@conference {60944,
	title = {Understanding the interaction of prolactin and leukaemia inhibitory factor signalling during the switch from lactation to involution : Brief Communication},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {69},
	year = {2009},
	month = {Jun},
	pages = {65-67},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {The molecular mechanisms involved in involution of the bovine udder, a process which underpins lactation persistency, are poorly understood. During rodent lactation, STAT5 is activated in response to prolactin (PRL) to stimulate milk protein production (Liu et al., 1997). At the onset of involution, STAT5 is rapidly inactivated (Schmitt-Ney et al., 1992), and STAT3 is activated by leukaemia inhibitory factor (LIF) to... Continued},
	issn = {1176-5283},
	author = {Singh K and Vetharaniam I and Prewitz M and Dobson J and Stelwagen K}
}
@conference {41548,
	title = {Software for evaluating sampling strategies and error rates in the identification of mixed meat products},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {65},
	year = {2005},
	month = {Jan},
	pages = {102-106},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {DNA verification of the origin of meat within traceability systems involves the comparison of DNA samples taken at a reference stage with samples taken further down the supply chain. While such verification is well established when whole cuts of meat are involved, this is not the case for mixed-meat products made from an unknown number of contributing animals. Spreadsheet based software has been developed to analyse one DNA verification scheme for determining whether a returned product did indeed originate from a particular manufacturing batch. The scheme involves the comparison of k individual DNA samples (comprising an unknown number of individuals) from the product, with a set of s DNA samples (comprising an unknown number of individuals) taken randomly before manufacture of the batch in question. The software gives the error rate for correctly matching the product to the batch, for different sampling rate combinations of the product and at the factory.
Key words: DNA verification; mixed meat; traceability; sampling. },
	issn = {1176-5283},
	author = {Vetharaniam I and Shackell GH}
}
@conference {41422,
	title = {Modelling optimum switch date from twice- to once-daily milking in dairy herds},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {63},
	year = {2003},
	month = {Jan},
	pages = {133-137},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Queenstown},
	abstract = {The production of a dairy herd was simulated at two different stocking rates (3.4 cows/ha and 4.0 cows/ha) and two seasonal conditions (an average and a dry Waikato summer). Cows were milked twice-daily (TDM) for varying periods, before being switched to once-daily milking (ODM) for the remainder of the lactation. Switching from TDM to ODM during the milking season reduced the total production of the herd. With 3.4 cows/ha in an average summer, at a break-even value of labour of $100 /milking ($200 /milking) the optimum switch-over date was January 13 (October 21); a dry season brought forward this date by approximately two weeks. Increasing payout increased the break-even value of labour at a given switch-over date. Under a commonly used farmer industry guideline, break-even labour values under average (dry) conditions were $53.47 /milking ($61.47) for 3.4 cows/ha and $36.07 /milking ($33.98) at 4.0 cows/ha. A stocking rate of 4.0 cows/ha switching to ODM after peak production had a lower cash surplus than a 3.4 cows/ha stocking rate with TDM due to additional ($30,000) feed costs with the higher stocking rate. These results suggest a formal approach could be used to complement industry guidelines in deciding when to switch from TDM to ODM. },
	issn = {1176-5283},
	author = {Westbrooke VCF and Dooley AE and Vetharaniam I}
}
@conference {41296,
	title = {Modelling the impact of milking frequency on lactation},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {61},
	year = {2001},
	month = {Jan},
	pages = {239-240},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Increasing milking frequency from the usual practice of twice-daily can enhance milk production and, thus, may be profitable in high-intensity dairy production systems. A decrease of milking frequency to once-daily decreases yield but may be used to alleviate nutritional stress, to conserve cow condition, or simply as a lifestyle choice. Published values in the literature indicate that reducing milking frequency from twice daily to once daily decreases yield by 7{\textemdash}34\%, and increasing milking frequency from twice daily to thrice daily increases yield by 7{\textemdash}20\% (Davis et al., 1999; Stelwagen, 2001). Additionally, milking frequency can influence the rate of decline in post-peak production in cows (Stelwagen, 2001).
