@conference {41655,
	title = {An economic evaluation of automatic milking systems for New Zealand dairy farms},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {66},
	year = {2006},
	month = {Jan},
	pages = {263-269},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Napier},
	abstract = {An economic analysis for automatic milking for a medium sized farm set up to milk 450 cows and installing either a 40-bail rotary dairy with automated cup removal and drafting or a 5-unit Greenfield system is evaluated. The analysis used a model that incorporated findings from the previous 5 years of research and development at the Greenfield automatic milking project and used physical and financial data collected in Dexcel{\textquoteright}s 2003/04 Economic Farm Survey for the conventional milking system comparison. The model assumed a payout of $4.25/kg milk solids (MS) and used current cost of technology. Once cows were established into the Greenfield System, the cost of producing 1 kg MS was 27\% higher than for the conventional rotary system. This was due to higher interest, depreciation and service contract costs, despite the lower labour, cow health and dairy costs. Sensitivity analysis showed that when other factors were held constant a 70\% decrease in capital cost or a more than two-fold increase in cow throughput was required for the Greenfield System to be as economic as the rotary system. Alternatively combining future improvements in AMS technology and farm system development including improved throughput to 112 cows/AMS, a 25\% decrease in milk harvesting system capital cost, equivalent production and a 10\% increase in the cost of labour produce a similar economic performance for the two systems. },
	issn = {1176-5283},
	author = {Jago JG and Davis KL and Newman M and Woolford MW}
}
@conference {41905,
	title = {Mastitis in cows milked in an automated or conventional milking system in New Zealand},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {66},
	year = {2006},
	month = {Jan},
	pages = {252-257},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Napier},
	abstract = {The viability of automated milking systems (AMS) for pasture-based dairying has been studied in New Zealand in the past four years. Automatic milking differs from conventional milk harvesting systems (CMS) in a number of ways, which may impact on udder health. These include fewer machines/cow, distributed vs. batch milking, variable milking intervals, automatic udder health monitoring systems, and pre and post-milking teat sanitation procedures. Three seasons of data from two pasture-based research farms that milked cows with either a two unit AMS or a 30 bail rotary CMS were compared. Quarter milk samples were collected routinely from all cows for bacteriological analysis during the 2002-03, 2003-04 and 2004-05 seasons, with sampling occurring throughout lactation and at detection of clinical mastitis (CM) cases. The number of cows in the AMS herd ranged from 94 to 196 and in the CMS herd, from 289 to 324 across the seasons. Clinical mastitis affected 7, 11, and 15 cows/100 cows/season in the AMS herd and 24, 23 and 14 cows/100 cows/season in the CMS across the three seasons, with Streptococcus uberis isolated from approximately 50\% of CM cases from both herds. Prevalence of S. uberis post-calving averaged 8\% of cows for the AMS and 16\% for the CMS across the three seasons. We compared several indicators of udder health between an AMS and a CMS herd managed under pastoral conditions. },
	issn = {1176-5283},
	author = {Lopez-Benavides MG and Williamson JH and McGowan JE and Lacy-Hulbert SJ and Jago JG and Davis KL and Woolford MW}
}
@conference {41654,
	title = {Stage of lactation affects the milking performance and behaviour of cows in a pasture-based automated milking system},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {66},
	year = {2006},
	month = {Jan},
	pages = {258-262},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Napier},
	abstract = {The successful implementation of automatic milking (AM) technology in pastoral dairy systems is dependent on the regular voluntary passage of cows from the grazing area to the dairy. A herd of 94 cows at the Dexcel Greenfield research farm was observed during a 31-day period to determine the effect of stage of lactation on milking performance and behaviour. Sixty-five cows were spring calved (late lactation, average 266 days in milk) and 29 were autumn calved (early lactation, average 19 days in milk). Cows were grazed as one herd in a rotational grazing management system with a fresh area of pasture available twice daily. Early lactation cows had a shorter average milking interval (14.6 vs 20.4 hours, p < 0.001) and a higher average daily production (20.0 vs 7.0 kg milk/cow/day, p < 0.001). They visited the selection units (from which they could gain access to water, fresh pasture and the raceway to the dairy housing the AM units) more often than cows late in lactation (2.8 vs 1.8 visits/cow/day, p < 0.001) and had a quicker transit time between pasture and the AM units (2.2 vs 2.7 hours/cow/milking, p = 0.026). Fewer early lactation cows needed to be manually moved from the grazing area for milking. The data indicates that stage of lactation will be a significant factor to consider when developing management systems for combining grazing with automatic milking. },
	issn = {1176-5283},
	author = {Jago JG and Davis KL and Woolford MW}
}
@conference {41833,
	title = {Factors influencing milk harvesting efficiency in an automatic milking system},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {65},
	year = {2005},
	month = {Jan},
	pages = {271-275},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Maximising milk harvested per robot is an important goal of pasture-based automatic milking systems (AMS). Results are presented from an analysis of 2937 cow milkings in a year-round milking system during January 2003 at the Dexcel Automatic farm (average herd size = 75 cows). Each cow milking was classified as OK (yield > 80\% of expected yield, EY), Yield Carry Over (YCO, 20\% < yield < 80\% EY), or Failed (F, yield < 20\% EY). The time and duration (from entry to exit from crate) of each cow milking was determined, as well as milk yield, and from these milk harvesting rate was calculated. There were an average of 95.8 cow milkings/day, average milking frequency was 1.13 milkings/cow/day (range 0.9 {\textendash} 1.9 milkings/cow/day). Eighty-four percent of milkings were classified as OK, 8.9\% as YCO and 7.1\% as F (after which the cow was returned to the yard for another attempt). Milking times {\textpm} SD (F = 3.76 {\textpm} 2.57, YCO = 7.63 {\textpm} 3.31, OK = 10.07 {\textpm} 4.09 minutes/event) and milk harvesting rate (F = 0.09, YCO = 0.76 and OK = 1.37 kg/minute) suggest that failed milkings were costly in terms of time. The data show potential for improving the 24 h milk harvest per AMS through cow selection, a more consistent flow of cows through the AMS and technological improvements.
