@conference {89235,
	title = {Insulin response to a glucose tolerance test in 18-month pregnant heifers as a predictor of subsequent survival},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {73},
	year = {2013},
	month = {Jan},
	pages = {117-119},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {<p>A decline in dairy cow fertility in the USA and in the UK (Beam \&amp; Butler 1999; Royal et al. 2000) has also been noted in New Zealand. Calving rate, the proportion of cows re-calving within the first 42 days of the subsequent seasonal calving period, in New Zealand decreased from approximately 70\% in 1991 to 60\% in 2004 (Harris et al. 2006). There has been no further deterioration in subsequent years.</p>
},
	issn = {1176-5283},
	author = {Hutchinson KJ and Davis SR and MacKenzie DDS and Blair HT and McNaughton LR and Sanders K and Spelman RJ}
}
@conference {41400,
	title = {The effects of insulin on the milk production of pasture-fed Jersey cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {63},
	year = {2003},
	month = {Jan},
	pages = {35-39},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Queenstown},
	abstract = {The aim of this experiment was to determine the effects of insulin on milk protein production in lactating, pasturefed dairy cows. Five lactating rumen-fistulated Jersey cows were subjected to a hyperinsulinaemic euglycaemic clamp (HEC) with and without an abomasal infusion of casein (310g/d) in a two period cross-over design experiment. The HEC significantly reduced milk yield in the control cows compared to casein-infused cows (9.9 {\textpm} 0.5 vs 13.2 {\textpm} 0.5 kg/d, P<0.001). Milk protein yield was significantly higher in the casein-infused cows compared to the control cows (482 {\textpm} 16 vs 421 {\textpm} 16 g/d, P<0.05). The HEC significantly reduced milk protein yield in the control cows compared to casein-infused cows (311 {\textpm} 16 vs 459 {\textpm} 16 g/d, P<0.001). The use of the HEC technique in pasture-fed cows did not result in the milk protein response reported in concentrate-fed cows. },
	issn = {1176-5283},
	author = {Back PJ and MacKenzie DDS and Davis SR and Harris PM and Lee J}
}
@conference {41300,
	title = {Influence of milk cytokines on mammary production of nitric oxide},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {62},
	year = {2002},
	month = {Jan},
	pages = {3-6},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {Cytokines such as interferon-gamma (IFN-g) can stimulate the production of nitric oxide (NO) from mammary epithelial cells, which in turn may play a role in intramammary defence of the mammary gland. In this study, comparisons were made with the production of IFN-g stimulated NO from Comma-D cells (murine mammary epithelial cell line) and explants of mammary tissue collected from both pregnant (day 12-14 of gestation) and lactating (day 12-14 postpartum) rats. Response to IFN-g was measured as the production of nitrate and nitrite (NOx) in the culture medium. Comma-D cells and explants of mammary tissue from pregnant and lactating rats responded to treatment with 250 U/ml IFN-g with an increase in NOx of 5231, 300 and 373\% respectively. The response to IFN-y was lower (P<0.001) in explants than in Comma-D cells. Inclusion of nitric oxide synthase (NOS) inhibitors aminoguanidine (100 mM) and Nw-nitro-L-arginine (1 mM) in the culture medium reduced NOx production by the Comma-D cells to 31 and 19\% of stimulated activity respectively. This suggests that Comma-D cells are a good model for investigating effects of cytokines on mammary epithelial cell production of NO, and may also provide a useful means of screening other milk bioactives for their potential role in intramammary defence. },
	issn = {1176-5283},
	author = {Turner S-A and MacKenzie DDS and Prosser CG}
}
@conference {41271,
	title = {Effects of insulin on amino acid uptake by the mammary gland of the pasture-fed lactating ruminant},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {61},
	year = {2001},
	month = {Jan},
	pages = {144-147},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Twelve lactating ewes housed indoors were allocated to one of two treatment groups (hyperinsulinaemic euglycaemic clamp (HEC) or control) in a randomised block design experiment. Mammary amino acid uptake from plasma and utilisation for milk protein synthesis was measured during the fourth day of the HEC using the arterio-venous concentration difference (A-V) technique. There was no change in milk protein output during the HEC (P>0.05). The HEC induced a significant decrease in arterial concentrations of all essential amino acids (EAA) except for histidine and an increase in the extraction efficiency of isoleucine (HEC, 61 {\textpm} 3\% vs. control, 52 {\textpm} 3\%, P<0.05) and leucine (HEC, 64 {\textpm} 3\% vs. control, 53 {\textpm} 3\%, P<0.05). There was no significant change in extraction efficiency of other EAA or mammary blood flow. The ratio of amino acid uptake from plasma to output in milk protein suggested deficits in uptake for some EAA in both treatments, especially histidine. These results indicate that the mammary gland can adapt to a changing arterial supply of amino acids to maintain milk protein output by increasing extraction efficiency and/or a greater reliance on amino acids supplied by erythrocytes and/or plasma peptides. },
