@conference {41323,
	title = {Effect of udder health on milk},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {62},
	year = {2002},
	month = {Jan},
	pages = {95-99},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {Mastitis is an inflammation of the udder tissue, normally arising from a bacterial infection. The effects of mastitis on the processing properties of milk have been widely researched over the past 40 years. This paper summarises the main effects of udder health on raw milk composition and its processing properties, reviews the progress made to date by the New Zealand dairy industry with regard to reducing the impact of mastitis on milk processing, and highlights continuing avenues of enquiry.},
	issn = {1176-5283},
	author = {Lacy-Hulbert SJ and Auldist MJ}
}
@conference {41302,
	title = {Endogenous synthesis and enhancement of conjugated linolieic acid in pasture-fed dairy cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {62},
	year = {2002},
	month = {Jan},
	pages = {12-15},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {The primary conjugated linoleic acid (CLA) isomer in milkfat, cis-9, trans-11 CLA, is a proven anticarcinogen in rodents and can be derived directly from ruminal biohydrogenation of linoleic acid. The major fatty acid in pasture, however, is alpha-linolenic acid; the biohydrogenation of which does not produce cis-9, trans-11 CLA as an intermediate. Therefore, in grazing cows, cis-9, trans-11 CLA must be produced by other sources, possibly via D9-desaturation of trans-11 vaccenic acid (TVA), a biohydrogenation product of both alpha-linolenic acid and linoleic acid. Studies were conducted to i) determine the importance of endogenous synthesis of cis-9, trans-11 CLA in pasture-fed cows and ii) increase the level of cis-9, trans-11 CLA. The first study involved abomasal infusion of sterculic oil (SO) to inhibit the activity of the D9-desaturase enzyme. Abomasal infusion of SO decreased the concentration of cis-9, trans-11 CLA in milk fat by 71\% (P<0.01; 3.6 c.f. 12.1 {\textpm} 0.15 mg/g fatty acid). The presence of cis-9, C 1 0:1, cis-9, C12:1 and cis-9, C14:1 in the milk fat of cows following SO treatment indicated D 9-desaturase was not completely inhibited. Using the changes in these fatty acids to evaluate the extent of D9-desaturase inhibition with SO treatment, an estimated 87-100\% of cis-9, trans-11 CLA in milk fat was of endogenous origin. In the second study, sunflower oil at 4\% DMI/cow/day invoked a 38\% increase (P<0.01) in milk fat TVA (61.3 c.f. 44.4 {\textpm} 0.51 mg/g fatty acid) and a subsequent 28\% increase (P<0.01) in cis-9, trans-11 CLA concentrations compared to control (28.5 c.f. 22.3 {\textpm} 0.19 mg/g fatty acid). Results demonstrate that endogenous synthesis is the major source of cis-9, trans-11 CLA in pasture-fed dairy cows and levels can be enhanced by increasing the supply of the ruminally-derived precursor, TVA. },
	issn = {1176-5283},
	author = {Kay JK and Mackle TR and Auldist MJ and Thomson NA and Bauman DE}
}
@conference {41324,
	title = {On-farm management to modify milkfat composition - a review of experiments undertaken at Dexcel to produce a spreadable butter directly from the cow},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {62},
	year = {2002},
	month = {Jan},
	pages = {100-103},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {For many years it has been known from overseas studies that the composition and physical characteristics of milkfat are influenced by diet. The feeding of oilseeds had been shown to reduce the concentration in milkfat of short- and medium-chain-length fatty acids and to increase the concentration of long-chain unsaturated fatty acids. It was also reported that these changes resulted in softer milkfat and butter with improved spreadability at low temperatures. With this knowledge, a six-year collaborative research programme between the New Zealand Dairy Research Institute and Dexcel was undertaken to investigate the economic feasibility of producing a spreadable butter directly from the cow. The programme investigated the influence of each component in pastoral dairying that may possibly influence milkfat composition. These were: pasture, (location, defoliation interval, and species effects) on pasture lipid composition, grazed pasture effects (species and grazing rotation), supplementary feed effects (ruminally and non-ruminally protected oilseeds),   frequency   of   feeding,   and   milking   management.   Following   the   study   of   each   component   the   various components will be combined to develop a total farm management system to achieve the programme{\textquoteright}s goals. The goal of producing a spreadable butter directly from the cow has been achieved, but the programme has yet to develop a profitable farm system to produce the product under existing returns for milksolids.},
	issn = {1176-5283},
	author = {Thomson NA and Auldist MJ and Kay JK and MacGibbon AKH and Murphy JJ}
}
@conference {41214,
	title = {Effects of diet on udder function and regression in Holstein-Friesian Cattle},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {60},
	year = {2000},
	month = {Jan},
	pages = {275-276},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {The rate of decline in milk yield after peak lactation is about 10\% per month, for cows in New Zealand grazing pasture diets, and less than 4\% per month in concentrate-fed animals in northern hemisphere environments. Much of the decline in milk yield after peak lactation is associated with a similar proportional loss of secretory cells from the udder and, once lost, these cells cannot be replaced until the dry period before the next lactation. Thus, we have found (unpublished data) that from peak lactation (October) to late-lactation in New Zealand, there was a loss of over 50\% of mammary DNA. Such a loss was also reflected in changes in udder volume (Davis et al., 1985) and also in changes in milk storage capacity in the udder (Davis et al., 1987).
