@conference {41270,
	title = {The influence of reproductive status on pituitary gland function in seasonally anoestrous red deer hinds},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {61},
	year = {2001},
	month = {Jan},
	pages = {141-143},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Changes in pituitary responsiveness to exogenous hypothalamic hormones were assessed during seasonal anoestrous in dry, pregnant and lactating hinds. Of the fifteen adult red deer hinds monitored, five were non-pregnant, five had their calves removed immediately after birth, and five suckled their calves. All hinds were given a single i.v. injection of hypothalamic releasing hormones (5mg each of GnRH, GRF and TRH) on four occasions between Nov/Dec (10 days prior to calving) and March. The pituitary response was determined from changes in plasma concentrations of LH, growth hormone, and prolactin in samples obtained by jugular venepuncture at 0, 15 and 30 min after injection. Reproductive state significantly (P<0.001) affected LH release with a mean response (over all sample dates) of 1.12 ng/ml in dry hinds compared with 0.85 ng/ml in hinds that had their calves removed and 0.60 ng/ml in lactating hinds. Neither growth hormone (average 5.65 ng/ml) nor prolactin (average 33.9 ng/ml) responses were affected by reproductive status. },
	issn = {1176-5283},
	author = {Fisher MW and McLeod BJ and Meikle LM and Martin SK}
}
@conference {41130,
	title = {Monitoring oestrus and ovulation in brushtail possums},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {59},
	year = {1999},
	month = {Jan},
	pages = {236-238},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The time of ovulation following removal of pouch young (RPY) was determined in 240 possums by repeated laparoscopic
observation of the ovaries, and in a subset of these animals (n=20) also from changes in vaginal mucus.  In a separate experiment (n=18), the time of oestrus was estimated from an influx of epithelial cells and leucocytes in urine, and confirmed by mating and hormonal data. A preovulatory follicle was observed at laparoscopy in all animals that ovulated (n=138), but not in any that did not (n=102).  An influx of neutrophils in vaginal mucus occurred in 12/20 possums, including 4 that failed to ovulate.  An increase in epithelial cells in urine was observed in 9/12 possums that exhibited an LH surge.  However, this change occurred after the time of the preovulatory LH surge in 6 of those animals and peak cell numbers varied widely between all animals. These studies confirm that although changes in the cell content of mucus and urine can retrospectively define stage of the oestrous cycle, they are of little value for predicting impending oestrus, the LH surge or ovulation},
	issn = {1176-5283},
	author = {McLeod BJ and Thompson EG and Crawford JL and Mahoney PM and Eckery D}
}
@conference {41129,
	title = {The prevalence of Wobbly Possum disease in a bush/farmland environment},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {59},
	year = {1999},
	month = {Jan},
	pages = {233-235},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The prevalence of Wobbly Possum disease was monitored in wild-caught possums captured at 16 different sites. All animals were assessed for clinical signs of Wobbly Possum Syndrome from the time of their capture. Any that displayed symptoms were euthanased immediately and submitted for post mortem examination to confirm disease status. Of the 887 possums screened, 39 (4.4\%) were infected with the Wobbly Possum virus. These had been trapped at 10 of the 16 sites (prevalence 0\% to 23.3\%). There were no significant differences in the proportion of infected animals among sites. The interval from time of capture to diagnosis ranged from 7 to 21 days. The presence of Wobbly Possum infection was not related to geographical location, sex of the animal or liveweight at the time of capture. This study suggests that both the natural prevalence of Wobbly Possum Syndrome, and the rates of cross-infection within a site are low. },
	issn = {1176-5283},
	author = {Thompson EG and McLeod BJ}
}
@conference {41128,
	title = {Synchrony of onset and cessation of breeding activity in brushtail possums (Trichosurus vulpecula) in coastal Otago, New Zealand},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {59},
	year = {1999},
	month = {Jan},
