Herd reproduction performance is strongly linked to farm profitability.
In addition to high lactation performance, modern dairy cows need to deliver a strong and healthy calf each year to maintain farm profitability.
We also know that properly balanced nutrition works harmoniously with the genetic ability of the cow to deliver the reproduction performance we desire in a dairy herd.
Available evidence suggest that low fertility of modern dairy cows is likely due to sub-optimal management, especially nutrition, that does not match the genetic progress.
Several studies have shown that supplementing dairy cows with B vitamins, especially in a rumen-protected form, reduces fatty liver and improves energy balance during transition, which then results in improved fertility.
More recently, an on-farm trial conducted in Australian pasture-based dairy production system showed the six-week in-calf rate was improved in cows supplemented with rumen-protected B vitamins during the pre-calving and lactation periods (Figure 1).
A previous study has also shown that in all-year-round calving herds, 100-day pregnancy rate was improved by 33 per cent.
Although B vitamins are co-factors and co-enzymes that facilitate various metabolic processes, such as glucose (energy) metabolism and protein synthesis, recent advances in nutrition and genetic sciences have shown that B vitamins can directly stimulate certain genes that work in a coordinated fashion to regulate different reproductive functions.
For example, there are two key areas to improve fertility in dairy cows.
The first step to getting a cow pregnant involves a series of processes, starting from developing a viable and large follicle containing a quality egg or oocyte that will eventually be ovulated.
Research has shown that the genes that are responsible for the coordination of these processes are stimulated when rumen-protected B vitamins are fed to dairy cows during the early stage of lactation (Figure 2).
Development of a quality egg is another step to promoting a successful pregnancy. A cow that does not ovulate will not get pregnant.
The second factor to consider in improving fertility of dairy cows is the implantation of the fertilised egg (embryo) in the uterus, and growth of the foetus to trouble-free calving.
The loss of pregnancy has been linked to an unhealthy environment within the uterus and the inability of the embryo to establish a successful attachment to the uterus.
Again, there are several genes that coordinate the preparation of the uterus so that the embryo can attach, be nourished and develop successfully.
When cows were supplemented with a blend of rumen-protected B vitamins, 11 genes were expressed — more than compared with cows that did not receive rumen-protected B vitamins (Figure 3).
These genes could cause changes in various important mechanisms in the uterus that will promote a favourable environment for a successful pregnancy.
So, beyond acting as co-enzymes or co-factors, B vitamins also act directly to stimulate gene expressions for coordinated processes that lead to improved fertility.
This highlights the importance of how nutrition can be used to enhance the genetic expression and improve the performance of modern dairy cows.
To learn more about how supplementing your cows with rumen-protected B vitamins will support healthy and productive herd, talk to your nutritionist or Jefo representative.
– Dr Razaq Balogun, technical sales manager, Jefo Australia