@conference {69528,
	title = {Methods of delivering salt to cattle},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {70},
	year = {2010},
	month = {Jun},
	pages = {296-298},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {Urine from farmed livestock contributes significant quantities of nitrate nitrogen (N) to water bodies, resulting in elevated phytoplankton and nuisance plant growth. Heavily nitrate-contaminated groundwater can impair animal and human health. Ammonia and nitrous oxide also emit from urine patches, especially in anaerobic soil conditions (Ledgard and Luo, 2008). Several N leaching mitigation treatments are being evaluated in the Lake Taupo catchment (Ledgardet al., 2007) with salt, fed as a diuretic to cows during winter, showing most promise in modelling research (Bryantet al., 2007). This is probably because leaching losses from urine patches decrease exponentially as the load of N in urine patches decreases (Ledgard, 2001).},
	issn = {1176-5283},
	author = {Costall DA and Betteridge K}
}
@conference {60932,
	title = {Strategically reducing time on pasture: Dairy cow intake, production, welfare, and excretory behaviour},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {69},
	year = {2009},
	month = {Jun},
	pages = {15-19},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {In wet spring conditions, cows are often stood off pasture reducing their pasture intake. However, studies indicate that despite reduced grazing access, pasture intake and milk production can be maintained. This study restricted daily grazing access to eight hours in early lactation to determine the effect on pasture intake, milk production, and urination distribution. Forty-eight Holstein-Friesian cows were allocated to three duplicated treatments. Cows had access to pasture for either four hours after each milking (2x4), eight hours between milkings (1x8), or for 24 hours, excluding milking times (Control). When not grazing, the 2x4 and 1x8 treatments were stood off on a bark pad. The 1x8 cows ate less pasture (10.9 kgDM/cow/d; P <0.05) than the Control (13.6 kgDM/cow/d), but the 2x4 intake (13.0 kgDM/cow/d; P = 0.46) was not different to the Control. The 1x8 and 2x4 cows produced less milk (20.2 and 21.5 kg milk/cow/d respectively; P <0.05), relative to the Control (23.3 kg milk/cow/d). Urinations on pasture and races were reduced (P <0.05) from 90\% (Control) to 62\% (1x8) and 65\% (2x4) of total urinations. Eight-hours grazing per day should be offered as two four-hour periods to maintain cow pasture intakes, although milk yields are reduced. Corresponding changes in urination distribution may have environmental benefits. },
	issn = {1176-5283},
	author = {McLeod KLM and Clark CEF and Glassey CB and Gregorini P and Costall DA and Betteridge K and Jago JG}
}
@conference {41260,
	title = {Genetic studies of resilience of Romney sheep to nematode challenge in New Zealand},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {61},
	year = {2001},
	month = {Jan},
	pages = {92-95},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {"Resilience" in sheep can be defined as the ability to withstand nematode challenge, and to maintain acceptable health and productivity, with minimal reliance on anthelmintic treatment. One heritable component trait is Total Drench Requirement (TDR), which is measured in lambs managed on a regime of "drench-on-demand" (where Trichostrongylus and Ostertagia are the predominant nematode genera in New Zealand sheep). A breeding experiment was established in 1994, selecting for increased resilience in Romney lambs. Currently, breeding ewes in the experiment are subdivided between Ballantrae, where four genetically equivalent sub-groups graze separate farmlets year-round, under Non-Chemical versus Conventional management (AgResearch{\textquoteright}s Low-Chemical Farming Systems Programme), and Wallaceville, where an Elite Resilient line was re-established in 1999 alongside the Control Faecal Egg Count (FEC) line. Selection responses up to 1999/00 in the Elite Resilient-line lambs (relative to the Control line) included a 27\% greater post-weaning weight gain (GAIN: Dec. to Apr.), a 0.48 unit reduction in dags, and a 45\% reduction in TDR (Dec. to Apr.). A favourable genetic correlation (-0.54) was recorded between TDR and GAIN in lambs, whilst that between TDR and log FEC was -0.17 (not significant). Mean autumn weights in lambs at Ballantrae were 5.8 kg (18\%) lower in the Non-Chemical than Conventional treatment groups (P<0.01). Through intense genetic selection, 51\% of Elite-line ram lambs are now resilient enough for low-chemical or organic production systems. },