Differences in lactational persistency between concentrate and pasture-fed animals suggest that nutrition exerts a long-term effect on milk production through maintenance of mammary secretory cell structures, as well as function. In the present experiment, our hypothesis was that cows fed concentrate diets would maintain milk production better than cows fed pasture over the summer months and that this would be reflected in the functional udder capacity (FUC). FUC is a measure of mammary cell numbers and is highly correlated with milk production (Davis et al., 1987). Further work attempted to correlate changes in FUC with concentrations of blood hormones sensitive to diet. },
	issn = {1176-5283},
	author = {Davis SR and Farr VC and Auldist MJ and Kolver ES}
}
@conference {40981,
	title = {Differential effects of short-term once-daily milking on milk yield, milk composition and concentrations of selected blood metabolites in cows with low or high pasture intake},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {58},
	year = {1998},
	month = {Jan},
	pages = {41-43},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Forty-eight Friesian cows were subjected to ad libitum grazing (pasture allowance 45 kg/cow/day) or restricted grazing (pasture allowance 16-18 kg/cow/day) in a cross-over experiment during spring. Mean milk yields for ad libitum and restricted cows after 10 day treatment periods were 21.4 and 16.2 l/day respectively. All cows were then subjected to once-daily milking (ODM) for 2 days. ODM reduced milk yield and casein:whey protein ratios but increased concentrations of fat, serum albumin, immunoglobulin G, whey protein and somatic cells. Effects of ODM were greater in fully fed and thus higher-producing cows. In blood, ODM decreased concentrations of non-esterified fatty acids and urea, but increased concentrations of glucose. Milk yield and composition were significantly affected by short-term ODM, but the effect was less in cows producing below their peak due to feed restriction. There were metabolic indications that ODM reduced the nutritional demands of milk production.},
	issn = {1176-5283},
	author = {Auldist MJ and Prosser CG}
}
@conference {40984,
	title = {Diurnal variation in concentration of Beta-lactoglobulin in bovine milk.},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {58},
	year = {1998},
	month = {Jan},
	pages = {49-51},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Two trials were conducted to define the variation in concentrations of b-lactoglobulin (b-LG) in bovine milk following different milking intervals. In the first, milk samples were collected from three herds of 20 cows. At the time of sampling in early summer, one herd was in each of early, mid and late lactation (30, 120 and 210 days post calving, respectively). Average b-LG concentrations were 41, 37 and 50\% higher (p<0.05) after a 16h than 8h milking interval for early, mid and late lactation, respectively. In the second trial, bulk milk was sampled from four herds of 12 cows. All cows were at the same stage of lactation and the milking interval was 16:8h. Samples were collected on three separate occasions when cows were on unrestricted pasture intake and once when intake was restricted by 50\%. On unrestricted pasture intake, concentrations of b-LG were 11\% higher in milk collected after 16h than 8h milking interval, whilst on restricted intake, concentrations were 44\% higher. There were no differences in concentrations of a-lactalbumin (a-LA). Both trials show a significant difference in b-LG levels in milk collected after 16h versus 8h milking interval, although only 71\% of all samples collected in the first trial exhibited this difference and it was less in the second trial using bulk milk. },
	issn = {1176-5283},
	author = {McLaren RD and Auldist MJ and Prosser CG}
}
@conference {40986,
	title = {The value of monozygotic twins in milk composition experiments.},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {58},
	year = {1998},
	month = {Jan},
	pages = {55},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Monozygotic (identical) twins have for many years been used to increase the statistical power of experiments in a range of scientific disciplines (Dick and Whittle,1951). In dairy cows, variation within identical twinsets for a given biological parameter is usually substantially less than the variation between unrelated cows or between fraternal twinsets (Hancock 1953; Brumby and Hancock, 1956). Thus the number of identical twins required in an experiment is often considerably less than the number of unrelated cows necessary to achieve the same statistical precision. The experiments described here were conducted to quantify the twin efficiency values of a range of milk composition parameters.},
	issn = {1176-5283},
	author = {Auldist MJ and Mackle TR and Hooper RJ and Henderson HV}
}
@conference {40985,
