Managing Alternative Forages

Reports indicate widespread alfalfa winterkill due to several thaws that reduced snow cover and created ice in fields. Many stands were either patched or put into an annual forage. Here are some tips on managing alternative forage crops.

First cut is usually (but not always) 60 days after planting

Table 1. Harvest guidelines for alternative forage crops

Crop Planting to 1st cut (days) Cutting Interval (days) Cut Height Stage for maximum quality Stage for maximum yield
Red clover
60-70
30-35
5 cm (2 in.)
Late bud to 20% bloom
After 20% bloom
Italian (or annual) ryegrass
Head emerges at 55-60
30-40
10 cm (4 in.)
Before boot stage
Head emerged
Cereals
For "grass": 45-50
For whole-crop: 60
Highly dependant on summer rainfall
7-10 cm (3-4 in.)
Before boot stage
Heads emerged to soft dough
Cereal/pea
45-50
Highly dependant on summer rainfall
7-10 cm (3-4 in.)
Before cereal boot stage
Emergence of head complete (cereal)
Sorghum-sudangrass, forage sorghum
60, but crop must be
>65 cm (26 in.) tall
Wait until crop is >65 cm (26 in.) tall
10 cm (4 in.)
Boot or early heading
Multiple-cut system; see max quality.
Millet
55-60
Pearl and Japanese: 30-35
Foxtail and Proso do not regrow very well
Pearl and Japanese: 10 cm (4 in.)
Foxtail and Proso: 5 cm (2 in.)
Pearl and Japanese: 36 in.
Foxtail and Proso: before heading
Cut for quality

Red clover harvested for quality has more rumen by-pass protein and NDFd than alfalfa. Quality does not decline as quickly as alfalfa.
Italian ryegrass prefers cool temperatures and consistent rainfall. Some producers graze the lower yielding mid-summer cut rather than running harvesting equipment across the field, but this requires grazing infrastructure.

Cereals provide options. Maximum protein content and fibre digestibility occurs before boot stage. Producers looking for more yield and starch content could wait until soft dough stage and ensile the crop to get something that feeds out more like corn silage than haylage. Producers could plant a warm-season grass after harvesting the cereal, provided there is enough soil moisture for germination.

Grasses lose their quality faster than legumes, so any time a mix is grown it should be harvested when the grasses are at the ideal maturity. In this case, cereals are grasses!

Don't make dry hay

Table 2. Suitability of alternative forages for different storage/feeding methods

Crop Dry Hay Baleage Silage Green Chop Grazing
Red clover
difficult
x
x
-
x
Italian (or annual) ryegrass
-
x
x
x
x
Cereals
-
x
x
-
x
Cereal/pea
-
x
x
-
x
Sorghum-sudangrass
-
x
x
x
x
Millet
Foxtail or Proso
x
x
x
x

Red clover takes a long time to dry which increases the risk of mouldy or dusty hay. Clover silage is generally very dark in colour, so can look like spoiled alfalfa. It resists protein breakdown during the ensiling process and has about 40% less non-protein nitrogen than alfalfa.

Cereals can be made into dry hay but take longer to dry than perennial grasses. Peas wilt more slowly than cereals, so producers should pay close attention to the crop's moisture content when working with mixtures.

Just like ensiling alfalfa or corn, the correct moisture content (Table 3), proper packing density, and a good seal are critical to preserving alternative forages. Baleage is most successful when crops are put up in dense bales and wrapped with 6-8 layers of 1 mm thick plastic.

Table 3. Correct moisture content for silage crops

Type of Silo Moisture Content Dry Matter Content
Horizontal silo (bunker or bag)
65-70%
30-45%
Tower silo
62-67%
33-38%
Oxygen-limiting tower silo
55-60%
40-45%
Baleage
45-55%
45-55%

Be aware of possible toxins!

Nitrate poisoning

Except red clover, all the crops discussed here are fast-growing grasses with high nitrogen demands. These crops can accumulate nitrates under certain growing conditions:

  • Very high soil levels of nitrogen (i.e. excessive rates of fertilizer or manure, or combinations of these following a legume crop - such as winterkilled alfalfa);
  • After the rain that breaks a long dry spell. In this situation, delay harvest by 10 days to allow nitrates to be converted to protein;
  • Any condition that kills the leaves while roots and stems remain active (frost, hail, sometimes drought)

If any of the above factors are present, allow crops to ferment for 3-5 weeks before feeding. Be aware of deadly nitrogen dioxide gas around silos.

Prussic acid poisoning

Sorghum, sudangrass, and their hybrids produce prussic acid (hydrogen cyanide) when stressed. To reduce the risk of prussic acid poisoning:

  • Do not pasture or green chop stands less than 60 cm (24 in.) tall.
  • Do not ensile or green chop sorghum over 76 cm (30 in.) tall for 3-5 days after a killing frost. Silage should be completely fermented before feeding (6-8 weeks).
  • Immediately after a frost, remove the livestock from the pasture until it has dried out (usually 6-7 days). If new shoots develop, harvest the field as silage rather than pasture.
  • After a drought-ending rain, do not graze animals on new growth.

Red clover can contain high levels of phytoestrogens which can interfere with breeding and early-stage pregnancy in sheep. Grasses and cereals may develop leaf or stem rusts under damp conditions. While rust reduces nutritional value and palatability, it does not produce toxins.

Alternative forage crops can make great feed. The trick is to not manage them like alfalfa.

References


For more information:
Toll Free: 1-877-424-1300
E-mail: ag.info.omafra@ontario.ca