In order to further understand and quantify the manner in which milking frequency affects lactation, a mechanistic mathematical model of mammary function has been developed (Vetharaniam, Davis, Soboleva, Shorten \& Wake, Unpublished), based on mechanisms presented by Davis et al. (1999). As well as allowing analysis of the effect of milking frequency, this model also facilitated the exploration of some of the pathways through which nutrition influences mammary gland development (Davis et al. 2001). },
	issn = {1176-5283},
	author = {Vetharaniam I and Davis SR and Soboleva TK and Shorten PR and Wake GC}
}
@conference {41295,
	title = {Modelling the impact of nutrition and genotype on lactation},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {61},
	year = {2001},
	month = {Jan},
	pages = {237-238},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Dairy cows grazed on pasture experience variation in their nutritional status during lactation, as both pasture quality and availability vary seasonally. This has both immediate and long-term consequences on cow performance. Acute effects of nutrition are related to availability of nutrients for milk secretion, and are manifested in day-to-day variation in milk yields. Of further importance are the chronic effects of nutrition, which act on the development of the mammary gland, impacting on the persistency of lactation. Typically, cows in a New Zealand, pasture-grazing environment exhibit a decline in milk yield of around 10\% per month, after peak lactation, whereas cows fed a concentrate diet in Northern Hemisphere systems show declines of less than 4\%. Post-peak declines in milk yield are associated with a proportional and permanent decline in the number of secretory cells in the udder, and this decline is modulated by nutrition (Davis et al., 2000).
Quantifying the milk-yield response of a cow to different nutritional regimes is useful from a breeding and selection point of view, but on its own does not give insight into which pathways are likely to be affected by nutrition, nor does it explain the origin of differences in responses between cows. To this end, mechanistic mathematical models that reflect the underlying biology of the udder are particularly useful. },
	issn = {1176-5283},
	author = {Davis SR and Vetharaniam I and Upsdell M and Kolver ES and Pleasants AB}
}
@conference {41153,
	title = {Role of reproductive technologies in reducing the time lag associated with the commercial application of genetic discovery in the sheep industry},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {60},
	year = {2000},
	month = {Jan},
	pages = {36-40},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {The recent and escalating emphasis on gene discovery has major implications for genetic improvement of the NZ sheep industry. However, the long lag phase in the dissemination of new genetic material through current breeding structures is a major impediment to rapid uptake of the improvements. Effective reproductive technologies are considered necessary for achieving the desired rates of dissemination but there is little evidence of their practical and economic values. To provide evidence, a series of modelling exercises were undertaken. This involved defining a particular commercial outcome (advancing the pattern of lamb kill in Otago/Southland by 1 month without changing lambing date), deciding on the relevant genetic trait to achieve this (terminal sires with a 20\% increase in mature size), modelling the rate of genetic gain using a number of breeding scenarios that included artificial insemination (AI) and multiple ovulation and embryo transfer (MOET), to determine the time required for sufficient commercial rams to be available to achieve the outcome. Selected scenarios were then chosen for more detailed modelling to ascertain the economic implications to the farm (Otago/Southland lamb finishing farm) and to the industry of adopting the technology. The advancement of the kill pattern by one month was worth $12,714 on the commercial farm. Based on a two-tiered breeding system (stud and commercial) without any reproductive technology it takes 26 years to achieve the outcome (assuming that the animal with this genetic advantage had been identified at the start). The use of AI at the stud level reduced this time by 11 years. The additional use of MOET on stud ewes gave a further reduction in time of 7 years and the application of AI using stud rams at the commercial level an additional 2 years. These results confirm the importance of reproductive technologies in reducing the lag phase in gene dissemination and their value to the industry. There is a need to further refine the efficiency and efficacy of the chosen technologies. },
	issn = {1176-5283},
	author = {Smith JF and Vetharaniam I and McCall DG and Tervit HR}
}
@conference {41176,
	title = {Sensitivity of ultimate meat pH to initial metabolite concentration when glycogen is not limiting},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {60},
	year = {2000},
	month = {Jan},
	pages = {120-123},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {The causes of variations in the ultimate pH of meat under conditions in which glycogen is in excess are considered using a model of energy metabolism in the post-mortem period. A key component of the model attributes the inhibition and ultimate cessation of glycolysis to the accumulation of lactate (which inhibits the regeneration of NAD+ via the lactate dehydrogenase reaction) rather than acidosis. The initial concentrations (concentrations at slaughter) of creatine phosphate, ATP, lactate, and also the buffering capacity of the muscle tissue are shown to affect the ultimate pH. The ultimate pH was particularly sensitive to initial lactate concentration and muscle buffer concentration such that increases in either resulted in an increase in ultimate pH. Variations in the initial conditions of muscle metabolites are attributed primarily to preslaughter physical exertions, while variation in muscle buffer concentration may be genetically linked. },
	issn = {1176-5283},
	author = {Vetharaniam I and Daly CC}
}
