科研之友
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摘要
Many dairy farms in the Manawatu and Southland regions of New Zealand are situated on poorly drained soils that are prone to treading damage - an undesirable occurrence on grazed pastures during the wetter months of the year. Standing cows on a loafing pad (stand-off) during wet conditions can reduce damage, but will incur costs. The objective of this study was to evaluate the trade-offs of grazing duration (from 0 to 10 hours grazing/day for lactating cows) versus pasture damage (wastage), feed and stand-off expenses, and farm operating profit. A simulated farm from each region was used in a farm systems model. This model simulates pasture-cow-management interactions, with site-specific climate data as input for the soil-pasture sub-models. Days to recover previous yield potential for damaged paddocks can vary widely. A sensitivity analysis (40 to 200 days to recover) was conducted to evaluate the effect of this parameter on results. Full protection when there is risk of damage (0 grazing hours/day) appeared to be less profitable compared with some level of grazing, because advantages of reduced damage were outweighed by disadvantages of managing infrequently grazed pastures. The difference in operating profit between full protection and some level of grazing became less as the recovery time increased, but for both regions, grazing durations of 6-8 hours/day when risk of damage is present appeared to be a sensible option irrespective of recovery time.
- 出版日期2013-9-1
