TY  - JOUR
T1  - Effects of Dietary Crude Protein Level on Growth Performance and Blood Parameters of Holstein Heifers and Steers Fed Ad Libitum
AU - , Mehmet Ali Bal AU - , Hale Yarar 
JO  - Journal of Animal and Veterinary Advances
VL  - 5
IS  - 3
SP  - 215
EP  - 219
PY  - 2006
DA  - 2001/08/19
SN  - 1680-5593
DO  - javaa.2006.215.219
UR  - https://makhillpublications.co/view-article.php?doi=javaa.2006.215.219
KW  - Growth
KW  -heifer
KW  -steer
KW  -protein
KW  -urea N
AB  - Two levels of dietary CP on growth performance, feed efficiency and blood parameters of Holstein heifers and steers were examined.  Experimental diets consisted of 12 and 16% CP along with 2.5 Mcal kg <SUP>1</SUP> of ME  (DM  basis).   Ratios  of CP: ME were 49 and 64 g/Mcal for 12 and 16% CP containing diets, respectively.  Eight animals were assigned to each experimental diet in a 2X2 factorial arrangement of completely randomized design for 8 wk period.  Diets containing 48% corn silage and 52% concentrate (DM basis) were fed twice daily in a total mixed ration.  Intake of DM was higher for 12% CP (11.0 kg d <SUP>1</SUP>) compared to 16% CP containing diet (7.7 kg d <SUP>1</SUP>) across the groups.  There was a higher BW gain for steers (1.27 kg d <SUP>1</SUP>) compared to heifers (0.99 kg d <SUP>1</SUP>) but no significant dietary CP level difference was observed for BW.  Feed efficiency was higher for 16% CP (0.17) compared to 12% CP containing diet (0.11).  There was no significant difference detected for serum urea N (8.6 mg dL <SUP>1</SUP>) and creatinine (1.1 mg dL <SUP>1</SUP>) concentrations between treatment groups.  Data indicates that heifers during the growth period responded to 12% dietary CP better than 16% CP based on higher BW gain (1.16 kg d <SUP>1</SUP>) and lower serum urea N concentration (8.3 mg dL <SUP>1</SUP>).  In steers, no difference in BW gain but higher feed  efficiency  (0.17  vs.  0.11)  made  16%  CP  containing  diet  more  preferable  than  12%  CP  during  the growth period.
ER  -