Document Type

Dissertation - Open Access

Award Date

2016

Degree Name

Doctor of Philosophy (PhD)

Department / School

Dairy Science

First Advisor

Jill L. Anderson

Abstract

Two studies were conducted to evaluate the effect of limit-feeding heifers distillers grains with solubles (DDGS) with varying forage to concentrate ratios. The effects on growth, feed efficiency, rumen fermentation, nutrient digestibility, metabolic profile and onset of puberty, as well as post trial performance were investigated. First, a 16-wk feeding trial was conducted using 48 Holstein heifers to evaluate effects of dietary treatment on dry matter intake (DMI), average daily gain (ADG), growth performance, rumen fermentation, and nutrient digestibility. Treatments were 1) 30% DDGS, with the diet fed at 2.65% of body weight (BW) (30DG), 2) 40% DDGS, with the diet fed at 2.50 % of BW (40DG), and 3) 50% DDGS, with the diet fed at 2.35% of BW (50DG). The remainder of the diet consisted of grass hay and 1.5% mineral mix. Heifers were individually limit-fed using Calan gates. There were no differences in growth parameters; however, gain: feed and nutrient digestibility increased with increasing amounts of DDGS. There was a linear increase in concentration of plasma linoleic acid with increasing amount of DDGS and a linear and quadratic response for arachidonic acid. Total fatty acid (FA) and polyunsaturated fatty acids (PUFA) were linearly increased with a quadratic response with 30DG and 50DG having the greatest concentrations. There was a quadratic response of plasma urea nitrogen (PUN) and a quadratic tendency for cholesterol. Age and BW at puberty were similar among treatments. After heifers completed the feeding trial, data were collected to assess post trial reproductive and lactation performance, which were comparable among treatments. . A second study was conducted to determine the effects of feeding a corn and soybean product based concentrate mix or distillers dried grains with solubles (DDGS) concentrate mix with ad libitum grass hay to dairy heifers. A 16-wk feeding trial was conducted using 24 heifers to evaluate the effect of diet on DMI, growth performance, rumen fermentation, metabolic profile, and nutrient digestibility. Treatments were 1) corn and soybean product concentrate mix (CON), and 2) DDGS based concentrate mix (DDG). Both concentrate mixes were limit-fed at 0.8% of BW and grass hay was offered ad libitum. Dry matter intake and growth parameters did not differ between treatments. Rumen fermentation was shifted, but metabolic profile was maintained for heifers fed DDG. Results from these studies indicate that the fat and protein in DDGS can be used as a replacement for the starch in corn in limit-fed heifer diets with varying forage to concentrate ratios to maintain growth performance, nutrient digestibility, and metabolic profile without detrimental effects to long-term performance.

Library of Congress Subject Headings

Dairy cattle -- Feeding and feeds

Heifers -- Feeding and feeds

Distillers feeds

Heifers -- Feed utilization efficiency

Heifers -- Growth

Heifers -- Metabolism

Description

Includes bibliographical references (pages 154-167)

Format

application/pdf

Number of Pages

186

Publisher

South Dakota State University

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Dairy Science Commons

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Rights Statement

In Copyright