	issn = {1176-5283},
	author = {Back PJ and Davis SR and MacKenzie DDS and Harris PM and Roy NC and Lee J}
}
@conference {41073,
	title = {Lack of effect of short term chromium supplementation in lactating Jersey cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {59},
	year = {1999},
	month = {Jan},
	pages = {58-61},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The responses of dairy cattle to chromium (Cr) supplementation reported in the literature suggest that it has the potential to reduce the incidence of both mastitis and ketosis. The effect of Cr supplementation of pasture fed dairy cows in early lactation was studied. Ten lactating Jersey cows fitted with rumen fistula were infused with either Cr-yeast (n=4), casein (n=3) or buffer only (controls; n=3) directly into the abomasum. All cows were subjected to a hyperinsulinaemic euglycaemic clamp. Preliminary results show that there was no effect of Cr supplementation on milk yield, cortisol and b-hydroxy butyrate concentrations and somatic cell counts. },
	issn = {1176-5283},
	author = {Back PJ and Lee J and MacKenzie DDS and Davis SR and Harris PM}
}
@conference {41025,
	title = {The effects of a cation-anion balanced diet on calcium and phosphorus metabolism in growing lambs},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {58},
	year = {1998},
	month = {Jan},
	pages = {192-194},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {During the past decade, there has been renewed interest and research in the role of the dietary cation-anion balance (DCAB) in controlling Ca and P homeostasis. Two diets differing in DCAB (either high DCAB, 250 meq/kg DM, or low DCAB, -100 meq/kg DM) were fed to 10 Romney lambs. Feeding low DCAB decreased urine pH by 2.0 pH units; from 8.2 (SE=0.45) to 6.2 (SE=0.50), indicative of the anticipated changes in the ionic balance associated with alterations in the dietary CAB. Plasma concentrations of Ca and P, and whole-body Ca and P balance (intake-excretion) were similar for both groups of sheep. Reducing the dietary CAB caused a 7-fold increase in the urinary excretion of Ca (low DCAB 0.75 g/day vs high DCAB 0.11 g/day; P=0.001).The apparent absorption of Ca in the low DCAB and high DCAB groups were 1.6 and 1.3 g/day, respectively, although there was no significant difference between the two groups. These data indicate that lowering the DCAB increases urinary excretion of Ca of growing lambs without affecting Ca balance due to an alteration in the movement of Ca to and from bone. Similar changes in Ca absorption and utilisation have been observed in dairy cows, suggesting that the growing lamb is a suitable model for future studies in the regulation of Ca homeostasis in dairy cattle. },
	issn = {1176-5283},
	author = {Wilson KL and Min S and Revell DK and Lee J and MacKenzie DDS and Cottam YH and Davis SR}
}
@conference {41029,
	title = {The effects of Insulin-nutrient supply interactions on ewe lactation},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {58},
	year = {1998},
	month = {Jan},
	pages = {205-208},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Six lactating abomasally cannulated ewes were subjected to a hyperinsulinemic euglycemic clamp with or without casein supplementation in a two period crossover design experiment. There was a significant response in milk (1169 {\textpm} 46 g/d vs 952 {\textpm} 46 g/d, P<0.001) and milk protein (66.4 g/d {\textpm} 2.7 g/d vs 54.2 g/d {\textpm} 2.7 g/d P<0.006), yield from casein supplemented ewes. There was no overall effect of the clamp on milk and milk protein yield, while the interaction was also non-significant. However, there was a significant reduction in feed intake (P<0.001) as the clamp continued, which may have compromised milk and milk protein response. There was also a significant period effect across all the measured parameters, which could also be a stage of lactation effect, due to the rapid decline of milk production during ewe lactation. In this study, in contrast to concentrate-fed cows, the utilisation of this technique did not increase milk protein yield in pasture fed lactating ewes. },
	issn = {1176-5283},
	author = {Back PJ and MacKenzie DDS and Davis SR and Harris PM}
}
@conference {40931,
