@article {3672,
	title = {An association between circulating copper concentrations and gammaglutamyl transferase activity in sheep after exposure to the toxin sporidesmin},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {80},
	year = {2020},
	month = {09/2020},
	pages = {34-38},
	address = {Online},
	abstract = {Copper is a potent catalyst of the reaction in which sporidesmin generates damaging free radicals causing facial eczema in grazing
livestock in New Zealand. This study sought to investigate whether circulating copper at the time an animal is dosed with the
toxin, influenced the way the animal responds to sporidesmin and whether the action of sporidesmin on the liver in susceptible
animals results in changes to circulating copper. Serum copper concentrations (CU) together with gamma glutamyl transferase
(GGT) activity, an indicator of bile duct damage, were opportunistically collected on over 400 animals from nine flocks in which
the animal{\textquoteright}s tolerance to sporidesmin was commercially assessed through measuring its response to a known dose of the toxin.
The association between CU concentration before the animals were dosed and natural log transformed GGT activity measured 21
days after the animals had been dosed was not significant, but there was a suggestive (P=0.06) interaction between flock and CU.
There was a significant positive association between natural log transformed GGT activity and CU concentrations measured 21
days after the animals had been dosed with the toxin (P<0.0001). For some individuals, the CU concentrations approached or met
copper-toxicity thresholds (above 40 μmol/L). The specific biological mechanisms causing this association remain unknown, but
given the role of copper in catalysing the sporidesmin reaction and the potential of toxic copper concentrations, further research
is warranted.

Keywords: sheep; facial eczema; copper; gamma glutamyl transferase},
	issn = {1176-5283},
	author = {PL Johnson and Amyes NC}
}
@conference {3672,
	title = {BRIEF COMMUNICATION: An update on genetic parameters for facial eczema tolerance in sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {76},
	year = {2016},
	month = {07/2016},
	pages = {43-45},
	address = {Adelaide},
	abstract = {Facial Eczema (FE) is a metabolic disease resulting
from liver and bile-duct damage, caused by ingestion of
the mycotoxin sporidesmin A, found in the spores of the
fungus Pithomyces chartarum. Risk of FE is associated
with temperature, humidity and dead leaf matter (Mitchell
et al. 1959; Brook 1963; Di Menna \& Bailey 1973). While
FE is predominantly prevalent in the North Island of New
Zealand, climatic change projections indicate that there
will be an increase in the geographical spread of the fungus
and associated sporidesmin, resulting in FE spreading to
regions that are currently unaffected (Dennis et al. 2014).
Clinical FE is characterised by photosensitisation
due to liver injury; however, reduced production (Smith
2000) and reproduction (Moore et al. 1983; Mcmillan et al.
1988; Morris et al. 1991) is also observed in both clinically
and sub-clinically affected animals. The heritability of
liver damage at slaughter post-sporidesmin challenge was
estimated to be 0.42 {\textpm} 0.09 (Campbell et al. 1981). In the
live animal, serum gamma glutamyltransferase (GGT)
collected 2 to 3 weeks after sporidesmin challenge can
be used as a measure of liver damage (Towers \& Stratton
1978). Romney FE selection lines, initially selected for
resistance or susceptibility on the basis of liver damage,
were established in 1975...},
	issn = {1176-5283},
	author = {Mcrae KM and Cullen NG and Amyes NC and PL Johnson}
}
@conference {3678,
	title = {Ramguard {\textendash} Increasing the Tolerance to Facial Eczema in New Zealand Sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {74},
	year = {2014},
	month = {06/2014},
	pages = {154-157},
	address = {Napier},
