An Examination of Pre -Service Teacher Knowledge of Subject Matter and Its Effects on Curriculum Selection and Instructional Decision Making

159 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2000.The findings of the study indicated variable knowledge of South Africa by teachers and the presence of teacher misconceptions about Africa in general and South Africa in particular. The study supported a schema-based theory of knowledge representation and the theory of constructivism. Those teachers that proved to be less knowledgeable about the topic concerned preferred the more focussed article and presented a less critical approach to teaching. The highly knowledgeable teachers were not constrained by the information presented in the articles, were flexible in terms of teaching methodology and presented more critical thinking in their approach to teaching. All the teachers had a positive attitude towards the teaching of content related to South Africa in the U.S., but felt ill-prepared and inadequate to teach the topic. Another finding that emerged from this study pertained to the double role played by media as a source of information and misinformation for the teachers.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD

Flavor effects on feed consumption and performance of dairy cattle in early lactation

A three-part study was carried out to investigate the potential effects of flavors on feed consumption of dairy cows in early lactation. Two sequential elimination trials, each with six multiparous Holstein cows, were conducted to test the effects of additives on the preference ranking of diets. Starting eight days postpartum cows were fed a total mixed ration (TMR) twice daily. Four additives and a control (no additive) were examined in each trial with the most preferred, highest total dry matter (DM) intake, being dropped after 5, 4, 3 and 2 d feeding segments. Sweet (sucrose, 1.5% of diet DM), sour (HCl, 1.25%), bitter (urea, 1%), and salt (NaCl 4%) were tested in Trial 1. Four of six cows ranked sweet first and mean (n = 6) intake was 12.8% more than for the second placed control. Mean intake in Trial 1 was 13.7 kg DM/d and milk yield was 32.8 kg/d. The probability of a cow ranking sweet or control first was.59 and.36 respectively, according to a Plackett-Luce Model analysis (X\sp2, P control $>$ bitter $>$ salt $>$ sour (Trial 1) and control = MSG $>$ molasses $>$ dehydrated alfalfa $>$ anise (Trial 2). The preference for sucrose and its potential to enhance feed consumption in early lactation were evaluated in a 12-wk lactation trial. Twenty four cows, 16 multiparous Jerseys and 8 primiparous Holsteins, were assigned at parturition to either a control or sucrose-sweetened (1.5% of diet DM) TMR in a randomized complete-block design. The diet included 10% corn silage, 30% alfalfa haylage, and 60% ground corn-soybean meal based concentrate on a DM basis, and was fed to insure 10% refusal. An additional 2.3 kg of alfalfa hay was fed the first 5 d postpartum. Covariate (body weight on the day of parturition) adjusted mean DM intake, milk yield, 3.5% fat corrected milk yields; and milk fat, milk protein, and solids-non-fat percentages were: 19.0 and 19.1 (P $>$.10), 28.4 and 29.3 (P $>$.10), 27.9 and 29.4 kg/d (P $>$.10), 3.4 and 3.3; and 3.5 and 3.28 (P .10) for the respective measures and treatments. In the absence of being offered a choice of diets, sucrose at 1.5% of diet DM did not enhance feed intake averaged over the first 12 wk of lactation.U of I OnlyETDs are only available to UIUC Users without author permissio

Lasalocid Supplementation of Dairy Cow Diets in Early Lactation

A 36-cow study was conducted to evaluate the effects of lasalocid on feed intake, milk production and composition, and various blood metabolites in early lactation. Multiparous Holstein cows were assigned at parturition to a total mixed diet containing 33% corn silage, 17% chopped alfalfa hay, and 50% concentrate mix on a DM basis for 10 wk. An additional 2.3 kg of alfalfa hay was fed during the first 7 d in milk (DIM). Diets were supplemented with 0, 180, or 360 mg/d of lasalocid in a completely randomized design. Covariant-adjusted mean (the covariate was mature equivalent milk production from the previous lactation) DMI; milk and fat-corrected milk (FCM) production; percentages of milk fat, protein, and solids-not-fat; milk somatic cell count; BW; body condition score; and concentrations of glucose, β-hydroxybutyrate, and non-esterified fatty acid (NEFA) in blood were unaffected by supplementation with lasalocid. A dose of 360 mg/d of lasalocid may not be enough to significantly affect high-producing cows consuming \u3e20 kg/d of DM