Source: Manitoba Agriculture, Food and Rural Initiatives
Collection, Handling and Feeding
Chaff can be handled and collected in either of two ways. It can be collected and dropped on top of the straw swath, where it can then be baled using a cyclone type of attachment, or it can be collected and blown into a chaff wagon using a chaff collector. The wagon then dumps piles of chaff in the field for later collection or field feeding. The first method of collection and handling is easy and requires a minimum of equipment purchases or modifications. Once baled, the chaff can be fed in round bale feeders, rolled out in the field, or tub ground and mixed with other feeds.
Chaff piles left in the field may be grazed or moved to a central feed pile and fed. Field grazing/feeding of chaff is inexpensive, efficient and effective; however, the field must be fenced and water (snow or dugout) provided. Field feeding is preferable to corral feeding because little if any yardage is taken up with the field-feeding scenario.
Corral feeding may also prove more expensive simply because there is a transportation cost associated with removing the chaff from the field, so farmers who choose this method of feeding chaff should be aware that small thick mats of straw may form at the field feeding sites. These areas may suffer from both poor seed germination and weed infestation the following year.
If yard feeding is preferred, most chaff piles can be collected using a forage harvester or a hay sweep on a front end loader. (This feeding method also removes weed seeds from the field.) Once in the feed yard, the chaff can be either mixed and fed with other feeds, or it can be piled and fed free-choice. An electric wire may be used to limit access to the chaff pile.
The advantages of mixing chaff with silage are that producers are better able to stretch their feed resources, can better match the feed to animal requirements and can reduce costs. Transportation is the biggest issue concerning the economics of chaff. Chaff is very light but very bulky. As a result, large amounts of chaff are quite costly to move long distances.
Some producers have trouble feeding certain types of chaff. For instance, cattle have developed mouth ulcers from eating chaff from rough-awned barley. Producers can avoid these problems by planning and evaluating the type of feed source they use.
Why Feed Test?
Chaff quality varies with type of crop, stage of maturity, weed content, method of harvest, combine settings, and crop and field variability. As a result, chaff must be tested to determine its feed value.
Feed testing is especially important when using lower quality feed. The feed must at least meet the minimum nutritional requirements of the class of livestock being fed. Feed samples should be taken appropriately and with care. Producers can either have a feed company sample their feed, or they can sample it themselves.
Feed Sampling Procedures
Use a core sampler to get samples from baled straw with chaff. For round bales, take about 20 samples from different bales. Sample from the round surfaces of the bales at a variety of locations. For rectangular bales, take one sample per bale from at least 20 bales. Take the samples from the middle of each bale end. Place the samples directly into a polythene sample bag.
Chaff piles can most easily be sampled by hand. Take at least 20 samples from a variety of different piles at different locations and depths to gain as representative a sample as possible. Place these samples on a smooth surface and mix. Divide the sample to obtain a sub-sample sufficient to fill a standard forage sample bag (about 2 litres).
Special care should be taken to ensure the sample is representative; heavier and lighter chaff components must be adequately represented. Ask that the feed testing laboratory to grind the entire sample to ensure adequate representation.
What to Test for
Feed laboratories offer many different types of analyses. The test or tests you choose will depend upon your own needs and budget. Most analyses include levels of crude protein, acid detergent fibre (ADF), neutral detergent fibre (NDF), calcium and phosphorus. The laboratory will use this information to estimate energy levels for you. You may also wish to test for trace minerals levels at least once every two or three years to assess the adequacy of your trace mineral supplement program.
Two methods of feed testing are available to beef producers. The wet chemistry test consists of simple chemical analysis. The Near Infrared Spectrometry or NIRA method uses light wave analysis. Unfortunately, the NIRA test uses localized databases (different growing conditions than your own). In addition, most of the feeds tested are of high quality, so feed quality estimations of low-quality feeds are often inaccurate. Although the wet chemistry analysis is more costly, it is considered to be the more accurate method of testing feed.
Quality Variability in Vhaff
Several variables can affect chaff feed quality:
- Combine settings. The more grain in the chaff, the better its feeding quality. If there is a large number of small kernels in the sample, the combine can be set to throw the light kernels over to the chaff, thereby improving the quality of the chaff.
