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Effect of propylene glycol and undegradable protein source on rumen fermentation, blood metabolism and milk production in lactating dairy cows
Author(s) -
BAIYILA Turigen,
HAN Jifu,
KANDA Shuhei,
ITOH Masahiro,
WASHIO Yuichiro,
SUZUKI Tamotu,
HORIKAWA Hiroshi,
KAMADA Toshihiko,
ITABASHI Hisao
Publication year - 2002
Publication title -
animal science journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.606
H-Index - 38
eISSN - 1740-0929
pISSN - 1344-3941
DOI - 10.1046/j.1344-3941.2002.00029.x
Subject(s) - hay , chemistry , lactose , dry matter , rumen , food science , fermentation , silage , metabolism , composition (language) , zoology , lactation , urea , biochemistry , biology , pregnancy , linguistics , philosophy , genetics
Eight lactating Holstein cows were divided into two groups ( n = 4) and used in a double reversal trial with three periods of 14 days each, to evaluate diets containing propylene glycol (PG) and ruminally undegradable protein (RUP) blend on milk yield and composition, ruminal fermentation and blood metabolism. The control diet contained 20% chopped Sudangrass hay, 20% cubed alfalfa hay, 12% corn silage, and 48% of the respective concentrate mixtures (dry matter basis). The experimental diet (PG + RUP) partially replaced the concentrate mixture from the control diet with 1.4% PG and 2.1% RUP. Both diets contained about 16% crude protein and 71% total digestible nutrients. Dry matter intake was similar between the two diets. Daily production of milk, milk lactose and milk solids‐not‐fat increased by 9.0%, 11.3% and 9.3%, respectively ( P < 0.1), for cows fed diets with PG + RUP; milk composition was unchanged. Although the concentration of ruminal total volatile fatty acids was unchanged, the proportion of propionic acid increased, and the proportion of acetic acid decreased with PG + RUP. The concentration of ruminal ammonia nitrogen and number of ciliate protozoa was not significantly affected by PG + RUP. The concentration of glucose in blood plasma increased, the concentration of urea nitrogen was unaffected, and the concentration of some essential free amino acids decreased with PG + RUP. It is suggested that these changes might be caused predominantly by PG, and the addition of PG may exert a favorable effect on milk production through increased metabolism.