The influence of associative effects on the in vitro-estimated utilizable crude protein (uCP) of feeds for ruminants.
Nineteen feed mixtures, formulated with 16 single feeds, were used to study the influence of associative effects on utilizable crude protein (uCP) of feed mixtures. The in vitro incubation technique of Zhao and Lebzien (2000) was used for uCP determination. It was found that the in vitro-determined uCP (D-uCP) was significantly higher than the weighted uCP (W-uCP) of feed mixtures and there was a significant regressive relationship between W-uCP (x) [g x kg(-1)DM] and D-uCP (y) [g x kg(-1)DM]: y=(0.94 +/- 0.23)x + (18.78 +/- 35.58), r2=0.49, n=19, p < 0.01. It was concluded that there exist significant associative effects of feed mixtures on uCP. In formulation of rations for ruminants the D-uCP should be used instead of W-uCP. Because of the low regression coefficient of the equation above, the D-uCP cannot be estimated from the W-uCP.
Zhao
Guang-Yong
GY
College of Animal Science and Technology, China Agricultural University, Beijing, PR China. zhaogy@cau.edu.cn
Li
Yuan-Xiao
YX
Ren
Jian-Bo
JB
Li
Ya-Jun
YJ
Guo
Dong-Sheng
DS
D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002417:Cattle; D004044:Dietary Proteins / Q000378:metabolism*; D004063:Digestion; D005260:Female; D066298:In Vitro Techniques; D008954:Models, Biological; D012044:Regression Analysis; D012417:Rumen / Q000378:metabolism*; D012418:Ruminants / Q000502:physiology*
D004044:Dietary Proteins