@conference {40526,
	title = {Investigation into the possibility of a major gene for fleece weight in screened sires},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {53},
	year = {1993},
	month = {Jan},
	pages = {355-358},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {This study investigated the effect of a progesterone containing intravaginal CIDR (Controlled Internal Drug Releasing) device on plasma progesterone and luteinizing hormone (LH) concentrations during 14-day device insertion and the subsequent oestrous cycle of fallow deer (Dama dama). Blood samples were collected from 4 entire does at 20 minute intervals for periods of 8-12h on three occasions following device insertion (i.e. insertion, mid-treatment and withdrawal) and on Days 0, 5, 12 and 19 of the subsequent oestrous cycle. Plasma was analysed for progesterone and LH concentrations by radioimmunoassay. Plasma progesterone values were elevated (>6 ng/ml) and LH values reduced (<1 ng/ml) during device insertion relative to pre-insertion values. Plasma LH concentrations were highest on Day 0 of the oestrous cycle, with a marked increase in the pulse amplitude.  One doe exhibited a pre-ovulatory LH surge. Plasma progesterone increased from <0.5 ng/ml on Day 0 to 1.5-4.2 ng/ml on Day 12 (luteal phase) and high amplitude progesterone pulses were exhibited by all does on Day 19 (onset of luteolysis). The study has demonstrated that CIDR devices deliver sufficient progesterone to inhibit ovulation and the declining plasma LH concentrations during device insertion support a hypothesis of negative feedback by progesterone on LH secretion.},
	issn = {1176-5283},
	author = {Wuliji T and Dodds KG and Fennessy PF and Andrews RN and McEwan JC and Turner P and Wheeler R and Hawker H}
}
@conference {40400,
	title = {Melatonin secretion in Romney ewes differing in wool growth and reproduction is not aligned to photoperiod during spring and summer},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {52},
	year = {1992},
	month = {Jan},
	pages = {149-152},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {A progeny test involving Romney (n=5) and Poll Dorset (n+5)  rams mated to Romney ewes was conducted to examine the relationship  between testis size and endocrine parameters, measured during the  transitional period from the non-breeding to the breeding season, in  rams, and reproductive performance of their daughters in the first and  second breeding seasons. More of the Poll Dorset cross hoggets reached  puberty during the first breeding season (80 v. 60\%; P<0.01) associated  with earlier onset (13 v. 22 May; P<0.10) at younger ages (264 v. 276  days; P<0.10) and more oestrous cycles (2.7 v. 2.0; P<0.05) than for  Romney hoggets. The date of onset of the second breeding season was  influenced by breed (P<0.001) and sire within breed (P<0.05). These  differences between Romney and Poll Dorset cross animals in reproductive  performance were associated with differences between their sires in the  pattern of seasonal variation in testis size and plasma gonadotrophin  concentrations. However, within-breed correlations between testicular  and endocrine parameters in the sires and date of onset of the breeding  season in the offspring were low. It is concluded that, while some of  the testis and endocrine parameters could potentially be used as  selection criteria for date of onset of the breeding season in ewes,  further studies are needed before these parameters can be incorporated  into selection programmes.  },
	issn = {1176-5283},
	author = {Scott IC and Heath D and Hawker H}
}
@conference {40119,
	title = {Production and characteristics of wool from the hogget progeny of sheep intensively screened for fleece weight},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {48},
	year = {1988},
	month = {Jan},
	pages = {207-212},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Dairy farmers made management decisions each season about which cow to replace. At present dairy farmers can use the production index. The production index is an historical measurement of a cow{\textquoteright}s milkfat production ranking, free from the influences of herd environment, age, stage of lactation and herd genetic level. A dynamic programming method is outlined which incorporates genetic, reproductive and economic information. This method ranks cows on their annualised present value. A sensitivity analysis was undertaken and the effects of the changes in the different economic parameters are discussed. The optimal cow rankings produced by the dynamic programming method were shown to be robust to changes in milkfat, manufacturing beef and heifer replacement prices and interest rate.},
	issn = {1176-5283},
	author = {Hawker H and Dodds KG and Andrews RN and McEwan JC}
}
@conference {40023,
	title = {Implications of objective measurement for sheep management},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {46},
	year = {1986},
	month = {Jan},
	pages = {198-200},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Fleeces from 2000 mixed age Merino ewes in each of 6 years were classed traditionally (i.e. by subjective assessment of fineness into 2 or 3 lines) or objectively (i.e. fleeces put into one line). Off-type fleeces (about 10\%) which differed markedly from the bulk of the clip were excluded from all the lines. The fleeces from 800 to 1000 Merino hoggets in each of 6 years were also used in comparisons of traditional and objective classing. The fibre diameter of each objective (OCP) line was very similar to the weighted mean of the corresponding traditional (TP) lines. Clean auction prices for the OCP lines were 0.8\% and 1.0\% lower than the weighted means of the TP lines for the ewes and hoggets, respectively. Research in Australia has shown that there is no difference in the processing performance of traditionally or objectively classed lines of fleece wool. The optimum classing method is therefore determined solely by the relationship between price and diameter. Wools 21 },
