@conference {40288,
	title = {The use of full-sibling pairs to measure plasma FSH concentrations in Booroola ewe and ram lambs},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {51},
	year = {1991},
	month = {Jan},
	pages = {87-90},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Forty-eight yearling Holstein-Friesian steers were assigned to  three diets (Panicum virgatum (P) var. Cave-in-rock, Dactylis  glomerata (D) var. Hallmark and Medicago sativa (M) var. Waterman  Loomis 316) fed at two levels of intake (low (L) 65g DM kg-1 liveweight  -0.75 day -1 or high (H) 90 g DM kg -1 liveweight -0.75 day -1) during a  6 month growth study. At the conclusion of the study animals were  stunned, exsanguinated and promptly eviscerated and the rumen quickly  emptied of its contents and subsequently weighed. Upon slaughter, rumen  tissue samples were acquired from the ventral sac and placed in  oxygenated M199 media. Mucosa and muscularis weights were determined  along with their total 02 consumption, ouabain-senitive- (OSO2) and  ouabain-insensitive-(OIO2) respiration. Tissue oxygen consumption was  determined in vitro using a YSI Clark style electrode. Total,  Mucosa and muscularis weights were greater (16.9-43.5\%) with H and  tended to be affected by diet (P<0.10). On a tissue basis, rumen muscle  O2 consumption was not affected by treatment but mucosal OSO2 and  percent inhibition of O2 consumption by ouabain were higher (6.9-94\%)  with Medicago. Total rumen O2, OSO2 and OIO2 consumption were higher  (8.6-80.5\%) in H (P<0.05) and diet affected OSO2. Rumen muscle total O2  consumption was greatest (3.51 ul 02/mg/hr) for D and altered by level  of intake (P<0.03). Mucosal OSO2 and OIO2 were greater with H (P<0.04  and P<0.07, respectively). Total rumen O2 consumption is dominated by  organ size rather than changes in weight specific O2 consumption.  Therefore, at high forage intakes part of the decrease in the efficiency  of ME utilisation is a consequence of increased heat production from the  larger rumen.  },
	issn = {1176-5283},
	author = {Isaacs KL and McNatty KP and Littlejohn RP}
}