	abstract = {Facial eczema (FE) is a metabolic disease resulting primarily from damage to the liver and bile ducts. It is caused in ruminants by the effects of a mycotoxin, sporidesmin, produced by the fungus Pithomyces chartarum. The disease causes significant loss in agricultural production mainly in northern New Zealand. Sporidesmin toxin is produced in a laboratory and made available to those sheep breeders who wish to increase the level of FE tolerance in their flocks. The sheep industry in NZ has made steady progress towards increasing genetic tolerance to FE by testing potential future sires in ram-breeding flocks with an artificial challenge of sporidesmin. Ramguard provides the sporidesmin to breeders to dose their sheep at a specified dose-rate which is dependent on the level of tolerance already obtained. The Ramguard service has operated from August 1988 and has 60 clients dosing a total of 800 to 1100 rams each year. Most of the long-term-testing flocks are now using a dose rate six times higher than at the outset, which indicates animals in these flocks are tolerant to all but the severest outbreaks of FE. The heritability estimate for resistance to facial eczema is high at 0.45 {\textpm} 0.03.},
	issn = {1176-5283},
	author = {Amyes NC and Hawkes AD}
}
@conference {79028,
	title = {Heritability and repeatability of resistance to nematode parasites in commercial beef cattle},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {72},
	year = {2012},
	month = {Jan},
	pages = {236-239},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Faecal egg count (FEC) is used commonly as a guide to nematode parasite burdens in animals in vivo. The objective of this study was to estimate the heritability and repeatability of FEC in commercial beef calves, along with breeding values for FEC in the calves and their sires, for future quantitative and molecular analyses. In 2008-2011, faecal samples from 4,621 weaned beef calves were obtained for FEC1 from 11 herds (mainly Angus or Hereford). FEC1 represented the first sample after weaning generally between May and July); a second sample (for FEC2) was taken by September from all calves in some herds, with FEC1 and FEC2 samplings separated by an effective anthelmintic drench. Calves were sired by a total of 325 and 57 separate Angus and Hereford sires, respectively. Heritability estimates for loge(FEC+50) in Angus at Times 1 and 2 were 0.28 {\textpm} 0.05 (standard error) and 0.11 {\textpm} 0.09, respectively, with a genetic correlation of 0.89 {\textpm} 0.22 between them. Treating FEC1 and FEC2 as repeated measurements of the same trait, the repeatability estimate for loge(FEC+50) was 0.38 {\textpm} 0.04. The parameters estimated for loge(FEC+50) in weaned beef calves under commercial grazing conditions were similar to those from experimental beef calves.},
	issn = {1176-5283},
	author = {Morris CA and Amyes NC}
}
@conference {69505,
	title = {Correlated responses following genetic selection to change age at puberty in Angus cattle},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {70},
	year = {2010},
	month = {Jun},
	pages = {202-205},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {Direct and correlated responses in a 23-year selection experiment to change puberty in heifers are reviewed. Selection was for age at first oestrus (AFO). It was applied in both sexes, using the genetic correlation (-0.25 {\textpm} 0.09) between scrotal circumference in juvenile males and AFO in female relatives. The main breeding lines were those selected for early AFO (AGE-), late AFO (AGE+), or unselected (Control). A 69-day difference (19\% of the herd mean) was achieved between the two AGE lines, with a 3.0 cm (9.9\%) difference in scrotal circumference. Relative to the AGE+ line, the AGE- line means were +10.8 {\textpm} 3.1 kg (3.9\%) in yearling weight, -6.0 {\textpm} 3.0 kg (1.3\%) in cow mature weight, -47 {\textpm} 6 kg (16\%) in heifer weight at first oestrus, and +3.7 {\textpm} 1.5 percentage points for mixed-aged cow pregnancy rate. There were significantly fewer sub-fertile yearling bulls in the AGE- line (P <0.001), and maternal effects on autumn and winter weights on calves of this line were positive. For carcass composition, only depot fat differed significantly between lines (AGE- mean < AGE+ mean). No major unfavourable traits were observed in the AGE- line in this study.},
	issn = {1176-5283},
	author = {Morris CA and Amyes NC}
}
@conference {60976,
	title = {Responses to selection for pubertal traits in Angus cattle over 23 years},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {69},
	year = {2009},
	month = {Jun},
