• Asian-Australasian Journal of Animal Sciences
• /
• v.14 no.10
• /
• pp.1383-1388
• /
• 2001

To explore the factors restricting animal performance in relation to sward structure under a strip-grazing system, measurements of sward factors, herbage intake and milk production at 3 levels of herbage allowance were made on perennial ryegrass (Latium perenne L.) sward for 3 experimental periods. About 29%, 36% and 52% of the biomass offered was removed by grazing in high $(42kg\;OM{\cdot}day^{-1}{\cdot}head^{-1})$, medium $(30kg\;OM{\cdot}day^{-1}{\cdot}head^{-1})$ and low $(18kg\;OM{\cdot}day^{-1}{\cdot}head^{-1})$ herbage allowance plots. Live leaf material was much more affected by grazing under different herbage allowance levels than dead material or leaf sheath. Grazing with a low herbage allowance decreased the proportion of live lamina by 93% and live lamina density by 96% before grazing. The density of dead material plus sheath was decreased by 17% after grazing at a low allowance, while it slightly increased or remained constant in the plots applied with high and medium allowances, respectively. The highly significant (p<0.01) correlations between herbage allowance and proportion (r=0.94) and density (r=0.91) of live lamina in residual sward after grazing were observed. Daily herbage intakes in the plots with high and medium levels of herbage allowance were not significantly different at $15.3kg\;OM{\cdot}head^{-1}$ in average, whereas with low level it decreased to $13.9kg\;OM{\cdot}head^{-1}$. Daily milk production was significantly (p<0.05) declined from $22.3kg{\cdot}head^{-1}$ (at high herbage allowance) to $19.7kg{\cdot}head^{-1}$ (at low herbage allowance). The data obtained clearly indicated that herbage intake and milk production were highly affected by the characteristics of residual sward, which were closely related to the level of herbage allowance.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.14 no.2
• /
• pp.99-109
• /
• 1994

The objective of this study was to examin some animal and sward factors which determine the daily herbage intake of high yielding dairy cows at different levels of daily herbage allowance. In this paper, the principal data relevent to the changes of sward characteristics after five days of daily strip grazing at three experimental peliods were summarized. The pregrazing herbage mass and extended height increased significantly from 5,047 kg OM/ha and 341 mm in period 1 to 6,877 kg OM/ha and 446 mm in period 3, while there was not a significant difference among herbage allowance treatments(average 6,068 kg OM/ha and 410 mm). The live leaf material in the residual herbage showed a greater reduction than the dead material and leaf sheath in terms of extended height, proportion and density. The decreased rates after grazing were higher when the level of herbage allowance decreased. Live leaves were vertically distributed to 50 cm of sward height before grazing. All live lamina distributed to 25 cm were grazed in the high and medium, and to 20 cm in the low levle of herbage allowance after grazing. The depth of grazing and grazed volume of forage material were heighly affected by the levels of hehage allowance. The biomass after grazing in the high, medium and low daily herbage allowance decreased 35, 36 and 52%, respectively, compared to before grazing level. The highly significant correlations between herbage allowance and extended tiller height(r=0.79), proportion of live lamina(r=0.94) and density of live lamina(r=O.91) after grazing, respectively, were observed.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.14 no.2
• /
• pp.110-119
• /
• 1994

Measurements of hehage intake and milk yield were made on high yielding dairy cows, which were strip-grazed on Loliurn perenne sward at three levels of herbage allowance in three experimental periods. The contents of nitrogen, chrome and ash in the faeces slightly decreased with the progress of growth period of experimental sward, and the decrease of herbage allowance. There were small difference in herbage digestibility among periods or the levels of herbage allowance with falling from 82.7% to 79.1% from period 1 to period 3 and from 81.6% to79.9% from high to low level of herbage allowance. Daily herbage intake was 15.8 and 15.9 kg OMIcow at the high and medium levels of hecbage aljowance, but reduced significantly to 14.6 kg OM/cow at the low level. Herbage intakes in three periods were shown a slight decrease. Daily milk yield in terms of 4% FCM significantly decreased from 23.6 to 20.6 kg/cow from period 1 to period 3. Milk yield at the high and medium levels of herbage allowance were 23.5 and 22.2 kg/cow at the low level of herbage allowance. The highly significant (P<0.01) correlations between the level of herbage allowance and herbage intake (r=0.88), or milk yield (r=0.81) were obtained.

• Journal of Environmental Impact Assessment
• /
• v.25 no.6
• /
• pp.369-383
• /
• 2016

A distributed watershed model CAMEL(Chemicals, Agricultural Management and Erosion Losses) was applied to a part of grazing grassland and vegetation buffer strip(VBS) located in Daegwanryeong, Korea. A set of scenario analyses was carried out for grassland and VBS with various combinations of VBS widths, soil textures and ground surface slopes. The simulation results indicate that annual direct runoff decreases with wider VBS and the removal efficiency of pollutants generally decrease with steeper slopes. The removal efficiency of sediment is not significantly different with VBS widths. For gentle and medium slopes($10^{\circ}$, $20^{\circ}$), the removal efficiency of TOC and TN is not significantly different with VBS widths. As for a steep slope($30^{\circ}$), however, the removal efficiency of TOC and TN increases with narrower VBS. The removal efficiency of TP is generally high except for medium and steep slope of sandy loam where the removal efficiency of TP increases with wider VBS. This result of TP is contrary to the results of TOC and TN due to the adsorption characteristics of phosphorus associated with fine sediment particles. It is expected that CAMEL can be used for evaluating the effectiveness of VBS to reduce non-point source pollution discharges.

