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Full-Text Articles in Entire DC Network
Analytical Model For Reactive Solute Transport In A Channel-Matrix System, Wei Nana, Li Xu, Xu Guangquan, Zhang Haitao, Shao Zefan
Analytical Model For Reactive Solute Transport In A Channel-Matrix System, Wei Nana, Li Xu, Xu Guangquan, Zhang Haitao, Shao Zefan
Coal Geology & Exploration
Objective The accurate quantitative characterization of fractured media and the theoretical research on solute transport in fractured media have become the key to the prevention and control of groundwater contamination in fractured aquifers. Currently, fractured aquifers are generalized to horizontal fractures, ignoring the geometric characteristics of the open parts of fractures, called channels, and the impacts of matrix diffusion on solute transport. Methods A model for solute transport in a single channel-matrix system was established, obtaining the semi-analytical solutions using Laplace and numerical inverse transforms. The COMSOL Multiphysics software was employed to construct a numerical model for verification. Furthermore, the …
Landslide Sensitivity Assessment Of Coal Mining Subsidence Areas Based On Information Value - Machine Learning Coupling Models, Niu Chenhao, Jiao Runcheng, Han Jianfeng, Wang Shengyu, Guo Xuefei, Liu Chang, Han Yucheng, Song Guofeng
Landslide Sensitivity Assessment Of Coal Mining Subsidence Areas Based On Information Value - Machine Learning Coupling Models, Niu Chenhao, Jiao Runcheng, Han Jianfeng, Wang Shengyu, Guo Xuefei, Liu Chang, Han Yucheng, Song Guofeng
Coal Geology & Exploration
Objective Due to their special geological conditions and coal mining background, coal mining subsidence areas are prone to suffer from ground cracks and subsidence, which tend to further induce geological disasters such as landslides. This makes it extremely necessary to conduct landslide sensitivity assessment of these areas using appropriate influencing factors and training models. Methods This study investigated the Xishan coal mine area in Beijing as an example to conduct landslide sensitivity assessment of coal mining subsidence areas by coupling slope units with mathematical statistical and machine learning models. With 10 influencing factors, including topographic and geomorphic factors such as …
Research And Application Of The Seismic Exploration Technique Using Reflected In-Seam Waves In Identifying Folds And Faults In Coal Seams, Wu Guoqing
Coal Geology & Exploration
Background Accurately identifying subsurface anomalies is crucial to building a geological transparency system in the transformation to intelligent coal mines. The precise exploration of fold anomalies is a challenge of underground geophysical exploration technology, holding great significance for reducing excavation costs, mining difficulties, and safety risks. Objective and Methods Previous in-seam seismic explorations reveal that folds pose significant impacts on the propagation characteristics of in-seam waves. However, conventional inversion techniques of in-seam waves are difficult to distinguish folds from faults. This study constructed numerical models for faults and folds with similar geometric shapes and equal exploration distances. Specifically, the differences …
A Method For Reconstructing Consecutively Missing Seismic Data Based On Recurrent Feature Reasoning, Li Zijuan, Chang Guangyao, Jia Yongna
A Method For Reconstructing Consecutively Missing Seismic Data Based On Recurrent Feature Reasoning, Li Zijuan, Chang Guangyao, Jia Yongna
Coal Geology & Exploration
Objective Due to the constraints of natural environments like rapids, rifts, and high mountains, the acquired seismic data are often challenged by consecutive missing, affecting subsequent seismic data processing and geologic analysis. Hence, it is necessary to reconstruct the missing data through interpolation. Methods This study proposed a method for reconstructing consecutively missing seismic data based on recurrent feature reasoning. First, the missing seismic data undergo partial convolution operations, in which the weight of the convolution results is adaptively adjusted based on the proportion of valid feature map data in the receptive field, avoiding invalid convolution operations on consecutively missing …
A Neural Network-Based Method For Analyzing Diffracted Wave Velocity, Tao Junhong, Zhao Jingtao, Sheng Tongjie
A Neural Network-Based Method For Analyzing Diffracted Wave Velocity, Tao Junhong, Zhao Jingtao, Sheng Tongjie
Coal Geology & Exploration
