The Cow-Calf Manager

Livestock Update, June 2004

John B. Hall, Extension Animal Scientist, Beef, VA

Management of Cow Nutrition Begins in the Hay Field
So far Virginia beef producers have had a good spring. Some places are a little dry, but overall the grass is growing well. Warm May weather has caused hay to mature ahead of most years. First cutting hay is being made. As producers struggle to get hay made between showers or in competition with other enterprises on or off the farm, it's hard to focus on the great importance of making good quality hay. Too often producers focus on getting the hay up without exposure to rain instead of timely cutting. When hay is cut may have greater impact on cow nutrition than whether it was rained on or not.

Maturity of hay at harvest impacts cow nutrition
Producers know that quality goes down as hay matures, but they also know that yield goes up with hay maturity. In striving for ³more is better², producers often end up with a lot of hay that has very little feed value. Normally, 1st cutting hay harvested by late May-early June (eastern VA) or early-mid May (western VA) produces acceptable quality (See chart for hay from 1998-2002). Last year was a classic example, producers kept waiting for dry days to come, but hay quality continued to deteriorate as the grass continued to mature. Hay harvested earlier was often rained on, resulting in slightly lower protein content and lower energy content (TDN) than previous years. Still earlier harvested hays had better quality then late cut hay even though early cut hays were rain damaged.

Producers are encouraged to harvest first cutting hay based on the following guidelines:

• Alfalfa: bud to 1/10 bloom.
• Red clover: 1/4 to 1/2 bloom.
• Timothy: late boot.
• Tall fescue: boot stage.
• Orchardgrass: blooms emerged.

So how does maturity at cutting influence the ability of the hay to meet the nutritional needs of beef cattle? First, there is a rapid decline in nutrient content of hay between the boot stage and heading (Table 2 & 3). However, the optimum compromise between nutrient content and yield occurs in the late boot to early heading stage of most forages. Nutrient content of the hay is terrible if seeds have formed before it is cut.

Lactating beef cows need a diet that is 10.5% crude protein and 59% TDN while late pregnant cows need 8.7% crude protein and 55% TDN. Dry cows without a calf only need 7% crude protein and 48% TDN. In Virginia, cool season hay crops such as fescue and orchardgrass will provide enough protein to meet the needs of lactating cows until full bloom (Table 2.). Add a little clover to the mix and protein is generally NOT a problem in Virginia hays. In contrast, the energy content of most grass hays falls below cow requirements after the late boot stage (Table 3). First cutting hay that is harvested after heading is only good for dry cows. Energy is the nutrient lacking in most Virginia hays.

Table 2. Protein content of Orchardgrass or Red Clover hay as influenced by maturity

	Vegetative	Boot	Heading	Full Bloom	Seeding
Forage	% Crude Protein (Dry Matter basis)
Orchardgrass	33	17	10	7.8	6
Red Clover	29	20	19	14	13

Table 3. Energy content of Orchardgrass or Red Clover hay as influenced by maturity

	Vegetative	Boot	Heading	Full Bloom	Seeding
Forage	% Total Digestible Nutrients/Energy (Dry Matter basis)
Orchardgrass	65	58	52	50	44
Red Clover	67	59	55	52	42

Producers should strive to harvest 1st cutting hay in the early heading stage. Hay harvested at this stage should meet the nutrient requirements for late pregnant cows. Second cutting hay should be used to feed lactating cows. The date of 1st cutting will be highly dependant on the type of spring weather. In Virginia, hay crops are 1 to 2 weeks ahead of normal this year.

Rain and bale wrapping
More producers are turning to wrapping bales for round bale silage to avoid rain damaged hay or delays in harvest. Rain damage leaches the soluble carbohydrates and proteins from the hay. Heavy rains can reduce quality similar to an increase in maturity of 7 to 10 days. Prolonged rains result in yield losses due to decomposition of finer leaves. Alfalfa and high percentage legume hays are much more susceptible to rain damage compared to grass hays. Legumes suffer much greater leaf loss during rain damage and subsequent re-raking.

Round bale silage is an excellent way to preserve nutrient content of forages, but it must be done correctly. First, hay should be harvested in the boot stage. This maximizes soluble carbohydrates, which are important to proper fermentation, while maintaining yield. Wrapping hay MAINTAINS nutrient content, it does not improve it. So, round bale silage made out of over mature forage is simply junk in a pretty package. Secondly, the forage should be 55 to 65% moisture after wilting. Therefore on dry sunny days, bales need to be made only a few hours after cutting; whereas, on cloudy days with heavy dew it may need to wilt overnight. Finally, bales should be wrapped within a few hours of baling. Producers need to take into account the time needed to transport bales to the wrapper and wrap them. When these high moisture bales sit too long before wrapping they heat causing damage to the proteins in the hay.

Several universities have good publications on making round bale silage. The University of Kentucky publication is available at http://www.ca.uky.edu/agc/pubs/agr/agr173/agr173.htm

The also have a video you can purchase.

Getting 1st cutting hay up correctly will greatly reduce your feed costs next year. Don't forget to test your hays for nutrient content. Your Animal Science Extension agent or nutritionist can help you evaluate your forage test results.

Visit Virginia Cooperative Extension