	title = {Brief Communication: Increased litter size elicits cell proliferation in the lactating murine mammary gland},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {57},
	year = {1997},
	month = {Jan},
	pages = {207-208},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Milk quality of dairy cows decreases both as lactation progresses and as milk yield declines (Lucey, 1996). De-clining milk yield has been associated with a diminishing population of secretory epithelial cells (Knight and Wilde, 1993). One approach to enhancing the persistency of lactation is to stimulate a wave of proliferation of epithelial cells within the gland. A new generation of epithelial cells could increase milk yield and might also improve the overall quality of the milk.},
	issn = {1176-5283},
	author = {Auldist D and McFadden T and MacKenzie DDS and Nicholas K}
}
@conference {40911,
	title = {The effects of methionine supply on milk composition and production of dairy cows in mid- lactation.},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {57},
	year = {1997},
	month = {Jan},
	pages = {147-150},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {A trial assessing the production response of dairy cows to supplementation with methionine (Met) was conducted indoors over a 21-day period with 26 Friesian cows in mid-lactation and individually fed fresh perennial ryegrass/white clover pasture. Group 1 (n=9) received twice daily oral methionine (15 g/d) that was protected from rumen degradation (RPM; Lactet); Group 2 (n=9) was given a continuous intravenous infusion of free Met (15 g/d; MET-i.v.); and Group 3 (n=8) was given no methionine supplement (Control). Supplementary methionine tended to slightly depress feed intake but milk yield tended to be higher (P=0.08) for the MET-i.v. group compared with the Control and RPM groups (18.5 {\textpm} 0.48 vs 17.1 {\textpm} 0.45 and 17.2 {\textpm} 0.38 kg/d {\textpm} SE). Compared with the control group, there was a trend for Met (both MET-i.v. and RPM) to reduce milkfat concentration and to increase the concentration of casein. Neither lactose or whey nitrogen (N) concentrations were affected by the treatments. Methionine supplementation did not affect yields of total protein nor protein components; however, when protein and casein yields were adjusted to equal crude protein intake, Met supplemented cows produced significantly (P=0.05) more total protein and casein per unit of N ingested. These results suggest that post-ruminal Met supplementation improved the efficiency with which dietary protein was converted to casein in the pasture-fed dairy cow. More research is required to investigate which AA, individually or in combination, are likely to limit milk protein synthesis in the mammary gland of the pasture-fed dairy cow. },
	issn = {1176-5283},
	author = {Pacheco-Rios D and McNabb WC and Hill JP and Barry TN and MacKenzie DDS}
}
@conference {40797,
	title = {The metabolic cost of hepatic ammonia detoxification},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {56},
	year = {1996},
	month = {Jan},
	pages = {130-132},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The quantity of ammonia removed from portal blood by the ovine  liver was measured using four sheep prepared with in-dwelling catheters in  the hepatic region and fed either lucerne pellets (L) or white clover (WC) at  900 gDM/day. Following blood sampling, plasma ammonia and oxygen  concentrations were determined. The portal ammonia concentration and  flow were significantly (P<0.01) affected by the diet (304 and 646 },
	issn = {1176-5283},
	author = {Greaney KB and Reynolds GW and Ulyatt MJ and MacKenzie DDS and Harris PM}
}
@conference {40792,
	title = {The role of the vagal innervation of the gut in insulin release in lactating ewes},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {56},
	year = {1996},
	month = {Jan},
	pages = {110-113},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The vagal innervation of the pancreas and upper gastrointestinal tract  has been implicated in the release of insulin in response to hyperglycaemia  in several mammalian species. Therefore the role of the vagal innervation of  the abomasum and upper small intestine in the release of insulin and its  effect on glucose metabolism was studied in lactating ewes because of the  importance of glucose for milk synthesis and secretion in ruminants. Vagal  fibres innervating the abomasum, pylorus and duodenum were sectioned in  3 lactating ewes (VAG); 3 control lactating ewes underwent sham- operations (SHAM). Seven and 14 days after the surgery, all animals were  given an intravenous injection of glucose (100 mg/kg BW) and jugular  blood samples collected for glucose and insulin determinations. Plasma  glucose concentration (mean },
	issn = {1176-5283},
	author = {Herath CB and Reynolds GW and MacKenzie DDS and Davis SR and Harris PM}
}
@conference {40656,
