Timestamps & Summary 

Chris Gwyn (01:50)
I was wondering if you could summarize for the audience what has been discovered to date about B vitamin nutrition in dairy cows, in particular B12 and folic acid.

Dr. Melissa Duplessis
I started my career in research 15 years ago. I was a master's student at that time in Christiane Girard’s lab at Agriculture and Agri Food Canada. And she was the first to challenge the well-established dogma that dairy cows do not need an exogenous supply of B vitamins because their ruminal bugs are producing the B vitamins. But now, as you know, dairy cows are producing more and more milk, especially during the early lactation. We can wonder if it is still true that they don't need supplementation in B vitamins. That's why my master’s project was conducted. […]

Chris Gwyn (10:19)
I wanted to talk about some of the more recent research that you shared because it helps one to think about what some of the other needs are and future research. And in particular you shared a study about the impact of pasture or housed fed heifers fed at TMR. I'm assuming in the housing and the difference in folate and B12 concentrations and wondering if you could share those findings and how that might impact at the farm level.

Dr. Melissa Duplessis 
I think you are referring to my recent collaboration with Mary Beth Hall, who recently retired from the USDA. This study was conducted in the US with heifers at 5 months of age. And half of the heifers were raised on pasture receiving grains, vitamins, and mineral supplements, and the other half were in the barn receiving TMR (total mixed ration). And this is a preliminary study. We obtained blood samples from those heifers, and we analyzed folic acid and vitamin B12. And we obtained that heifers raised on pasture had a higher plasma folate, and the opposite was observed for vitamin B12. So, heifers raised on pasture had lower vitamin B12 concentration. […]

We did not record dry matter intake, but we also observed that there is a link with dry matter intake, and the ruminal synthesis of B vitamins could also be an explanation. And so, as I mentioned, it's a preliminary study. So, when we conduct a study, sometimes we have 10 other questions raised by that study. So it's normal, [it's the nature of the work we do].

Chris Gwyn (14:04)
I know recently you did also some work where you looked at pre calving nutrition and the impact of colostrum quality and yield and wondering if you can maybe touch base on that one. What does B vitamin levels look like in colostrum?

Dr. Melissa Duplessis
We conducted two studies with colostrum that have already been published. The first one was during my PhD thesis at Cornell University. So we collected colostrum samples from a project evaluating the impact of different levels of energy during the pre-calving period. And we observed that the impact on colostrum was that cows fed controlled energy prepartum had higher B vitamin concentration in colostrum. And when looking at the rations, we observed that the controlled energy had the highest NDF or fiber concentration. […]

Interestingly, we also observed that calves born to mothers receiving folic acid and vitamin B12 were heavier one day after birth. One hypothesis is that epigenetics, which includes folic acid and vitamin B12, has a link to epigenetics. So, it could be an explanation. So, it's a recent study that has not yet been published. We conducted it in 51 dairy herds, and we collected pre-calving rations served to cows in these herds. And we also collected colostrum from over 300 dairy cows. With our fancy statistical models, we evaluated the link between the prepartum diet and the impact of colostrum quality. […]

Chris Gwyn (19:26)
But certainly as you point out in your study, the effect on fiber and energy level again continuing having on the quantity and quality of colostrum is something that when struggling with those things producers should be discussing with their nutritionist.

Dr. Melissa Duplessis 
Yes. And if you are interested with our ranges, for example, like if you want to know the dairy ration of our herds, you can contact me, I would be more than happy to help in that regard.

Chris Gwyn (22:44)
What are some of the key points in your most recent research that you'd like to share with the audience?

Dr. Melissa Duplessis
I would like to say that from other studies I conducted, stressful events for the animals, for the cows or for the calves can modify or make a change in the B vitamin status of the cow. For example, a stressful event can be the calving, but it can also be heat stress or it can be weaning for the calf, or something like that. So, future research needs to be conducted to answer whether there is a practical implication of the change. Would animals benefit from supplementation? It's all good questions to be answered, hopefully in the future.