Title page for ETD etd-06122012-040012

Type of Document Master's Thesis
Author Tomlinson, Dana J.
URN etd-06122012-040012
Title Effect of varying levels of neutral detergent fiber and total digestible nutrients on dry matter intake of dairy heifers
Degree Master of Science
Department Dairy Science
Advisory Committee
Advisor Name Title
James, Robert E. Committee Chair
McGilliard, Michael L. Committee Member
Stallings, Charles C. Committee Member
Vinson, William E. Committee Member
  • Heifers
Date of Defense 1988-05-12
Availability restricted
One hundred and eight Holstein dairy heifers were divided into two weight blocks based

on beginning body weight (E = < 182 kg, light, > 270 kg, heavy). Heifers within weight

blocks were randomly assigned to one of five treatments. Treatments consisted of three

levels of NDF (35%, 45%, 55%) at 100% ofNRC TDN recommendation, and three levels of TDN (85%, 100%, 115 of NRC) at 45% NDF for light heifers. For heavy heifers, treatments consisted of three levels of NDF (40%, 50%, 60%) at 100% NRC

TDN, and three treatments with similar levels of TDN at 50% NDF. Heifers were fed total mixed rations of corn silage, alfalfa haylage, ground orchardgrass hay, soybean meal, high moisture corn and a mineral mix formulated for 0.68 kg ADG. Mean gains

(kg/d) were 1.07 and .96 for the light and heavy blocks, respectively. DMI as a percent

of BWT differed across NDF levels for light heifers (3r'= 2.96, 2.56, 2.57, 2.57, and 2.87

% of BWT for the low, med., high NDF, and low, high TDN treatments, respectively).

Heavy heifer DMI% did not differ (.¥= 2.45, 2.40, 2.24, 2.15, and 2.42 % ofBWT for

low, med., and high NDF, and low, high TDN treatments, respectively). Equations to

predict DMI were developed using intake information from this and a previous study.

Backward stepwise regression was utilized to generate a simplified model. Model selected was: DMI (kg/d) = -5.9781 + (2.2120E-05 * BWTSQ) - (5.5527 * GAIN) + (2.7837 * GAINSQ) + (0.4668 * NDF) + (5.3930 * NDFSQ) + (0.03285 * DM) +

1 (7.7859E-03 * BWT * GAIN);11 = 514, rz = .67.

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