Short communication: Effect of dietary protein on growth and nitrogen balance of Holstein heifers

Citation
Pc. Hoffman et al., Short communication: Effect of dietary protein on growth and nitrogen balance of Holstein heifers, J DAIRY SCI, 84(4), 2001, pp. 843-847
Citations number
20
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Food Science/Nutrition
Journal title
JOURNAL OF DAIRY SCIENCE
ISSN journal
0022-0302 → ACNP
Volume
84
Issue
4
Year of publication
2001
Pages
843 - 847
Database
ISI
SICI code
0022-0302(200104)84:4<843:SCEODP>2.0.ZU;2-1
Abstract
A growth study and a companion N balance study were conducted to evaluate t he effect of dietary protein on growth and N utilization of postpubertal Ho lstein heifers. Forty heifers (398 +/- 9.4 kg) were fed one of four diets c ontaining 8, 11, 13, or 15% elude protein (CP) for 121 d. Body measurements were taken at the beginning and end of the experimental period. Blood was collected via jugular vein every 28 d and evaluated for serum protein, albu min, and urea nitrogen. Curvilinear relationships were observed between die tary CP and gains in wither height and hip width, with maximal gains occurr ing at 13% CP. Feeding heifers higher amounts of dietary CP resulted in lin ear increases in heart girth gain, serum protein, albumin, and blood urea n itrogen. In the companion N balance study, feeding increasing amounts of di etary CP to heifers resulted in linear increases in N intake, fecal-N, urin ary-N, and absorbed-N. There was a numerical trend towards maximal N retent ion in heifers fed diets containing 13% CP. Curvilinear relationships also were observed between dietary CP and dry matter, organic matter, and CP dig estibility with maximal nutrient digestibilities occurring when heifers wer e fed diets containing 13% CP. Data suggest 13% dietary CP was optimal for postpubertal (400 kg) Holstein heifers.