Background In seismic imaging, accurate velocity models are crucial for characterizing subsurface structures in a fine-scale manner. Notably, in coal mining, small-scale geological structures like faults and collapse columns are closely associated with mining accidents. These structures typically occur as diffracted waves in seismograms.Objective and Methods To effectively image these small-scale geological bodies, fine-scale velocity modeling using diffracted wave information is particularly important. Hence, this study proposed a neural network-based method for analyzing diffracted-wave velocity. First, diffracted-wave velocity spectra were generated using the gathers of diffracted waves that were separated in the common virtual source domain. Second, a gamma-ray …
Key Technology And Practice Of Deep Borehole Pneumatic Directional Drilling In Broken-Soft Coal Seam In Yangquan Mining Area, Liu Fei, Li Quanxin, Fang Jun, Liu Jianlin, Yang Weifeng, Chu Zhiwei, Zhao Jianguo, Wang Siyi
Key Technology And Practice Of Deep Borehole Pneumatic Directional Drilling In Broken-Soft Coal Seam In Yangquan Mining Area, Liu Fei, Li Quanxin, Fang Jun, Liu Jianlin, Yang Weifeng, Chu Zhiwei, Zhao Jianguo, Wang Siyi
Coal Geology & Exploration
Objective In response to the need for precise, proactive, and regional management of gas in the broken-soft coal seam of the Yangquan Mining Area, a technical scheme utilizing pneumatic directional drilling for pre-drainage boreholes was proposed. Methods Based on the analysis of the technical challenges in pneumatic directional drilling, a series of technologies suitable for the broken-soft coal seam in the Yangquan Mining Area were developed. These include stable operation technology for pneumatic downhole motors, precise control technology for drilling boreholes, efficient deep-hole slag discharge technology, and pneumatic milling and salvage technology. The pneumatic directional drilling equipment was optimized, and …
Emergency Response And Critical Technologies For Large-Diameter Boreholes In Mine Rescue Through Surface Drilling, Ma Tan, Zhuge Lei, Zhao Weidong
Emergency Response And Critical Technologies For Large-Diameter Boreholes In Mine Rescue Through Surface Drilling, Ma Tan, Zhuge Lei, Zhao Weidong
Coal Geology & Exploration
Objective Large-diameter lifesaving holes have been successfully applied multiple times in mine rescue through surface drilling. However, they show limitations in emergency response like quick dispatch and cross-regional rescue, and their technological adaptability is insufficient to cope with complex strata. Methods From the perspective of overall emergency rescue, with rescue timeliness as an indicator, this study summarized the critical technologies like response capability enhancement and borehole-forming technology for complex strata. It constructed an emergency handling process for mine rescue through surface drilling, specified the improvements in contingency plan activation, response actions, and response speeds, and established the hierarchical cross-regional rescue …
Accumulation Patterns And Exploitation And Utilization Targets Of Geothermal Resources In The Coal-Bearing Area In North China, Pang Zhonghe, Duan Zhongfeng
Accumulation Patterns And Exploitation And Utilization Targets Of Geothermal Resources In The Coal-Bearing Area In North China, Pang Zhonghe, Duan Zhongfeng
Coal Geology & Exploration
Objective China is a major producer and consumer of coal resources in the world. The urgent need for the transition of the coal industry necessitates the investigation of both the origin and distribution patterns of geothermal resources in the coal-bearing areas of the country. The coal-bearing area in North China, with geothermal reserves accounting for 74.7% of the whole country, stands out as one of the areas with the most abundant geothermal resources nationally. This area encompasses four major coal-bearing basins: the Bohai Bay, Ordos, Qinshui, and Southern North China, with the lithospheric thermal state gradually weakening from east to …
Convection - Heat Transfer Coupling Mechanism For Closed-Loop Heat Extraction From Hydrothermal Resources Using Horizontal Wells, Gu Feng, Li Youwu, Zhang Yue, Gao Ying, Yang Peng, Wang Anran, Cui Jingyun
Convection - Heat Transfer Coupling Mechanism For Closed-Loop Heat Extraction From Hydrothermal Resources Using Horizontal Wells, Gu Feng, Li Youwu, Zhang Yue, Gao Ying, Yang Peng, Wang Anran, Cui Jingyun
Coal Geology & Exploration
Objective Closed-loop heat extraction technology, which extracts geothermal energy without draining geothermal water, has emerged as a research focus in geothermal energy exploitation. However, there is a lack of studies on the impacts of convection in reservoirs on heat transfer. Methods To improve single-well heat extraction, this study proposed a technology of closed-loop heat extraction from hydrothermal reservoirs using horizontal wells. This technology aims to increase the contact area between wellbores and reservoirs while fully leveraging the convection in reservoirs. A flow and heat transfer model characterized by the coupling of horizontal wells, circulating water and reservoirs was established to …
Development Of Intensive Grassland Systems: From Science To Practice, D G. Mccall, G W. Sheath