	pages = {201-205},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Selection to change age at puberty over 23 years was monitored in Angus cattle in a Ruakura study. A foundation herd was divided in 1984 into four lines: a control unselected line, and lines selected for high age-at-puberty (Age+), low age-at-puberty (Age-), and high scrotal circumference (SC), with the last two lines being merged later. Age at puberty (first oestrus, AFO) was determined in heifers from observations of first behavioural oestrus date; puberty was determined in bulls from SC records from 8 to 13 months of age. Selection for AFO was applied mainly to bulls, using the genetic correlation between AFO and SC from our data (-0.25 {\textpm} 0.09). Puberty records from 6,473 weaned calves were analysed, using restricted maximum likelihood methods to determine genetic changes achieved by line. Realised heritability estimates were 0.26 {\textpm} 0.03 (standardised AFO), and 0.40 {\textpm} 0.04 (individual SC records; repeatability over ages, 0.68 {\textpm} 0.01). Averaging over recent year{\textquoteright}s data, Age- line heifers had lower AFO than Age+ line heifers by 69 days (19\%; 1.33 phenotypic standard deviations), and bulls had larger SC by 3.0 cm (9.9\%; 1.17 phenotypic standard deviations). Correlated responses in pregnancy rate favoured Age- over Age+ females at all ages. },
	issn = {1176-5283},
	author = {Amyes NC and Morris CA}
}
@conference {42061,
	title = {Field test of production traits in genetically correlated with zearalenone resistance in sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {68},
	year = {2008},
	month = {Jan},
	pages = {122-123},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Brisbane, Australia},
	abstract = {Zearalenone is a naturally occurring toxin from the Fusarium fungus which grows on pastures in autumn. The toxin has been found in New Zealand from Northland to Southland (Garthwaite et al., 1994), but high concentrations are particularly common in the Gisborne/East Coast region. The toxin interferes with reproductive function in susceptible sheep (Smith et al., 1986), reducing fertility, ovulation rates and thus lambing percentages. Under research conditions with Romney sheep at Ruakura Research Centre, we have developed a protocol ...Continued },
	issn = {1176-5283},
	author = {Amyes NC and Morris CA}
}
@conference {41758,
	title = {Puberty in Angus bulls from lines selected for heifers{\textquoteright} age at puberty},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {67},
	year = {2007},
	month = {Jan},
	pages = {365-369},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Wanaka},
	abstract = {In reproductive studies of juveniles, puberty has to bedefined and decisions made on how to record it in both sexes. Our recording criterion for age at puberty in heifers is the date (and hence age) of first behavioural oestrus. This is a heritable trait under New Zealand grazing conditions, with a realised heritability estimate from a long-term AgResearch selection experiment of0.27 {\textpm} 0.04. Data published in Edinburgh by R. B. Land suggest that male puberty traits in mammals are also inherited and are related to female puberty traits, but the difficulty is in measuring puberty in males. Our indicator in the selection experiment mentioned above is scrotal circumference (SC), where single SC records had a heritability of 0.40 {\textpm} 0.03 and a repeatability over time of 0.67 {\textpm} 0.01. Our objective in the present study was to determine whether another indicator might be semen quality, derived from a serial assessment of semen samples over the likely puberty period, and to compare this with serial SC records. The selection experiment was established in 1984/85 with Angus cattle. Genetic selection was applied in one line ({\textquoteleft}AGE-{\textquoteright}) for lower age at puberty in heifers, and in a second line ({\textquoteleft}AGE+{\textquoteright}) for greater age at puberty in heifers. SC data were monitored each year in bulls from both lines. Young bulls from the 1997 and 1998 calf crops (25 per year) were also monitored for semen quality from about 9 to12 months of age. Semen samples were obtained by ampullary massage, and quality was assessed on a warmmicroscope stage, using a 0-5 scale. Semen score was plotted against SC from means for each breeding line and month, and the correlations over both lines were 0.98 in 1997 and 0.86 in 1998. The AGE- line was superior to the AGE+ line by 0.81 semen score units (P < 0.001) and by 4.0 cm (14\%) in SC (P < 0.001). Results showed that semen quality was associated with SC, and that both had responded to heifer puberty selection. It was easier to measure SC as the male puberty trait.},
	issn = {1176-5283},
	author = {Morris CA and Amyes NC}
}
@conference {41980,
	title = {Responses to selection in ryegrass staggers lines of sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {67},
