No description available.

Crossbred lambs were injected with L-arginine hydrochloride (arg) to determine the effects of single of multiple arg challenges on growth hormone (GH) secretion. Indwelling jugular catheters were inserted. At the beginning of each of 3 trials, lambs were injected with saline and blood samples were collected for 90 min to establish baseline GH. Blood sampling continued at 5-min intervals until 1 h after the final injection, then at 10-min intervals for one additional hour. In trial 1 arg (.5g/kg) was injected into 6 lambs while the other 6 received a second saline injection. Trial 2 consisted of 3 arg injections given at 1-h intervals. Trial 3 utilized 4 arg injections given at 15-min intervals. Trials 2 and 3 were replicated using a switchback design. Serum GH and insulin were measured by double antibody RIA. Mean GH for treated lambs in trial 1 was 3.89 ng/ml versus 1.74 ng/ml in controls (P<.01). GH peaked 30 min after injection (9.47 ng/ml), declined to 5-times baseline and remained near that level throughout the sampling period. Serum insulin was not different between treatments. In trial 2 arg treated lambs had higher mean GH (2.57 ng/ml) than controls (.86 ng/ml; P<.01). Peaks of GH were observed 20 min after the first injection (7.59 ng/ml) and 1 h after the second injection (5.6 ng/ml). No increase in GH was observed after the third injection. Insulin tended to follow the same pattern, but was not significantly elevated in treated lambs. Differences in trial 3 mean GH between arg-treated lambs (5.25 ng/ml) and controls (1.16 ng/ml) were significant (P<.01). GH peaked (13.8 ng/ml) at 25 min after the first injection, surged again 100 min later (7.4 ng/ml), declined to levels 3-times baseline and remained elevated. Trial 3 insulin levels were significantly higher in treated lambs (.64 ng/ml) compared to control lambs (.15 ng/ml; P<.01). Control lambs showed no significant GH or insulin increases at any time. GH secretion patterns were significantly altered in lambs injected with arg. One arg injection caused GH to peak within 30 min. Further challenges resulted in smaller, delayed rise and persistence of elevated GH levels. Insulin levels tended to increase with arg stimulus, but were not significantly elevated except at extremely high doses of arg. The data reflects a consistent relationship between arg stimulus and serum GH. / Master of Science / incomplete_metadata

Call number: LD2668 .T4 1952 S96 / Master of Science

No description available.

No description available.

Thesis (Ph. D.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains viii, 160 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 132-159).

In the studies described in this thesis the amounts of Ca, P and Mg retained by growing lambs were determined following the slaughter of the lambs and their analysis. In experiment 1, the effects of growth rate on body composition and mineral retention were studied. The lambs were grown at different rates from 24 kg to 50 kg live-weight. The composition of empty-body gain (EBG) was estimated based on an initial slaughter group at the beginning of the trial. Fast growing lambs contained more fat and less protein, ash, Ca and P than slow growing ones. However, in the fat-free empty-body (FFEB), there were no significant differences found attributable to growth rate, except for Mg which was decreased with slow growth. Supplementary CaCO<SUB>3</SUB> significantly increased ash, Ca and P retention in FFEB of the fast growing lambs. In experiment 2, the retention of minerals from lambs fed either forage or concentrate diets was studied. Three groups of 8 Suffolk x Blackface wether lambs were (a) allowed to graze the grass outdoors (b) fed-concentrate indoors and (c) fed grass indoors. The lambs were grown from 24 kg and slaughtered at about 40 kg live = weight over 100 days. Retentions of Ca and P in empty-body gain (EBG) and fat-free empty-body gain (FFEBG) were significantly higher in grass-fed lambs. Higher mineralisation in the latter group was attributed to differences in acid-base balance between the diets and was not a function of either exercise or sunlight. Experiment 3 was designed to re-assess the requirements of Ca and P for growing lambs. Four groups of 10 Suffolk x Blackface lambs were fed concentrate diets containing different concentrations of Ca and P over a 93 day experimental period. Lambs fed on normal Ca-normal P diet (based on TCORN's (1988) new estimate) appeared to meet their requirement. Lambs fed on high Ca-high P diet showed no increase in mineral retention while those on low Ca-low P diet were more poorly mineralised. A high Ca-low P group had low concentration of P in blood and rumen liquor. Radiographic studies of the metacarpus and metatarsus from these trials were of limited value in predicting the mineral content of the empty-bodies of lambs.

Thesis (Ph. D.)--University of Wyoming, 2005. / Title from PDF title page (viewed on Nov. 14, 2007). Includes bibliographical references (p. 167-211).

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 171-201). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 171-201). Also available on the Internet.