Oertzenweg 19 b
+49 30 838 62600
Enhancement of the absorption of short-chain fatty acids (SCFA) and lactate across reticuloruminal wall while maintaining its epithelial integrity is instrumental in increasing energy supply and preventing health disorders in cattle. The present study investigated whether the reticuloruminal absorption of SCFA and lactate, permeability, and endotoxin concentration in the gastrointestinal tract, as well as the systemic acute phase response was altered by different strategies of high-grain feeding. Eight rumen-cannulated, nonlactating Holstein cows were fed a forageonly diet (baseline) and then gradually adapted to a 60% grain level in a crossover 2 × 2 experimental design. The grain-rich diet was fed for 4 wk either continuously (CON) or interruptedly (INT) with a 7-d break in-between in the INT model. Ruminal absorption of SCFA and permeability to lactulose across the reticuloruminal wall were determined in vivo with the washed reticulorumen technique. Compared with baseline, ruminal and fecal endotoxin concentrations dramatically increased (P < 0.001) by grain-rich feeding, though cows in CON group tended (P < 0.10) to have greater endotoxin than INT cows. In contrast, the grain feeding did not affect the absorption of lactulose across rumen wall and the activation of a systemic acute phase response. Data showed that the absorption rates of individual and total SCFAs were higher in CON vs. INT cows (P < 0.05). Lactate was not absorbed during forage-only feeding and 1-wk grain feeding, but after 4-wk of grain feeding lactate was absorbed from reticulorumen wall independent of the feeding model. In conclusion, SCFAs absorption across the reticulorumen was enhanced by the 4-wk continuous grain feeding, which seems to be more advantageous in terms of rumen acidosis prevention compared with the interrupted grain feeding model. The study also provided evidence of lactate absorption across the reticulorumen of nonlactating cattle after both continuous and interrupted 4-wk grain feeding. The feeding of 60% grain either transiently or continuously did not compromise rumen permeability or trigger an acute phase response in cows.