	issn = {1176-5283},
	author = {Sumner RMW and Hawker H}
}
@conference {40028,
	title = {Live weights, fleece weights and wool characteristics of screened high fleece weight and randomly selected Romney ewe hoggets},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {46},
	year = {1986},
	month = {Jan},
	pages = {219-224},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Trials between 1979 and 1984 with Angora or Saanen donors showed that synchronisation of oestrus with progesterone injections delayed oestrus compared with progestagen sponges and that this delay was associated with fewer follicles and increased egg recovery and fertilisation rates. Highest ovulation rates were achieved when FSH was injected instead of PMSG and when donors were Saanens rather than Angoras. Surgical egg recovery rates decreased in donors with prematurely regressing ovulations. The response of recipients (feral or Angora) to sponge treatment varied markedly between years. Recipient pregnancy rate and embryo survival both increased when recipients were surgically twinned rather than singled. The various trials have enabled the development of an effective transfer regime. This involves synchronising/superovulating donors with progesterone/FSH and twinning or tripleting of recipients. Under these conditions Angora and Saanen donors average respectively, 14.0 and 24.5 ovulations, 10.8 and 18.6 transferable embryos and 7.5 and 11.8 kids born to recipients.},
	issn = {1176-5283},
	author = {Hawker H and Littlejohn RP}
}
@conference {40026,
	title = {Rationalised classing of fine wools},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {46},
	year = {1986},
	month = {Jan},
	pages = {209-213},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Oestrus synchronisation in hoggets was compared using either polyurethane sponges containing progestagen or 9 mm diameter silicone elastomer CIDRs (controlled internal drug releasers) in 600 hoggets in 3 trials. CIDRs and sponges were removed after 12 days in late May and 200 IU PMSG given to hoggets in 2 of the trials. Hoggets in the third trial received 0 or 300 IU PMSG. Half of the hoggets were shorn 1 month prior to the 4-day joining with entire rams. The loss rate of CIDRs and sponges was low (2\%). No hoggets mated in the first 24 hours after removal and most matings occurred during the second day. During the peak of mating, more CIDR-treated hoggets appeared to mate in 2 trials, but fewer in the third (28 v 44\% P<0.01). By the end of the entire joining, there was little difference in total mated. Treatment with CIDRs or sponges did not affect ovarian activity. Pregnancy rates were unaffected by method of synchronisation in 2 trials and improved by CIDRs in the third (38 v 20\% P<0.05). Shearing generally had no effect on reproductive performance. PMSG improve oestrous and ovarian activity, but did not affect pregnancy rate. CIDRs were an effective substitute for sponges in achieving synchronised pregnancies in hoggets. Low pregnancy rates limited the ability to fully capitalise on the benefits of synchronisation.},
	issn = {1176-5283},
	author = {Andrews RN and Hawker H}
}
@conference {39963,
	title = {Effect of herbage allowance on the productive performance of lactating and non-lactating hoggets},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {45},
	year = {1985},
	month = {Jan},
	pages = {147-150},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Techniques of real time ultra sound (ADR 2130), Toshiba Sonolayer-L SAL 22A) and radiography (DSIR X-ray) were assessed to determine the accuracy of identifying ewes carrying 3 or more lambs. Ewes were scanned between 62 and 75 days of gestation with ultra-sound and between 110 and 124 days with X-ray. There were 94.2\% (ultra- sound) and 96.2\% (X-ray) of ewes predicted to be carrying 3 or more lambs that actually lambed with 3 or more lambs. However, 21.1\% (ultra-sound) and 8.4\% (X-ray) of ewes which lambed with 3 or more lambs were predicted to lamb with<3 lambs. Because ultra-sonic diagnosis is carried out at an earlier stage of gestation it gives greater flexibility to apply nutritional management to ewes carrying 3 or more lambs in order to sustain foetal growth in these high litter sizes.},
	issn = {1176-5283},
	author = {McEwan JC and Mathieson CD and Hawker H}
}
@conference {39982,
	title = {Effects of level of nutrition in winter and summer on the wool growth of Romney and Perendale ewes with a history of high or low winter wool growth},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {45},
	year = {1985},
	month = {Jan},
	pages = {225-228},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The active immune system involves phagocytic, cell mediated and humoral processes plus complement proteins, all interacting to protect the individual from pathogenic organisms. Passive immunity is acquired by new-born ungulates by ingestion of immunoglobulins from colostrum. Research in laboratory animals has established that peak antibody synthesis following challenge with a foreign antigen responds readily to directional selection. The increased titre frequently results in enhanced resistance to some diseases but enhanced susceptibility to others. Oregon State University research has produced conflicting results as to the heritability of the ability of new-born calves and lambs to acquire and absorb colostral immunoglobulins and as to the heritability of this passive immunity considered as a trait of the dam. Significant differences among breeds, selection lines and strains did exist for level of colostral immunoglobulins, and low levels (and, in one experiment, high levels as well) were associated with lower neonatal survival. In cattle, there was little evidence that either active immune response or level of complement protein C3 was heritable; but in ewes, the antibody titre to a challenge antigen was moderately to highly heritable. The authors speculate that stabilising selection for immune system traits might be most effective to improve generalised disease resistance and overall livestock production efficiency.},
