What you need to know: A TMR, or total mixed ration, is a term used to describe various feed ingredients mixed into a singular and consistent product. Nearly all feedlots and dairies utilize this method of feeding. But why do we do this? What is the purpose of mixing the feedstuff together?
The answer is twofold. First, we mix the ingredients so that each animal gets a consistent proportion of nutrients. And second, we mix so that animals eat the less palatable feeds instead of "sorting" the good stuff out and leaving the rest in the feed bunk.
Mixing feedstuffs into a TMR does accomplish these two things, for the most part. However, there is still some level of sorting occurring, which researchers attempted to solve in this paper. They focused on what could be added into silage to hinder sorting.
What was their magic ingredient? Water. They added water (12.5 or 14 liters per cow) to some of the rations while mixing feedstuffs in the feed truck. Cows were then fed either a standard dry TMR or the new wet TMR, and were monitored for their sorting and intakes.
The water method worked rather well at decreasing sorting, with ratios of fine, intermediate, and large particle feedstuffs staying similar through the day. There was a 16% higher large particle proportion in the dry TMR versus the wet TMR. Think Chex-mix–it was like the cows had picked out all the good stuff, like the Chex pieces and the cracker-sticks, but not the gross pretzels (I mean, who likes pretzels anyway?). They would be left with mostly pretzels or, in this case, the large particles from the grass silage, corn silage, and hay.
Based on the numbers reported, the wet ration seemed to do the trick and decrease sorting. This method worked because water essentially clumped the feedstuffs together, where cattle were forced to eat all the ingredients in each mouthful. There was little chance for the cows the eat the small particles without eating large ones as well.
Important to Note:
- This research was conducted on dairy cattle, which are fed different ingredients than beef operations. However, the findings are still applicable to beef operations that have small particles in their ration.
- Some earlier research studying the same concept found either no effect or the opposite effect as this paper. This, however, does not take away from the paper's validity.
- The first trial went for 90 days, and the second went for 70 days. Although this is adequate time, cattle are clever creatures and could learn to better sort over time. I would be interested in the presence or absence of learned ability over a few seasons.
Industry Application: Adding water to your TMR could drive feed intake and decrease sorting behavior from animals eating out of feed bunks. This could, in turn, better regulate the animal's digestive system and improve feed efficiency and animal health.