@conference {3672,
	title = {Estimation of a premium for milk with a high concentration of unsaturated fatty acids based on farm and processor profit: A simulation study.},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {75},
	year = {2015},
	month = {07/2015},
	pages = {54-59},
	address = {Dunedin},
	abstract = { The objective of this study was to determine, via simulation, the premium required for dairy farmers supplying milk with a high
concentration of unsaturated fatty acids (UFA) to a dairy processor to equal the operating profit ($/ha) of average farms, under
New Zealand conditions. Fifty average farms (AVE farms) and fifty farms that fed an oilseed supplement to dairy cows (UFA
farms) were simulated. The processing of milk produced by AVE farms and UFA farms into skim-milk powder and butter was also
simulated. The physical and financial characteristics of dairy farms and a dairy processor were investigated under two scenarios:
1) no premium for UFA and 2) a premium for UFA which equalled the operating profit ($/ha) of UFA farms to that of AVE farms.
UFA farms were not different from AVE farms in yields of milk, milkfat and protein, but their farm expenses were greater (P<0.05)
than for AVE farms. A premium of $0.15/kg milkfat (for each 0.1 g UFA/100 g milkfat increase) was necessary for UFA farms
to have an operating profit ($/ha) similar to AVE farms. These results may be used to further evaluate the impact of modifying
milkfat UFA concentration at the farm level.},
	issn = {1176-5283},
	author = {Silva-Villacorta D and Lopez-Villalobos N and Hickson RE and Blair H and MacGibbon A}
}
@conference {79014,
	title = {Productivity and financial characteristics of herds that produce milkfat with different concentration of unsaturated fatty acids using a stochastic farm model},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {72},
	year = {2012},
	month = {Jan},
	pages = {175-180},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {The objective of this study was to describe the characteristics of dairy farms with different concentrations of unsaturated fatty acids (UFA) in milkfat using a stochastic farm model. Daily phenotypic cow performance was simulated using an exponential function including terms for milk, fat, protein and live weight, and a third order orthogonal polynomial of milkfat UFA concentration. Daily and yearly feed requirements were estimated from metabolisable energy requirements for maintenance, lactation, pregnancy and growth. Two groups of farms were simulated: (1) Average UFA farms (30 farms, milkfat UFA concentration = 30.04 g/100g milkfat) and (2) High UFA farms (30 farms, milkfat UFA concentration = 35.99 g/100g milkfat). Each farm was 140 ha and had 386 cows, a replacement rate of 18\% and a spring calving between 20 July and 10 September. The simulation was replicated 1,000 times. High UFA farms produced significantly (P < 0.05) less milkfat (338 vs 502 kg/ha) and milksolids (692 vs 927 kg/ha) than Average UFA farms. This resulted in High UFA farms having lower (P < 0.05) gross farm income ($3815 vs $5075 /ha) and cash operating surplus ($-331 vs $598/ha) than Average UFA farms. This highlights the need to develop a payment system that rewards concentration of UFA in milkfat.},
	issn = {1176-5283},
	author = {Silva-Villacorta D and Lopez-Villalobos N and Blair HT and Hickson RE and MacGibbon AKH}
}
@conference {75905,
	title = {Effect of lactation stage and breed on the concentration of unsaturated fatty acids in milkfat of New Zealand dairy cattle},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {71},
	year = {2011},
	month = {Jan},
	pages = {203-207},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Invercargill},
	abstract = {Milkfat composition influences the nutritional value and manufacturing characteristics of milk. This research studied the influence of: 1) stage of lactation on the concentration of unsaturated fatty acids (UFA) in milkfat of Holstein-Friesian, Jersey and Crossbred cows, 2) segregation of cows according to their UFA concentration in milkfat. The concentration of UFA in milkfat was predicted with a calibration equation using Fourier transform infrared spectroscopy. The data (21,757 test-day records) were analysed using a mixed model with a third-order orthogonal polynomial. In the three breeds studied, after early lactation the concentration of UFA in milkfat decreased steadily as the lactation progressed, but in Holstein-Friesian cows it increased slightly at the end of lactation. Throughout lactation, Holstein-Friesian cows produced milkfat with a higher concentration of UFA than Jersey and Crossbred cows. In each herd, cows were split into a high and a low group according to the average UFA concentration of the herd. The high UFA group had higher (P <0.001) milk yield, but lower (P <0.001) yields and concentrations of fat and protein than the low UFA group. This study indicates that concentration of UFA in milkfat is affected by breed and stage of lactation in New Zealand dairy cattle.},
	issn = {1176-5283},
	author = {Silva-Villacorta D and Lopez-Villalobos N and Blair HT and Hickson RE and Spelman RJ and Melis J and Davis SR and Berry SDK and Lehnert K and Snell RG}
}
@conference {41538,
	title = {The productivity of pasture-based dairy farms in New Zealand with different levels of extra feed input},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {65},
	year = {2005},
	month = {Jan},
	pages = {63-67},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {The objective of this research was to study the physical and financial performance of commercial dairy farms in New Zealand that differed in the amount of extra feed used. Data from Dexcel{\textquoteright}s ProfitWatch corresponding to 626 owner-operated dairy farms between 1998/1999 and 2001/2002 were analysed. The data were classified according to each of the four dairy seasons and the extra feed used per cow. Extra feed comprised supplements imported (hay, pasture silage, maize silage, concentrates and other feeds), winter grazing and maize silage grown on the farm. The statistical analyses were done in SAS and comprised analyses of variance and regression analyses. High feed input farms (H farms, 740-940 kg extra DM /cow/year) had higher stocking rates (2.7-2.8 vs 2.4-2.5 cows/ha), lower comparative stocking rate (83-86 vs 83-92 kg live weight/t DM), and higher milksolids (MS) production per cow (293-341 vs 249-295 kg MS/cow) and per hectare (826-921 vs 616-744 kg/ha) than low feed input farms (L farms, 20 kg DM extra feed/cow/year). The use of nitrogen fertiliser was also higher in the H farms than in L farms (85-116 vs 53-67 kg N/ha/year). There were no significant differences in farm size, herd breeding worth, reproductive characteristics of the herds and estimated pasture consumed per hectare. On average, extra feed was significantly associated with extra cows (0.17 extra cows/ha for 1 t extra DM) and extra milk solids (50 g extra MS/cow for 1 kg extra DM/cow and 96 g extra MS/ha for 1 kg extra DM/ha), but the wide variability is shown by the low values for R2 (0.13 to 0.16 for the three relations above). The H farms produced higher gross farm incomes per hectare (by $0.47 to $0.49/kg extra DM offered) but had higher farm working expenses per hectare (by $0.36 to $0.37/kg extra DM offered), so that Economic Farm Surplus per hectare was not higher for these farms in any year. High management skills and control of costs are necessary for profit to be increased by the use of extra feeds.
KEYWORDS: low-input; high-input; extra feed. },
	issn = {1176-5283},
	author = {Silva-Villacorta D and Holmes CW and Shadbolt NM and Lopez-Villalobos N and Prewer W and Glassey CB and Blackwell M}
}
