Effects of dietary protein concentration on postweaning growth of Boer crossbred and Spanish goat wethers.
Boer (3/4) x Spanish (1/4) (BC; n = 23) and Spanish (SP; n = 22) goat wethers, 4 to 4.5 mo of age and 17.6 and 19.4 kg initial BW, respectively (SE = 0.57), were used to determine effects on growth of protein concentration in 70% concentrate diets provided for ad libitum intake for 30 wk in confinement. Offered diets contained 10.2, 14.2, 18.3, and 23.6% CP (DM basis), and CP concentration in consumed DM was 9.3, 13.8, 17.1, and 22.1% (P1, P2, P3, and P4, respectively); supplemental protein was from soybean meal for P1 and P2 and from soybean meal plus a blend of blood, fish, and feather meals for P3 and P4. Dry matter intake was similar between breeds and among diets (732, 712, 698, and 740 g/d for P1, P2, P3, and P4, respectively; SE = 27.0). Average daily gain was greater for P2 (P = 0.07) and P4 (P < 0.05) than for P1 (76, 90, 85, and 100 g/d for P1, P2, P3, and P4, respectively; SE = 5.3) and for BC than for SP (97 vs 78 g/d, SE = 3.7; P = 0.05). Similarly, ADG:DMI was lowest (P < 0.05) among diets for P1 (0.106, 0.126, 0.121, and 0.132 for P1, P2, P3, and P4, respectively; SE = 0.0053) and greater (P < 0.05) for BC than for SP (0.135 vs 0.108; SE = 0.0037). In conclusion, with 70% concentrate diets, the protein requirement for both BC and SP seemed to have been met by consumption of diets with at least 14% CP, with no apparent benefit from addition of ruminally undegraded protein.
Prieto
I
I
E (Kika) de la Garza Institute for Goat Research, Langston University, OK 73050, USA.
Goetsch
A L
AL
Banskalieva
V
V
Cameron
M
M
Puchala
R
R
Sahlu
T
T
Dawson
L J
LJ
Coleman
S W
SW
D000821:Animal Feed; D000818:Animals; D004044:Dietary Proteins / Q000008:administration & dosage / Q000494:pharmacology*; D005227:Fatty Acids / Q000032:analysis; D006041:Goats / Q000254:growth & development*; D006824:Hybridization, Genetic; D008297:Male; D012417:Rumen / Q000737:chemistry; D014886:Weaning
D004044:Dietary Proteins; D005227:Fatty Acids