Effects of dry period management and parity on rumen fermentation, blood metabolites, and liver triacylglyceride in dairy cows

Khazanehei, H., Li, S., Khafipour, E. and Plaizier, J. C. 2015. Effects of dry period management and parity on rumen fermentation, blood metabolites, and liver triacylglyceride in dairy cows. Can. J. Anim. Sci. 95: 445–453. The effects of dry period management on rumen fermentation, blood metabolites and liver triacylglyceride (TAG) were determined in 11 second-parity (PAR 2) and 15 third-parity and older (PAR 3+) cows. Cows were paired and randomly assigned to two treatments: (1) a short 40-d dry period (SHORT) with only a close-up diet [1.43 Mcal kg –1 dry matter (DM)], or (2) a conventional 60-d dry period (CONV) with 39 d far-off diet (1.28 Mcal kg –1 DM) and 21 d close-up diet (1.43 Mcal kg –1 DM) in a randomized block design. Concentrations of total volatile fatty acids, ammonia, and lactate in rumen fluid, and also concentrations of lactate, beta hydroxybutyric acid (BHBA), urea and insulin in plasma were not affected by treatment. Across the 3 wk after calving, cows on the SHORT treatment had higher blood non-esterified fatty acid (NEFA) and glucose, and at 1 wk after calving, these cows had a higher liver TAG than cows on the CONV treatment. Also, during this time, PAR 3+ cows had higher serum NEFA compared with PAR 2 cows. Results suggest that the SHORT treatment resulted in more lipolysis, TAG accumulation in the liver and glucose sparing in early lactation compared with the CONV treatment, and that this effect was greater in PAR 3+ cows than in PAR 2 cows.