Total Mixed Rations (TMR): What Can Go Wrong


Source: Manitoba Agriculture Food, and Rural Initiatives

We all know the reported advantages of feeding a TMR (total mixed ration) – improvements in milk production of 6-8%, decreased feed costs of about 5%, and a reduction in metabolic health problems. We also know, however, of situations where the change to a TMR feeding system has not resulted in production improvements, and may in fact be associated with a drop in production. What has gone wrong?

A TMR, by definition, provides a balanced diet in each mouthful a cow consumes. Let’s look at some of the factors which can contribute to poor performance of a TMR.

Poor Ration Programming

The use of inadequate or incomplete ration programming is a sure way to put together a TMR that will be disappointing. Attention should be paid to ensuring an adequate forage to concentrate ratio. Moisture contents of wet forages should be taken weekly and the amount of forage in the TMR adjusted accordingly.

Improper Measuring of Feeds

This is due to the absence or improper use of weighing devices on mixer wagons. A set of scales kept in good working condition and used daily is a necessity.

Feeding Other Feeds

Giving a cow a choice of feedstuffs is providing her the opportunity to consume an unbalanced ration.

When dairymen are feeding in stall or stanchion barns, there can be some supplemental feeding of small amounts of hay or grain if the supplemental feed is included in the feed formulation.

Fine Grinding the Mix

One of the problems with TMR’s can be a ration that has no long chopped forage. If this is made worse by running the mixer until the particle length of the forage is too short, cows will react negatively to the absence of long particles. Over 15% of the forage particles should exceed 1 1/2″ (4 cm) in length.

Hours of Feed Availability

There should always be more feed than the cows will eat. It is important to return to the feed bunk several times a day either to provide feed, or simply to stir up the remaining feed to renew the cows’ interest in eating.