	pages = {229-232},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The onset of breeding was monitored in 117 female brushtail possums trapped at a single location between December and May, with reproductive status being determined at the time of capture. The cessation of breeding activity was monitored in captive animals in which reproductive status was determined in October (N=38), November (N=39) and January (N=30), by laparoscopic observation of their reproductive tracts. Comparison was made between animals that had pouch young removed (RPY) 7-9 days previously, and possums that had not had pouch young present for at least 40 days. Only 1/57 possums trapped over the period from 1 December to 31 March had recently bred. In contrast, 49/60 (82\%) possums captured between 1 April and 6 May, were either pregnant or had new-born pouch young. In spring (mid-October) 45\% of possums continued to cycle, only 13\% were cycling in late November and all were anoestrous in January. There were no relationships between liveweight or RPY and reproductive status. },
	issn = {1176-5283},
	author = {McLeod BJ and Thompson EG and Crawford JL}
}
@conference {40864,
	title = {Factors influencing induced oestrus in the ewe at the start of the breeding season},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {56},
	year = {1996},
	month = {Jan},
	pages = {381},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The objectives of this study were to monitor the physiological events associated with decreasing liveweight in Bos indicusheifers and to determine the characteristics which best predicted the onset of nutritional anoestrus. Eleven post-pubertal Brahman heifers received a diet resulting in a liveweight loss of 0.7 kg/day. Changes in ovarian morphology were monitored using daily transrectal ultrasonography. Liveweight was recorded twice weekly. Heifers became anoestrus after 98 {\textpm} 9 days, following a decrease in liveweight of 68.6 {\textpm} 4.9 kg, equivalent to 21.5 {\textpm} 1.5\% of initial weight. At this time, maximum diameters of ovulatory follicles and corpora lutea (CL) had decreased by 16.7 {\textpm} 3.9\% and 23.7 {\textpm} 3.1\%, respectively. Onset of anoestrus was best predicted by liveweight and maximum diameter of CL when expressed as proportions of initial liveweight and size of CL. The percentage decreases in liveweight and maximum diameter of CL to give a 50\% probability of anoestrus were 21.0\% (95\% confidence interval = (17.7, 27.4)) and 23.0\% (16.7, 37.0), respectively.},
	issn = {1176-5283},
	author = {Fenton LS and Shackell GH and Ramsay ML and Dodds KG and Reid PJ and McLeod BJ}
}
@conference {40861,
	title = {Ovarian follicle development in the red deer hind},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {56},
	year = {1996},
	month = {Jan},
	pages = {370-372},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Ovaries were recovered either 0, 12, 24 or 36 hours or 10 days after  CIDR withdrawal, from 25 hinds in which oestrus had been synchronised.  All follicles > 2 mm diameter were dissected free of stromal tissue and their  health assessed on the basis of oocyte and theca condition, follicular fluid  oestradiol content, granulosa cell numbers and oestradiol synthesis. Hinds had an average of 26.6 + 3.45 follicles > 2 mm, of which about half  were healthy and 1-3 were oestrogenic. Every animal had at least 1 healthy  follicle > 7.5 mm diameter. Over the follicular phase, the percentage of  healthy follicles ranged from 46-66\%, but this did not change significantly  with time. Neither did the mean diameter of the largest oestrogenic follicle  change over the follicular phase. In summary, the total number of antral  follicles varied widely, but every hind had at least one large healthy follicle  present, irrespective of stage of the oestrous cycle.},
	issn = {1176-5283},
	author = {McLeod BJ and Meikle LM and Heath DA and McNatty KP and Fisher MW and Whaanga AJ}
}
@conference {40852,
	title = {Reproductive senescence in aged red deer hinds},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {56},
	year = {1996},
	month = {Jan},
	pages = {344-346},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {This study reports on the performance of some of the original animals  used to establish the Invermay deer farm. These comprised a selection of  some of the original 1973 animals, 21 hinds of unknown age and 19 of the  first hind calves born at Invermay in that year. Reproductive performance, expressed as the percentage of hinds weaning  calves, decreased slowly from 90\% at 6 and 7 years of age, to 50\% at 17  years, then dropped markedly with only one calf being successfully reared in  each season when the hinds were 19 and 20 years. Similarly, few (5/21) of  the older unknown-age hinds raised calves when > 17 years old. When  blood sampled twice-weekly during the breeding season (rising 21 years of  age), only 6/12 of the known-age hinds had significant plasma progesterone  concentrations, with only 3 animals displaying anything like normal cyclical  patterns. In addition, most had elevated plasma LH concentrations. Post  mortem examination revealed that all these hinds had small reproductive  tracts and very few ovarian follicles at this age. Despite an ability to live beyond 20 years, these results suggest that waning  reproductive performance with age may be due to ovarian failure.},