	year = {2007},
	month = {Jan},
	pages = {204-208},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Wanaka},
	abstract = {Ryegrass Staggers (RGS) is predominantly a summer/autumn metabolic disorder in ruminants, caused by ingestion of the lolitrem-B toxin from endophyte-infected perennial ryegrass, and it is common in New Zealand. It causes lack of neuromuscular co-ordination in susceptible animals under stress, e.g. when mustered by sheep dogs. It is of welfare concern, and it is costly to farmers because it severely compromises grazing management. A flock was established at AgResearch in 1993, with two lines bred for resistance (RGS-R) or susceptibility (RGS-S) to RGS. Lambs are scored for susceptibility each year, when grazing on high endophyte pastures, and mustered by sheep dogs. In 2005 and 2006, 94\% and 91\% of lambs respectively in the RGS-S line showed clinical staggers, when grazing together with the RGS-R line which had 2\% and 6.5\% of clinical cases, respectively (P < 0.001). Using the latest standardised RGS scoring system, the heritability estimate of resistance/susceptibility to RGS was 0.36 {\textpm} 0.04. To understand more about why and how the RGS lines differ, blood samples were taken from the breeding-ewe flock (n = 126) in June 2005, outside the usual RGS and facial eczema season. Compared with the RGS-R line, the RGS-S line ewes had a 23\% higher activity (P < 0.001) of aspartate transaminase (AST), an enzyme indicating hepatic or muscular damage; there were similar findings inewes sampled four weeks apart (between-animal repeatability for AST = 0.85). In plasma samples from selection-line yearling females (two birth years; n = 95), the RGS-S line had 27\% and 37\% higher AST and alanine transaminase activities, respectively (both P < 0.001), and a 38\% higher creatine kinase activity (P < 0.05) than the RGS-R line. One explanation of these results is that, compared with the RGS-R line, selection in the RGS-S line may have changed two functions, a reduced ability to detoxify lolitrem-B, and an increased sensitivity to stress expressed as a tendency to show increased muscle tetany and damage.},
	issn = {1176-5283},
	author = {Morris CA and Amyes NC and Orchard RL}
}
@conference {41841,
	title = {Zearalenone challenge in sheep : urine sampling to measure response},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {65},
	year = {2005},
	month = {Jan},
	pages = {316-319},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Zearalenone is a fungal toxin produced by Fusarium species commonly found on autumn pastures in New Zealand. It may interfere with reproductive functions in sheep. In a search for a genetic measure of susceptibility, ewe and ram lambs were dosed orally with a suspension of zearalenone at a series of rates, at 8 and 11 months of age. Urine samples were taken at intervals from 2 to 50 hours later. The concentration of urinary zearalenone and its metabolites (Zen) was assayed using an ELISA. Adjustment for urinary volume was made by measuring the urinary concentration of creatinine (Cr), and results were expressed as Zen/Cr ratio (loge-transformed). In a separate experiment, breeding ewes were dosed with zearalenone at a single rate, and Zen/Cr response was measured. The following effects were evaluated in lambs: a) sex difference (ewe versus ram lambs), b) responses to three dose rates, c) time-series response data. The heritability of Zen/Cr was determined in lambs and breeding ewes; results were analysed after standardising for each treatment and sampling group. Urinary Zen/Cr, 6 h after dosing, differed between ewe and ram lambs by a factor of 1.75 (ewe lambs higher; P < 0.01). Zen/Cr values for three dose rates (3, 6 and 9 mg zearalenone per lamb), averaged over three sampling time points after dosing, were 23.5, 43.2 and 59.3, respectively (P < 0.0001). Zen/Cr values for three sampling time points (2, 4 and 6 h after dosing), averaged over three dose rates, were 58.0, 35.8 and 29.0, respectively (P < 0.0001). By 50 h after dosing, the Zen/Cr average had fallen to 4\% of its 2-h value. The interaction between dose rate and time of urinary sampling was not significant for log Zen/Cr. A preliminary estimate of the heritability for standardised Zen/Cr was 0.32 {\textpm} 0.10 (P < 0.01). The dosing regime reported here could be used for a test of animal response to zearalenone in ram breeders{\textquoteright} flocks.
