@conference {69018,
	title = {Parasite-related traits in lambs sired by resistant or resilient Romney sires : Brief Communication},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {69},
	year = {2009},
	month = {Jun},
	pages = {228-229},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Finding methods of dealing with increasing levels of anthelmintic resistance is important to the New Zealand sheep industry. Genetic selection within the sheep population for animals that are less reliant on anthelmintic therapy is one approach, and AgResearch has bred selected lines of Romneys over recent decades. These have included lines for resistance and for resilience (Bisset et al., 2001). The resistant line, selected for low faecal egg count (FEC) in lambs, was established in 1979. The line selected for increased resilience in lambs was set up in 1994. Resilience is the ability of animals to maintain acceptable health and growth under high parasite challenge, with minimal need for anthelmintic treatment. We report results here from a study to evaluate sires from these two long-term breeding lines, with progeny measured for weaning weight (WWT) and faecal egg count (FEC) at weaning.},
	issn = {1176-5283},
	author = {Wheeler M and Morris CA and Devantier BP}
}
@conference {41979,
	title = {Ultrasonic measurement of backfat and muscling in sheep selected for parasite-related traits},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {67},
	year = {2007},
	month = {Jan},
	pages = {198-203},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Wanaka},
	abstract = {This paper reports on backfat depth and muscling comparisons of sheep selected for nematode parasiterelated traits. Results are from two AgResearch projects, the first located at Kaitoke Farm (Upper Hutt), in which experimental Romney lines wereselectively bred for susceptibility (S) or resistance (R) to nematode infection (high or low faecal egg count), or for resilience to nematode challenge whilst maintaining acceptable growth with minimal anthelmintic treatment (RL line); these lines grazed alongside an unselected control line (C). The second project was located at Ballantrae (Northern Wairarapa), in which Romney breeding lines were selected for resilience, with two replicate farmlets under {\textquoteright}Conventional{\textquoteright} parasite management (with anthelmintic treatment), and with two further replicate farmlets under {\textquoteright}Low-Chemical{\textquoteright} management. The four replicate lines at Ballantrae were serviced by rams of equivalent genetics, from elite RL-line sires bred at Kaitoke or Ballantrae. Ultrasonic backfat depth and eye muscle dimensions (length, depth and area) of ewe lambs from each project were assessed at 8-9 months of age (234 C-, S-, R- and RLline lambs born in 2003 at Kaitoke, and 154 resilient lambs born in 2004 at Ballantrae). Adjustments were made for significant fixed effects including covariate adjustment for live weight. No significant differences were found among the R, C and RL lines for either trait, but the S line had 5-10\% smaller eye-muscle dimensions (P < 0.05) than the other lines following an extended period of natural nematode challenge with minimal drench treatment. The two replicate lines under Low-Chemical management were 3.8 {\textpm} 0.6 kg (11.8\%) lighter in May than the replicates under Conventional management (P < 0.001). After adjustment for live weight, lambs in the Conventional treatments had 15\% larger eye-muscle areas (P < 0.001) but not backfat depths than those in the Low-Chemical treatments. Results suggest that muscle dimensions of the Sline lambs were more affected than those of their R-line counterparts by parasite infection, whilst the C-, R- and RL-line lambs did not differ significantly. At Ballantrae, even at equivalent live weights, the two Conventional replicates had more muscling but not fat depth than the two Low-Chemical replicates.},
	issn = {1176-5283},
	author = {Wheeler M and Morris CA and Bisset SA and Vlassoff A and Mackay AD and West CJ and Devantier BP}
}
@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 {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 {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}
}
