@conference {69534,
	title = {Jim Peterson: {\textendash} A career in reproductive biology},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {70},
	year = {2010},
	month = {Jun},
	pages = {319-331},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {Our collaboration was both long and successful with a total of 39 publications as co-authors over a period of 32 years. Our first paper was in 1973 and our last in 2005. The collaboration was successful because it combined Jim{\textquoteright}s unique and pioneering ability to develop hormone assays with my knowledge and experience in reproductive physiology. It resulted in a number of seminal papers containing new knowledge that was then used by workers nationally and internationally to increase the understanding of hormones, their effects and interactions.},
	issn = {1176-5283},
	author = {Back P and Smith JF and Welch RAS and Macmillan KL and Ledgard AM and Peterson AJ and Tervit HR}
}
@conference {60936,
	title = {Effects of sub-clinical endometritis on ovarian follicular activity in postpartum dairy cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {69},
	year = {2009},
	month = {Jun},
	pages = {32-36},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {The effects of sub-clinical endometritis (scEndo) on ovarian follicular activity in pasture-fed dairy cows were determined. The uterine-health status of lactating dairy cows (n = 169) was assessed on day (D) 21 ({\textpm} 3 days) postpartum by Metricheck. In a sub-population (n = 47; 32 clean, 15 scEndo), Metricheck assessment was repeated on D42 and uterine cytology undertaken on D21 and D42 [scEndo = polymorphicnuclear (PMN) cells >18\%]. Follicular activity was assessed by ultrasound on D42 and D63. Metricheck evaluation revealed that the proportion of cows with scEndo was 15/169 (8.9\%) and 4/47 (8.5\%) on D21 and D42 respectively. Irrespective of the method used to determine scEndo, dominant (P <0.001) but not subordinate (P >0.1) follicles were larger and grew faster on D63 than on D42. Based on the D21 Metricheck but not the \%PMN classification, dominant follicles of scEndo cows were larger and grew faster (P = 0.02) than those in clean cows. No overall effect of uterine status was found on the subordinate follicles, although these tended (P = 0.06) to be larger on D63 than on D42 but only in clean cows. Thus early postpartum scEndo appears to modulate the subsequent size of the dominant follicle. However, it remains to be determined whether this affects the subsequent fertility of these cows. },
	issn = {1176-5283},
	author = {Back PJ and Ledgard AM and Beaumont S and Berg MC and Peterson AJ and McNatty KP and Green MP}
}
@conference {60937,
	title = {Prevalence and identification of systemic markers of sub-clinical endometritis in postpartum dairy cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {69},
	year = {2009},
	month = {Jun},
	pages = {37-42},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {The prevalence of sub-clinical endometritis (scEndo) and identification of serum markers of scEndo was investigated in pasture-fed, postpartum dairy cows. Mixed age lactating dairy cows (n = 169) were examined for uterine health status on day (D) 21 postpartum ({\textpm} 3 days) by Metricheck classification. On D42 in a subpopulation (n = 47; 32 clean, 15 scEndo) Metricheck assessment was repeated and uterine cytology undertaken on D21 and D42 [scEndo = polymorphicnuclear (PMN) cells >18\%]. Uterine bacteriology, as well as haematological, biochemical and milk parameters were also measured. The prevalence of scEndo was 15/169 (8.9\%) and 4/47 (8.5\%) cows on D21 and D42 respectively. A high incidence of self-resolving scEndo (11/15, 73\%) was revealed. Numerous species of pathogenic bacteria were isolated from both scEndo and clean cows. Despite the uterine infection being sub-clinical, systemic markers were detectable as on D21 and D42 haematological and biochemical parameters differed. Irrespective of the scEndo classification method used, the mean blood neutrophil concentration was higher (P <0.05) and plasma albumin lower (<0.05) in scEndo cows compared to clean cows. Milk fat and protein \% also differed (P <0.05) between scEndo and clean cows. The monitoring in early lactation of these markers could aid identification of scEndo, thereby preventing potentially detrimental effects on subsequent fertility. },
	issn = {1176-5283},
	author = {Green MP and Ledgard AM and Berg MC and Peterson AJ and Back PJ}
}
@conference {41843,
	title = {Mathematical modelling of anoestrus in dairy cows and the linkage to nutrition},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {65},
	year = {2005},
	month = {Jan},
	pages = {324-328},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Postpartum anoestrus is a major reproductive problem in New Zealand dairy cows and its duration is related to the nutrition levels both pre and post calving. However, the mechanistic details of this relationship are largely unknown. A better understanding of the interactions between nutritional status, and the levels of the reproductive hormones controlling follicle development and ovulation is needed. A mathematical model consisting of a set of interactive nonlinear differential equations and describing the dynamics of the interactions among luteinising hormone (LH), follicle stimulating hormone (FSH) and oestradiol was developed. The model depicts oestradiol profiles generated by individual follicles from the first follicular wave after calving until ovulation, and changes in LH pulsatility leading to the first pre-ovulatory surge are also produced. The robustness of the model was ascertained from iterative processes, and it was also checked against existing experimental data so as to mimic observed changes in hormone levels. It was shown that two mathematical parameters which control: i) the speed of changes in the feedback of LH activity to oestradiol; and, ii) the sensitivity of the ovarian response to LH, have the greatest effect on duration of anoestrus.