	title = {Mitogenic activity of lamb mammary fat pad in vitro is distinct from that of mouse mammary fat pad},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {55},
	year = {1995},
	month = {Jan},
	pages = {23-25},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Apple pomace, a by-product of the apple juicing industry, was  assessed as a supplementary feed for lactating dairy cows during autumn.  Cows were offered a base diet of 6 kg DM/cow/day from grazed pasture and  one of three supplement treatments; control (7 kg DM/cow/day grass  silage); apple pomace (AP) (3 kg DM/cow/day grass silage plus 4 kg  DM/cow/day fresh AP); and AP+"balancer" (3 kg DM/cow/day grass silage  plus 3 kg DM/cow/day fresh AP plus 1 kg DM of by-pass protein meal  supplement ("balancer"). Treatment groups each comprised 10 mixed age  Friesian-Jersey crossbred cows which were fed the supplement(s) in their  respective groups in two equal portions following morning and evening  milkings. Groups were grazed independently on similar pastures between  these times.    Herd test milk yields over the 28 day supplementary feeding period were  greater for the AP and AP+"balancer" groups (14.1 \& 14.7 litres/cow/day,  respectively) than for the control group (12.1 litres/cow/day; P<0.001).  Milk protein yields were lower for the control than the two AP groups  (0.43 vs 0.54 \& 0.57 kg/cow/day for control, AP and AP+"balancer",  respectively; P<0.01). Yields of milkfat (0.58 vs 0.70 vs 0.77  kg/cow/day) and milksolids (1.01 vs 1.24 vs 1.34 kg/cow/day) differed  between all three treatment groups (P<0.05). Cow condition and  bodyweights were similar between the three treatment groups at both the  start and end of the trial. Apple pomace was therefore shown to be a  useful supplement for dairy cows in late lactation.   },
	issn = {1176-5283},
	author = {Hovey RC and McFadden TB and MacKenzie DDS}
}
@conference {40578,
	title = {The effect of peripartum administration of ovine prolactin on lactogenesis in autumn-lambing ewes.},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {54},
	year = {1994},
	month = {Jan},
	pages = {115-118},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Two routes of oPRL supplementation were used to elevate peripheral or  
local concentrations of PRL in autumn-lambing ewes which, based on previous  
results, were expected to have low plasma PRL concentrations and milk yields  
relative to spring-lambing ewes.  Administration of 10 mg oPRL directly into  
the gland or subcutaneous injection of 0.5 mg/kg oPRL did not increase the  
milk yields, or change the composition of milk, compared to controls.  These  
results suggest that the circulating and intramammary concentrations of PRL in  
autumn-lambing ewes are not limiting lactogenesis.  However, because the  
plasma prolactin concentration in the ewes was unexpectedly high, it was not  
possible to reach firm conclusions regarding possible effects of supplementary  
oPRL in ewes with naturally low plasma PRL concentrations.  Nevertheless,  
the results indicate that raising the intramammary concentration of PRL around  
the time of parturition, in ewes with circulating PRL concentrations  
characteristic of normal spring-lambing ewes, does not enhance lactogenesis. 
 },
	issn = {1176-5283},
	author = {Peterson SW and MacKenzie DDS and McCutcheon SN and Lapwood KR}
}
@conference {40618,
	title = {Effects of once daily milking in late lactation on cows with either low or high initial somatic cell counts},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {54},
	year = {1994},
	month = {Jan},
	pages = {285-288},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The present study was carried out in order to measure the effects of  
once daily milking on somatic cell count (SCC) of cows which had either low 
SCS  
or high SCC at the start of the experiment in late lactation.  Thirty six cows  
were used, 18 with low SCC and 18 with higher SCC.  Nine cows from each  
group were randomly allocated to once or twice daily milking for the four week  
experimental period in March.  The yields of milk, fat, protein and lactose were  
significantly reduced by once daily milking (P<0.01) in both groups.  However,  
the effects of once daily milking on yields was larger for high SCC cows  
(interaction P<0.01).  Once daily milking significantly increased the  
concentration of protein (P<0.001) in both groups and fat (P<0.01) in only the  
low SCC group.  Once daily milking significantly reduced the concentration of  
lactose, the effect being larger in the high SCC group (interaction P<0.001).   
SCC (per ml) was increased by once daily milking, but the effect was  
significant only in the high SCC group (interaction P<0.10).  The total number  
of cells produced per day were not affected by once daily milking. 