	issn = {1176-5283},
	author = {Fisher MW and McLeod BJ and Mockett BG and Moore GH and Drew KR}
}
@conference {40860,
	title = {Seasonal changes in FSH and LH concentrations in ewes with gonadal hypoplasia: Evidence that steroid-independent mechanisms control seasonality in sheep?},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {56},
	year = {1996},
	month = {Jan},
	pages = {367-369},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Current hypotheses for the control of seasonality are based on the  premise that seasonal changes in sensitivity to ovarian steroid hormones  drive changes in reproductive status. Most studies have used the  ovariectomised, oestrogen-treated ewe as an experimental model, but such  animals may be influenced by previous entrainment or exposure to gonadal  steroids. This study uses an infertile animal - the homozygous Inverdale ewe  - as a unique },
	issn = {1176-5283},
	author = {McLeod BJ and Kyle SE and Ramsay MR}
}
@conference {40745,
	title = {Hormone secretion patterns associated with increased ovulation rates or with ovarian dysfunction in Inverdale (FecX) ewes},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {55},
	year = {1995},
	month = {Jan},
	pages = {304-306},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Ewes that are heterozygous (I+) carriers of the Inverdale gene  (FecX) have increased ovulation rate, whereas ewes that are homozygous  (II) for the gene are infertile and have {\textquoteright}streak{\textquoteright} ovaries in which  normal follicle development does not occur. A proportion of ewes with  streak ovaries develop structures that have some characteristics of  ovarian tumours. We have monitored the growth of ovarian structures and  (c) assess the effectiveness of using hormone concentrations to identify  the genotype of individual ewe lambs.    No differences in hormone secretion related to differences in ovulation  rate were evident between I+ and non-carrier (++) Inverdale ewes (mean  ovulation rates 3.1+/-0.22 ng/ml) nor inhibin concentrations of  gonadotrophins were consistently elevated (FSH 16.9+/-1.8 ng/ml; LH  4.5+/-0.5 ng/ml; N+14) and were comparable to those observed in  ovariectomised ewes. In contrast, inhibin was always undetectable  (<3.0I.U./ml). These patterns of hormone secretion often change  markedly when ovarian structures develop, with inhibin concentrations  increasing acutely, which in turn causes FSH levels to fall.    To assess the potential of using these differences to identify II  genotype, Inverdale ewe lambs were blood-sampled at two, five or seven  months of age. Over 95\% of II Inverdale ewe lambs had genotype assigned  correctly (confirmed by laparoscopy) on the basis of plasma FSH  concentrations alone.   },
	issn = {1176-5283},
	author = {McLeod BJ and Kyle SE and Ramsay MR and Manley TR}
}
@conference {40406,
	title = {Effect of sire, breed and age on plasma FSH concentrations in FecB FecB and Fec+ Fec+ Booroola rams before and after castration},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {52},
	year = {1992},
	month = {Jan},
	pages = {175-178},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Feed intake and wool production data on unmated, single- and  twin-bearing/rearing ewes from a year-long field trial were incorporated  into feed budget models of a hill country farm. Increasing the basal  liveweight of an unmated ewe from an average of 45 to 55 kg increased  greasy wool production from 4.15 to 5.10 kg/ewe. Relative to the annual  feed requirements (614 kg DM/y) of a typical breeding ewe (1 sheep stock  unit (ssu) on the case farm the annual feed requirements of unmated 45,  50 and 55 kg ewes were estimated to be 0.58, 0.66 and 0.72 ssu. At 1991  costs and prices the gross margins (GM) were $15.50/ssu for breeding  ewes (100\% lambs weaned) and, depending on liveweight, from $7.12 to  $8.11/ssu for the all-wool options. The breeding ewe policy remained  more profitable even if low lamb prices or a poor lambing percentage  were achieved.  },
	issn = {1176-5283},
	author = {Isaacs KL and McNatty KP and McLeod BJ and Condell L and Littlejohn RP}
}