KEYWORDS: mathematical model; anoestrus; dairy cows; nutrition; oestradiol; LH; FSH. },
	issn = {1176-5283},
	author = {Smith JF and Soboleva TK and Peterson AJ and Pleasants AB and Chagas LM and Burke CR}
}
@conference {41844,
	title = {Relationships among metabolic hormones, luteinising hormone and anoestrus in periparturient dairy heifers fed two nutritional levels prepartum},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {65},
	year = {2005},
	month = {Jan},
	pages = {329-334},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {A mathematical model that describes the dynamics of reproductive hormones was developed to estimate the duration of the postpartum anoestrus interval (PPAI) in cows. The model identified two relatively separate mechanisms: one influenced PPAI through luteinising hormone (LH) release; and it is suggested that another one controlled ovary sensitivity to LH. Examining the role played by these mechanisms in the relationships between nutrition and PPAI involved analysing the data from an experiment that measured the effects of prepartum nutrition on PPAI in which levels of insulin-like growth factor-I (IGF-I), insulin, glucose, leptin and growth hormone (GH) were recorded. Five months before calving, 30 Holstein-Friesian heifers were randomly allocated to a high (HP) or low plane (LP) of nutrition. Body condition scores at calving were 6.3 and 4.1 for the HP and LP treatments respectively. Both groups were fed ad libitum after calving. Secretion patterns of LH were measured at 2, 5 and 8 weeks after calving. PPAI differed between treatments (HP 62.0 {\textpm} 7.95 days; LP 83.1 {\textpm} 6.95 days; P < 0.05), as did the level of GH at calving (HP 5.8 {\textpm} 1.23 ng/ml; LP 10.3 {\textpm} 1.23 ng/ml; P < 0.001). The within treatment variation in PPAI was partitioned into that associated with LH frequency post calving and that orthogonal to LH pulse frequency. Within each treatment, GH was associated with the LH frequency and insulin was associated with the component orthogonal to LH frequency. These results link nutrition to the PPAI through the dynamics of insulin and GH.
