Type of Document Dissertation Author Tomlinson, Dana J URN etd-07282008-135549 Title Effect of nonstructural carbohydrates and rumen undegradable protein on intake, growth, and body condition of dairy heifers Degree PhD Department Animal Science (Dairy) 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 Keywords
Date of Defense 1990-05-12 Availability restricted AbstractOne hundred and eight Holstein dairy heifers were divided into two weight blocks based
on beginning body weight (x = < 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% of NRC 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 mixes 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 heiferi(i-= 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 (Z= 2.45, 2A0, 2.24, 2.15, and 2.42 % of BWT 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) +
(7.7859E-03 * BWT * GAIN); n = 514, r2 = .67.
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