@conference {41913,
	title = {Increased hepatic skatole exposure via rumen infusion increases skatole concentration in peripheral circulation and inter-muscular fat in sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {66},
	year = {2006},
	month = {Jan},
	pages = {295-299},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Napier},
	abstract = {Skatole meat taint is unique to pastoral systems where high forage digestibility results in tryptophanderived skatole production at rates that exceed the clearance capacity of the liver. We hypothesise that under conditions of minimal endogenous skatole production (diet low in rumen degradable protein) a continuous rumen infusion of skatole will elevate hepatic exposure and modify tissue skatole metabolism. A 72 hour rumen infusion of skatole (140 mg/h; n = 6) dissolved in propane-1,2-diol (PD) or PD media alone (n = 6) was performed. Samples of rumen fluid and blood were collected at 0, 2, 4, 6, 8, 12, 16, 24, 48 and 72 hours for determination of skatole concentration. Infusion of skatole increased (P < 0.01) levels of skatole in rumen fluid (21 {\textmu}g/g), peripheral plasma (154 ng/ml) and inter-muscular fat (4240 ng/g). A two-compartment model was fitted to the rumen and plasma skatole concentration of treated sheep to estimate the rate of transfer from rumen to peripheral plasma (k = 0.23 {\textpm} 0.03/h) and the rate of elimination from peripheral circulation (k = 2.10 {\textpm} 0.56/h). A negative correlation (P < 0.05) between the rate of elimination and level of skatole deposition in inter-muscular fat was also found. },
	issn = {1176-5283},
	author = {Deighton MH and Pacheco D and Tavendale MH and Schreurs NM and Peters JS and McNabb WC and Roy NC}
}
@conference {41853,
	title = {Digestion kinetics of New Zealand native flax},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {65},
	year = {2005},
	month = {Jan},
	pages = {367-371},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {This experiment compares the nutritive value of New Zealand native flax, Phormium tenax, by-products i.e. leaves (L), butts (B), thrash-stripped fibre (F) and green matter (G), with white clover (WC) via digestion kinetics derived from in vitro and in sacco incubations. The WC had a high nutritive quality (11.1 MJME/kg DM, CP 28\% DM), G a moderate (10.1 MJME/kg DM, CP 9\% DM), and L, B, F were of very low nutritive quality (< 8 MJME/kg DM, CP < 6 \% DM). After 24 hours, 96, 76, 47, 47, and 30 \% of the DM was degraded for WC, G, L, B and F, respectively (P < 0.001). The degradation rates (\%/h) of digestible DM were faster (P < 0.001) for WC (13) and G (11) than B (3.8), L (4.6) and F (2.7). Flax by-products had a net loss of ammonia after 2 (B), 4 (F and L) and 8 hours (G). The proportion of DM converted to VFA by 8 hours was 21 \%, and 14 \% for WC and G respectively, but only 9-10 \% for the other flax by-products (P < 0.001). The feeding model BestFeed{\texttrademark} predicted that G could grow a 500 kg bull at 0.8 kg/day and had potential as a supplement for pasture-fed animals.
KEYWORDS: flax; Phormium tenax; in sacco; in vitro; digestion kinetics; nutritive value; forage ration, BestFeed. },
	issn = {1176-5283},
	author = {Litherland AJ and Layton DL and Burke JL and Corson DC and Peters JS}
}
@conference {41319,
	title = {Ammonia and urea utilisation in lambs infected with Trichostrongylus colubriformis and fed fresh lucerne (Medicago sativa)},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {62},
	year = {2002},
	month = {Jan},
	pages = {77-80},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {The effect of a Trichostrongylus colubriformis infections on ammonia and urea fluxes across the mesenteric-drained viscera (MDV), portal-drained viscera (PDV), and liver was investigated using an arterio-venous preparation in lambs fed fresh lucerne (Medicago sativa). The lambs were infected with 6000 T. colubriformis L3 larvae per day for 6 days (n=5) or kept as parasite free controls (n=5). On day 48 of the experiment, the lambs were infused continuously for 8 hours with r-aminohippuric acid (688 mg/h) into the mesenteric vein in order to measure plasma flow across the MDV, PDV and liver. Blood was continuously collected from the mesenteric artery and vena cava for consecutive two hour periods throughout the infusion period and plasma was harvested. Plasma concentrations of ammonia and urea were unaffected by the presence of intestinal parasites. Ammonia fluxes across the MDV, PDV, and liver were similar between treatment groups. Urea fluxes were also similar between treatment groups with the exception of the PDV, which showed a net release of urea in the parasite group and a net uptake by the control group (P=0.03). This suggests that the presence of a sub-clinical T. colubriformis infection does not increase the demand on the lamb for amino acids for ureagenesis. },
	issn = {1176-5283},
	author = {Bermingham EN and Roy NC and Reynolds GW and Sinclair BR and Peters JS and Sutherland IA and Waghorn GC and Revell DK and McNabb WC}
}
@conference {41357,
	title = {The effect of condensed-tannins in fresh Sulla (Hedysarum coronarium) on the net flux of fatty acids across the mammary gland and their secretion in the milk of lactating ewes},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {62},
	year = {2002},
	month = {Jan},
	pages = {231-235},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {<p>Twelve sheep were surgically prepared with catheters in the mesenteric artery and mammary vein and a transonic flow probe around the pudendal artery to quantify the effect of condensed-tannins (CTs) on net mammary flux of fatty acids (FAs) and their secretion in milk. Two weeks later (Day 0), sheep were fed fresh Sulla (1500 g DM/d), which contains medium to high concentration of CTs (43.7 g CTs/kg DM). Six ewes were orally drenched (four times/d) with polyethylene glycol (160 g/d in water) to remove the effects of CTs; the remaining ewes received water. On Day 28, the mammary plasma flow and net flux of most FAs were similar between treatments. Arterial supply of C23:0, C18:2, C18:3, C20:1 and C22:5 to the mammary gland was increased (P\&lt;0.10) with CTs. The increase for C18:2 and C18:3 was concomittant with increased (P\&lt;0.10) concentrations in milk. No effect of CTs on total fat concentration and yield in milk was observed. Conclusions from this study indicate that CTs in Sulla increased the milk concentration of C18:2 and C18:3 by increasing arterial supply of these FAs to the mammary gland.</p>},
	issn = {1176-5283},
	author = {Roy NC and Knight TW and Reynolds GW and Deighton MH and Death AF and Sinclair BR and Peters JS and McNabb WC}
}