KEYWORDS: mathematical model; anoestrus; dairy cows; nutrition; metabolites; LH. },
	issn = {1176-5283},
	author = {Pleasants AB and Chagas LM and Burke CR and Smith JF and Soboleva TK and Peterson AJ}
}
@conference {41283,
	title = {Relationship between bulk milk urea nitrogen and reproductive performance of New Zealand dairy herds},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {61},
	year = {2001},
	month = {Jan},
	pages = {192-194},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {New Zealand dairy cows grazing lush spring pasture have relatively high plasma urea nitrogen levels as a consequence of the high soluble crude protein content of this rapidly growing pasture. The elevated plasma urea levels have been implicated as a cause of poor reproductive performance in dairy herds. The aim of this trial was to determine if the bulk milk urea nitrogen levels (BMUNs) collected during the period from calving and through mating were related to the reproductive performance of the herds. Bulk milk samples were collected twice a week from 127 farms during the spring of 1998. The farms were suppliers of the NZ Dairy Group and Kiwi co-operatives. Reproductive performance data was collected from all herds. BMUNs were determined spectrophotomically using Sigma blood urea nitrogen kits. The twice-weekly BMUNs were averaged for each farm and these weekly mean values were centred on the nominated week of mating (W=+1) for the individual farms. There were significant among-farm differences in BMUNs with individual weekly farm values ranging from 5.4 to 26.8 (mg/dl) and the mean (W-3 to W+5) value for farms ranging from 9.6 to 18.8 (mg/dl). There were significant between farm differences in reproductive performance. The percentage of cows submitted for AI in first 3 weeks of mating (\%SR21) ranged from 29.9 to 95.3\%. The percentage of SR21 cows conceiving to that AI (\%Preg1) ranged from 39 to 98.6\% and the percentage of all cows in the herd pregnant by the end of mating (\%Pregall) from 44.9 to 98.4\%. There was some indication of a relationship between reproductive performance and BMUNs in that the change in BMUN level from W-3 to W+5 was significantly correlated within geographic zones with \%SR21 and \%Pregall, correlation coefficients being 0.36 (P=0.013) and 0.37 (P=0.010) respectively. The corresponding correlation for \%Preg1 was only 0.21(P = 0.15). Thus farms for which BMUNs rose over the period W-3 to W+5 had higher reproductive performance than those in the same zone, which showed a fall. However, this accounted for very little of the overall variability. Farms were ranked on their reproductive performance and the average weekly BMUNs for the farms in each quartile calculated. There was no difference in the pattern of BMUNs for the different quartiles of each reproductive parameter. Thus, the measurement of BMUNs would appear to be of little value as an indicator or predictor of reproductive performance. },
	issn = {1176-5283},
	author = {Smith JF and Beaumont S and Hagemann L and McDonald RM and Peterson AJ and Xu ZZ and Duganzich DM}
}
@conference {40405,
	title = {Timing of the LH peak and ovulations in superovulated Coopworth ewes synchronised with progesterone-containing CIDR devices},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {52},
	year = {1992},
	month = {Jan},
	pages = {171-174},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {A replicated trial with 4 stock rates of {\textquoteright}wet{\textquoteright} ewes (9.0, 10.5,  12.0, 13.5 sheep/ha) and 4 stocking rates of {\textquoteright}dry{\textquoteright} ewes (11.0, 13.5,  16.0, 18.5 sheep/ha) was established at the DSIR Grasslands {\textquoteright}Ballantrae{\textquoteright}  Hill Country Research Station to enable hill country farmers to make  informed decisions as to the economics of farming breeding or unmated  ewes.   Stocking rate had a large effect on liveweight throughout the year with  the greatest effect being in winter. Mean weaning weight of lambs was  25.4 kg at 9.0 ewes/ha and 19.7 kg at 13.5 ewes/ha.   Dry ewes grew more greasy wool/ha than wet ewes (P<0.05). Greasy wool  production ranged from 41.6 kg/ha at 9 wet ewes/ha to 81 kg/ha at 18.5  dry ewes/ha. At 13.5 sheep/ha dry ewes grew 28\% more greasy wool than  wet ewes which reared 1.2 lambs to weaning. November/December fleece  weight/ha was unresponsive to increasing stocking rate for both wet and  dry ewes (P<0.01). November/December fleeces were 18.6\% heavier from  ewes in paddocks having a sunny aspect than in paddocks with a  predominantly shady aspect (P<0.001). Slowest wool growth occurred  during August, being 5.3 to 8.3 mm/month and maximum wool growth  occurred during January within the range 17.3 to 18.5 mm/month.  },
	issn = {1176-5283},
	author = {Thompson JG and Simpson AC and James RW and Tervit HR and Asher GW and Peterson AJ}
}
@conference {40249,
	title = {Absorption of DNA to the sperm of rams, bulls and fallow bucks},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {50},
	year = {1990},
	month = {Jan},
