Document Type

Dissertation - University Access Only

Award Date

2008

Degree Name

Doctor of Philosophy (PhD)

Department / School

Dairy Science

First Advisor

Arnold Hippen

Abstract

Three studies were conducted to determine the effects of fat from com coproducts on the performance of dairy cows. In the first study, the effects of feeding com germ as a potential source of fat in dairy cow diets and its effect on DMI, milk production and composition, and milk CLA concentrations were evaluated. The second study was part of the first lactation study, in which, four multiparous Holstein cows with ruminal cannulae were used to examine the effect of feeding increasing concentrations of com germ on ruminal fermentation parameters and total tract nutrient digestibility. The third study was designed to determine the effects of feeding com germ to lactating dairy cows on milk fat and fatty acid composition compared with dried distillers grains and com oil. Results indicated that com germ can be included in dairy cow diets at 7% and 14% ofDM with no adverse effect on dry matter intake, milk yield, and milk composition. Inclusion of com germ in dairy cow diets increased milk fat concentrations of mono- and polyunsaturated fatty acids, which has been associated with several health benefits. Feeding CG in dairy cow diets increased milk fat concentration of cis-9, trans-11 CLA and had no adverse effect on ruminal fermentation and total tract nutrient digestibility. Fatty acids in com germ appear to have minimal impact on ruminal fermentation characteristics and nutrient digestibility. Fat from com germ appears to have no effect on milk fat concentration when compared with fat from dried distillers grains and com oil, suggesting that oil from com germ may be relatively protected compared with that from dried distillers grains; however, dried distillers grains may contain small concentrations of free oil that may be available during ruminal digestion, thus interfering with ruminal fermentation and biohydrogenation. In conclusion, germ from ethanol production provides an alternative source of fat for energy in lactating dairy cow diets when fed at 14% of diet DM. Although, feeding dried distillers grains at 30% ofDM had no substantial negative effect on milk fat percentage, fat from com germ appears to have minimal impact on milk fat content when compared with dried distillers grains and com oil. Inclusion of com co-products in dairy cow diets increased the concentration of monounsaturated and polyunsaturated fatty acids in milk fat, which have been associated with several health benefits.

Library of Congress Subject Headings

Dairy cattle -- Feeding and feeds
Corn products industry -- By-products
Oils and fats in animal nutrition
Milk yield
Milkfat

Publisher

South Dakota State University

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Rights Statement

In Copyright