KEYWORDS: milk harvesting efficiency; automatic milking systems; grazing; dairy cows. },
	issn = {1176-5283},
	author = {Davis KL and Jago JG and Wieliczko R and Copeman PJA and Bright K and Woolford MW}
}
@conference {41825,
	title = {Predicting next oestrous date and drafting automatically milked cows for focused attention on oestrous detection},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {65},
	year = {2005},
	month = {Jan},
	pages = {231-235},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {The autumn-calving herd at the Dexcel Automatic milking farm was used to test a system of predicting next oestrous date for individual cows and automatically drafting them for focused observation of behavioural oestrus. During the first 21 days of artificial inseminations (AI), the automatic milking system was programmed to draft cows into a holding paddock on each of three days either side of the due date for next oestrus, which was predicted from oestrous dates and milk progesterone concentrations collected prior to the planned start of mating. Cows drafted into the holding paddock were visually checked in the morning, released if not in oestrus or retained if in oestrus for AI later in the morning. The remainder of the herd was also visually checked for oestrus in the morning and afternoon. During the first 21 days of mating, 29 of the 37 cows (78\%) were inseminated, and 22 (76\%) of these were inseminated within the predicted {\textquoteleft}six-day separation window{\textquoteright}. Of these 22 cows, 15 (68\%) were detected as being in oestrus after being drafted into the holding paddock. A system for drafting cows due to be in oestrus for focused observation is achievable in practice, although improved performance will be necessary to reach the desired level of reliability.
KEYWORDS: oestrous detection; automation; dairy cattle. },
	issn = {1176-5283},
	author = {Burke CR and Davis KL and Jago JG}
}
@conference {41308,
	title = {Predicting the onset of parturition during the late gestation in dairy cows using udder scoring and hormonal profiling},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {62},
	year = {2002},
	month = {Jan},
	pages = {34-37},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {Sixty-four cows were blood sampled and physical signs of impending parturition were scored daily from Day 272. Sampling and scoring ceased on Day 282 of gestation or when parturition occurred, whichever came about first. Mean udder development scores increased from 2.0 {\textpm} 0.76 ({\textpm} SD) on Day -10 (ten days prior to parturition) to 3.2 {\textpm} 0.72 ({\textpm} SD) on Day 0 (day of parturition) with 84\% of cows having an udder score of 3 or 4 on the day prior to parturition (Day -1). Teat distension, vulva swelling and oedema were not useful as indicators of imminent parturition. Udder score was the most useful predictor, but the low frequency of scores less than 2 and greater than 3 on any one day resulted in unstable models. Plasma samples were assayed for progesterone, PGF2a metabolites (PGFM), cortisol and oestradiol. Oestradiol concentration on Day 274 was a useful predictor of whether an individual cow would calve within eight days (P=0.02). Plasma oestradiol concentrations used to build models to predict whether a cow would calve within the next five days were accurate from Day 272 to 275 of gestation (P<0.05). Progesterone, PGFM and cortisol were unreliable indicators. },
	issn = {1176-5283},
	author = {Davis KL and Macmillan KL}
}
@conference {41281,
	title = {Controlled Calving with induction of parturition on Day 274 of gestation in dairy cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {61},
	year = {2001},
	month = {Jan},
	pages = {184-187},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {The response and effects of inducing parturition on Day 274 of gestation in dairy cows with synchronised conception dates was investigated in selected herds around Victoria. Cows (n=227) were injected with dexamethasone trimethylacetate (30 mg, i.m.) with 444 herdmates as controls. Randomisation was based on scored udder development. Blood samples taken on Days 272 and 274 had average plasma progesterone concentrations of 4.50 and 4.49 ng/ml respectively (P>0.05). Treated (T) cows calved an average of 2.61 {\textpm} 0.21 days before their due date, compared to 0.17 {\textpm} 0.20 days for control (C) cows (P<0.001). There were no differences in the proportion of cows displaying symptoms of milk fever, mastitis, paralysis or acute metritis. The incidence of retained foetal membranes at 12h postpartum differed between the two groups (3\% vs. 16\%; C vs. T; P<0.005). Control cows received more assistance at parturition (15\% vs. 10\%, P<0.05). There were no differences between groups for cow or calf mortality, or for any parameter of milk yield. The effect of treatment on subsequent fertility was minimal. },
	issn = {1176-5283},
	author = {Davis KL and Macmillan KL}
}
