Balchem sponsored several abstracts presented at the 2024 ADSA Annual Meeting. This episode consists of five segments, each focused on an abstract.

Segment 1: Evaluating the total mixed ration stability of rumen-protected lysine products.

Guests: Kari Estes, Balchem; Dr. Mark Hanigan, Virginia Tech

This research compared the TMR stability of a Balchem prototype, several commercially available rumen-protected lysine products and a positive control of unprotected lysine. (3:39)

A sample of TMR and the equivalent of one gram of lysine from each product were mixed and placed in a  plastic zip bag for 0, 6, 12, or 24 hours. After each time point, the sample was placed in a strainer bag, dipped in distilled water, and drip-dried. The solution was collected and analyzed for free lysine content. (5:28)

About 85% of the unprotected lysine was recovered at 0 hours. After 24 hours, around 50% was recovered. The rumen-protected lysine products varied widely; one product released nearly 87% of its lysine in 24 hours, while another only released 9%. TMR stability should be taken into account when determining feeding rates and handling of rumen-protected lysine products. (7:19)

Segment 2: Evaluating the total mixed ration stability of rumen-protected choline products.

Guests: Kari Estes, Balchem; Dr. Mark Hanigan, Virginia Tech

In this experiment, Kari evaluated TMR stability of five commercially available rumen-protected choline products, along with a positive control treatment of unprotected choline chloride. (14:04)

At 0 hours, about 80% of the unprotected choline was recovered and 50% was recovered at 24 hours. Results for the rumen-protected choline products were highly variable, ranging from 5% release to 100% release at 24 hours. Rumen-protected choline products should be evaluated for TMR stability in addition to rumen stability and intestinal release. (17:25)

Segment 3: Effect of dry period heat stress and rumen-protected choline on productivity of Holstein cows. 

Guests: Maria Torres de Barri and Dr. Geoff Dahl, University of Florida

The experiment had four treatments: heat stress with and without rumen-protected choline, and cooling with and without rumen-protected choline. Cows in the cooling treatment were provided shade, soakers, and fans, while cows in the heat stress treatment were only provided shade. (24:45)

Heat-stress cows had higher rectal temperatures and respiration rates than cooled cows. Heat-stress cows also had lower dry matter intakes, shorter gestation length, lighter calves, and produced less milk. (29:36)

For cows in the cooling group, choline supplementation increased milk production. However, cows in the heat stress group supplemented with choline produced less milk than cows who did not receive choline. (31:04)

Dr. Dahl suggests that not cooling cows in heat-stress environments when they’re receiving choline will not result in optimal results. (33:49)

Segment 4: Effects of dietary rumen-protected, ruminal-infused, or abomasal-infused choline chloride on milk, urine, and fecal choline and choline metabolite yields in lactating cows. 

Guests: Mingyang (Charlie) You and Dr. Joe McFadden, Cornell University

This experiment evaluated early and late lactation cows supplemented with choline via three different methods. Each treatment had 12.5 grams of choline ion provided daily: fed in rumen-protected form, continuously infused into the rumen, or continuously infused into the abomasum. (36:29)

Choline bioavailability was influenced by the delivery method of choline. Fecal and milk choline concentration was only observed in early lactating cows with abomasal infusion. Abomasal infusion increases the choline metabolite betaine in feces and urine. These results suggest there is potential saturation of choline metabolism in the lactating cow. (40:53)

Segment 5: The metabolic fate of deuterium-labeled choline in gestating and lactating Holstein dairy cows. 

Guests: Dr. Tanya France, University of Wisconsin; Dr. Joe McFadden, Cornell University

Dr. France explains that choline can be metabolized via two different pathways. Using deuterium-labeled choline (D-9 choline) allows researchers to know which pathway is used. If D-3 or D-6 choline is measured, the methionine cycle is used, and if D-9 choline is measured, the CDP choline pathway is used. The hypothesis was that the physiological stage (late gestation vs early lactation) would influence choline metabolism. (51:06)

Dr. France found that both choline metabolism pathways were used in both physiological stages. This experiment also confirmed that choline is a methyl donor and that choline recycling can occur. The research also evaluated the relative amounts of choline and choline metabolites in each pool. (53:40)

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