- Combine efficiency. The poorer the efficiency, the more cracked grain and unthreshed heads that will pass over the sieves and into the chaff.
- Underseeding. Underseeded crops such as alfalfa add green leaf material to the chaff, increasing crude protein levels.
- Time of harvest. If the sample contains more broken straw than bits of grain and leaf material, it will have a lower feed value.
- Crop moisture and height. If the crop is short, more straw will be collected with the chaff, lowering the overall quality of the sample.
Table 1 summarizes data from more than 200 feed samples taken during the 1996/97 and 1997/98 Northeast Chaff and Chaff/Straw Survey done in Alberta
Table 1. Average feed values for all chaff and chaff/straw combinations 1996/1997 to 1997/1998
|Sample||#||Dry matter (%)||Protein (%)||Energy Mcal/lb||Calcium (%)||Phosphorus (%)||Magnesium (%)||ADF* (%)||TDN** (%)|
|Wheat chaff||53||91.1 (86.5-95.7)||4.6 (2.9-6.3)||0.9 (0.73-0.97)||0.24 (0.13-0.35)||0.08 (0.04-0.12)||0.12 (0.07-0.12)||51.5 (46.5-56.5)||43.6 (37.8-49.4)|
|Wheat chaff and straw||21||86.1 (81.7-90.5)||4.0 (2.5-5.5)||0.8 (0.70-0.88)||0.25 (0.11-0.39)||0.12 (0.08-0.16)||0.09 (0.06-0.12)||51.3 (47.1-55.5)||39.7 (35.3-44.1)|
|Barley chaff||51||88.8 (84.8-92.8)||6.5 (4.2-8.8)||1.0 (0.91-1.17)||0.52 (0.25-0.79)||0.13 (0.07-0.19)||0.17 (0.12-0.23)||42.8 (37.3-48.3)||53.0 (47.2-58.8)|
|Barley chaff and straw||28||88.5 (84.9-92.1)||5.0 (3.2-6.8)||0.9 (0.80-1.00)||0.45 (0.27-0.63)||0.11 (0.06-0.16)||0.15 (0.09-0.21)||49.6 (44.0-54.7)||45.6 (40.2-51.0)|
|Oat chaff||17||87.4 (80.2-94.6)||7.2 (5.0-9.4)||1.1 (0.95-1.15)||0.71 (0.25-1.16)||0.14 (0.08-0.20)||0.23 (0.17-0.28)||42.6 (38.0-47.2)||53.1 (48.2-58.0)|
|Oat chaff and straw||5||84.4 (76.9-91.9)||5.1 (2.8-7.4)||0.9 (0.78-1.02)||0.39 (0.25-0.53)||0.1 (0.05-0.10)||0.15 (0.09-0.21)||50.1 (44.3-55.9)||45.1 (38.9-51.3)|
|Canola chaff||18||88.6 (83.9-93.3)||5.9 (4.0-7.8)||0.8 (0.63-0.91)||1.45 (1.08-1.82)||0.12 (0.06-0.18)||0.33 (0.20-0.44)||56.0 (48.8-63.2)||38.5 (31.2-45.8)|
|Pea chaff||11||79.4 (74.2-84.6)||9.2 (4.5-13.9)||0.8 (0.74-0.92)||1.76 (1.28-2.24)||0.13 (0.04-0.22)||0.35 (0.25-0.45)||46.1 (42.0-50.2)||42.0 (37.6-46.4)|
|Pea chaff and straw||4||89.1 (85.9-92.3)||7.0 (4.6-9.4)||0.8 (0.69-0.89)||1.56 (1.47-1.65)||0.11 (0.05-0.17)||0.27 (0.18-0.36)||54.8 (50.0-59.6)||40.1 (35.0-45.2)|
|* ADF: acid detergent fibre ** TDN: total digestible nutrients|
Meeting Nutritional Requirements
Note, chaff and chaff/straw type roughages are only suitable for mature animals in good body condition. Mature beef animals have stopped growing and only require energy for maintenance. These roughages are especially suited to cows in their second or early third trimester.