	issn = {1176-5283},
	author = {Morris CA and Bisset SA and Vlassoff A and Mackay AD and Betteridge K and Alderton MJ and West CJ and Devantier BP}
}
@conference {41045,
	title = {Pregnancy diagnosis of twinning beef cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {58},
	year = {1998},
	month = {Jan},
	pages = {259-261},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Technology now exists to make beef cows twin-pregnant. Accurate detection of pregnancy status is a prerequisite for differential management of twin and single-bearing cows. Calving outcome for about 50 beef cows was compared with predicted outcome by foetal counting using transrectal ultrasonography at day 50-70 of pregnancy, and veterinary palpation to confirm pregnancy at day 111-156. The trial ran for 4 annual calvings, and different combinations of scanning operator and equipment were used in each year. Overall accuracy of prediction of calving outcome ranged from 74-94\%, and did not differ for cows carrying singles or twins. Prediction accuracy was highest in the 2 years where scanning equipment provided a high degree of visual detail, and the operator was experienced in distinguishing foetal abnormalities. It was concluded that the combination of early foetal counting using ultrasound, and later determination of wet/dry status by palpation, could lead to levels of accuracy close to those being achieved by competent commercial scanning operators for sheep. },
	issn = {1176-5283},
	author = {Lambert MG and Perkins NR and Devantier BP and Knight TW and Betteridge K}
}
@conference {40977,
	title = {Sampling strategy for estimating dairy-pasture quality},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {58},
	year = {1998},
	month = {Jan},
	pages = {25-28},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Rapid determination of pasture quality using near infrared reflectance spectroscopy (NIRS) makes it feasible for farmers to
incorporate forage composition in feed budgeting and feed supplementation decisions for grazing animals.  In grazed pastures,
heterogeneity in the distribution of the mass and quality, necessitates a sampling strategy to accurately predict the diet. A single paddock
was systematically sampled by selecting 60 sites according to a pre-determined grid. At 12 of these sites, 4 separate but adjacent samples
of 150 x 150 mm were taken from within a 300 x 300 mm quadrat. To characterise vertical heterogeneity, the herbage at each of the
60 sites was cut sequentially into 4 equal strata, the depth of each being one-quarter of the canopy surface height at that site. These
samples were used to derive a statistically-based 3-dimensional characterisation of variability of herbage mass and of several
parameters of herbage quality determined using NIRS. This description was used to calculate the number of samples necessary to
estimate parameters to arbitary, pre-determined levels of accuracy of {\textpm} 50 kg DM/ha for herbage mass in each stratum, {\textpm} 50 g/kg protein
(PROT), acid detergent and neutral detergent fibre (ADF; NDF), {\textpm} 20 g/kg for soluble carbohydrate (CARB), {\textpm} 25 g/kg for in-vitro
dry matter digestibility (DIG) and {\textpm} 0.5 MJ/kg for metabolizable energy (ME). A minimum of six samples bulked together is necessary
to estimate PROT, CARB, NDF and ADF to the specified level of accuracy, and this number was similar for each stratum. Twelve
samples are required to estimate ME and DIG for each of the 3 upper strata, but in the lowest stratum with greater variability, 48 and
19 samples would be required for ME and DIG, respectively, to reach the same accuracy. A sampling strategy should take the suggested
number of samples by systematically covering the paddock area. Uncertainty in the depth of sampling because of the necessity to sample
before grazing has little effect on the number of samples required or on the accuracy of estimates, providing the lowest stratum is not
penetrated during either sampling or grazing.},
	issn = {1176-5283},
	author = {Cosgrove GP and Betteridge K and Thomas VJ and Corson DC}
}
@conference {40865,
	title = {Winter feeding of twinning beef cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {56},
	year = {1996},
	month = {Jan},