	issn = {1176-5283},
	author = {Hawker H and Crosbie SF}
}
@conference {39962,
	title = {Effects of shearing and herbage allowance on the intake, live weight gain and wool growth of Romney ewe hoggets in spring/summer},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {45},
	year = {1985},
	month = {Jan},
	pages = {141-146},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Previous work showed that nutrition during pregnancy substantially affected ewe live weight, but that subsequent effects on ewe and lamb survival and weaning weights were small. However, farm advisers have suggested that industry ewes suffer more weight loss than in the above trials with serious consequences for ewe and lamb survival. These problems were investigated in a trial involving 2 levels of nutrition in mid-pregnancy followed by 3 levels of nutrition in late pregnancy. Average conceptus-free live weights of the 6 groups at lambing ranged from 47.6 to 38.1 kg. The ewes had weighed 53 kg at the start of the trial. Ewes severely under-nourished throughout had an 86\% survival during the trial period compared with 94\% for the 5 better-fed groups. A line of ewes within the severely under-nourished group had, however, only 80\% survival. There was a decline in the percentage of ewes lambing due to very nutrition in mid-pregnancy (78 v 85\%). Similarly, lambing percentage of those ewes lambing was affected (126 v 142\%). There was some effect on twin lamb survival. Birth weight, particularly twin lambs, was reduced by low nutrition but there was no effect on weaning weight.},
	issn = {1176-5283},
	author = {Hawker H and Crosbie SF and Barber M and Andrews RN}
}
@conference {39819,
	title = {Date of lambing and sheep production during lactation in Southland},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {43},
	year = {1983},
	month = {Jan},
	pages = {45-48},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {In a series of 10 trials involving over 5000 lactating dairy cows, animals inseminated when detected in oestrus from 3 days after an injection of a prostaglandin F2a (PGF) had an average pregnancy rate of 68\% compared to 59\% in untreated herdmates. The variation in the post injection interval to oestrus necessitated detecting oestrus before the PGF-related fertility effect could be repeatedly demonstrated. When a synthetic analogue of gonadotrophin releasing hormone (GnRH) was injected before PGF in an attempt to reduce the variation in this injection-to-oestrus interval, the opposite effect occurred, the average interval was increased by 3 days (4.13 v 7.03) and the PGF-related fertility effect was eliminated. A second trial with GnRH confirmed that an injection of this hormone had an effect on the corpus luteum which prevented complete luteolysis by PGF. This interaction between GnRH and the corpus luteum was studied in 3 further trials in which GnRH was injected once at from 1 to 13 days post insemination. Positive fertility effects were observed in each trial, but they were not consistent. Nonetheless, the strategic use of these 2 types of hormones offer prospects for significantly increasing pregnancy rates to first insemination in lactating dairy cows.},
	issn = {1176-5283},
	author = {McEwan JC and Mathieson C and Hawker H}
}
@conference {39826,
	title = {Fleece tenderness - a review},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {43},
	year = {1983},
	month = {Jan},
	pages = {73-78},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The heritability of loose wool bulk and yellowness (CIE Tristimulus value Y-Z) and the genetic and phenotypic correlation of these with other wool traits were determined from data obtained on ewe hoggets born in 1979 and 1980 in the strains trial at Rotomahana. Heritability estimates were 0.41 },
	issn = {1176-5283},
	author = {Bigham ML and Sumner RMW and Hawker H and Fitzgerald JM}
}
@conference {39805,
	title = {Effects of season and pasture allowance on the wool growth of Romney ewes},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {42},
	year = {1982},
	month = {Jan},
	pages = {183-186},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The minimal drenching recommendations for lambs of the N.Z. Society of Animal Production Study Group (2 or 3 drenches) were compared with 5 and 12 fortnightly drench regimens on safe (low larval count) and contaminated (high larval count) pastures. Lambs grazing safe pastures had lower (P<0.05) gastrointestinal worm burdens than lambs grazing contaminated pastures, and increased drenching frequency significantly reduced (P<0.01) the average faecal egg count. The minimal drenching regimen did not adequately control parasitism in lambs. Increasing the number of drenches improved parasite control and increased wool and live-weight production.},
	issn = {1176-5283},
	author = {Hawker H and Crosbie SF and Thompson KF}
}
@conference {39685,
	title = {Wool production and characteristics of Merino and Longwool ewes and their respective Booroola crosses},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {40},
	year = {1980},
	month = {Jan},
	pages = {205-208},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	issn = {1176-5283},
	author = {Hawker H and Davis GH and Allison AJ}
}
