Glucose Metabolism in Steers Receiving High Fibre Diets and Glucose Infusion Into Abomasum

Abstract

Glucose has been the subject of a number of studies due to its important role in
ruminant metabolism Nevertheless, there is paucity in the literature dealing with glucose metabolism when ruminants are offerred a low-quality roughages. Eight Brahman steers approximately two years old and weighing 238 i 23 kg were alloted
randomly into an individual metabolism cage. Each steer received barley straw ad 1ib., 150 g/d mineral mix and 75 g/d urea which was infused eontinously into the rumen. In addition to that, two steers were infused continously per abomasum with 1500 ml water/head/d, whilst the remainders were infused with 50, 100, 150, 200, 250 and 300 g/1500 rnl/d anhydrous glucose during which the following parameters were observed I feed consumption, rumen metabolites, nitrogen balance (NB), and metabolism of glucose. The last parameter was  studied using a radio isotope technique. The results showed that abomasal infusion of glucose significantly improved (P<0.0l) the consumption of dry matter and organic matter as well as NB. The latter was associated with a significant reduction of urinary N excretion suggesting that there was a competition of glucose requirement on the expense of amino acid eatabolism. There was no significant alteration (P>0.1) on the rurnen metabolites attributable to glucose infusion. Pool size of glucose was not altered by infusion but glucose entry rate (GER) and T 1/2 were linearly increased as the level of glucose infusion increased. The implication of this study is discussed in relation to practical application with particular emphasis given to enhancement of ruminant productivity on low-quality roughage.