Development Of Intensive Grassland Systems: From Science To Practice, D G. Mccall, G W. Sheath
IGC Proceedings (1977-2023)
Level of nnimal production from grassland is determined by the amount of pasture grown, pasture utilisation and animal conversion efficiency. The key components affecting production are pasture growth and animal conversion efficiency. These arc mainly influenced by environment, genetics and through inputs to maintain soil fertility or animal health. Systems development aims to link pasture growth and animal conversion through efficient strategies for pasture utilisation. The means of influencing pasture utilisation is through adjustments to animal feed demand, feed supply or grazing management. Stock policies that adjust the pattern and level of feed demand are of greatest significance in developing …
The Ecology Of Grazing Management, R K. Heitschmidt
The Ecology Of Grazing Management, R K. Heitschmidt
IGC Proceedings (1977-2023)
The broad objective of this paper is to review the fundamental principles of grazing management as a means of assessing the inherent value of intensive and extensive grazing systems. Conceptual analyses of intensive and extensive grazing systems reveal that the fundamental differences between intensive and extensive grazing systems are related to differences in non-grazing rather than grazing tactics. Intensive grazing systems employ a wide array of non-grazing tactics in an attempt to overcome the inherent ecological constraints that limit secondary (i.e., livestock) productivity in extensively grazed systems. Moreover, analyses of the ecological or true efficiency of various agricultural production systems …
An Analysis Of The Dry Matter Intake And Rate Of Live-Weight Gain Of Growing Cattle Fed Forage Diets, J G. Buchanan-Smith
An Analysis Of The Dry Matter Intake And Rate Of Live-Weight Gain Of Growing Cattle Fed Forage Diets, J G. Buchanan-Smith
IGC Proceedings (1977-2023)
The intake and rate of live-weight gain of 500 growing steer calves fed experimental forage diets in 7 trials were compared with corresponding values predicted using the Na1ional Research Council (NRC) model (1984). The cattle were predominantly weaned calves and most of the experimental diets were alfalfa-grass silage, either unsupplemented or supplemented with various protein sources, but some diets were based on maize silage or maize grain. The feeding period evaluated in this study ranged between the first 84 and 147 days when protein accretion rate in the cattle would be relatively high. Dry matter intakes were overpredicted by the …
Management Of Extensive Pastures For Dairy Youngstock, G.E J. Fisher, D J. Roberts
Management Of Extensive Pastures For Dairy Youngstock, G.E J. Fisher, D J. Roberts
IGC Proceedings (1977-2023)
The effects of low input systems on the ground cover of species and yield and chemical composition of herbage cul from extensive lowland swards was studied over 3 years. The live-weight gain of dairy heifer replacements offered grazed or conserved forage from these pastures was also assessed, The swards were sown with a mixture of grasses, wildflowers and herbs and received no inorganic fertilizers, Applications of slurry in January and February increased herbage yield by 43%, but reduced the cover of flowers and herbs. Using a 2- cut conservation system improved yield of metabolisable energy/ha in herbage by 33%, and …
Intensive Grazing Of Alfalfa By Beef Steers, M Rasnake, W R. Burris, G D. Lacefield, J Randolph, N Gay, L Davis
Intensive Grazing Of Alfalfa By Beef Steers, M Rasnake, W R. Burris, G D. Lacefield, J Randolph, N Gay, L Davis
IGC Proceedings (1977-2023)
In the temperate region of North America, high temperature and moisture deficit cause low forage growth during the summer of most years, making it difficult to grow beef (Bos taurus), calves through summer grazing. Alfalfa (Medicago sativa), offers some potential to provide high dry matter production during summer if an effective system of grazing can be developed. The objective of this study was to test a system of intensive grazing of beef steers on alfalfa to maximise live-weight gains/ha and maintain plant population. Alfalfa was no-till seeded into a 6.5 ha field in autumn 1988 after …
Variance Across Years In Growth Of Cattle On Annual Pastures In A Mediterranean Climate, K D. Greathead, J Zorrilla Rios
Variance Across Years In Growth Of Cattle On Annual Pastures In A Mediterranean Climate, K D. Greathead, J Zorrilla Rios
IGC Proceedings (1977-2023)
Annual pastures were continuously grazed by new drafts of yearling cattle each year for 4 years at 2 sites. The variability of weight gained across years at any date was not different between sites. The level of rainfall in April, but strongly influenced weight gained by the cattle in any year. Variances in weight change were small up to April, they increased rapidly from April to late July and were not different after July (P<0.05).