 
These results show that SCC can be used with confidence to identify  
subclinically infected cows in later lactation milked once or twice a day.  The  
results also show that cows with a low incidence of subclinical mastitis can be  
milked once daily in later lactation, with much less effect on yield of milk and  
its constituents than would be expected in cows with a higher incidence of  
infection. },
	issn = {1176-5283},
	author = {Kamote HI and Holmes CW and MacKenzie DDS and Holdaway RJ and Wickham BW}
}
@conference {40605,
	title = {The effects of season on placental development and fetal growth in sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {54},
	year = {1994},
	month = {Jan},
	pages = {227-230},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Autumn-born lambs have been reported to have lower birth weights  
than spring-born lambs by 0.4 to 1.0 kg, but the physiological basis of this  
difference is unknown.  This study examined the effects of season on fetal  
growth and placental development independent of the confounding effects of  
maternal nutrition.  Romney ewes (aged 5 and 6 years) were randomly  
allocated to groups mated in December (n=13) or March (n=13 with a similar  
live weight at mating (55.6{\textpm}1.8 vs 55.7{\textpm}1.9 kg, mean{\textpm}SE, P>0.10) and  
managed for a similar live weight at day 140 of gestation (62.5{\textpm}1.8 vs 62.9{\textpm}1.9  
kg, P>0.10).  At day 140 of gestation, measures of fetal growth and placental  
development, adjusted for litter size, were (December- vs March-mated):  
individual fetal weight (4.15{\textpm}0.16 vs 5.07{\textpm}0.16 kg, P<0.001); total fetal weight  
per ewe (6.42{\textpm}0.18 vs 7.14{\textpm}0.22 kg, P<0.01); caruncle number (114.5{\textpm}4.1 vs  
121.0{\textpm}4.2, P>0.10); placentome number (89.4{\textpm}4.2 vs 106.9{\textpm}4.3, P<0.01);  
caruncle occupancy, i.e. number of placentomes/number of caruncles  
(0.79{\textpm}0.03 vs 0.88{\textpm}0.03, P<0.05); and total placentome weight (564.7{\textpm}34.0 vs  
679.0{\textpm}34.9 g, P<0.05).  These results suggest that seasonal differences in birth  
weight of lambs are mediated not by differences in maternal nutrition but rather  
by a direct seasonal effect on placental size (specifically the formation of  
placentomes and hence total placental weight). 
 },
	issn = {1176-5283},
	author = {Jenkinson CMC and Peterson SW and MacKenzie DDS and McCutcheon SN}
}
@conference {40563,
	title = {Growth-promoting and metabolic actions of recombinant ovine placental lactogen and bovine growth hormone in young lambs},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {54},
	year = {1994},
	month = {Jan},
	pages = {59-62},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {It has been shown previously that ovine placental lactogen (oPL) has a  
growth-promoting effect in the growth hormone (GH)-deficient dwarf rat.   
However, this effect has not been verified in an homologous system using  
animals with an intact somatotrophic axis.  To examine the effects of oPL in  
the sheep, we injected lambs with recombinant oPL (0.1 mg/kg liveweight/day,  
n=16) or saline (n=16) for 21 days commencing on day 3 of life and compared  
their effects on body growth and energy intake with those in lambs treated with  
the same dose of recombinant bovine growth hormone (bGH, n=16).   
Circulating concentrations (ng/ml) of hormones in saline- vs bGH- vs oPL- 
treated lambs at day 20 of treatment were (mean{\textpm}SE): oPL, <0.5 vs <0.5 vs  
12.8{\textpm}0.5; GH, 10.8{\textpm}5.0 vs 48.4{\textpm}5.0 vs 12.6{\textpm}5.0, P<0.001; insulin-like growth  
factor-I (IGF-1), 267.6{\textpm}14.4 vs 302.4{\textpm}14.2 vs 291.7{\textpm}14.4.  Average daily gain  
(kg/day) during treatment was significantly (P<0.05) greater in oPL-treated  
lambs (0.28{\textpm}0.01) than in saline-treated (0.25{\textpm}0.01) or bGH-treated  
(0.24{\textpm}0.01) lambs.  Similarly, there were significant (P<0.05) increases in 
total energy intake (over the 21 day treatment period) during treatment with 
oPL (112.5{\textpm}3.5 MJ ME), compared with bGH (102.0{\textpm}3.5 MJ ME) or saline  
(102.0{\textpm}3.5 MJ ME) treatment.  It is concluded that oPL is somatogenic in  
young lambs.  This effect may be mediated by stimulating voluntary feed 
intake rather than by elevating circulating concentrations of IGF-I. },
	issn = {1176-5283},
	author = {Min SH and MacKenzie DDS and Breier BH and McCutcheon SN and Gluckman PD}
}
@conference {40576,
	title = {Mammary involution in ewes: Changes in milk plasminogen and plasmin},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {54},
	year = {1994},
	month = {Jan},
	pages = {107-110},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Multiparous Border Leicester x Romney ewes were weaned early (day 35  
of lactation), milked to empty the mammary gland and again milked 18 h later  
(day 0 of experiment) to establish baseline milk yields and concentrations in  
milk of the proteolytic enzyme plasmin and its zymogen plasminogen.  They  
were then divided into 3 groups to be milked 3 (n=5), 8 (n=6) or 15 (n=5) days  
after the day 0 milking to determine changes in concentrations and yields of  
plasmin and plasminogen in mammary gland secretions during involution.   
