@conference {41774,
	title = {Comparison of mastitis prevalence between an organic and conventional dairy herd from 2004 to 2006},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {68},
	year = {2008},
	month = {Jan},
	pages = {8-11},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Brisbane, Australia},
	abstract = {This study compared mastitis bacteriology and somatic cell counts (SCC) between an organic and a conventional dairy herd, each managed as a pastoral-based system, in the 2004/05 and 2005/06 seasons. Single quarter foremilk samples taken from both herds at calving, 14 days post-calving, mid-lactation and dry-off were cultured for bacteriological analysis. Individualcow SCC were obtained from monthly herd tests. The percentage of cows infected with Staphylococcus aureusand Streptococcus uberiswas generally higher in the organic herd than the conventional herd. However, these differences were only significant for S. aureusat midlactation 2005/06, when 56\% of the organic herd was infected compared to 23\% of the conventional herd (P <0.05), and for Str. uberisat dry-off 2005/06, when 7\% of the organic herd was infected but none of the conventional herd (P <0.001). The organic herd had a significantly higher mean lactation back transformed SCC than the conventional herd, in 2004/05 (96,921 vs. 75,608 cells/mL, P <0.05) and 2005/06 (103,968 vs. 63,096 cells/mL, P <0.0001). The 2004/05 season was the first time that a significant difference in mean SCC between the organic and conventional herds had been measured, since the organic and conventional dairy systems comparison trial was established in 2001.},
	issn = {1176-5283},
	author = {McLeod KLM and Holmes CW and Morel PCH and Dowson KR and Thatcher A and Shadbolt NM and Kelly TC}
}
@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}
}
@conference {41557,
	title = {A study of mastitis in two small experimental dairy herds managed either organically or conventionally during one year},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {65},
	year = {2005},
	month = {Jan},
	pages = {148-152},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Mastitis infection status of two small herds located at the Dairy Cattle Research Unit of Massey University was assessed. Single quarter milk samples from 45 cows under organic production (first and second year of organic certification) and 50 cows under a conventional system were taken on four occasions: mid lactation (these samples were frozen); prior to the last milking before dry-off (season 2003/2004); before the first milking after calving and 14 days post calving (season 2004/2005). Milk samples were cultured for bacterial analysis. Somatic cell counts (SCC) from monthly herd tests, and clinical mastitis cases were recorded and analyzed.
The percentages of quarters with positive bacterial growth, and SCC, were generally higher in the organic herd, but differences were only significant for Staphylococcus aureus in all four sample periods, and for Streptococcus spp. 14 days post calving. The results suggest that in organic herds Staphylococcus aureus infections could become an important concern, because of constraints on the use of antibiotic treatments. Effective prevention of infections by this organism will be essential, in order to prevent high culling rates.
KEYWORDS: mastitis; organic dairy; New Zealand. },
	issn = {1176-5283},
	author = {Silva KE and Quinn AK and Morel PCH and Holmes CW and Thatcher A and Shadbolt NM and Kelly T}
}
@conference {41414,
	title = {Forage intake and feed conversion efficiency in high-producing dairy herds in New Zealand: a case study},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {63},
	year = {2003},
	month = {Jan},
	pages = {96-100},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Queenstown},
	abstract = {In 1998 a three-year dairy farm monitoring programme was established on twelve dairy farms in the southern North Island of New Zealand where production policy had changed from a focus on high production per hectare through high stocking rates to a strategy based on high production per hectare through enhanced production per cow. Results of the third year for nine of these farms revealed a range of apparent feed intake (50,669 - 70,135 MJ ME/cow/year), milksolids production (372 - 432 kg MS/cow/year) and feed conversion efficiency (6.0 - 7.4 g MS/MJ ME intake). There was a significant positive correlation (R2= 0.57, P<0.05) between annual apparent ME intake per cow and annual milksolids production per cow, with a regression coefficient equivalent to 2.5 g MS produced per MJ ME intake, but a significant negative correlation (R2 = 0.80, P<0.01) between ME intake and feed conversion efficiency. The apparent ME intakes measured were 21\% and 8\% higher than theoretical requirements for the farms with higher and lower (compared to each other) milksolids yield values, respectively. This suggests that the high-performance farms may have wasted more feed. Implications for management of feed resources to optimise efficiency in high-production systems are discussed. },
	issn = {1176-5283},
	author = {Salles PV and Matthews PNP and Holmes CW and Hodgson J and Shadbolt NM}
}
@conference {41423,
	title = {Frequency of mastitis and variation in somatic cell counts throughout the lactation in cows managed organically or conventionally; Year 1},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {63},
	year = {2003},
	month = {Jan},
	pages = {138-139},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Queenstown},
	abstract = {Interest in organic milk production is growing in New Zealand. At present milk is being collected from 13 organically certified farms in the North Island and 66 farms have been identified as either certified organic or interested in converting from conventional production (Stevenson, 2002).
