TY - JOUR
T1 - The Effects of Nitrogen and Forage Source on Feed Efficiency and Structural Growth of Prepubertal Holstein Heifers
AU - Kononoff, P. J.
AU - Heinrichs, A. J.
AU - Gabler, M. T.
N1 - Publisher Copyright:
© 2006 American Registry of Professional Animal Scientists.
PY - 2006/2/1
Y1 - 2006/2/1
N2 - Eighty Holstein heifers averaging 189.6 ± 6.8 kg of BW were used to evaluate the effects of forage level and rumen degradable nitrogen source on feed efficiency and structural growth. A randomized complete block design was used with heifers blocked according to BW (=136.0 kg and >136.0 kg) and assigned to 1 of 4 treatment diets in a 2 × 2 factorial design. Treatments were constructed with 2 levels of forage (65 or 75%) and 2 nitrogen sources. Forage sources were a mixture of corn silage and chopped timothy hay. Nitrogen sources were either soybean meal (SBM) or a slow-release, polymer- coated urea product (Optigen 1200, CPG Nutrients, Syracuse, NY), which was fed at 1.8% of diet DM on low-forage diets and at 1.3% of diet DM on high-forage diets. Average daily gain and feed efficiency did not differ between rations of different forage level or nitrogen source, averaging 0.87 ± 0.05 kg and 7.4 ± 0.5, respectively, across treatments. Similarly, no differences were observed in change of withers height, hip height, hip width, or heart girth. No differences were observed in plasma urea nitrogen, which averaged 12.3 ± 0.4 mg/dL across treatments. Results of this experiment suggest that feeding moderately different levels of forage along with either SBM or a polymer- coated urea product does not result in any significant differences in feed efficiency or structural growth. Polymercoated urea can be used in heifer diets to effectively replace SBM as a nitrogen source in either low- or high-forage rations.
AB - Eighty Holstein heifers averaging 189.6 ± 6.8 kg of BW were used to evaluate the effects of forage level and rumen degradable nitrogen source on feed efficiency and structural growth. A randomized complete block design was used with heifers blocked according to BW (=136.0 kg and >136.0 kg) and assigned to 1 of 4 treatment diets in a 2 × 2 factorial design. Treatments were constructed with 2 levels of forage (65 or 75%) and 2 nitrogen sources. Forage sources were a mixture of corn silage and chopped timothy hay. Nitrogen sources were either soybean meal (SBM) or a slow-release, polymer- coated urea product (Optigen 1200, CPG Nutrients, Syracuse, NY), which was fed at 1.8% of diet DM on low-forage diets and at 1.3% of diet DM on high-forage diets. Average daily gain and feed efficiency did not differ between rations of different forage level or nitrogen source, averaging 0.87 ± 0.05 kg and 7.4 ± 0.5, respectively, across treatments. Similarly, no differences were observed in change of withers height, hip height, hip width, or heart girth. No differences were observed in plasma urea nitrogen, which averaged 12.3 ± 0.4 mg/dL across treatments. Results of this experiment suggest that feeding moderately different levels of forage along with either SBM or a polymer- coated urea product does not result in any significant differences in feed efficiency or structural growth. Polymercoated urea can be used in heifer diets to effectively replace SBM as a nitrogen source in either low- or high-forage rations.
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U2 - 10.15232/S1080-7446(15)31065-2
DO - 10.15232/S1080-7446(15)31065-2
M3 - Article
AN - SCOPUS:80053463597
SN - 1080-7446
VL - 22
SP - 84
EP - 88
JO - Professional Animal Scientist
JF - Professional Animal Scientist
IS - 1
ER -