	pages = {407-410},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The algorithm for a Fortran program which simulates growth of a   lamb is presented. The basis of the algorithm is the theory of growth   and feed intake by Emmans. The advantages of the current algorithm are   its simplicity, the few generalised equations and its easy use at any   stage of the growth curve.    },
	issn = {1176-5283},
	author = {Peterson AJ and Schofield KM and McLaughlin RR}
}
@conference {40214,
	title = {Developments in domestic animal embryo manipulation technology which support the application of molecular biology to animal production},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {50},
	year = {1990},
	month = {Jan},
	pages = {181-190},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {A simulation model for mixed infections of gastrointestinal   nematodes in lambs was used to compare with a series of extended   drenching programmes.     The model output concurs with the results of field trials showing that   preventive drenching will control parasites adequately except when   autumn conditions are particularly favourable for development and   migration of larvae onto pasture. The model suggests that the level of   pasture contamination in spring will have a significant influence on   parasite control throughout much of the year. A reduction in pasture   contamination was simulated by the addition of a post-lambing ewe drench   prior to the preventive lamb drenching programme. This gave better   parasite control and increased production compared with extended   drenching of lambs in the autumn. This is likely to be the result of   reduced larval challenge. These model predictions will require   validation in the field.    },
	issn = {1176-5283},
	author = {Tervit HR and Thompson JG and Peterson AJ}
}
@conference {40210,
	title = {The effects of nutrition oestradiol, phenobarbital and carbon tetrachloride on ovulation rate and plasma FSH in ewes},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {50},
	year = {1990},
	month = {Jan},
	pages = {149-154},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Recent advances in the genetic manipulation of animals have   raised some familiar and some less familiar ethical issues. The   obligation to safeguard the welfare of animals must be extended to   include the production of transgenic animals, to ensure that the   well-being of such "products" takes precedence over profitability. Human   welfare must also be safeguarded especially in relation to the equitable   distribution of the benefits from genetic engineering and the protection   of the environment. The change in the relationship between human and   non-human animals, exemplified in the patenting of genetically modified   animals, has serious implications for the integrity of animal science.    },
	issn = {1176-5283},
	author = {Payne E and Smith JF and Peterson AJ and McGowan LT and Cope BC and McLaughlin R}
}
@conference {40143,
	title = {Development of cattle with a modified genotype: Embryological techniques needed for the efficient production of transgenics},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {49},
	year = {1989},
	month = {Jan},
	pages = {65-70},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The manipulation of ovulation rate in the red deer hind was investigated by administration of steroid-free bovine follicular fluid (bFF). Twenty-four adult hinds, treated with intravaginal progesterone (CIDR), received a daily intramuscular injection of either 0, 4, 7.5 or 11 mls of dextra-charcoal treated bFF (n = 6 per group) on days -1, 0 and +1 from the time of CIDR withdrawal. After CIDR removal, plasma progesterone concentrations declined in all animals. In control hinds, oestrus occurred 2-3 days later and mean plasma progesterone concentrations began to increase thereafter. In bFF-treated hinds, oestrus was delayed by 3-5 days, and plasma progesterone concentrations remained low for at least 7 days after CIDR withdrawal. Plasma LH concentrations were 2-3 fold higher in the bFF- treated groups, relative to the control hinds, for at least 6 days after the end of bFF treatment. Twin ovulations were recorded in 1/6 control and 5/17 treated animals. At pregnancy diagnosis, 10/23 hinds were pregnant having conceived at the treated oestrus (3/6 control and 7/18 treated), but none had more than one foetus. There was no evidence of a dose-response to bFF treatment. These results indicate that in the hind, bFF can be used to manipulate the timing of oestrus and ovulation rate. A component(s) of bFF may thus have the potential to regulate fecundity in deer.},
	issn = {1176-5283},
	author = {Thompson JGE and Peterson AJ and Tervit HR}
}
@conference {39712,
	title = {The hormonal induction of lactation in dry dairy cows - Brief Communication},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {41},
	year = {1981},
	month = {Jan},
	pages = {68-70},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	issn = {1176-5283},
	author = {Davis SR and Welch RAS and Pearce MG and Peterson AJ}
}
