TMR CORNER: Focus on forage quality for better results

Published on Fri, 06/10/2016 - 4:16pm

 I have recently returned from a couple trips to South East Asia that highlighted the importance of forage quality in TMR preparation and animal performance. In much of Asia, the challenge for producers is first to find sufficient land to grow forages, and then to source environmentally adapted species that are capable of producing acceptable quality with sufficient yield.

As a result, producers in S.E. Asia generally default to focusing on high yields of relatively mature cuttings of native species such as elephant or Napier grass (Pennisetum purpureum), which can be substantial (growth to 10 feet or higher), as well as using rice straw. But, the nutritional value of this forage, by itself, is often insufficient to maintain the body weight of the animals being fed. For the animals to survive, let alone produce, excess quantities of forage must be provided so that the animals can select the least mature leaves and sort out the coarse stems, and thereby improve the nutritional value of what is actually consumed. However, when this same forage is harvested at an immature stage (around 3 feet in height), it is readily consumed, and capable of producing liveweight gains of up to 2 lbs. per head per day, and milk production of over 20 lbs. per day (4% fat) (Source: www. > Forages Fact Sheets > Select Pennisetum purpureum)

In an effort to solve the problem of sorting and waste of forage by sorting and poor animal performance, producers have begun to embrace vertical TMR mixer technology as a solution: first, to process the coarse forage to limit sorting and improve forage utilization, and second, to enable them to more economically improve nutritional value of the ration by incorporating byproducts and other more cost-effective ingredients into the ration. Does this start to sound familiar to the goals of many in the cow-calf sector in North America?

While it is true that a vertical TMR mixer is effective in reducing forage waste and decreasing feeding cost by expanding the range of cost-effective ingredients that can be easily fed, it still remains that one of the most important determinants of animal performance and profitability is to ensure one has sufficient forage quality for a given feeding program. Here’s why:

1. Both nutrient content (e.g. digestible energy and protein) and intake potential go down as forage matures.

It is well known that the digestible energy content of forages decline as forages mature, and fiber content and degree of lignification increase. However, forage intake also decreases as maturity and fiber content increase (see figure). Thus forage maturity has a two-fold effect (decreased energy content, and decreased intake potential) on decreasing digestible energy intake from forages as it advances.

2. As forage maturity increases, the amount and proportion of grain fed in the TMR must increase.

When forage quality declines to the point that potential digestible energy intake is insufficient to meet the nutritional requirements of an animal, other sources of energy, such as grains or byproducts, must be added to increase the digestible energy content of the ration to an acceptable level. The further the forage quality declines, the greater will be the proportion of concentrates that will be required to be fed in the TMR. This increases the risk of digestive upset, and related intake and health problems.

3. Poor-quality forage is harder to process and incorporate into the ration, and easier and
more desirable for animals to sort against.

Poor-quality, high-fiber forages, take more time and are more difficult to process in TMR mixers than are better quality forages. This creates a tendency to create rations with a higher incidence of sorting. This, along with the need to feed higher proportions of concentrate to compensate for the poor forage quality, further increases the risk and incidence of digestive upset and related problems.

Thus, even when one feeds with a TMR mixer, and regardless where one lives, ensuring adequate forage quality for the animals being fed is a fundamental factor for cost-effective livestock production. As we enter the major part of the forage production season, it is beneficial to concentrate on the forage production characteristics that will yield the appropriate concentration of digestible energy in your forage to ensure the most cost-effective utilization of your forage resources — Because Nutrition Matters.™