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Beta-Carotene In The Bovine Corpus Luteum, Stephen Grimmell Judd

Doctoral Dissertations

There have been conflicting reports which associate a low dietary intake or plasma concentration of beta-carotene (BC) with decreased fertility in dairy cows. The bovine corpus luteum (CL), a transient endocrine gland formed subsequent to ovulation, produces the steroid hormone progesterone which sustains pregnancy and is associated with fertility. Because of its high concentrations of the antioxidant nutrient beta-carotene, the CL was examined to identify an in vivo function for BC, other than that as a precursor of retinol. Five non-lactating Jersey cows were fed a basal ration containing a low BC concentration. Each cow received either 0, 1.6, 8.0, …

Ruminally Undegraded Protein And Ruminally Protected Amino Acids For Dairy Heifers, Brian David Garthwaite

Doctoral Dissertations

A series of growth experiments was conducted to evaluate the feeding of ruminally undegraded protein alone, or in combination with ruminally protected lysine and methionine. Eighty Holstein heifer calves were blocked by date of birth as they became available at 6 wk of age and assigned to a 2 x 2 factorial arrangement of treatments. Main effects of the 2 x 2 factorial were amount of ruminally undegraded protein in diet dry matter and whether ruminally protected lysine arid methionine were supplemented to diets. Four phases of growth were evaluated: Phase (1) 6 wk to 100 kg; Phase (2) 100 …

Ecological Database Development And Analyses Of Soil Variability In Northern New England, Michael Anayo Okoye

Doctoral Dissertations

The 1983 Forest Inventory and Analysis (FIA) data of the states of Maine, New Hampshire and Vermont (the study area) contain large amounts of field-measurements of many ecologically important variables. Despite the vast potential usefulness of the FIA data for scientific research, the data were until now, literally unused except for a few administrative purposes, because of problems in the way the data were organized, summarized, and coded for storage. The primary objective of this research was to solve the problems that had thus precluded these FIA data from use in scientific applications, and present the data in a form …

Foraging Strategies Of Two Sympatric Lagomorphs: Implications Of Habitat Fragmentation, Douglas Foxall Smith

Doctoral Dissertations

I studied the effects of variation in food patch quality and predation risk on the foraging patterns and measures of foraging behavior of New England (S. transitionalis) and eastern (S. floridanus) cottontails, and their survivorship and weight change during these experiments. I then superimposed the results of these experiments onto real habitat patches to determine the amount of habitat each species could occupy and maintain similar survivorship. Finally, I measured an adaptation (eye size), and predator detection of both species in an effort to explain the difference in survival between S. floridanus and S. transitionalis.

In outdoor enclosures (5.7 x …