Massey University started a trial on August 2001 to monitor the difference between organic and conventional dairy farming systems, and to provide New Zealand dairy farmers with proven information on differences between the two systems. A key focus of the organic farming system is the maintenance of health and well-being of cows in the herd, without the routine use of conventional methods (e.g., antibiotics). Mastitis has been recognised as the main disease problem. The objective of this report is to present results on the variation in somatic cell counts (SCC), frequency of clinical mastitis (CM) and frequency of acute levels of SCC of cows managed according to either organic or conventional farming practices for the season 2001 to 2002, the first year after the change to organic farming. },
	issn = {1176-5283},
	author = {Lopez-Villalobos N and Scott J and Smith Z and Holmes CW and Shadbolt NM and Harvey TG}
}
@conference {41343,
	title = {Use of Lotus corniculatus to increase sheep production under commercial dryland farming conditions without the use of anthelmintics},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {62},
	year = {2002},
	month = {Jan},
	pages = {177-178},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {Legumes are an important component of feeding systems in temperate zones to fix nitrogen and to produce high quality forage as a feed for livestock. However, marginal protein deficiency exists when ruminants are fed on fresh temperate forages due to high degradation rates of forage proteins in the rumen. Consequently, there is a large absorption of NH3 from the rumen, leaving absorption of essential amino acids (EAA) from the small intestine that is below animal requirements for these AA (Barry, 1982).
Condensed tannins (CT) in Lotus corniculatus (Birdsfoot trefoil) reduce rumen protein degradability and increase EAA absorption from the small intestine (Waghorn et al., 1987). Separate feeding experiments with sheep have shown that CT in lotus increased wool production and milk secretion (Wang et al., 1996a\&b) and both ovulation rate during mating, and lambing percentage (Min et al., 1999: Min et al., 2001), all with no increase in voluntary feed intake (VFI). In addition, lambs fed lotus accumulated fewer dags than lambs grazed on perennial ryegrass (Lolium perenne)/white clover (Trifolium repens) pasture (Leathwick \& Atkinson, 1995). Each of these effects was measured in separate specific experiments.
The objective of this study was to assess the effect of feeding Lotus corniculatus upon wool production and lamb weaning weight under commercial dryland farming conditions without anthelmintic drench input, using a systems approach, where effects upon animal productivity and parasites were measured in the same experiment. },
	issn = {1176-5283},
	author = {Ramirez-Restrepo CA and Barry TN and Lopez-Villalobos N and Kemp PD and Pomroy WB and McNabb WC and Harvey TG and Shadbolt NM}
}
@conference {41007,
	title = {Evaluating the business risk associated with feeding supplements to dairy cows on pasture},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {58},
	year = {1998},
	month = {Jan},
	pages = {125-127},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The beta analysis technique provides a practical tool for evaluating the business risk associated with feeding supplements to dairy cows. The break-even cost, the expected profitability and the probability of making a profit can all be derived by predicting the marginal milksolids (MS) response, and applying prices for MS and supplements. The range of possible outcomes is simulated from specified maximum and minimum values, and the associated response distribution for each of these variables. The profitability of feeding maize silage on a market milk supply dairy farm was used to demonstrate the possible application of formal risk analysis to dairy herd management with a 50\% spring: 50\% autumn calving pattern. To be profitable, the marginal response to maize silage has to be maximised when no milk premium is paid, but, in the months when a premium is earnt, the risk of not making a profit is small. },
	issn = {1176-5283},
	author = {Laborde D and Shadbolt NM and Parker WJ}
}
