Dairy cow metabolism and nutrition play key role in safeguarding embryo development
Take Home Message: Reducing negative energy balance, irrespective of breed or milk yield can improve embryo quality, potentially improving fertility.
It is not genetic merit for milk production or breed that has an adverse impact on embryo quality, but rather that a variety of factors associated with milk production, such as metabolism and nutritional management, induce hostile conditions that prevent optimal embryo development.
So says Belgium’s Jo Leroy, who led a study to examine the consequences of metabolic changes in high-yielding dairy cows on oocyte and embryo quality.
“Unsatisfactory reproductive performance in dairy cows, such as reduced conception rates, in addition to an increased incidence of early embryonic mortality, is reported worldwide and has been associated with a period of negative energy balance (NEB) early post partum,” he said.
Typically, NEB is associated with biochemical changes such as high non-esterified fatty acid (NEFA), high β-hydroxybutyrate (β-OHB) and low glucose concentrations. So his team’s work looked at and analysed the concentrations of these and other metabolites in the follicular fluid (FF) of high-yielding dairy cows during NEB.
These were then replicated in in-vitro maturation models to investigate their effect on oocyte quality.
“And the typical biochemical serum changes observed in dairy cattle during the negative energy balance early post calving are well reflected in the FF of the dominant follicle, thus exposing the granulosa cells and the maturing oocyte,” he said.
In vitro maturation models revealed that NEB was associated with elevated NEFA and lowered glucose concentrations are indeed toxic to the oocyte, resulting in both diminished oocyte maturation and embryo developmental competence.
Even after the period of NEB, and when the carry-over effects of the NEB were no longer present, high-yielding dairy cows produced statistically significantly inferior embryos in comparison with dairy heifers and beef cows.
“With a newly developed lipid evaluation technique, it was possible to demonstrate that high-producing dairy cow embryos contained up to 45% more lipids, compared to the embryos of non-lactating animals,” added Professor Leroy
“Further research is required to fully comprehend how a dairy cow’s milk production and nutrition influences embryo health and metabolism via an altered environment in the oviduct and uterus.”
Full details: Leroy JLMR, Van Soom A, Opsomer G and Bols PEJ: “The consequences of metabolic changes in high yielding dairy cows on oocyte and embryo quality.” Animal 2, 1120-1127 www.bsas.org.uk For further information contact: BSAS on 0131 4 45 4508
