This episode comes to you from the “New Developments in Transition Cow Nutrition” seminar in Stoke-on-Trent, England. Dr. Santos, Dr. Reynolds and Dr. Zimmerman spoke at the seminar. Each speaker gives a brief overview of their seminar presentation, and then the panel takes questions from the audience.

In his presentation, Dr. Santos discussed some of the latest research using rumen-protected choline in transition cows. There is substantial evidence that choline plays an important role in transition cow nutrition, particularly because of its consistent positive effect on the yield of energy-corrected milk and benefits that extend beyond the supplementation period. (1:16)

Dr. Reynolds’s presentation focused on protein nutrition in very early lactation cows. Cows are in a substantial negative balance for metabolizable protein in the first week or two postpartum. Recent research, with abomasal infusions of casein, or the amino acids in casein, immediately after calving, has resulted in substantial increases in milk yield. In his lab, Dr. Reynolds has used rumen drenches to supplement cows immediately postpartum as palatability of supplements has been an issue. Providing essential amino acids and total protein to cows immediately after calving is a challenging problem.  (2:10)

Dr. Zimmerman’s presentation discussed differences in rumen encapsulated products. There are four parts of a good ruminant encap: good ruminal stability, good intestinal digestibility, good feed mixing and TMR stability and biological response in the animal. (3:44)

Questions from speakers and attendees were as follows:

What is the optimum level of choline to feed to a transition cow? Given the close relationship between methionine and choline, is there a similar ratio between them like the 3:1 lysine:methionine ratio? (4:56)

Around 98-99% of dietary choline will be degraded in the rumen whereas, with lysine and methionine, we know there's an amount that escapes with the bypass protein fraction of the diets. Has the ruminant animal evolved not to require any bypass choline? (13:46)

Dr. Santos’s presentation focused on the benefits of choline supplementation to the transition cow. What are the benefits for the in-utero calf? (19:45)

What is the mechanism by which choline increases colostrum production? Is it just similar to the effect on milk yield generally? (28:21)

Does choline impact younger or older cows differently? (30:36)

Given the increase in intestinal length and changes in the architecture in early lactation, does this result in suboptimal absorption and scouring? Could it be a nutrient deficiency problem as opposed to something like acidosis? Should we analyze fecal samples to assess this? (34:50)

Do you think fundamentally we are underestimating metabolizable protein requirements in very early lactation? Or are we just not managing that transition particularly well? And if so, what sort of safety factors should we evaluate regarding protein nutrition? (41:45)

In the early lactation studies where metabolizable protein is supplemented in high concentrations, we see big milk and energy-corrected milk responses, but no increase in dry matter intake. Why is that? (43:34)

Dr. Santos describes an experiment in beef cattle, evaluating the inflammation impacts of pneumonia on essential and nonessential amino acids in the gut. This model might be quite similar to that of a dairy cow with metritis. (50:24)

Do you have any recommendations for amino acid supply for cows on grass? Is there anything new coming in that regard? Are there any specific recommendations for synchrony and/or ratios of energy and amino acid supplies? (55:58)

When should amino acids be fed after calving? (1:01:13)

In closing, each panelist provides a take-home message. (1:06:00)

Dr. Santos: Consider choline a required nutrient. 

Dr. Reynolds: Most of our cows have the genetic potential to produce a lot more milk than they are achieving in very early lactation. We need to look at that in terms of how we might be able to help them achieve that potential yield.

Dr. Zimmerman: Not all encaps are created equal. Make sure that you’re able to see published in-vivo research with these products, done by reputable institutions, to prove that these products are working in the animals. 

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