Yields (mean{\textpm}SE) on days 0 (groups 1 + 2 + 3), 3 (group 1), 8 (group 2) and 15  
(group 3) were: secretion (g), 785{\textpm}31.2 v. 598{\textpm}94.8 v. 478{\textpm}86.8 v. 51{\textpm}66.6;  
plasminogen (mg), 7.8{\textpm}2.2 v. 78.7{\textpm}11.1 v. 22.4{\textpm}4.6 v. 3.9{\textpm}2.1; and plasmin  
(ug), 11.5{\textpm}2.38 v. 148.5{\textpm}8.00 v. 51.6{\textpm}7.92 v. 4.9{\textpm}2.32.  Corresponding  
concentrations in the secretions were (ug/ml): plasminogen, 0.01{\textpm}0.002 v.  
0.15{\textpm}0.027 v. 0.046{\textpm}0.005 v. 0.061{\textpm}0.007; and plasmin, 0.015{\textpm}0.006 v.  
0.275{\textpm}0.027 v. 0.118{\textpm}0.011 v. 0.083{\textpm}0.009.  There was a linear decline in the  
volume of secretions from day 0 to day 15.  In contrast there was a transient  
increase (15 fold) in plasminogen and plasmin yields by 3 days after milking.   
These data suggest that any role of plasmin in mammary gland involution is  
likely to be limited to the first week after early weaning. },
	issn = {1176-5283},
	author = {MacKenzie DDS and Cottam YH and Knutson RJ and McCutcheon SN}
}
@conference {40581,
	title = {Mouse mammary fat pad interacts with mitogens to stimulate epithelial growth in vitro},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {54},
	year = {1994},
	month = {Jan},
	pages = {125-130},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Issues of sustainability in animal production in developed countries  involve a trend away from intensive production systems and destruction of the  environment, towards improved animal welfare and increased product quality,  with an emphasis on reduced use of chemicals in production systems. The  negative environmental impact and the loss of biodiversity, due to livestock  production systems, are major issues in both developed and developing  countries. In developing countries, desertification and deforestation, the  sustainable management of wildlife systems and the need to reduce competition  between humans and animals for scarce resources, are all major issues of  sustainability. While the developed world is looking towards "de-intensifying"  its animal agriculture, the developing regions of the world have a perceived  need to intensify animal production systems in order to support increasing  populations, urban growth and an increased demand for animal products.   The implications for scientific research include: aiming to optimise rather than  maximise production; greater emphasis on the ecological aspects of sustainable  systems, maintenance of biodiversity and natural resources; and minimising  external inputs and satisfying the food, income and social needs of rural  communities. Scientific communities must increasingly seek international  collaboration in a global approach to the challenge of sustainable animal  production.  },
	issn = {1176-5283},
	author = {Hovey RC and McFadden TB and MacKenzie DDS}
}
@conference {40575,
	title = {The utilisation of whole body cysteine by the mammary gland of the lactating goat},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {54},
	year = {1994},
	month = {Jan},
	pages = {103-106},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Three lactating Saanen goats weighing 55-71 kg, producing 1.2-3.6 kg  
milk/day and fed <I>ad libitum</I> concentrates and hay, were infused via a  
jugular catheter with 35S-cysteine (35S-Cys) at 9.3 mCi/min for 9 hours.   
Blood samples were taken hourly and mammary tissue biopsied terminally.   
Concentrations and specific radioactivities (SRA) of cysteine (Cys) and  
glutathione (GSH) were determined in whole blood, plasma and mammary tissue.   
Mean arterial concentrations (nmoles/g{\textpm}SE) of Cys and GSH in whole blood,  
plasma and red blood cells were: 71{\textpm}7, 79{\textpm}9 and 19{\textpm}8; and 823{\textpm}30, 1.6{\textpm}01 and   
3426{\textpm}124 respectively.  Arterial SRA in whole blood at plateau (7-9h) of  
35S-Cys (352{\textpm}13 dpm/nmole) was higher than that for GSH (5.9{\textpm}0.7 
dpm/nmole).   
