Patterns of nutrient interchange and oxygen use among portal-drained viscera, liver, and hindquarters of beef steers from 235 to 525 kg body weight.

Abstract

Our objective was to quantify changes in supply and use of nutrients and O2 by large-frame, multicatheterized beef steers as they grew from 235 to 525 kg BW. Steers consumed 5.25 to 9.87 kg DM/d of a 62% concentrate diet that provided 126 to 217 g N/d and 1 kg ADG. Steers were assigned to three groups (eight, nine, and eight steers each) that divided the BW range into thirds. Weights at first sampling for the three groups were 236, 319, and 445 kg, respectively. Each group was sampled twice. Groups were killed after the second sampling. Tissue weights and hindquarters (HQ) contents of fat, protein, and ash were measured. Blood flow, oxygen uptake, and net uptake or release of metabolites were regressed against functions of BW.75 to assess changes during growth. Blood flow in all tissues except liver and oxygen use by all tissues decreased per unit tissue weight as BW.75 and age increased. Changes with age per unit liver weight were as follows: decreased uptake of propionate and lactate, increased uptake of alpha-amino N and glutamine, decreased production of urea and glutamate, and increased production of acetate and beta-hydroxybutyrate. Glucose and urea production per unit liver weight was constant. Changes with age per unit HQ weight were as follows: increased uptake of glucose, decreased uptake of alpha-amino N and glutamate, decreased release of lactate, and increased release of glutamine. Weight of the portal-drained viscera (PDV) increased from 91 to 97 g/kg EBW as BW increased from 236 to 522 kg; PDV fat increased from 375 to 552 g/kg PDV tissues. Liver decreased from 16 to 12 g/kg EBW. Hindquarters decreased from 286 to 266 g/kg EBW; HQ protein was 200, 197, and 200 g/kg HQ tissue for Groups 1, 2, and 3, respectively. Corresponding fat was 131, 182, and 177 g/kg HQ tissue. Changes in net flux reflect changes in nutrient partitioning and tissue deposition as steers grew and aged.

Energy expenditure of splanchnic tissues and hindlimbs in growing lambs fed frozen rye-grass: effects of barley supplementation and changes between 2.5 and 7 months of age

“…0.4 and 0.6. This trend is coherent with the known decrease in the contribution of splanchnic tissues to body weight with age in ruminants [1,4,24].…”

“…3). This tendency was the opposite to that noted by Eisemann et al [4] who found a light decrease in EE. These differences could not be explained by changes in body composition with age between ovine and bovine species since the percentage of muscles in the empty body weight is not greatly different between species (33% in ovines vs. 30% in bovines, on average) and is quite stable between the 0.4 to 0.6 maturity stages in both species [21,24].…”

“…A more likely hypothesis is that in those animals, the growth rate of the carcass, and thus of the hindlimb, had been temporarily slowed down to the benefit of the splanchnic tissues. Furthermore, the number of animals we used was limited and the effects noted at the hindlimb level are always proportionally lower than those noted for the splanchnic tissues [4].…”

Effects of wheat processing and dietary fat sources on performance, ruminal and blood parameters, and steak fatty acids profile of Holstein steers

“…Reynolds et al (1997) stated that compared to ruminal infusion abomasal infusion of starch from wheat (1200 g/d) to cows in late phase of lactation increased milk yield, because glucose is the main substrate for lactose synthesis. Eisemann et al (1996) reported that blood insulin was increased when steers received abomasal infusions of starch. Intestinal absorption (as glucose) reduced liver glucose production from propionate.…”

Conception and development of a bibliographic database of blood nutrient fluxes across organs and tissues in ruminants: data gathering and management prior to meta-analysis

“…With the third type of treatment, a physiological state was described according to different stages, e.g. growing animals were studied at different age and body weight [26]. Finally, in a small number of cases, other treatments were studied, e.g.…”