Modification Of The Botanical Composition Of Perennial And Annual Temperate Pastures By Strategic Grazing Practices, D R. Kemp, P M. Dowling
Modification Of The Botanical Composition Of Perennial And Annual Temperate Pastures By Strategic Grazing Practices, D R. Kemp, P M. Dowling
IGC Proceedings (1977-2023)
Where livestock production depends upon pastures, management is more difficult in environments where rainfall varies considerably from season to season and year to year. Flexible grazing practices are needed to optimise species composition and pasture productivity. Results presented in this paper show that pasture composition can be improved within climatic constraints, by grazing practices within seasons, In temperate annual pastures, long rests in winter (similar to a long rotation during that season) increased annual legume content in early spring from 20 to 50%. Annual grass content was unchanged. In perennial (phalaris) pastures, the dominant legume can change over years from …
Development Of Grass-Clover Pasture Systems For Autumn-Calving Beef Cows. I. Forage Production, G D. Mooso, D G. Morrison, J I. Feazel, D R. Morris
Development Of Grass-Clover Pasture Systems For Autumn-Calving Beef Cows. I. Forage Production, G D. Mooso, D G. Morrison, J I. Feazel, D R. Morris
IGC Proceedings (1977-2023)
Four 8-ha areas of bermudagrass-based (Cynodon dactylon (L.) Pers.) grazing systems were sodseeded and received annual N fertiliser as follows: I) clover (Trifolium sp.)+81 kg Nnm, 2) annual ryegrass (Lolium multiflorum Lam)+clover +81 kg N/ha, 3) ryegrass+clover+l39 kg N/ ha, and 4) ryegrass+139 kg N/ha. Monthly forage accumulation was estimated for 3 years by clipping samples from 2 exclosures/pasture. Environmental conditions had a significant effect on total annual forage dry matter (DM) production. Systems 3 and 4 produced more (P<0.05) forage DM than Systems 1 and 2 (11.0 v. 10,3 Mg/ha). System I produced more (P<0.l) forage DM than 2 (10.6 ll, 9.8 Mg/ha). Systems 3 and 4 were similar, producing I 1.0 Mg/ha. Monthly forage accumulation was lowest in winter (December to February) and highest in spring and summer (March to August). The results of this study demonstrate that at a low N level, there was no benefii from including ryegrass in the system and al a moderate N level, there was no benefit from including clover.