• Journal of Korean Society of Forest Science
• /
• v.83 no.4
• /
• pp.545-555
• /
• 1994

The objective of the study was to provide the useful scientific data on the early rehabilitation of the legging road after timber harvesting in the forest area. This study was carried out at logging roads which were constructed during 1989 and 1994 in Mt. Baekwoon. The field survey was conducted in July, 1991. Judging from the analysis of soil bulk density, time required for recovery as the undisturbed forest soil condition was more than 10 years in the road which was left, and the regression equation is as follows, $$Y_1=1.4195-0.0744{\cdot}X(R^2=0.91)$$ $$Y_2=1.4673-0.0688{\cdot}X(R^2=0.73)$$ (X : elapsed year after road construction. $Y_1$, $Y_2$ : soil bulk density($g/cm^3$) at 0~7.5cm, and 7.5~15.0cm, respectively) Especially soil bulk density with buffer strip-woods was $0.890-0.903g/cm^3$, so it was 20% lower than that of logging road surface without buffer strip-woods. Among the 7 factors, location, sand content, and soil hardness had statistically significant effect on the soil bulk density in logging road surface. The pioneer species on logging road surface were Rhus cratargifolius, Prunus chinensis, and Lespedeza cyrtobotrya, etc. in woody species, and Pteridium aquilinum, Arundinella hirta, and Lysimachia clethroides, etc. in herb species. So, in process of year, average plant coverage were 70% on cutting and banking slope and 20% on logging road surface which elapsed 6 years after logging road construction. Through this research, buffer strip-woods must be remained for environmental conservation of forest conditions, and from the time to be closed the road, planting, seeding, and grazing works could be effective to the soil condition and vegetation recovery.

• Asian-Australasian Journal of Animal Sciences
• /
• v.17 no.11
• /
• pp.1615-1634
• /
• 2004

A review was undertaken to obtain information on the sustainability of pig free-range production systems including the management, performance and health of pigs in the system. Modern outdoor rearing systems requires simple portable and flexible housing with low cost fencing. Local pig breeds and outdoor-adapted breeds for certain environment are generally more suitable for free-range systems. Free-range farms should be located in a low rainfall area and paddocks should be relatively flat, with light topsoil overlying free-draining subsoil with the absence of sharp stones that can cause foot damage. Huts or shelters are crucial for protecting pigs from direct sun burn and heat stress, especially when shade from trees and other facilities is not available. Pigs commonly graze on strip pastures and are rotated between paddocks. The zones of thermal comfort for the sow and piglet differ markedly; between 12-22$^{\circ}C$ for the sow and 30-37$^{\circ}C$ for piglets. Offering wallows for free-range pigs meets their behavioural requirements, and also overcomes the effects of high ambient temperatures on feed intake. Pigs can increase their evaporative heat loss via an increase in the proportion of wet skin by using a wallow, or through water drips and spray. Mud from wallows can also coat the skin of pigs, preventing sunburn. Under grazing conditions, it is difficult to control the fibre intake of pigs although a high energy, low fibre diet can be used. In some countries outdoor sows are fitted with nose rings to prevent them from uprooting the grass. This reduces nutrient leaching of the land due to less rooting. In general, free-range pigs have a higher mortality compared to intensively housed pigs. Many factors can contribute to the death of the piglet including crushing, disease, heat stress and poor nutrition. With successful management, free-range pigs can have similar production to door pigs, although the growth rate of the litters is affected by season. Piglets grow quicker indoors during the cold season compared to outdoor systems. Pigs reared outdoors show calmer behaviour. Aggressive interactions during feeding are lower compared to indoor pigs while outdoor sows are more active than indoor sows. Outdoor pigs have a higher parasite burden, which increases the nutrient requirement for maintenance and reduces their feed utilization efficiency. Parasite infections in free-range pigs also risks the image of free-range pork as a clean and safe product. Diseases can be controlled to a certain degree by grazing management. Frequent rotation is required although most farmers are keeping their pigs for a longer period before rotating. The concept of using pasture species to minimise nematode infections in grazing pigs looks promising. Plants that can be grown locally and used as part of the normal feeding regime are most likely to be acceptable to farmers, particularly organic farmers. However, one of the key concerns from the public for free-range pig production system is the impact on the environment. In the past, the pigs were held in the same paddock at a high stocking rate, which resulted in damage to the vegetation, nutrient loading in the soil, nitrate leaching and gas emission. To avoid this, outdoor pigs should be integrated in the cropping pasture system, the stock should be mobile and stocking rate related to the amount of feed given to the animals.