Forage Focus: May Showers Brings June Hay20 June 2013
US - This spring much of the southeast has received adequate precipitation which is evident in the drought monitor map for the end of May, writes Dr. Jeff Lehmkuhler, Beef Extension Specialist, University of Kentucky.
Pasture and hay fields in the upper southeast have been thriving under these conditions. However, these same conditions have delayed field work and in particular hay harvest.
Our cool-season grass fields have passed their prime in regards to quality yield. The optimal harvest time is late boot stage to early flowering for the balance between yield and quality. Much of the grass is approaching dough stage in which the seeds are developing and soon the plant will be at full maturity.
The quality decline is rapid from flowering to maturity. It has been stated that the crude protein content of the entire plant may decline as much as 0.5 per cent each day from boot to mature seed stage. As the plant matures, it becomes less digestible limiting energy availability to support production. Can digestibility be improved once the forage is in the bale?
Research from Missouri with Kentucky-31 tall fescue following seed production revealed crude protein values of less than 8 per cent in the forage and acid detergent and neutral detergent fiber values of 47 per cent and 69 per cent , respectively. This aftermath did not provide enough energy to maintain the body weight of growing steers leading to a loss of weight over the 56-day feeding trial.
Ammoniating the fescue hay at a rate of 3 lbs of ammonia per 100 lbs of hay doubled the crude protein content and increased animal performance to 0.4 lbs per day compared to a loss of 0.15 lbs per day for the non-ammoniated fescue.
Ammoniation of low quality forages such as straw has been shown to improve forage digestibility by 8-15 per cent while little improvement is seen in higher quality forages. The greatest responses to ammoniation in tall fescue are expected to occur for mature tall fescue.
Ammoniating forages requires great caution and should only be conducted after the appropriate safety measures have been implemented. Sealing the plastic is critical and the plastic must remain intact.
What does this late cut hay mean for the cow herd? This question is one that doesn't come up too often because hay is hay, right? We can go through various ways to put a value on hay or feedstuff using common reference feeds.
What about setting a goal for a hay crop and then paying a premium or discounting the hay value based on how much the hay misses the target? If one were to set a TDN value of 55 per cent for their cow hay, this would mean that for each ton of hay produced or purchased there would be 1,100 lbs of TDN.
If the weather delayed cutting or one was too busy with other things and the hay crop was cut later resulting in the hay testing only 48 per cent , we can agree that it is of lower quality and the hay would have 960 lbs of TDN per ton.
What is the value difference? Using the lowest cost energy supplement, one could value the hay based on this comparative energy difference. If corn gluten feed was the reference feed and it cost $240/ton, the cost per pound of TDN from corn gluten feed having 80 per cent TDN is calculated to be $0.15.
The difference between the two hay qualities is 1,100-960 lbs of TDN = 140 lbs of TDN. Making up the difference using corn gluten feed would cost $21 per ton of hay on a dry matter basis or about $18 on an as-fed basis. If round bales weigh in at 1,000 lbs, then the discount for the late cut hay would be about $9/roll.
Granted this is an over simplified approach, but it suffices to drive home the point that hay is not harvested equally. Hopefully, this is something to chew on as you make laps around the hay field and begin counting the number of bales per acre you got. Another thing to ponder, consider how much additional supplement will be needed per bale. May you get your hay up before the rain!
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