However the difference between intracellular SRA for Cys and GSH in  
mammary gland tissue was much less (231{\textpm}23 vs 146{\textpm}13 dpm/nmole).  Total  
uptake of Cys by one half of the mammary gland was 0.5{\textpm}0.2 g/day.  Whole  
body irreversible loss rate of Cys was 7.3{\textpm}0.7 g/day, giving a percentage  
utilisation of whole body Cys by the mammary gland of 13.6{\textpm}4.3. },
	issn = {1176-5283},
	author = {Knutson RJ and Lee J and Davis SR and Harris PM and MacKenzie DDS and McCutcheon SN}
}
@conference {40477,
	title = {The effect of once daily milking concentrations and yields of plasminogen, plasmin and other whey proteins},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {53},
	year = {1993},
	month = {Jan},
	pages = {155-158},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Lambs of ewes with a high maternal behaviour score (MBS) located the udder in less time after birth than lambs of low MBS ewes. Rapid location of the udder increased immunoglobulin concentration in lamb plasma 24 hours after birth and may contribute to the improved lamb survival and growth (ewe productivity) associated with high MBS ewes.},
	issn = {1176-5283},
	author = {Knutson RJ and MacKenzie DDS and Davis SR and McCutcheon SN}
}
@conference {40531,
	title = {Metabolic changes in sheep divergently selected for plasma IGF-1},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {53},
	year = {1993},
	month = {Jan},
	pages = {381-384},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The detection of small amounts of biologically active material in animals may require quantification of radioactive label. Here we compare several image analysis methods for quantifying relative levels of radioactive probe detected by x-ray film or photographic emulsion. Total RNA "dot blots" and ovine muscle sections were probed for the presence of muscle actin mRNA using 35S-labelled riboprobes. Bound probe was detected by x-ray film in both cases. The probed sections were further exposed to photographic emulsion, while the dot blots were individually quantified by scintillation counting. Bound probe was quantified macroscopically by digitisation of optical density (OD) and thresholding of the x-ray film image. Dot blot image ODs were correlated with scintillation counts (r>0.96), demonstrating that the levels of mRNA detected in tissues by autoradiography are proportional to cellular mRNA concentration. Densitometry of section macroautoradiographic images can therefore be useful in determining relative probe signal at the tissue level. When probe was quantified microscopically by counting silver grains in emulsion autoradiographs, simple thresholding correlated with manual counts (r=0.88) but was unreliable at higher grain densities. Processing of the gray image gave a more direct estimate of silver grain density (r= 0.98).},
	issn = {1176-5283},
	author = {Sherlock RG and Blair HT and Kuhn B and MacKenzie DDS and Breier BH and Gluckman PD and McCutcheon SN}
}
@conference {40365,
	title = {The effects of milking once daily throughout lactation on the performance of dairy cows grazing on pasture},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {52},
	year = {1992},
	month = {Jan},
	pages = {13-16},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The influence of selection for rapid (Fast GC) or slow (Slow GC)  clearance of exogenous glucose on the pH of lamb meat was investigated  using preslaughter stress, adrenaline and energy supplement treatments.  Ultimate pH values were elevated (P<0.001) by a high level of  preslaughter stress in the Fast GC line only. This response was  suppressed by an oral energy supplement, indicating that recharge of  muscle glycogen stores was impaired. The demonstration of this genetic  relationship makes the selection lines valuable for study of the  influence on meat quality of post mortem energy metabolism in  muscles.  },
	issn = {1176-5283},
	author = {Holmes CW and Wilson GF and MacKenzie DDS and Purchas J}
}
@conference {40412,
	title = {Effects of shearing method on the physiology and productivity of sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {52},
	year = {1992},
	month = {Jan},
	pages = {199-202},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Three groups of sheep housed in metabolism crates were fed  Lotus corniculatus (low tannin), L. pendunculatus (medium  tannin) and ryegrass pasture (control) respectively. After a period of  adaptation to each of the diets, labelled 35S-cysteine and },
	issn = {1176-5283},
	author = {Holmes CW and Kamil KA and Parker WJ and MacKenzie DDS and Purchas G and Kidd R}
}
@conference {40309,
	title = {The effects of once daily milking as a management practice in late lactation},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {51},
	year = {1991},
	month = {Jan},
	pages = {191-196},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Five goats were milked hourly for 43 h on two occasions, on one  occasion receiving injections of growth hormone (GH; 15 mg S.C.) after 4  and 28 h of the milking period and on the other occasion were untreated.  Blood samples were taken before each milking, the latter facilitated by  intravenous injection of oxytocin (100 m i.u.).   Milk yield began to rise 4-5 h after the injection of GH and continued  to rise for a further 8-9 h until a level of production 18\% above the  pre-treatment yield was achieved. Following the second injection of GH  the yield increment was reduced such that by the end of the experiment  the yield increase was 24\%. In one goat the milk yield response was not  sustained and these data were excluded from the above calculations.   Plasma insulin-like growth factor-I (IGF-I) and insulin concentrations  increased in a similar time-course to the change in milk yield  following GH treatment but were relatively constant in control  experiments. IGF-I and insulin content of plasma was approximately  doubled by GH treatment by the end of these experiments.  },