Development Of Grass-Clover Grazing Systems For Autumn-Calving Beef Cows. Ii. Cow-Calf Production And Economic Analysis, D G. Morrison, J I. Feazel, G D. Mooso
Development Of Grass-Clover Grazing Systems For Autumn-Calving Beef Cows. Ii. Cow-Calf Production And Economic Analysis, D G. Morrison, J I. Feazel, G D. Mooso
IGC Proceedings (1977-2023)
Four 8-ha areas of bermudagrass-based (Cynodon dactylon (L.) Pers.) grazing systems were sod seeded and received annual N fertiliser as follows: I) clover (Trifolium sp.)+81 kg/ha, 2) annual rye grass (Lolium multiflorum Lsm.)+clover +81 kg/ha, 3) ryegrass+clover+139 kg/ha, and 4) ryegrass+l39 kg/ha. Each system was stocked year-round with 20 (2,5/lla) cows each with crossbred suckling calf. Cow and calf performance data for 3 of 4 years are included. Year affected (P<0.01) cow and calf live weight, Cows in System 2 were 25-50 kg lower in live weight in autumn and winter than cows in other systems. From February to July, cow daily live-weight gains were 0.11 kg higher (P<0.01) for Systems 2 and 3, Cow live weight in July was affected by N level (Systems 1,2<3,4; P<0,01), Year by system interactions (P<0.05) occurred for cow live weight in February, April and July because of live weight increasing over years in Systems 3 and 4 but not in Systems 1 and 2. Calf daily live-weight gain February to weaning (July) was higher (P<0.01) for System 2 v. 1 (0.06 kg), Syuem 3 v. 4 (0.07 kg), and Systems 3, 4 v. 1, 2 (0.07 kg), Estimated net returns favoured Systems 3 and 4 over Systems 1 and 2.
Improved Grazing Systems For Lamb Production On Appalachian Hill Farms, R L. Reid, J R. Puoli, G A. Jung, D P. Belesky
Improved Grazing Systems For Lamb Production On Appalachian Hill Farms, R L. Reid, J R. Puoli, G A. Jung, D P. Belesky
IGC Proceedings (1977-2023)
Improved grazing methods were tested to increase lamb outputs per ha from Appalachian hill farms. Components of a grazing system were cool-season grass [tall fescue (Festuca arundinacea Schreb.), Grasslands Matua prairie grass (Brom us willdenowii Kunth)J or grasslegume [Kentucky bluegrass (Poa pratensis L.)•red clover (Trifolium pralense L.)] pastures in spring and early autumn, warm-season grass [switchgrass (Panicum virgatum L.)] in summer, and brassicas in late autumn and early winter. Matua was highly productive in cool weather but was subject to fungal infection and grazing ewes had low Mg status in spring. Rotationally grazed switchgrass maintained high numbers …
Use Of Brassica Forage Crops To Extend The Grazing Season In The North-East Usa, G A. Jung, H W. Harpster, M G. Lambert, K T. Leath, R A. Byers
Use Of Brassica Forage Crops To Extend The Grazing Season In The North-East Usa, G A. Jung, H W. Harpster, M G. Lambert, K T. Leath, R A. Byers
IGC Proceedings (1977-2023)
Forage turnip (Brassica rapa L,) can be made available for animal utilisation in late summer or In late autumn-early winter, when coolseason grass pastures have a low animal carrying capacity. field trials were conducted to identify and quantify factors that influence turnip yield in December or January and to determine whether these factors affect turnip cultivars similarly. Different levels of production in late autumn-winter were attributed to summer drought, foliar diseases, freezing temperatures and rate of leaf senescence. In all instances, the effects of these factors varied with turnip cultivar. However, cultivar ranking generally was the same whether mean …
Interactions Of Rotational And Continuous Grazing With Stocking Rate On Warm And Cool-Season Pastures, David I. Bransby
Interactions Of Rotational And Continuous Grazing With Stocking Rate On Warm And Cool-Season Pastures, David I. Bransby
IGC Proceedings (1977-2023)
With more intense commercialisation of electric fencing many production and economic advantages have been claimed for rotational grazing compared with continuous grazing. However, very little research data are available from the south-eastern USA to verify these claims, Therefore, the objective of this study was to evaluate animal performance under conditions of continuous and IO-paddock rotational grazing on cool- and warm-season pastures commonly used in this region. Three 2-year grazing experiments were conducted, one each on a mixed rye-annual ryegrass (Secale cereale-Lolium multiflorum) pasture, Coastal bermudagrass ( Cynodon hybrid) and Pensacola bahiagrass (Paspalum notatum). In each experiment continuous …
