FEEDING FACTS

YOUR LIVESTOCK'S NUTRITIONAL NEEDS

THREE IMPORTANT FORAGE TEST RESULT NUMBERS

BY JIMMY PARKER

As fall approaches, it is time to start considering how you will approach your livestock’s nutritional and forage needs and what supplementation may be needed throughout the fall and winter. Hay will likely be an integral part of the feeding plan and to get an accurate assessment of what you have a forage test should be done on the hay you plan to utilize. There are many important numbers on those test results that are useful and will help you make a good decision on when to feed different cuttings to best match your animals' needs based on weather and stage of production. Some of the numbers that should be considered first are crude protein levels, TDN (total digestible nutrients) and NDF (neutral detergent fiber) levels. There are other important numbers but without getting too far into the weeds we can look at these three.

Crude Protein is the most discussed number when buying feed or planning for hay needs and while it is important it is usually not the most important number to look at. Hay will typically range from six percent to occasionally twenty-three or four percent, with most grass hay being in the eight to twelve percent range. Grown cattle that are not lactating don’t need a great deal of protein and most average hay or standing forage will meet their daily needs unless intake is limited in some way. Ewes and does that are dry and not in late gestation would also get all the protein they need from average hay. Lactating animals may have protein needs that are greater than average hay can provide and should be fed higher quality hay or supplemented with a feed or a tub.

TDN is more often overlooked or misunderstood, and it can usually be used as a good indicator of energy levels within a forage or feed. TDN will typically range from the mid forty percent range in mature forages and as high as eighty percent in some energy-rich feeds. Typically, mature cattle would need forage TDN levels to be in the mid fifty percent range or above to do well and higher is better up to a point. The lower the intake will be the higher the TDN percentage needs to be and if access to forages is limited then a higher percentage of TDN will be required to meet animal requirements. If TDN levels are low, supplementing with higher TDN supplements will be needed and lactating animals have a much higher requirement than animals that are not in production.

NDF is another important number and probably the least understood of the three mentioned here among producers when forage sample results come back. NDF is a measure of digestibility and will indicate intake. The higher the NDF number, the less forage your animal can digest in a given day. NDF values will range from mid to low thirty percent in some grains to seventy or eighty percent in mature forages. And the higher the NDF number is, the slower the feed or forage will be digested and the longer it will stay inside the stomach of the animal. If the stomach stays full, they can’t eat as much and if they can't eat as many pounds of total hay or grass in a day, supplementation will most likely be needed to meet their nutritional requirements.

These high NDF numbers are most often associated with late fall forages and hay that was cut at a mature growth stage. The older the grass is, the higher the NDF (and slower it will be digested), and the lower the protein and TDN usually is. So, it limits your animals in two ways. They can’t eat as much and what they do eat has less protein and energy per pound. Sample results like these really drive home the need to cut hay at the correct time and make sure stockpiled forages were managed properly before frost killed them.

If you do find yourself with some mature hay that didn’t test very well, you still have options. Feeding higher protein or higher energy feeds are the most common solutions and as high as calves are selling, supplementation makes a great deal of sense economically at this time. Another option would be tubs. Stimulyx tubs are almost always a good userfriendly option that will help the cattle digest the poor quality forages in a fairly efficient way. Purina high fat tubs are also a good option in many places where TDN is the most limiting factor. No matter what your forage situation is, sending off samples and knowing just where you stand will pay dividends almost every time. That is really the only way to plan correctly and make good decisions early before feed and supplement prices drift up through the winter feeding season.