Document Type
Thesis - Open Access
Award Date
1990
Degree Name
Doctor of Philosophy (PhD)
Department / School
Dairy Science
Abstract
Effects of added fat to diets for dairy cows on milk production and composition were determined in two experiments. In the first experiment, 36 Holstein cows were assigned to one of three diets containing soybean meal (SBM-16; 16% CP), added fat from extruded soybeans (ESB-16; 16% CP), and added fat and protein (ESB-18; 18% CP) form extruded soybeans plus soybean meal to determine if feeding excess protein will prevent the depression in milk protein percentages usually experienced when cows are fed additional fat. Total mixed diets (OM basis) contained 25% corn silage, 25% alfalfa hay, and 50% of respective concentrate mix were fed individually wk 4 through 16 postpartum, with pretreatment (wk 3 postpartum) milk production and composition data used as covariates. Milk production (33.0, 35.8, and 34.2 kg/d) was higher (P<.01) for cows fed MEG-18 than for cows fed ESB-18. Milk fat from cows fed added fat was more unsaturated (P<.01) than from cows fed SBM-18, and was more unsaturated (P<.01) from cows fed ESB-18 instead of MEG-18. Dry matter intakes (17.8, 18.4, and 16.6 kg/d) were similar for all diets. Molar percentages of ruminal butyrate were higher (P<.05) and concentrations of ruminal total volatile fatty acids were lower (P<.05) for cows fed added fat diets. Extruded soybeans and calcium soaps of fatty acids were equally effective in increasing milk production but some differences in milk composition occurred.
Library of Congress Subject Headings
Dairy cattle -- Feeding and feeds Oils and fats in animal nutrition Proteins in animal nutrition Milk yield
Format
application/pdf
Number of Pages
147
Publisher
South Dakota State University
Recommended Citation
Kim, Yong Kook, "Lactational Response of Dairy Cows to Diets Containing Added Fat and Added Protein" (1990). Electronic Theses and Dissertations. 1168.
https://openprairie.sdstate.edu/etd2/1168