By Dr. James Coomer, Ph.D., P.A.S.
The 2019 annual meeting of the American Dairy Science Association (ADSA) was recently held in Cincinnati, OH with almost 2,000 dairy industry professionals in attendance. There were over 1,100 scientific presentations made either orally or by poster presentation (about 550 of each type). There were over 340 presentations related to ruminant nutrition alone, so it will be impossible to highlight all the information that was presented at the meeting, however, here are highlights of a few hot topics that were presented.
Mycotoxins are a topic that we deal with daily and are one reason that this is a hot topic. There was a session dedicated to mycotoxins with 6 total presentations. I want to concentrate on the first two, which were invited to present. The first presentation was “Ruminants – Are they as resilient to mycotoxicosis as we think?” given by D. Diaz from the University of Florida. The presenter started by mentioning that there have been several hundred mycotoxins described in the scientific literature, but less than 10 have been extensively studied since the early 1960’s when Aflatoxin was discovered. He discussed how ruminant diets are composed of both forages and concentrate feedstuffs and this makes them more complex and may increase their risk of multiple mycotoxin contamination. He discussed how it has long been widely accepted that ruminants were less susceptible to mycotoxin poisoning than non-ruminants due to microbial action in the rumen. However, he discussed and presented research that showed that some rumen metabolites of mycotoxins are equally or more toxic than the original mycotoxin. Given this information, we may conclude that ruminants are not less susceptible to mycotoxicosis than monogastric animals.
The second presentation was “Use of technology to better understand multi-mycotoxin and emerging mycotoxin challenges.” Presented by A. Weaver from Alltech in Nicholasville, KY. The presenter discussed the different types of technologies used to identify and quantify mycotoxins in feedstuffs and some of the strengths and drawbacks of each technology. The most common technology used is the Elisa test which is cost-effective, quick and easy to perform but is limited in that each mycotoxin requires a separate test. This is the type of toxin test that is performed in Agri-King’s lab. The most advanced mycotoxin test currently utilized incorporates multiple chemical and laboratory steps and can identify and quantify multiple mycotoxins at one time. The drawback of this technology is that a single sample analysis costs about $200 to run currently. The presenter also said that over the last 6 years of analyzing over 25,000 feedstuff samples from around the world, greater than 96% of the samples contained at least one mycotoxin and 89% contained 2 or more mycotoxins (avg of 5 mycotoxins per sample).
These two presentations give us reasons to make sure we are continually looking for and addressing mycotoxin challenges in the herds we work with. One way to help with this is by making sure the rumen microbial population is functioning optimally. Having a well-balanced diet that avoids unnecessary acidosis challenges and using Tri-Lution® to help the rumen microbes and the cow’s digestive system work at their best.
Transition Cow Calcium Homeostasis
There was a session dedicated to calcium in the transition cow with four invited presentations related to the topic. The last presentation “Use of oral calcium for treatment of hypocalcemia and effects on health and production”, presented by J.A.A. McArt from Cornell University was very interesting from a practical standpoint. Her research was on the use of calcium treatments on cows post-calving. She indicated that IV calcium should only be used for treating clinical milk fever cows or down cows. Her research indicated that treating subclinical milk fever cows with IV calcium actually resulted in delaying the cows return to normal calcium status following a brief increase in blood calcium. She presented additional research on the use of calcium boluses post-calving. This research showed that the use of calcium boluses on all cows is not recommended as this treatment may harm normal calcium status recovery in some cows. Her research indicated little to no positive effect on giving boluses to first lactation heifers at calving, and the best responses were on third and greater lactation cows with a history of high production or previous history of milk fever issues.
The best treatment for milk fever; is to prevent milk fever issues with a good dry cow and prefresh cow feeding program, utilizing Agri-King’s exclusive PCI and constantly monitoring prefresh cows’ urine pH.
Fat and Lipid Metabolism
There were a lot of presentations related to fat and lipids, However, I want to concentrate on work from Dr. Adam Lock’s research group at Michigan State University. There were multiple presentations from this group. There were two main areas that are of interest in their work:
- Effect of an emulsifier on fatty acid digestibility
- Effects of palmitic acid blends as fat supplements
They found that abomasal infusion of a specific emulsifier increased fatty acid digestibility and milk fat content in cows. While the abomasal infusion of emulsifiers is not going to be a practical option on a commercial dairy farm, this research may lead to the development of some type of feed additive that can be fed that will result in increased emulsifier supplied to the lower digestive tract. The group’s work with palmitic acid supplementation has shown that feeding more palmitic acid increases the digestibility of the fatty acids in the diet and that a combination of fatty acids is most likely ideal. However, they found that high and low producing cows do not respond the same to different fatty acid mixtures. High producing cows respond more favorable to a blend of palmitic acid and oleic acid, while low producing cows responded better to a blend of palmitic acid and stearic acid. This research would suggest that feeding by-pass fat sources with higher levels of palmitic acid may result in more energy available to the cow for productive purposes. There are already products on the market that are utilizing blends of fatty acids trying to achieve the best utilization of the fat in the diet.
Histidine is an amino acid that we at Agri-King have been talking about for some time as being important as a limiting amino acid in dairy diets. There has not been a lot of research on Histidine in the past, partially due to there not being a by-pass Histidine source available. Ajinomoto Co has developed a by-pass Histidine source now (not commercially available yet) and that has resulted in more research on Histidine. There were 6 presentations related to Histidine at the meeting this year. Only 2 of the studies were production-related trials and both of them did show some increase in milk production with the supplementation of Histidine. AK