a forest chronosequence in stands aged 30, 50, 70 and 90 years. Lichen biomass increased as a function of time for all genera, especially Alectoria. Logging activities result in direct losses of lichen biomass, but careful selection cutting that retains large lichen bearing trees and maintains post-harvest conditions not detrimental to lichen growth, particularly for Bryoria spp., can ensure a substantial biomass of lichens post-harvest. Such measures may ultimately contribute to maintaining woodland caribou herds that rely on arboreal lichens. 相似文献
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Juvenile Epinephelus coioides were exposed to three nominal concentrations (8, 32, 128 mg wet sediments L?1) of suspended sediments (SS) from Port Shelter (PS), Mirs Bay (MB) and Victoria Harbour (VH) for 10 and 30 days using semi‐static system. Sediments from VH contained higher concentrations of Cu and polycyclic aromatic hydrocarbons (PAHs) than sediments from PS and MB. Gill damages including lamellar blood sinus dilation and vascular congestion were prevalent after just 10 days of exposure to SS. Fish exposed to SS at the highest concentration of 128 mg L?1 showed higher incidence of lamellar aneurism. Hyperplasia in the base of lamellae was recorded in fish that had been exposed to contaminated SS from VH. Significant increases in the density of chloride cells and mucous cells were found on the gills of fish that had been exposed to 128 mg L?1 of SS from PS. Clogging of gills by SS produced hypoxic‐like responses in fish. Polluted sediments from VH produced addictive or synergistic effects between SS and chemical contaminants on fish. 相似文献