Integrating Pasture Technology Research With Farm Management, R T. Cowan, T M. Davison, K F. Lowe, G K. Reason, G D. Chopping
Integrating Pasture Technology Research With Farm Management, R T. Cowan, T M. Davison, K F. Lowe, G K. Reason, G D. Chopping
IGC Proceedings (1977-2023)
An applied research programme which involved farmers in a continuum of trials measuring pasture, soil and milk responses to the application of nitrogen fertiliser to tropical grasses is described. Pasture responses were consistent across farms, grass species and, within limits, rainfall zones and soil types. Soil pH declined by 0.03 lo 0.2 units each year. Additional milk production ranged from 4 to 14 I/kg nitrogen, the response being greater at lower levels of application. Results from farm and research station experiments were consistent. The high adoption rate, reaching 68% in 6 years, was ' attributed to the integration of farm …
Hay Supplementation And Stocking Rate Effects On Live Weight Gain Of Steers Grazing Rye And Ryegrass, Susan E. Sladden, David I. Bransby
Hay Supplementation And Stocking Rate Effects On Live Weight Gain Of Steers Grazing Rye And Ryegrass, Susan E. Sladden, David I. Bransby
IGC Proceedings (1977-2023)
The objective of this study was to evaluate continuous ad lib. supplementation of hay as a means of compensating for the uneven growth distribution of rye (Secale cereale) and ryegrass pastures (Lolium multiflorum) grazed by steers in the south-eastern USA. Pastures were continuously grazed by 230 to 270 kg steers at stocking rates of 2.5, 3.1, 4.1 and 4.9 head/ha with and without hay supplementation for 2 grazing seasons. On average, average daily live-weight gain (ADO) at the highest stocking rate (4.9 steers/ha) was 0.47 kg higher (P<0.01) when hay supplement was provided. Although not significant, in both years ADO tended to be higher for h_ay supplementation even at low stocking rates .
Improved Pasture Species, Fertilizer And Pasture Use To Increase The Productivity Of Wool Sheep In South-Western Victoria, G R. Saul, D Jowett, T Morgan, P Noble, D Borg
Improved Pasture Species, Fertilizer And Pasture Use To Increase The Productivity Of Wool Sheep In South-Western Victoria, G R. Saul, D Jowett, T Morgan, P Noble, D Borg
IGC Proceedings (1977-2023)
Pastures were upgraded by sowing perennial grasses and subterranean clover (Trifolium subterranum) and applying fertiliser to paddocks on S farms in the wool sheep region of south-western Victoria. Upgraded pastures were stocked at higher rates to ensure utilisation of feed grown. In the third year after sowing, wool production was increased by 56% (35 v. SS kg/ha), and ewe live weights by 4% (49.4 v. 51.4 kg) from upgraded pastures compared with untreated pastures. The results demonstrate the considerable potential to increase output from sheep farms in the region by upgrading pastures. Poor persistence of sown perennial grasses may …
System Research: Preliminary Results From A Farmlet Comparison Between A Biological And Conventional Sheep And Beef System, A D. Mackay, D I. Gray, I M. Brookes, P J. Budding, B Devantier
System Research: Preliminary Results From A Farmlet Comparison Between A Biological And Conventional Sheep And Beef System, A D. Mackay, D I. Gray, I M. Brookes, P J. Budding, B Devantier
IGC Proceedings (1977-2023)
Initial findings of a farm let study comparing biological (agrochemical free) and conventional sheep and beef production are presented and discussed. Little difference was found in sheep production between the two systems in 1991-92, despite large differences in the level of internal parasitism, particularly in young sheep. In contrast! growth rates of rising 1 year steers and heifers on the conventional unit were superior to those of the biological farmlet throughout spring and summer of the first year. While a reduction in the use of anthelmintic drench would have little impact on the productivity of sheep systems, the productivity of …
A Management System For The Planning, Implementation, And Monitoring And Evaluation Of Farmlet Trials, D I. Gray, A D. Mackay, P J. Budding, I M. Brookes
A Management System For The Planning, Implementation, And Monitoring And Evaluation Of Farmlet Trials, D I. Gray, A D. Mackay, P J. Budding, I M. Brookes
IGC Proceedings (1977-2023)