Although suitable roughages, chaff and chaff/straw mixes lack sufficient protein to meet a beef cow’s nutritional needs. For instance, a 1,400 pound mature beef cow with a body condition score (BCS) of 3.5 (Canadian scale) will require a minimum 6.5 per cent crude protein (CP) ration and 54 per cent TDN. As indicated in Table 1, chaff is generally deficient in CP and TDN, so it would thus require protein supplementation.
Protein supplementation of chaff and chaff/straw combinations (crude protein (CP) less than 6 per cent) is an effective way to improve dry matter intake and digestion. It is also a better way to maintain cow body weight and condition over the winter months. These supplements increase ruminal ammonia (NH3) available for bacterial digestion. With supplementation, bacteria multiply faster, and digestion of the low-quality roughage is enhanced. Throughput of the roughage and dry matter intake is increased and animal performance improves.
Many protein supplements are available to producers feeding chaff and chaff/straw combinations. To identify the type of supplement best suited to your operation, contact your local ruminant nutritionist or beef specialist. You may have the right supplement available on hand. Before you purchase a protein supplement, ask yourself: “Does this type of supplement work in my feeding program and am I getting the value for my money?”
Table 2 shows the costs of various rations. The amounts are based on the winter feeding needs of a mid-gestation 1,300 pound mature cow.
Table 2. Cost of rations: Winter feeding of a mid-gestation 1,300 pound mature cow
|$/ton||Ration #1 lbs||Cost||Ration #2 lbs||Cost||Ration #3 lbs||Cost||Ration #4 lbs||Cost|
|32% protein lick||$240||0||$0.00||0||$0.00||0||$0.00||4||$0.48|
* Note that producers also should consider handling and labor costs associated with each of the rations.
- 100 cow/calf operation
- 1,200 – 1,300 lb cows calving March 1
- chaff feed for 100 days November 1 – February 15
- chaff yield 400 lbs/acre
- wastage 15 per cent on chaff (collection, transporting and storage)
Cow Ration (Maintenance)
- 30 lbs chaff
- 20 lbs barley silage
Chaff Acres Required
- 30 lbs/day/cow x 100 days = 3,000 lbs/cow = 150 tons/100 cows
- 400 lbs/acre (15% waste) = 340 lbs/acre
- acres = 9/cow = 18 cows/ quarter section = 900 acres/100 cows
|Investment/depreciation = $75,000/10 yrs = $750/yr / 150T||$5/ton|
|Operation Cost (fuel, repairs etc)||$3/ton|
|Total in Field||$10/ton|
|In Feed Yard|
|50 hrs x $30/hr = $1500 / 150 T||$10/ton|
|($3/mile) x 10 miles = $30 / 10 tons/load||$3/ton|
|Total in Feed Yard||$13/ton|
|Total Chaff Costs||$23/ton|
|30 lbs chaff @ 1.15¢/lb||0.34¢|
|20 lbs silage @ 1.25¢/lb||0.25¢|
|Chaff Costs/cow||3,000 lbs x 1.15¢||$34/cow|
|Chaff Value per acre||$34/cow / 9acres/cow||$3.78/acre|
- The above economic estimates assume cows have a body condition core (BCS) of 2.5 (Canadian scale); if cows are thinner, extra feed will be required.
- Animals would require extra feed at temperatures below -20 degrees Celcius.
- Savings (chaff $10/T) can be achieved by feeding chaff piles in the field along with silage.
- Chaff can be fed for longer periods, allowing for nutritional adjustment at calving and during lactation.
Chaff is a dependable and economical feed supply that works well in a mixed farming operation. However to stay economical, you must pay close attention to the costs of harvesting and feeding chaff. As a cattle feeder, you must take care to balance your feeds to ensure your cows’ nutritional needs are met. Consult your ruminant nutritionist or beef specialist for advice on formulating chaff-based rations.
Christoph Weder, Beef Specialist Alberta Agriculture, Food and Rural Development
Northeast Forage and Beef Specialists
Northeast Conservation Connection and Agricultural Service Boards.