• Topics: Dairy and Poultry Sciences  |  Forage Testing  | Dairy Nutrition  | Dairy Forage  |  Animal Sciences  |  Harris, Barney, Jr. 

Pasture Forage for Dairy Cattle¹

Grazing dairy cattle on pasture grasses and legumes is a common practice in many areas of the country. Forages (hay, pasture, and silage) play a vital role in meeting the nutrient requirements of dairy cattle and many dairymen may use all three forms of forages.

The quality of pasture or green chop forage varies considerably throughout the year. This variation in quality becomes exceedingly important where large quantities of forages are fed. The contribution that pasture forages can make in meeting the nutrient requirements for high producers is affected by both the quality and quantity of forage. Care must be taken to avoid overestimating both the quality and quantity of forage intake or underfeeding may result, causing a drop in milk production.

NUTRIENT VALUE OF PASTURE

A laboratory analysis is useful in determining the nutrient value of stored feeds. The use of green forages, however, presents a different problem since quality varies with maturity and some plants mature at a rapid rate. Even so, with good knowledge and an accumulation of data from forages being analyzed, the nutrient content of the forage can be estimated fairly close to the real value. The values in Table 1 are averages accumulated from Florida forages which were tested in laboratories.

The protein content of forages is easily influenced by the level of fertilization. For this reason, one can anticipate some variation in the protein content as compared to the average figures given in the above table.

QUANTITY OF PASTURE CONSUMED

After one has arrived at a realistic figure to place on the quality of the forage, the quantity to be fed becomes the next important step. If the forage is green chopped and fed in a bunk, the amount fed per cow can be calculated. Generally, this can be accomplished by either weighing the wagon, estimating the amount on the wagon, or weighing short sections of the forage placed in the bunk and calculating the amount available per cow. In order to have a good feeding program, the dairyman needs to know the average forage consumed per cow. Too many dairymen ignore this part of their feeding program.

Pasture consumption from grazing may be more difficult to estimate (Table 2). Generally, for high producers receiving grain, consumption will vary from 30 lb to 100 lb per cow per day. The wide variation in consumption is due to pasture quality and the quantity available. Also, season of the year has a great influence on pasture consumption. During the hot summer months, pasture consumption may drop 25 to 40%.

The consumption values in Table 2 may be obtained where cows are allowed to graze for one to two hours per day. Cows will obtain their greatest consumption in the first 30 minutes of grazing; by the end of one hour, they will have a good fill. Cows remaining on winter or summer annual grasses beyond one hour will cause danger to the plants by trampling.

Dairy cows will usually remain on permanent pastures such as bahia, bermuda, and pangola for longer periods.

After establishing an estimated value for the quality and quantity of pasture or green chop being consumed, the formulation may be completed through computer usage or extensive hand calculations.

Tables

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U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Millie Ferrer-Chancy, Interim Dean.

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