A management system used to operate the farmlet component of a farm· systems research programme investigating biological sheep and beef production is described and the advantages and disadvantages of this approach are discussed,
Economics Of Milk Production From Perennial Ryegrass Cultivars With Different Seasonal Growth Patterns, I M. Brookes, A F. Mcrae, D I. Gray, N Cameron
Economics Of Milk Production From Perennial Ryegrass Cultivars With Different Seasonal Growth Patterns, I M. Brookes, A F. Mcrae, D I. Gray, N Cameron
IGC Proceedings (1977-2023)
Cutting trials at 4 sites throughout New Zealand over 2 years with perennial ryegrass (Lolium perenne L) cultivars showed that Bmbassy (B) produeed similar annual dry matter (DM) yields to Supernui (S) and Yatsyn (Y). However, B grew 10% more DM in January-August, but 5% less DM in September-December. The economic value of these diffecent patterns of growth for milk production was assessed using a computer model. The model constrained pasture covers within specified limits by removing excess feed for conservation and adding additional feed as supplements during periods of deficit. Stocking rates needed to maintain the system in equilibrium …
Effect Of Sward Surgace Height On Herbage Intake, Grazing Behavior And Productivity Of Ewes Lambing In June (Winter) Or August (Spring), S T. Morris, W J. Parker, H T. Blair, S N. Mccutcheon
Effect Of Sward Surgace Height On Herbage Intake, Grazing Behavior And Productivity Of Ewes Lambing In June (Winter) Or August (Spring), S T. Morris, W J. Parker, H T. Blair, S N. Mccutcheon
IGC Proceedings (1977-2023)
Herbage organic mailer intakes (OMI) were measured, using chromic oxide capsules, during the last 4 weeks of pregnancy in ewes due to lamb in June (winter) or August (spring). OM! (averaged across lambing date groups) were 1.4±0.1, 1.8±0.1, 1.8±0.1 and 2.0±0.1 kg OM/ewe/day (mcan±s.e.m. P<0.05) in ewes maintained at sward surface heights (SSH) of 20, 40, 60 and 80 mm respectively. There were no differences in OM! between June- and August-lambing ewes from pregnancy day 122 to day 125 (Pl22-Pl25), but between Pl35 and 139 June-lambing ewes had lower OMI than August-lambing ewes (1.5±0.1 v. 1.7±0.1 kg OM/ewe/day (P<0.05)). Live-weight gain of ewes was lowest on the 20 mm sward and highest on the 80 mm sward (157±34 v. 315±31 g/day, P<0.05). SSH had no effect on lamb birth weight. Preliminary data presented here suggest that, at the same SSH, June-lambing pregnant ewes can achieve OMI similar to those of August-Jambers.
Seasonal Herbage Intake Of Once-Bred Heifers, A A. Khadem, S T. Morris, W J. Parker, R W. Purchas, S N. Mccutcheon
Seasonal Herbage Intake Of Once-Bred Heifers, A A. Khadem, S T. Morris, W J. Parker, R W. Purchas, S N. Mccutcheon
IGC Proceedings (1977-2023)
Once-bred heifer (ODH) beef production systems, which are new to New Zealand, involve mating heifers at 15 months of age to cnlve as 2-year-olds and then slaughtering the heifers (at less than 30 months of age) as prime beef. Never-pregnant, pregnant and lactating Hereford x Friesian heifers were used in 4 experiments. There were no significant differences between pregnant (days 260-270 of pregnancy) and never-pregnant heifers in their herbage organic matter intake (OMI), ingestive behaviour or daily live-weight gain (LWG) when a restricted pasture allowance of 7 kg DM/head/day was offered. Heifers at days 50-60 of lactation and never-pregnant heifers …
A Response Of Angora-Type Goats To Increases Of Legume And Chicory Content In Mixed Pastures, D R. Stevens, M J. Casey, G S. Baxter, K B. Miller
A Response Of Angora-Type Goats To Increases Of Legume And Chicory Content In Mixed Pastures, D R. Stevens, M J. Casey, G S. Baxter, K B. Miller
IGC Proceedings (1977-2023)
Live-weight gain of angora-type year-old wethcr goats in the spring and summer of 2 years was compared with the total legume and chicory content of 9 different grass, legume, chicory ( Cichorium intybus) mixtures. These pastures were grown in a cool moist temperate climate on fertile silt loam soil. The goats were held on a self• contained rotationally grazed system on each pasture type, leaving a post-grazing residual height of 10 cm. The live-weight gain of the goats responded quadratically to increasing legume and chicory content in both spring and summer. Live-weight gain was optimised when approximately 40% of …