BRASSICA FEEDING RECOMMENDATIONS
For Grazing Dairy Cattle & Other Ruminants
Fay Benson1and Melanie Soberon2
Feeding Recommendations:

Sulfur-containing volatiles and glucosinates derived from Brassica plants may contribute
negatively to the flavor and odor of milk and meat of animals grazing Brassicas.
Therefore, it is advisable for lactating cattle to graze Brassicas immediately after milking
to allow at least 4 hours to pass between Brassica consumption and the subsequent
milking. To avoid milk taint, it is also recommended that the Brassica crop not constitute
more than one third of the animals’ diet throughout the day. Meat animals should be
removed from a Brassica crop 3-7 days prior to slaughter to minimize the risk of tainting
the meat.

It is important to graze only mature Brassica crops as various health problems are
associated with cattle grazing immature Brassica plants. Check with your seed
distributor to determine the expected time after planting for a specific Brassica crop to
reach expected maturity.

Introduce cattle to the crop slowly over an adjustment period of 1-2 weeks to allow
rumen microbes to adjust to the change in diet. This can be done by restricting grazing to
1-2 hours per day and slowly increasing to unrestricted access over 7-10 days. Strip
grazing with an electric fence can be used to restrict grazing during the adjustment
period, while also encouraging uniform utilization and reducing trampling.

Strip Grazing is also recommended after the animals have adjusted to the Brassicas to
insure efficient use of the plants. If the Brassica is designed for multiple grazing, be sure
to remove the animals from them so as not to damage the regrowth portion of the plants.

Due to the low fiber content of Brassicas, it is recommended to provide additional
roughage. During adjustment periods, it is best to offer additional roughage prior to the
grazing of Brassicas to reduce the likelihood of problems associated with overeating.

When estimating the nutrient availability in Brassica crops, their high nutritional value
must be considered
o 1.22-1.52 MegaCalories Metabolizable Energy/lb Dry Matter
o 15-25% protein in leaves, 9-16% in turnips and swede bulbs

Reported livestock weight gains while grazing Brassicas
o 0.33-0.55 lb/head/day for lambs
o 1.76-2.64 lb/d for growing cattle
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Associated Animal Health Problems and their Treatments/Preventions

Brassica Poisoning
o Glucosinolates and sulfur-containing amino acids in Brassicacae plants can cause
signs of poisoning ranging from goiter, hyperthyroidism, blindness, diarrhea, redcolored urine, hemolytic anemia and pulmonary emphysema
o These compounds are found in highest concentration in young plants and in the
seeds
o Rehydrating severely affected animals with large volumes of oral fluids and
providing a good quality grass/alfalfa hay is beneficial in treating animals with
Brassica poisoning
o Most health problems associated with Brassicas can be prevented by grazing
plants at their maturity and allowing proper adjustment periods when transitioning
into Brassica crops. In addition, waiting to graze until after a hard freeze can
markedly reduce the risk of acute pulmonary emphysema.

Choking
o Although rare, it is possible for a cow to choke on a turnip bulb. One can reduce
choking by using slightly lighter sowing rates so the bulbs can grow larger and
aren’t as likely to be swallowed whole.
The following sources were used in developing this fact sheet.
Ayres, L. and B. Clements. 2002. Forage brassicas – quality crops for livestock production.
Agfacts NSW Agriculture, The State of New South Wales.
Knight, A.P. and R.G. Walter. 2003. Plants affecting the blood: a guide to plant poisoning of
animals in North America. Teton NewMedia, Jackson, WY.
For more Brassica information go to the Organic Dairy Initiative Website:
http://www.organic.cornell.edu/cals/cuaes/organic/projects/dairy/dairy-initiative/index.cfm
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2
Cornell Cooperative Extension-Cortland County Small Dairy Extension Support Specialist
Grad-Student Cornell University Animal Science
This project was funded by: “Towards Sustainable Farming Foundation,” And
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