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Metabolism of grazed vs. zero‐grazed dairy cows throughout the vegetation period: hepatic and blood plasma parameters
Author(s) -
Kaufmann L. D.,
DohmeMeier F.,
Münger A.,
Bruckmaier R. M.,
van Dorland H. A.
Publication year - 2012
Publication title -
journal of animal physiology and animal nutrition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.651
H-Index - 56
eISSN - 1439-0396
pISSN - 0931-2439
DOI - 10.1111/j.1439-0396.2011.01142.x
Subject(s) - pasture , grazing , zoology , nefa , barn , biology , metabolism , lipogenesis , chemistry , endocrinology , agronomy , insulin , civil engineering , engineering
Summary Grass may have a differential impact on the metabolism of the dairy cow, depending on the grazing system applied. In this study, the hypothesis was tested that metabolism of grazed vs. zero‐grazed dairy cows is differently regulated throughout the vegetation period. The study included three experimental periods (p1, p2 and p3) of 14 days each, and two treatments [grazing from pasture, PASTURE, n = 9; or zero‐grazing in a free‐stall barn (BARN, n = 9)]. Blood and liver samples were collected at the end of each period when the cows were on average 64, 120 and 197 DIM. Concentrations of metabolites and hormones, and activities of various enzymes were determined in plasma. Liver samples were measured for mRNA abundance of genes encoding enzymes and nuclear receptors involved in metabolic pathways. PASTURE cows had higher plasma concentrations of T 3 , BHB, and total protein than BARN cows across periods (p < 0.05). BARN cows had higher concentrations of NEFA (in p1) and urea (in p1 and p2) in relation PASTURE cows (p < 0.05), and had higher mRNA abundance of liver‐X‐receptor‐α and glycerol‐3‐phosphate‐acyltransferase across periods (p < 0.05). The results confirm the hypothesis that metabolism is different between BARN and PASTURE cows throughout the vegetation period, and show that the observed differences are mainly reflected in parameters of lipid metabolism.