KEYWORDS: sheep; zearalenone; dose response; urine; heritability. },
	issn = {1176-5283},
	author = {Morris CA and Amyes NC and Sprosen JM and Hawkes AD and Finch SC and Miles CO}
}
@conference {41842,
	title = {Zearalenone challenge in sheep : variation in ovulation rate},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {65},
	year = {2005},
	month = {Jan},
	pages = {320-323},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Zearalenone is a fungal toxin produced by Fusarium species commonly found on autumn pastures in New Zealand, and it may interfere with reproductive functions in sheep. We have measured both ovulation rate after challenge with zearalenone, and also a metabolic indicator, Zen/Cr (the concentration of zearalenone and its breakdown products (Zen) in urine, after adjustment for urinary volume using creatinine concentration (Cr)). A small self-replacing flock of Coopworth ewes was used for the study. This paper reports a preliminary assessment of whether Zen/Cr might be an equivalent but cheaper method than laparoscopic ovulation rate for measuring an animal{\textquoteleft}s resistance to zearalenone. Ovulation rates were determined in ewes in autumn before dosing (Lap1; Years 1 and 2), and after dosing (Lap2; Years 1 to 4) with 10 mg zearalenone per animal per day for 6 days. The average reduction in ovulation rate following dosing (Years 1 and 2: Lap1 minus Lap2) was 0.60 ovulations or 31\% of the mean. Lap2 was used for the present correlation analyses. The heritability of Lap2 was estimated (0.11 {\textpm} 0.09), and breeding values (BVs) for Lap2 were determined. Subsequent to the laparoscopy, the ewes were mated at pasture, and the resulting natural litter sizes were monitored in relation to BVs for ovulation rate after challenge. Urine samples were taken during and after dosing in Years 3 and 4, to measure Zen/Cr, and a heritability for Zen/Cr (0.32 {\textpm} 0.10) was estimated from these and other Zen/Cr data. Preliminary analyses of BVs for Lap2 and Zen/Cr revealed a negative correlation between them (r = - 0.55). Ewes with higher BVs for ovulation rate also had higher mean litter sizes following natural ovulation. In conclusion, zearalenone affects ovulation rate at moderate challenge levels, and this ovulation rate may be negatively related to the concentration of measurable urinary zearalenone metabolites.
KEYWORDS: sheep; zearalenone; dose rate; ovulation; heritability. },
	issn = {1176-5283},
	author = {Morris CA and Amyes NC and Smith JF and Sprosen JM and Towers NR}
}
@conference {41524,
	title = {Flystrike in lambs selected for resistance or susceptibility to ryegrass staggers, when challenged with high or low endophyte pastures},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {64},
	year = {2004},
	month = {Jan},
	pages = {297-299},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {Research has shown that incidence of flystrike is reduced in sheep grazing low endophyte ryegrass. This experiment was designed to test the hypothesis that where lambs are bred specifically for resistance to ryegrass staggers (RGS), their susceptibility to flystrike on the body should be correspondingly low, even when challenged with high levels of endophyte.
Ewe and ram lambs were sourced from two lines, one selected for resistance (n = 85) and the other for susceptibility (n = 143) to ryegrass staggers. A further group of lambs (n = 63) produced by intercrossing the two lines was included. The lambs were run in 2 mobs, on high and low endophyte pasture, and monitored daily for signs of flystrike on the body. During the course of the experiment, susceptible (n = 34) and resistant (n = 1) lambs suffering from clinical ryegrass staggers had to be removed from the high endophyte pasture. These were excluded from the analysis. Ram lambs made up the majority of animals removed.
Only ram lambs were flystruck on the body, particularly around the scrotal area. Significantly more resistant ram lambs (7 of 49) were flystruck than susceptible (3 of 85) or intercross ram lambs (2 of 27), regardless of pasture endophyte level (P < 0.1). More lambs (P < 0.1) were flystruck grazing ryegrass with high endophyte (n = 9) than low endophyte (n = 3). The only lambs flystruck while grazing non-endophyte pasture were RGS resistant rams.
