@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 {41358,
	title = {Salt supplementation of lactating cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {62},
	year = {2002},
	month = {Jan},
	pages = {236-239},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {<p>Increased intensification of dairy production has contributed to a decrease in the sodium (Na) status of soils throughout New Zealand. This decline has the potential to detrimentally affect animal health and production. A trial was established to determine whether milk production responses would be obtained to sodium supplementation of cows receiving about 0.1\% (0.06-0.14\%) Na in pasture. The cows were in mid-lactation and were randomly allocated to either the control group or a group receiving 14 g Na/cow/day. Supplementation with 14 g Na did not increase milk yield or affect milk composition and there was no interaction with stocking rate. Serum Ca, Mg, Na, and Cl concentration were not affected by treatment, but serum K concentration decreased with Na supplementation. In summary: 0.1\% Na in the diet is sufficient for mid-lactation dairy cows producing 10-12 litres milk/cow/day (0.9 kg milksolids/cow/day) and a milk production benefit will not be achieved through Na supplementation.</p>},
	issn = {1176-5283},
	author = {MacDonald KA and Lile JA and Lancaster JAS and Coulter M and O{\textquoteright}Connor MB}
}
@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}
}
