The Importance of Fibre Quality in Cow Feed
What is the role of roughage in cattle feed?
Roughage predominantly consists of fiber and is poor in protein. While farmers often face the question of how much roughage should be included in the feed, it is important to note that roughage is extremely important for animal health and productivity. Cows have a larger rumen volume than most ruminants and the passage rate from the rumen is also a lot slower. The best way to measure the quality of roughage is to determine Acid Detergent Fibre (ADF) and Neutral Detergent Fibre (NDF). These tests can be done in most feed analysis laboratories. The acid detergent fiber test measures the cellulose and lignin content of a feed. Cellulose is a digestible form of fiber, while lignin is an indigestible form. ADF is a good measure for calculating the energy value of forages, while the NDF test measures the cellulose, hemicellulose (a poorly digestible material), and lignin content of the feed. With feeds that have plenty of long roughage, the minimum recommended NDF level is 25%, failing which the rumen ecosystem becomes vulnerable and potentially dangerous to the animal’s health. Research has proved that when cows are grazing in native pastures they can manipulate their diet by selecting forages that are good for their rumen. If they eat something that tends to make their rumen more acidic, they can then search for another long roughage forage with a higher fiber content to balance out their diet. When the animal is fed on a farm, the selection is limited to what the farmer feeds them; also, since the feed is ground up, cows are not able to sort or forage for themselves.
Unfortunately, the nutritional information available on most packaged feed provides only the value of the crude fiber content and does not break it down according to ADF or NDF. As a general rule, a higher crude fiber value in feed indicates that the feed is rich in roughage. If the feed label reflects that the roughage level is low but the crude fiber level is high, then the fiber is from a source that is not useful in lumen activation or rumination. Based on several studies it is now proved that when cows are fed a concentrate ration that is not mixed with hay or silage, the concentrate should comprise at least 16% crude fiber.
When to suspect that the cow is not getting enough good quality fiber:
It is important to take regular rounds of the farm to observe the behavior of cows, as it can reveal a lot about feeding management.
- Count how many cows are
- Feeding near the manger
- Standing and ruminating
- Lying and ruminating
- Lying and resting
In general, 20-30 % of the cows should be feeding (provided that feeding is ad-lib and the feed is always available to them) 70-80% of the cows that are not feeding should be ruminating and most of these should be comfortably lying and ruminating. When cows are found ruminating in a standing position it indicates the paddock floor is not comfortable. Take a round of the paddock after taking your boots and socks off. If the floor does not hurt you, it is surely comfortable for cows. Ruminating cows should secrete sufficient foam at the mouth, which indicates enough salivation. In case water availability is less salivation rate is affected.
If the herd’s behavior is not in accordance with this statistic, the quality of fiber in the feed may be at fault.
Also Read : Farmers Should Include Silage in Cow Feed
Author:
Dr. Abdul Samad