In contrast to the hypothesis, this experiment indicates that selection of animals for resistance to RGS may exacerbate their susceptibility to flystrike. The evidence presented here supports the literature that sheep grazing high endophyte pasture are more susceptible to flystrike. The question for farmers is whether their selection priority should be for pasture with resistance to insect pests, or for stock with resistance to RGS, or both. },
	issn = {1176-5283},
	author = {Young SR and Scobie DR and Morris CA and Amyes NC}
}
@conference {41525,
	title = {Resilience to nematode parasite challenge in industry and AgResearch selection flocks},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {64},
	year = {2004},
	month = {Jan},
	pages = {300-303},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {A large-scale industry project on the resilience of lambs to nematode parasite challenge was undertaken in 2001/02 and 2002/03, to evaluate the feasibility of recording standardised age at first drench (StAge) and postweaning weight gain under nematode challenge, and to estimate genetic differences among flocks. The project involved 15 Romney flocks from two ram breeding groups, with some flocks having been part of an earlier AgResearch study of the genetics of resilience traits. This provided the opportunity to assess any correlated changes in resilience over time (where direct selection over that time period in the industry flocks had been applied to productivity traits, but not to resilience), and to compare the industry performance with AgResearch Resilient-selected and Control lines. The overall estimates of heritability for StAge and weight gain (2 time periods: Gain1 and Gain2) were 0.14 {\textpm} 0.014, 0.30 {\textpm} 0.015 and 0.15 {\textpm} 0.007, respectively. Genetic correlations between StAge and either Gain1 or Gain2 were 0.30 {\textpm} 0.06 and 0.41 {\textpm} 0.06, respectively. Genetic differences for all traits between the two industry groups were small and not significant. The genetic differences of the current industry-group means (all 15 flocks) above the AgResearch Control line were small (0.8 days, 0.5 kg and 0.9 kg, respectively). In comparison, the genetic differences of the AgResearch Resilient-selected line over the Control line after eight years of selection were 19 days, 0.7 kg and 1.4 kg (11, 8.3 and 9.6\% of the industry means). The results confirm that while selection for increased resilience is feasible (although very time-consuming) under commercial conditions, a ram breeder would need to consider an index approach which combined production and resilience traits, to make best use of his animal resources. },
	issn = {1176-5283},
	author = {Morris CA and Amyes NC and Bisset SA and Mackay AD}
}
@conference {41096,
	title = {Genetic progress in a Romney Group Breeding Scheme},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {59},
	year = {1999},
	month = {Jan},
	pages = {117-120},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The Auckland Romney Development Group was established in 1968 and its aims continue to be to test and select rams for Group Members, and to breed rams for sale under conditions relevant to farming in the greater Auckland district. Breeding objectives include increased litter size (NLB), weaning weight (WWT), yearling live weight (YLW), yearling greasy fleece weight (YFW), and also increased facial eczema (FE) tolerance. Each year until 1993, members received selected nucleus-bred 15-month rams for use at home, and the next cut of nucleus rams and some elite homebred rams were offered as breeding stock for sale. From 1993, restricted maximum likelihood methods were introduced to calculate breeding values, and across-age ram selection was applied. At the same time, the nucleus ewes were re-distributed across all Members{\textquoteleft} flocks, and between-flock and between-year genetic links were maintained by movement of sires for mating. Estimates of total genetic progress by birth-year (obtaining data from Animalplan files, which were only available from 1986) were: WWT (1986-97) 1.83{\textpm}0.17 kg (7.8\% of the mean), YLW 2.76{\textpm}0.24 kg (6.4\%), YFW 0.23{\textpm}0.01 kg (7.3\%) and NLB (1986-95) 0.029{\textpm}0.015 lambs (1.8\%), and all flocks have contributed to the long-term genetic changes. Annual genetic trends over the period were approximately linear, except for YLW which appeared to show an increasing response rate. This is probably related to the extensive progeny testing carried out since 1994 to study sire families which appear to be elite for YLW, using progeny-test matings of rams to outside tester ewes. Segregation tests for a possible major gene have been carried out. Some evidence of bimodal distributions for YLW within sire was found, with a gene whose effect was +9\% of the mean, in heterozygotes. Since 1993, secondary selection decisions based on FE have been complicated by across-flock selection, but genetic progress for this trait appears to be linear, with a heritability estimate for log (gamma glutamyltransferase; GGT) of 0.34{\textpm}0.09. Over the birth years 1981-1997 there was genetic change in GGT by a factor of 0.71 (29\% improvement), compared with a factor of 0.30 (70\% improvement) over the same time period in the single-trait FE selection lines at Ruakura (Resistant versus Control lines). },