	pages = {382-385},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {A grazing trial was conducted in southern North Island hill country  during 1994, to determine the influence of pasture allowance during winter  on cow/calf performance of 40 twin- (T) and 40 single-calf (S) bearing  Friesian-cross beef cows. Groups of T and S cows were grazed at low (L),  medium (M) and high (H) pasture allowances for the last 4 months of  gestation. Average LW in late autumn was 467 kg, and change up to 4 weeks pre- calving was LS -7.8\%, MS -2.4\%, HS +1.5\%, LT -8.1\%, MT -3.0\%, HT - 3.5\%, suggesting S cows responded to a increased pasture allowance in late  gestation, but T only to M and no further to H. Blood serum bOH  concentration, which was used as a measure of energy status, was not  influenced by allowance treatment, but T (2.2 mmol/l) had higher  concentrations than S (0.9). Twinning cows had a shorter gestation length  than S cows (277 vs 284 d). Twin calves were lighter at birth (30.9 vs 44.2  kg), had lower perinatal survival (73 vs 96\%), and grew more slowly to 4  months of age than single calves (0.76 vs 1.11 kg/d). Our results suggest that },
	issn = {1176-5283},
	author = {Lambert MG and Devantier BP and Betteridge K and McMillan WH and Pugh PA}
}
@conference {40448,
	title = {Intake and liveweight change of hoggets grazing pastures differing in dead matter content in autumn},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {53},
	year = {1993},
	month = {Jan},
	pages = {29-32},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {White clover herbage in the vegetative stage of growth has a high nutritive value for milk production, but he high crude protein content could be better utilised if cows were given a suitable readily fermentable carbohydrate source. Six rumen fistulated Friesian cows in late lactation were housed in metabolism cages and fed either fresh white clover herbage or white clover and maize silage (50:50). The experiment was a cross over design that allowed measurement of nutrient intake, rumen function and milk production. At similar digestible organic matter intakes (9.6 kg/d vs 9.9 kg/d), replacing 50\% of the white clover dry matter with maize silage reduced crude protein intake by 30\% (3 kg/d vs 2.1 kg/d), and urinary N excretion from 251 gN/d to 137 gN/d without affecting milk yield (12.6 l/d vs 12.51 l/d) or milk protein output (400g/d vs 413 g/d). Rumen pH was similar for both treatments (6.1 vs 6.0) but there was a higher utilisation of neutral detergent fibre (2.6 kg/d vs 3.4 kg/d) when the cows were fed the mixed diet. The excess intake of nitrogen when the cows were fed white clover only was calculated to be largely wasted as ammonia absorbed from the rumen and excreted as urinary urea.},
	issn = {1176-5283},
	author = {Hawkins C and Betteridge K and Costall DA and Liu Y and Vallentine I and Parker WJ}
}
@conference {40416,
	title = {Wool production from wet and dry ewes on southern North Island hill country},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {52},
	year = {1992},
	month = {Jan},
	pages = {217-220},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Two trials were conducted which examined the effect of duration  of CIDR},
	issn = {1176-5283},
	author = {Betteridge K and Lambert MG and Devantier BP and Budding PJ and Costall DA and Fletcher RH}
}
@conference {40238,
	title = {Goat fibre response to melatonin given in spring in two consecutive years},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {50},
	year = {1990},
	month = {Jan},
	pages = {335-338},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {No abstract supplied   },
	issn = {1176-5283},
	author = {Welch RAS and Gurnsey MP and Betteridge K and Mitchell RJ}
}
@conference {40160,
	title = {Fibre growth cycles of unselected, reproducing cashmere does discussed in relation to winter shearing},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {49},
	year = {1989},
	month = {Jan},
	pages = {163-164},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Animalplan is an integrated set of data processing packages that meets the pedigree and performance recording requirements of many animal species in a unified way. The package offers much flexibility in terms of specification of breeding objectives, the traits to be recorded and presentation of reports. Technical aspects discussed include breeding objectives, trait adjustment for non-genetic effects using standard or flock/herd specific adjustments, prediction of breeding values using selection index techniques, restricting a trait to zero genetic change and the estimation of direct and maternal effects.},
	issn = {1176-5283},
	author = {Mitchell RJ and Betteridge K and Welch RAS and Gurnsey MP and Nixon AJ}
}
