@conference {41301,
	title = {Modelling dairy production in different regions of New Zealand},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {62},
	year = {2002},
	month = {Jan},
	pages = {7-11},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {A whole-farm model is being developed at Dexcel for researchers to simulate whole-farm system trials. Climate and management information is entered and the model utilises published sub-models for pasture growth and cow metabolism. The model predicts pasture and animal production. A test of the model{\textquoteright}s validity in different New Zealand regions using climate, land and management information particular to each region was undertaken. Regions selected were; Northland, Taranaki, Canterbury and Southland. The model predicted 92-129\% of per cow milk production and, while it followed observed pasture growth patterns, there was a tendency to over-predict annual growth (5-57\%) especially during spring-early summer and more notably in the Northland region. Annual pasture growth in Southland was consistently under-predicted by approximately 20\%. This variation is likely due in part to differences in pasture species, soil types and the method of collecting pasture data, influencing how well the model predicted growth. Using specific climate data and management information, the model successfully predicted dairy production in most regions of New Zealand. },
	issn = {1176-5283},
	author = {Lile JA and Bright KP and Palliser CC and Prewer WE and Wastney ME}
}
@conference {41329,
	title = {A whole-farm model applied to a dairy system},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {62},
	year = {2002},
	month = {Jan},
	pages = {120-123},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {The complex interactions between the biological, physical and management aspects of a farm can be represented mathematically using a computer model. A whole-farm model has been developed that links published sub-models for cow metabolism together with climate-driven pasture models, in a framework that allows for different management options. The model framework is written in VisualWorks Smalltalk, with submodels written in several programming languages linked to the framework using Microsoft COM protocol. Predictions of the whole-farm model have been compared with pasture and animal production data obtained from a dairy system trial at Dexcel in the Waikato. The system consisted of a herd of 19 cows, at a stocking rate of 3.2 cows/ha. The Whole Farm Model was used with Baldwin{\textquoteleft}s MOLLY cow model of metabolism, the McCall (1984) model of pasture growth, daily climate data and a management policy whereby daily activities on the farm were enacted by the framework. These activities included, for example, assignment of paddock for grazing, closure and cutting of paddocks for conservation, calving and drying off dates of each cow, and supplement feeding. At the end of each season the whole-farm model predicted 75\% of pasture growth compared with observed values assessed by visual assessment, 98\% of milk yield and 98\% of cow live weight. In addition to annual production by the whole farmlet, the whole-farm model can simulate individual animal and paddock production on a monthly and daily basis, so that patterns of change can be compared over the whole season. The whole-farm model is being used as a tool to design and analyse new dairy farm systems. },
	issn = {1176-5283},
	author = {Wastney ME and Palliser CC and Lile JA and MacDonald KA and Penno JW and Bright KP}
}
@conference {41294,
	title = {Adapting the MOLLY cow model to fit production data from New Zealand animals},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {61},
	year = {2001},
	month = {Jan},
	pages = {234-236},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {To assist in the planning of farm systems trials, Dexcel is developing a computer model of a pasture-based, rotationally grazed dairy system. The model includes published component models (or submodels) for cow metabolism and pasture growth, as well as climate and management information. It is currently being evaluated against production data obtained from the Whole Farm Efficiency Trial at Dexcel No 2 Dairy. The cow component being used is MOLLY, a dynamic model based on the underlying processes of ruminant digestion and metabolism. The parameters of MOLLY are based on animals that are efficient on high-energy diets. To make the computer model more accurate as a predictive tool for use in NZ, some of the parameters of the MOLLY submodel have been adjusted to fit the production data of NZ dairy cows on pasture, namely bodyweight changes and daily milk yields. MOLLY initially under-predicted by approximately 20\% the body weight of older cows (>4 years) for the pre-calving and early lactation periods. Resetting some parameters in MOLLY significantly improved the prediction of these bodyweight changes: to 2\% for the pre-calving period and 14\% for early lactation. Milk yield per cow was under-predicted in early lactation by MOLLY but the fit for each cow was improved by entering the observed peak daily milk value, although further fitting is required. We conclude that MOLLY is suitable for use as a research tool to gain insights into changes in metabolism of NZ cows grazed on pasture.},
	issn = {1176-5283},
	author = {Palliser CC and Bright KP and MacDonald KA and Penno JW and Wastney ME}
}
