@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}
}
@conference {40644,
	title = {Use of simulation models in research},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {54},
	year = {1994},
	month = {Jan},
	pages = {403-412},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Simulation models are increasingly used in animal research both  
independently and in conjunction with experimental research.  This paper  
describes the potential uses of models within research programmes and  
categorises research into three main types, component research, systems  
research and management research.  The contribution of models to component  
research into lactation, growth, wool growth and feed intake is reviewed.   
It is suggested that the concepts and data concerning interactions within the  
pastoral livestock system are now sufficient for a comprehensive modelling  
analysis of this system to be undertaken.  The potential use of production  
systems models in management research is illustrated through the analysis of  
farm management factors affecting production and returns from fine wool using  
a pastoral sheep farm simulation model. 
 },
	issn = {1176-5283},
	author = {Bywater AC and Cacho OJ}
}
