Source: Oklahoma Cooperative Extension Agency | May 27, 2019
Understanding wet hay
by Glenn Selk, Oklahoma State University Emeritus Extension animal scientist
Frequent spring rains in Oklahoma have allowed cool season forages to grow in abundance. Even when the fields and meadows dry enough to cut standing forages, harvesting and baling cool season crops such as fescue and wheat hay can be a challenge during a wet spring. The timing of the rains can make it difficult for cattlemen that are trying hard to put quality hay in the bale for next winter’s feed supply. All producers that harvest hay occasionally will put up hay that gets wet from time to time. Therefore, ranchers and hay farmers need to understand the impact of wet hay in the tightly wound bales.
Extra moisture in hay can cause heat inside the hay bale or hay stack. Heat produced by the bale comes from two sources: First) biochemical reactions from plants themselves as hay cures. (This heating is minor and rarely causes the hay temperature to exceed 110 degrees F. Very little if any damage occurs if the hay never exceeds 110 F.); Second) Most heat in hay is caused by the metabolic activity of microorganisms. They exist in all hay and thrive when extra moisture is abundant.
When the activity of these microbes increases, hay temperature rises. Hay with a little extra moisture may not exceed 120 degrees F., whereas, wetter hay can quickly exceed 150 degrees. If the hay rises above 170 degrees, chemical reactions can begin to occur that produce enough heat to quickly raise the temperature above 400 degrees and the wet hay can begin to burn and cause fires. Be wary of the fire danger of wet hay and store it away from buildings and other “good” hay just in case this would occur.
Below is a table with moisture guidelines at time of baling. (Adapted from “Preventing hay fires” Martinson, University of Minnesota)
| Moisture ranges (%) | Comments |
| Less than 10 | Too dry. Hay may be brittle and dusty |
| 10 – 15 | Recommended moisture range. Minimal risk of fire |
| 16 – 20 | Could mold. Slight risk of fire hazard |
| 21 -25 | Will likely mold. Moderate risk of fire hazard |
| Greater than 25 | Severe heat damage likely. High risk of fire hazard |
Several commercially produced hay temperature probes are available. Also, homemade probes can be constructed and will help monitor the heating in the hay bales. Information from the University of Kentucky (Overhults) discusses both commercial and homemade probes. Go the website: https://uknowledge.uky.edu/cgi/viewcontent.cgi?article=1115&context=ky_alfalfa
Heat damage causes hay to be less digestible, especially the protein. Heat damaged hay often turns a brownish color and has a caramel odor. Cattle often readily eat this hay, but because of the heat damage, its nutritional value might be quite low. Some ranchers have reported that “the cows ate the hay like there was no tomorrow, but they did very poorly on the hay”.
Testing wet hay may be very important. Determining the internal temperature of large bales or stacks of hay should be done carefully. Make certain that checking the temperature in suspicious hay is done safely. Read the E-Extension Fact Sheet “Preventing Fires in Baled Hay and Straw” (http://www.extension.org/pages/66577/preventing-fires-in-baled-hay-and-straw#.VV-WALco7L8).
Testing the protein and energy content of stored wet hay will allow for more appropriate supplementation next winter when that hay is fed. Moldy hay could be a source of mycotoxins that could present several health problems for cattle. Many animal disease diagnostic laboratories can examine feedstuffs for mycotoxins or can recommend laboratories that do such testing.
Tough week in Oklahoma; Cattle on Feed
by Derrell S. Peel, Oklahoma State University Extension livestock marketing specialist
May is the season of severe storms in Oklahoma. The week leading up to Memorial Day included numerous severe storms and several tornadoes in the state with lots of damage and, most regrettably, several injuries and fatalities. A bit more unusual this year is the persistent pattern of wet weather.
According to the Mesonet, the year so far through May 26 is the fourth wettest year on record in the state with the last thirty days the second wettest for the period. Regionally, the north central and northeast regions of the state are experiencing the wettest 30-day rain totals with the second wettest 30 day totals in the west central and central regions. Several areas have experienced double-digit rain totals in the past week bringing 30-day rain totals to more than 330 percent of normal.
Widespread flooding is impacting numerous locations around the state. The Arkansas and Cimarron river drainages are particularly hard hit with water levels still rising and more rain expected this week. Keystone Lake, into which the Arkansas and Cimarron rivers flow, is currently reported at 33.53 feet above normal with the flood control pool 112 percent of full. Keystone dam is releasing 275 thousand cubic feet per second of water as flood conditions inevitably move down the Arkansas River. The Arkansas River at Tulsa, just below Keystone Dam, is projected to crest this week at about 23 feet, well above flood stage of 18 feet, and just below the record level of 25.2 feet in 1986.
Commercial navigation on the McClellan-Kerr Arkansas River Navigation System (MKARNS) is being disrupted due to high waters. MKARNS provides inland ports that connect directly to the Mississippi river as far inland as the Port of Catoosa, near Tulsa, Oklahoma. The MKARNS is an important transportation artery for agriculture in a multi-state region, providing a market for grain shipments downstream and the arrival of inputs such as fertilizer.
The May Cattle on Feed report showed April feedlot inventories of 11.8 million, 102.2 percent of last year and the largest May 1 total in the current data series since 1996. April feedlot placements were up 8.7 percent year over year, at the low end of pre-report expectations. Feedlot marketings in April were 6.9 percent higher year over year, equal to expectations. April 2019 had one more business day compared to last year, accounting for some of the year over year increase in marketings and placements.
Cow-Calf Corner is a weekly newsletter by the Oklahoma Cooperative Extension Agency.