Abstract

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<0.10) with CTs. The increase for C18:2 and C18:3 was concomittant with increased (P<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.

NC, Roy, TW Knight, GW Reynolds, MH Deighton, AF Death, BR Sinclair, JS Peters, and WC McNabb

Proceedings of the New Zealand Society of Animal Production, Volume 62, Palmerston North, 231-235, 2002