	issn = {1176-5283},
	author = {Morris CA and Amyes NC and Hickey SM}
}
@conference {41015,
	title = {Preliminary results of selecting sheep for resistance or susceptibility to ryegrass staggers},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {58},
	year = {1998},
	month = {Jan},
	pages = {154-156},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Ryegrass staggers (RGS) is a neurotoxic disease in ruminants caused by the mycotoxin lolitrem B, found in endophyte-infected swards of perennial ryegrass (Lolium perenne L.). This paper reviews genetic studies on the incidence of RGS at Ruakura, and the early responses to selection achieved since 1993. Using a coarse 0 or 1 criterion only, the incidence of RGS each year was recorded on weaned lambs (born in 1988-92), 2-tooths and all mixed-aged ewes, between January and March of each year 1989-93. Clinical cases of RGS occurred in 17 of 25 contemporary groups, with incidences per group up to 0.16. With 3587 records from 2307 animals representing 232 sires, animal-model restricted maximum likelihood estimates of heritability and across-year repeatability for RGS incidence were 0.068 {\textpm} 0.028 and 0.24 {\textpm} 0.05 respectively. Breeding value data were used to screen ewes and 2-tooths in 1993 into resistant and susceptible selection flocks, and to allocate elite rams for mating. Over the 1993-97 mating years, 14 and 12 rams have been used in the two flocks, respectively (11 of these twice or more). There was no significant effect of gender on incidence of RGS. From the most recent completed recording year (i.e. 1996-born lambs), 82 resistant-flock and 56 susceptible-flock animals had RGS incidences of 0.20 and 0.75 respectively (P<0.001). One hundred and eighty-five first-crosses between the two selection lines were also generated in 1996 and 1997, which may eventually provide more evidence on the mode of inheritance. The selection flocks are being continued. The selection response so far indicates that genetic differences in RGS susceptibility can be achieved while using recording under extensive conditions. },
	issn = {1176-5283},
	author = {Morris CA and Towers NR and Amyes NC and Wheeler M}
}
@conference {40785,
	title = {Faecal nematode egg counts and facial eczema susceptibility in Romneys},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {56},
	year = {1996},
	month = {Jan},
	pages = {84-86},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {A study was carried out in two groups of flocks to estimate the  relationship between susceptibility to facial eczema (FE) and susceptibility  to nematode parasites. Faecal egg count (FEC) data on lambs born in 1989- 92 from 53 sire groups were collected on the Ruakura Romney flocks which  have been divergently selected for resistance/susceptibility to FE. In  addition, the Romney flocks selected at Rotomahana/Tokanui Stations for  resistance/susceptibility to FEC were sampled to provide the converse (i.e.  FE data) on lambs born in 1988 and 1989, and representing 43 sires. Faecal  samples for FEC were collected from lambs in January and March  (separated by an anthelmintic treatment) and the FEC data were analysed  using a loge transformation. FE susceptibilities, using the enzyme gamma- glutamyltransferase (GGT) as an indicator, were obtained in the FE flocks at  Ruakura after an oral sporidesmin challenge in May, and in the FEC flocks  at Tokanui after unintentional field challenge; the GGT data were also  analysed using a loge transformation. The weighted average heritabilities of  loge GGT and loge (FEC+100) were 0.44},
	issn = {1176-5283},
	author = {Morris CA and Towers NR and Watson TG and Wheeler M and Amyes NC and Hosking BC}
}
@conference {40088,
	title = {Carcass composition of exotic sheep breeds},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {48},
	year = {1988},
	month = {Jan},
	pages = {53-56},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	issn = {1176-5283},
	author = {Clarke JN and Parratt AC and Malthus IC and Amyes NC and Uljee AE and Woods EG}
}
@conference {40087,
	title = {Early growth and reproduction of exotic sheep breeds - a preliminary report},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {48},
	year = {1988},
	month = {Jan},
	pages = {49-52},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	issn = {1176-5283},
	author = {McMillan WH and Malthus IC and Clarke JN and Amyes NC}
}
@conference {39755,
	title = {Level of nutrition of the ewe and lamb survival},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {42},
	year = {1982},
	month = {Jan},
	pages = {13-14},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {No abstract supplied},
	issn = {1176-5283},
	author = {Johnson DL and Clarke JN and MacLean KS and Cox EH and Amyes NC and Rattray PV}
}
