@conference {40639,
	title = {Use of a grazing model to study management and risk},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {54},
	year = {1994},
	month = {Jan},
	pages = {377-382},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {A model which simulates the operation of a pastoral farm was used to  
perform a {\textquoteright}computer experiment{\textquoteright} on an irrigated Canterbury property.  The  
effects of seven stocking rates, ranging from 9 to 21 stock units per hectare  
(SU/ha), on the performance and profitability of a self-replacing sheep flock  
were tested.  The same experiment was performed under two scenarios  
(deterministic and stochastic).  The deterministic scenario was equivalent to a  
controlled experiment, where the same pasture growth pattern occurred every  
year, reflecting average production in the area.  The stochastic scenario  
introduced random variation between years, reflecting the area{\textquoteright}s natural  
variability in pasture production. 
 
In the deterministic experiment, maximum meat production (258 kg/ha) was  
obtained at 21 SU/ha, while maximum wool production (89 kg/ha) occurred at  
19 SU/ha.  Lambing percentage reached a maximum (135\%) at 13 SU/ha.   
Under the assumed set of costs and prices maximum gross margin was obtained  
by maintaining a stocking rate of 21 SU/ha.  Introducing stochastic behaviour  
caused maximum production levels to decrease and gross margin was  
maximised at a lower stocking rate (17 SU/ha), reflecting the costs associated  
with weather variability.  Results were used to examine the trade-off between  
profits and risk in stocking rate decisions. },
	issn = {1176-5283},
	author = {Cacho OJ and Bywater AC}
}
