Submitted to: Journal of Animal Science
Publication Type: Proceedings
Publication Acceptance Date: 5/1/2002
Publication Date: 2/1/2003
Citation: Hersom, M.J., Krehbiel, C.R., Horn, G.W., Phillips, W.A. 2003. Effects of previous liveweight gain on visceral organ mass and oxygen consumption in cattle duing high-grain feeding. Journal of Animal Science. 81(81):3130-3140.
Interpretive Summary: Abstract Only.
Technical Abstract: Forty-eight fall-weaned crossbred steers (231+/-25 kg) were used in a completely random design to determine the effect of previous liveweight gain on visceral organ mass and oxygen consumption. During the 143-d growing phase, treatments were high (HGW; 1.28 kg/d) or low (LGW; .48 kg/d) daily BW gain on wheat pasture or dormant native range (NR; .21 kg/d). Steers were individually fed a high-grain diet for to a common 1.27 cm of backfat. Initial empty body weight (EBW) was greater (P<.01) for HGW steers than LGW, which were greater than NR steers (382>303>245 kg EBW, respectively). Liver, rumen, and small intestine (g/kg EBW) were greater (P<.01) in NR than HGW or LGW. Similarly, total gastrointestinal tract (GIT) and total splanchnic tissues (TST) were greater (P<.01) in NR than HGW and LGW (80.3>51.8 and 57.9, and 108.3>90.0 and 90.2 g/kg EBW, respectively). Initial oxygen consumption by the liver was greater (P=.02) )in HGW and LGW than NR (35.2 and 33.8>16.2 mL*min-1*tissue-1), whereas duodenal initial oxygen consumption was greater (P=.02) in LGW than HGW or NR (12.06>5.77 or 4.97 mL*min-1*tissue-1). Initial ruminal epithelium oxygen consumption in HGW was greater(P=.03)than NR. During finishing, NR steers increased EBW at a greater rate (P<.01) than either HGW or LGW (1.83>1.38 and 1.28 kg.d-1). In contrast, change in GIT and TST were less (P<.01) in NR than HGW and LGW steers (-.12<.13 and .08, and .01<.23 and .21 g/kg EBW*d-1, respectively). Native range steers had a greater rate of EBW gain and a lower rate of GIT and TST gain than HGW or LGW steers. Coupled with lower oxygen consumption by splanchnic tissues, this could relate to an increased efficiency of energy use for maintenance during feedlot finishing in NR steers.