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Digitized by Kansas State University Libraries

Digitized by Kansas State University Libraries

Three (intact) Angus males and three females which were half-sibs and born within 21 days of each other were selected for this study. Each animal was bled and biopsied periodically from suckling calves to mature slaughter weights, to determine the qualitative composition of lipoproteins and to differentiate the lactate lipogenic activity of subcutaneous tissue during growth and development. At slaughtered, a sample of intramuscular adipose tissue was taken to determine the lactate lipogenic activity at this location. Two days later, one side of each carcass was separated into wholesale cuts. Each wholesale cut was dissected into separable bone and soft tissue and sampled for protein, lipid and moisture determinations. The elution profiles of lipoproteins were similar for all animals. Major peaks observed were (1) very low density (VLDL), (2) low density (LDL) and (3) high density lipoproteins (HDL). Triglycerides, cholesterol and protein were not significant (P < .05) between males and females for the VLDL. At one year of age, females had large (P < .05) amounts of protein for the HDL. In both groups of cattle, largest (P > .05) amounts of protein were greater in the HDL at 9 months of age. Profiles of HDL apoproteins at all ages showed that in both groups of cattle, a distinct band with a weight of about 28,000 was present representing apo-AI. Apo-protein components of pooled LDL fractions showed a protein which was unable to enter the acrylamide gel (7.5 – 20%) used. The component may represent apo-B with a molecular weight of about 250,000. The lactate lipogenic activity of subcutaneous adipose tissue was larger in the males and only significant (P < .05) at 9 months of age. The lipogenic activity was higher (P > .05) in the subcutaneous tissue when compared to the intramuscular tissue at slaughter. In both cases, males showed to use more (P > .05) lactate for fatty acid synthesis in intramuscular and subcutaneous tissue than the females. Magnitude of quality and yield for carcass traits were better for the males than females. Bone, meat and lean weights were significantly (P < .05) greater for the males, however, on a percentage basis per side weight, differences were eliminated. In addition, no significant (P > .05) effect was present between male and female wholesale and side carcass composition.

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2007. / Title from title screen (site viewed Dec. 4, 2007). PDF text: vii, 141 p. ; 6 Mb. UMI publication number: AAT 3271905. Includes bibliographical references. Also available in microfilm and microfiche formats.

Thesis (M.S.)--University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (February 23, 2007) Includes bibliographical references.

The objectives of this study were accomplished with two experiments in growing Bonsmara bulls (N = 68) (experiment 1), and Simmental crossbred calves (N = 132) (experiment 2). Specific objectives for experiment 1 were to characterize residual feed intake (RFI) in growing bulls, and examine relationships between RFI and performance, fertility, temperament and body composition traits. In experiment 2, the objectives were to examine stocker-phase supplementation effects on feedlot feed conversion ratio (FCR) and RFI and to characterize relationships between these feed efficiency traits, and performance and carcass traits in finishing calves. In both experiments, individual feed intakes and BW were measured. Ultrasound technology was used to measure body composition in experiment 1, while actual carcass measurements taken at harvest were used for experiment 2. Experiment 1 demonstrated that temperament affected ADG and DMI, but not FCR or RFI. Residual feed intake was not phenotypically correlated to scrotal circumference or bull fertility traits. Experiments 1 and 2 demonstrated that RFI was independent of ADG and BW, but that there was a tendency (P < 0.10) for RFI to be phenotypically correlated with 12th rib fat thickness (r = 0.20 and 0.22). However, RFI was not correlated with longissimus muscle area in either experiment. Both experiments demonstrated that low RFI (< 0.5 SD below mean RFI) calves consumed significantly (20 and 22%) less feed and had improved (21%) FCR compared to calves with high RFI (> 0.5 SD above mean RFI). Results from experiment 2 suggest that RFI measured while calves are consuming high-grain diets may be less influenced by previous level of stocker supplementation compared to FCR or residual gain efficiency traits. In summary, RFI was found to be phenotypically independent of growth rate and BW, had no effect on bull fertility or temperament traits, and was less impacted by previous plane of nutrition compared to FCR.

The objectives of this study were accomplished with two experiments in growing Bonsmara bulls (N = 68) (experiment 1), and Simmental crossbred calves (N = 132) (experiment 2). Specific objectives for experiment 1 were to characterize residual feed intake (RFI) in growing bulls, and examine relationships between RFI and performance, fertility, temperament and body composition traits. In experiment 2, the objectives were to examine stocker-phase supplementation effects on feedlot feed conversion ratio (FCR) and RFI and to characterize relationships between these feed efficiency traits, and performance and carcass traits in finishing calves. In both experiments, individual feed intakes and BW were measured. Ultrasound technology was used to measure body composition in experiment 1, while actual carcass measurements taken at harvest were used for experiment 2. Experiment 1 demonstrated that temperament affected ADG and DMI, but not FCR or RFI. Residual feed intake was not phenotypically correlated to scrotal circumference or bull fertility traits. Experiments 1 and 2 demonstrated that RFI was independent of ADG and BW, but that there was a tendency (P < 0.10) for RFI to be phenotypically correlated with 12th rib fat thickness (r = 0.20 and 0.22). However, RFI was not correlated with longissimus muscle area in either experiment. Both experiments demonstrated that low RFI (< 0.5 SD below mean RFI) calves consumed significantly (20 and 22%) less feed and had improved (21%) FCR compared to calves with high RFI (> 0.5 SD above mean RFI). Results from experiment 2 suggest that RFI measured while calves are consuming high-grain diets may be less influenced by previous level of stocker supplementation compared to FCR or residual gain efficiency traits. In summary, RFI was found to be phenotypically independent of growth rate and BW, had no effect on bull fertility or temperament traits, and was less impacted by previous plane of nutrition compared to FCR.

Thesis (M.S.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains viii, 52 p. : ill. Vita. Includes abstract. Includes bibliographical references (p. 36-39).