Effects of dietary management on the energy metabolism of periparturient dairy cows: regulation of lipidome and transcriptome

The high nutrient demand of milk production leaves the high-producing cows susceptible to various metabolic diseases after calving. Improving the health and welfare of high-producing dairy cows has been a long-term goal of dairy research and it is critical for the sustainability of the dairy industry. Previous research has suggested that the nutrition strategies during the dry period and early lactation have significant impacts on dairy cow metabolism after calving. Therefore, careful dietary management in the weeks leading up to and immediately after calving is important for dairy cow health and welfare. In Nanbing Qin's doctoral research project, the cows received two types of dietary management: a prepartal high-energy feeding regimen and a milk fat depression (MFD) feeding regimen.

The high-energy feeding provided 130% of the recommended intake of a pregnant dairy cow during the last six weeks before parturition. The MFD diet was achieved by applying either a diet with a conjugated linoleic acid (CLA) supplement (cis-9, trans-11 and trans-10, cis-12 CLA) or a high-starch diet with polyunsaturated fatty acid (PUFA) supplement which contained mixture of sunflower oil and fish oil in a 2:1 ratio.

The primary objective of this thesis was to investigate the effects of the dietary management on the energy metabolism and insulin resistance of dairy cows. The study was aimed to investigate the potential molecular mechanisms underlying maternal insulin resistance and the physiological adaptation of dairy cows during the periparturient period based on analyses of lipidome and transcriptome.

Main findings were as follows, increasing prepartal energy intake (130% of the energy requirement for a pregnant dairy cow) did not impair the normal liver function and insulin sensitivity of dairy cows near calving. Moreover, this diet attenuated the hepatic inflammatory status during the final stage of pregnancy. Both the CLA-supplemented diet and the high-starch and PUFA-supplemented diet potentially reduced the cows’ metabolic stress by decreasing the necessity to mobilize body reserves. However, these two MFD-inducing diets may have had different effects on the inflammatory status of dairy cows. The CLA supplement may attenuate systemic inflammation during early lactation, while the high-starch and PUFA-supplemented diet may have exacerbated inflammation during the later lactation stages.

MSc Nanbing Qin defended his PhD thesis on November 23th, 2018 in animal science. The topic was  "Effects of dietary management on the energy metabolism of periparturient dairy cows: regulation of lipidome and transcriptome”.

The opponent was professor Helga Sauerwein from University of Bonn and the custos was professor Aila Vanhatalo.
Link to the thesis