	title = {Variation in milk whey composition throughout lactation in cows of different Beta-lactoglobulin phenotypes.},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {58},
	year = {1998},
	month = {Jan},
	pages = {52-54},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The association between b-lactoglobulin (β-LG) variants and milk composition throughout lactation was determined by sampling from 44 Friesian cows (22 homozygous for b-LG AA and 22 homozygous for b-LG BB) in early (day 6 postpartum), established (1-3 months postpartum) and late lactation (on the day of drying off). Results indicated that differences between β-LG AA and BB phenotype milk (expressed as a percentage of the level in phenotype AA) in concentrations of bovine serum albumin (BSA; -15.9\%, -32.0\%, -42.5\%) and b-LG (5.9\%, 16.0\%, 32.2\%), in early, established and late lactation respectively, increased steadily as lactation progressed. The differences in a-lactalbumin concentrations were less variable (1.2\%, -9.0\%, -9.1\%). These results provide new evidence that compositional differences are not seen between b-LG AA and BB phenotype milk until established lactation.},
	issn = {1176-5283},
	author = {Turner S-A and Auldist MJ and Molan PC and Prosser CG}
}
@conference {40930,
	title = {Brief Communication: Seasonal and lactational influences on milk composition in New Zealand},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {57},
	year = {1997},
	month = {Jan},
	pages = {205-206},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {In New Zealand, seasonal calving has created marked variations in the volume and composition of milk supplied to processors across the season. As a consequence, there are also seasonal variations in the manufacturing properties of the milk (Kefford et al.1995). In particular, milk from later in the season can have manufacturing properties which are different from those of early and mid-season milk. Milk from this time typically has elevated concentrations of blood proteins, low casein:whey ratios and an altered min-eral balance (Lucey, 1996). The 2 major factors attributed to causing this phenomenon are the stage of lactation (SOL) of the cows, and seasonal influences which affect both pasture and cows. In a seasonally-calving dairy sys-tem, the precise contributions of these factors to the re-ported changes in milk composition are difficult to define because of the confounding influences of other factors. The aim of the investigation presented here was to separate the respective effects of season and SOL on milk composition.},
	issn = {1176-5283},
	author = {Auldist MJ and Walsh BJ and Thomson NA}
}
@conference {40929,
	title = {The effect of time-of-calving on dairy production.},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {57},
	year = {1997},
	month = {Jan},
	pages = {204},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The adoption of seasonal calving in New Zealand has lead to marked irregularities in the supply of milk to processors in terms of both quantity and quality. The need to accommodate peak milk flow means that manufacturing plants are under utilised for most of the year. Further, there are difficulties manufacturing high quality products early and late in the season. This study presents data from an all-year-round calving system which may help to overcome the above mentioned problems.},
	issn = {1176-5283},
	author = {Auldist MJ and Thomson NA and Walsh BJ}
}
@conference {40830,
	title = {Effect of calving liveweight on milk yield and composition and daily dry matter intake in Friesian and Jersey heifers},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {56},
	year = {1996},
	month = {Jan},
	pages = {260-262},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Milk yield and composition were measured weekly throughout  lactation, and daily dry matter intake (DMI) on 7 occasions, for Friesian  (n=16) and Jersey (n=16) heifers calving at either high (H) or low (L)  liveweights. During the 8 weeks pre-partum, heifers were fed to achieve  calving liveweights of 404 (H Friesian), 354 (L Friesian), 334 (H Jersey) and  277 (L Jersey) kg. All heifers were fully fed on pasture as one group for the  whole of lactation. Calving liveweight had no effect on average DMI over the season. Average  DMI was higher for Friesians than Jerseys while average liveweight- corrected DMI was slightly greater for Jersey than Friesians. Average daily  milk yields and yields of lactose were lower for L than H heifers. Solids- corrected milk yields and yields of milkfat and protein were unaffected by  calving liveweight, but milkfat \% and protein \% were higher for L than H  heifers. The Friesians had higher milk yields, and yields of protein and  lactose, but lower milkfat \% and protein \% than Jerseys. No effect of restricted feeding during late pregnancy in heifers was  demonstrated on milk solids production in the subsequent lactation.},
	issn = {1176-5283},
	author = {Mackle TR and Parr CR and Stakelum GK and Bryant AM and Macmillan KL and Auldist MJ}
}
