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Mold and yeast consume feed nutrients and impact livestock performance by inhibiting rumen function, producing mycotoxins, and reducing aerobic stability.

Did You Know?

Mold_plot_vertical

30% of samples tested contain less than:

  • 1,000 cfu/g of mold
  • 10,000 cfu/g of yeast
Mold_plot_vertical

For example, fusarium mold grows prolifically at 75-85°F without producing much mycotoxins, but when temperatures approach freezing, they produce large quantities of mycotoxin with minimal mold growth. (Joffe, 1986)

To measure mycotoxin risk, analyze for mycotoxins directly. Visit Dairyland's Mycotoxin Page for more testing solutions and interpretations.

Mold_plot_vertical

30% of samples tested contain more than:

  • 60,000 cfu/g of mold
  • 900,000 cfu/g of yeast

Clean feeds do not contain detectable levels of mold and yeast

More mold does not equal more toxins

Mold and yeast grow exponentially

Mold species:

  • Have predictable color

  • Produce specific mycotoxins

  • Grow in specific conditions

Interpretation PDF

Mold species

Color

Toxin

Conditions favoring production

Aspergillus

Yellow-green

Aflatoxin
Ochratoxin
Citrinin

Heat and drought stress pre-harvest. Heat and humidity post harvest.

Fusarium

White to pinkish-white

Zearalenone
T-2/HT-2
Vomitoxin(DON)
Fumonisin
Fusaric acid

Associated with ear and stalk rot in corn, head scab in small grains, red ear rot, pink ear rot.

Penicillium

Green to green-blue

Ochratoxin

Cool, wet, and low pH (acid tolerant) post harvest.

Cladosporium

Dark blue-green to gray or black, white

None

Early frost, neutral pH, high grain moisture (30-40%), temperatures at 75-125°F. Commonly invades corn after premature frost.

Mucor

Grey-white

None

Grows at low temperatures, typically in storage.

Rhizopus

Grey-white

None

High moisture and advanced decay.

Mold Count Interpretation

cfu/g

Under 500,000

500,000 - 1 million

1 to 2 million

2 to 3 million

3 to 5 million

Over 5 million

Feeding risk and cautions

Relatively low count

Relatively safe

Discount energy (x .95). Feed with caution.

Closely observe animals and performance. Discount energy (x .95)

Dilute with other feeds. Discount energy (x .95). Observe closely.

Discontinue feeding

a Risks refer primarily to effects of mold per se without regard to possible mycotoxin content. Depressed digestibility, feed intake, and performance may occur from a high mold content without mycotoxins present. Harmful mycotoxins may be present, even when there is little or no obvious mold content.

b Mold spore counts may sometimes underestimate the degree of mold present, especially in feeds that have been ensiled for some weeks. Observe and record relative amounts of mold present.

References  +
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Mycotoxins

Learn more about mycotoxin packages and interpretation

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Dairy & Beef Nutrition

Learn about our services for dairy and beef cattle

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Equine, Small Ruminants, & Other Species

Learn about our services for other species

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