	issn = {1176-5283},
	author = {Lynch GA and Hunt ME and MacKenzie DDS}
}
@conference {40269,
	title = {Milk production and plasma prolactin levels in spring- and autumn-lambing ewes},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {50},
	year = {1990},
	month = {Jan},
	pages = {483-485},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Methane and nitrous oxide produced by farmed ruminants may cause  over one third of the potential greenhouse warming which can be  attributed to New Zealand. This is a result of high populations of  domestic ruminants (mainly sheep and cattle), and the large warming  potential of methane and nitrous oxide. New Zealand{\textquoteright}s total greenhouse  gas production is an insignificant component of the global total, but  this fact cannot be used as a reason to ignore New Zealand{\textquoteright}s  contribution. International negotiations have commenced with the aim of  producing a treaty to limit global greenhouse gas production by  ruminants in New Zealand, and identifies areas needing further research.  It concludes that; (1) the accuracy of estimate of greenhouse gas  emissions from agriculture needs to be improved; (2) technology to  reduce greenhouse gas emissions from ruminants should be developed for,  and applied to, New Zealand farming systems; and (3) that equitable  methods of implementing limitation policies need to be investigated.  },
	issn = {1176-5283},
	author = {Peterson SW and MacKenzie DDS and McCutcheon SN}
}
@conference {39933,
	title = {Blood metabolites and infertility in dairy cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {45},
	year = {1985},
	month = {Jan},
	pages = {17-20},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Kallikrein-like enzyme (KE) activity has been detected in bovine saliva from the front of the mouth and from the cannulated mandibular gland. The maximal activity (39 mUnits ml-1) was present in secretions from the mandibular gland of cows stimulated with carbachol (parasympathomimetic). A lower activity (24 mUnits m-1) was obtained under isoprenaline (sympathomimetic) combined with carbachol stimulation. No detectable KE activity was present in parotid gland secretions. When tested for vasodilator activity in sheep, all samples tested were positive, but the greatest response was mandibular secretions collected under carbachol stimulation. Using purified salivary proteins, it was demonstrated that the KE activity was associated with bands 7 and 8, major proteins secreted by the mandibular gland.},
	issn = {1176-5283},
	author = {Wilson GF and MacKenzie DDS and Holmes CW}
}
@conference {39934,
	title = {A physiological basis of genetic improvement in milk production of Friesian and Jersey cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {45},
	year = {1985},
	month = {Jan},
	pages = {21-26},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Changes in rumen digesta and electrolyte composition were investigated in 4 high (HS) and 4 low (LS) bloat susceptible cows for 7.5 h following intraruminal loading with 10 litres water containing 0 (L), 1.76 (C), 3.52 (H) or 7.04 (HH) moles Na. Pre-treatment Na concentrations averaged 130 mmol/litre for both susceptibility groups, with increases averaging -20, 10,42 and 95 mmol/litre after addition of L, C, H and HH respectively. Susceptibility groups did not differ in rate of return of Na concentration toward pre-treatment values. Increasing Na loading decreased fluid loss from the rumen but LS cows consistently lost more fluid than HS cows, with no treatment- susceptibility interaction.},
	issn = {1176-5283},
	author = {Davis SR and Hughson GA and Bryant AM and MacKenzie DDS}
}
@conference {39824,
	title = {Nutritional and physiological studies of differences between Friesian cows of high and low genetic merit},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {43},
	year = {1983},
	month = {Jan},
	pages = {67-70},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Fleece tenderness is a serious fault of New Zealand crossbred wool costing the sheep industry between $50 and $100 million annually. Wool fibres break at the point where fibre diameter is at its minimum and factors which influence minimum fibre diameter will influence the incidence of fleece tenderness, e.g. breed and strain of sheep, age of ewe, level of feeding and reproductive status. Tender fleeces are on average lighter than sound fleeces and often have other associated faults such as cotting and yellow discolouration. Variation in minimum winter fibre diameter accounts for only about 40\% of the variation in staple strength within a flock suggesting that factors other than fibre diameter may be involved. There are fibre structural and compositional differences between sound and tender wools of the same diameter and these may be associated with fleece tenderness. The wool producer can influence the incidence of fleece tenderness by the level of feeding during mid pregnancy but it may not always be economic to feed better. Choice of shearing time will also influence the level of fleece tenderness. A preliminary estimate of the heritability of fleece tenderness of 0.58 },
	issn = {1176-5283},
	author = {Davey AWF and Grainger C and MacKenzie DDS and Flux DS and Wilson GF and Brookes IM and Holmes CW}
}
