Ag Biz News Column
By: Chad Gulley
County Extension Agent–Ag/NR
Producing Quality Hay
Many producers this year have harvested their first cutting of hay. Hopefully with adequate rainfall, additional cuttings of hay are made this year. Is your goal is to produce or purchase high quality hay for your livestock? When producing hay, what determines quality hay?
When evaluating hay for beef cattle many components should be considered. Crude protein (CP), TDN is total digestible nutrients, mineral concentration, palatability, and factors related to storage losses (i.e. bale size, bale shape, bale density, forage species, etc.). Crude protein (CP) and total digestible nutrients (TDN) represent two major nutritional requirements of beef cattle.
It is common to see advertisements for hay for sale as “well fertilized.” What does “well fertilized” truly tell us about hay quality? “Well fertilized hay” tells us very little about hay quality and the hay’s feeding value. To better understand why, let’s consider the effect that nitrogen fertilizer has on hay yield and quality. Assuming other plant nutrients are adequate and that forage maturity is the same, then increasing the amount of nitrogen fertilizer will typically increase forage yields as well as crude protein (CP) concentration in the forage. However, nitrogen fertilizer has very little if any effect on total digestible nutrients (TDN) concentration.
When analyzing hay quality many people focus solely on crude protein (CP) concentration of the hay, but this is not a good idea. Both CP and TDN should be considered when evaluating hay because a high CP content does not always correspond to a high TDN content. Additionally, a high TDN content does not always correspond to a high CP content.
As plants increase in maturity, lignin and fiber concentrations increase and forage digestibility decreases. This results in both a decrease in TDN and CP concentration. To optimize both forage quality and forage yield, it is commonly recommended that forages such as bermudagrass be harvested every 3 to 5 weeks. Other forages such as sudangrass and sorghum/sudangrass hybrids are harvested before mature seed head production.
Another factor that has a major impact on forage quality of warm season grasses is temperature. As temperature increases, lignin deposition in the plant increases which in turn decreases forage digestibility. Lignin is the single most important factor affecting forage digestibility and utilization by ruminants. Remember, as lignin increases forage digestibility decreases. Because of the relationship between temperature and lignin deposition in warm season grasses, hay harvested in the spring and fall will typically be more digestible and have higher TDN that hay harvested during mid-summer.
Cattle dietary requirements for CP and TDN at various stages of production to maintain body condition under typical production conditions are as follows. A 2-year old lactating cow will require an 11% crude protein (CP) and 62% TDN diet. A 3-year old lactating cow or a mature lactating cow producing 25 pounds of milk per day will require an 11.5% crude protein (CP) and 63% TDN diet respectively. A mature lactating cow producing 15 pounds of milk per day will require 10% crude protein (CP) and 60% TDN diet. A mature dry cow, 270 days pregnant will require 8% crude protein (CP) and 55 % TDN diet. A mature dry cow, 180 days pregnant will require 7% crude protein (CP) and 49% TDN diet. (Beef Cattle NRC, 1996)
As you can see, producing or purchasing quality hay is an important management decision of the livestock operation. A forage analysis is important to determine quality and to aid in feeding management of the hay either purchased or raised to maintain your livestock this winter. Information in the above article comes from Dr. Jason Banta, Assistant Professor and Extension Beef Cattle Specialist from the Texas AgriLife Research and Extension Center in Overton, Texas.
On another note, anyone needing a private applicator license to purchase and spray restricted-use or state limited use pesticides on your own farm or ranch should make plans to attend the July 17 Private Applicator Training and Testing. This training and testing will take place in the Texas AgriLife Extension Service meeting room located in room 116 of the Cotton Belt Building in Tyler. Study materials are available for purchase for $40 in advance of the training. The training will begin at 8:00 a.m. on July 17 with the Texas Department of Agriculture representative on hand at the conclusion of the training to administer the exam. A $10 training fee will be charged the day of the training. Calculators may be used for calculations on the exam. Please contact the Texas AgriLife Extension Office at (903) 590-2980 to register and to purchase study materials.
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