@conference {41738,
	title = {Evaluation of a model that estimates insulin sensitivity in dairy cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {67},
	year = {2007},
	month = {Jan},
	pages = {261-265},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Wanaka},
	abstract = {Glucose challenge data was used to model parametersdescribing the dynamics of the glucose-insulin system such as glucose effectiveness (SG), acute insulin response to glucose (AIRg) and insulin sensitivity (SI) in dairy cows. The relationship of these parameterswith post-partum anovulatory interval (PPAI) was also determined. Twenty-five HF cows of New Zealand (NZ; n=13) and Overseas (OS; n=12) origin, were fed either pasture (n=12) or a total mixed ration (TMR; n=13) in a 2x2 factorial design. At two weeks postpartum, they were challenged intravenously with 300 mg of glucose/kg live weight. There was no effect of diet on SG(P=0.302), SI(P=0.17) or AIRg(P=0.093) despite TMR cows of both genotypes having higher values. There was no effect of genotype on SG(P=0.234), SI(P=0.742) or AIRg(P=0.385). Correlations of these parameters with PPAI were not statistically significant: SI  (r 2=0.087, P=0.310), SG(r 2 = 0.001,  P=0.962) and AIRg(r 2 =0.036, P=0.320). Use of this model demonstrated that insulin response parameters  were not closely associated with PPAI.},
	issn = {1176-5283},
	author = {Back PJ and Boston RC and Palliser CC and Kolver ES and Chagas LM}
}
@conference {41621,
	title = {Predicting cow production based on an estimate of animal genotype within a whole farm model},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {66},
	year = {2006},
	month = {Jan},
	pages = {93-97},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Napier},
	abstract = {Body condition score (BCS) has been proposed for inclusion in the New Zealand national dairy index, Breeding Worth (BW), to account for replenishment of body tissue. Currently, the breeding objectives model positively accounts for body tissue mobilisation (through extra yield), but not the negative cost of replenishing body tissue. Two methods have been proposed: 1) Including BCS directly into BW by calculating and assigning an economic value to BCS and 2) Adjusting liveweight Breeding Values (BVs) for BCS, which would mean that liveweight BVs would beexpressed at a constant BCS (indirect method). Energy equations were used to calculate the direct economic value for BCS and included a sensitivity analysis. With an economic weight of $25, the percentage emphasis of BCS in BW would be 3.4\%. Including BCS in BW, either directly or indirectly, had little impact on sire rankings (rank correlations with and without BCS within breed were >0.99) and would only have a small impact on the economic response of BW ($0.02 net /cow/annum) and the improvement in BCS(0.006 BCS units/cow/annum). It is concluded that there would be little benefit to including BCS as an independent trait in BW. Body condition score is already included as a predictor in the genetic evaluation of fertility and breeding values for BCS will be estimated routinely from the fertility model.},
	issn = {1176-5283},
	author = {Beukes PC and Palliser CC and Lancaster J and Leydon-Davis C and Levy G and Folkers C and Macdonald K and Thorrold BS and Montgomerie B and Wastney M}
}
@conference {41610,
	title = {Using a whole farm model to explore options for feed grown on-farm to achieve 1750 kg milksolids per hectare in the Waikato},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {66},
	year = {2006},
	month = {Jan},
	pages = {29-34},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Napier},
	abstract = {Dexcel{\textquoteleft}s Whole Farm Model (WFM) is a computer model of a dairy farm that simulates individual cows and paddocks, with pasture growth driven by observed climate data and with management policies guiding decisions on a daily basis. The aim of the study was to design a farm system to produce 1750 kg milksolids (MS)/ha/yr from feed grown on-farm. An average predicted pasture growth curve was derived by initialising the WFM for a typical all-pasture Waikato farm (3 cows/ha) with "best practice" management policies and running the simulation for 29 years of Ruakura climate data. The model was then used with this average growth curve to design the high producing system. Pasture growth alone (17.3 t DM/ha) did not fulfil the feed requirement for the 1750 kg MS/ha scenario, with an overall feed deficit of 3.1 t DM pasture/ha. Improvements in ryegrass cultivars and N-fertilisers could be expected to increase pasture production by around 10\%, reducing the overall feed deficit to 1.6 t DM pasture/ha. These improvements together with irrigation at 2 mm/day over the three summer months (Dec - Feb) reduced the feed deficit to zero. Irrigation could be replaced by cropping between 11\% and 20\% of the farm in a rotation of annual ryegrass yielding 7 t DM/ha and maize yielding 22 to 28 t DM/ha respectively. },
	issn = {1176-5283},
	author = {Beukes PC and Clark CEF and Wastney ME and Palliser CC and Levy G and Folkers C and Lancaster JAS and Leydon-Davis C and Thorrold BS}
}
@conference {41512,
	title = {Modelling farm systems with once-a-day milking},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {64},
	year = {2004},
	month = {Jan},
	pages = {237-240},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {Our objectives were to investigate how a cow model, "Molly", deals with once-a-day milking and to use "Molly" in a Whole Farm Model to explore farm systems where once-a-day milking might produce results on a per hectare basis comparable to twice-a-day milking. We compared our model outputs to observed data from a Milking Frequency trial run by Dexcel at a research farm in Taranaki. Changing the rate constants for milk removal and degradation of the lactation hormone complex in "Molly" resulted in the model expressing the acute and chronic effects of once-a-day milking. The once-a-day cow model fed ad lib seasonal grass pasture showed a decrease in milksolids yield (kg/cow) of 31\% in Friesians compared to the observed 28\%. When we used .Molly. in the Whole Farm Model it showed that farm performance with once-a-day milking was 1135 kg milksolids/ha when a Friesian herd was stocked at 7\% higher and their lactation was extended by 14 days compared to a twice-a-day herd (1132 kg milksolids/ha). We conclude that farm performance with once-a-day milking is strongly dependent on selecting cows with higher lactational persistence under once-a-day milking and managing for extended lactations. },
	issn = {1176-5283},
	author = {Beukes PC and Thorrold BS and Wastney ME and Palliser CC and Clark DA}
}
@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}
}
