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Kenaf for grazing David G. St. Louis*, Animal Scientist; Carl H. Hovermale,
Agronomist; Background Cattle production is one of the most widespread agricultural enterprises in Mississippi. In 1998, there were 1.3 million cattle and calves in Mississippi. Growing of forage is a major undertaking for cattle producers. Winter pastures consist of high quality annual grasses such as ryegrass or legumes. Summer pastures, mostly bermudagrass and bahiagrass, have moderately high quality during the early summer months. Then, starting in August, growth rates and quality both decline due to longer day length and drought. Later in the season cooler weather causes growth to slow and finally stop. A forage deficit normally lasts from mid September until winter annuals are ready to graze in early December. Kenaf is a forage being considered to fill this gap. Until recently most kenaf research in Mississippi was concerned with cultural practices for fiber production. Research began in 1998 to investigate the feasibility of kenaf for grazing of summer stocker cattle and to determine how late in the season kenaf can be grazed. Research Findings Animals grazing kenaf did not gain as well as those on summer grasses with or without supplementation. However, kenaf was able to provide quality grazing until the end of November. This resulted in less supplementation with hay and grain after summer perennial pasture was gone; a distinct economic advantage for retained ownership past weaning. The average daily gain of animals grazing kenaf was 1.05 lb per day and the average daily gain of animals grazing bahia/bermudagrass with and without supplementation was 1.6 and 1.3 lb per day, respectively. Laboratory analysis for nutrient quality of grazed kenaf was superior to that of normal mixed summer perennial pastures. Kenaf grazing began later than summer perennial grazing. Materials and Methods Tainung 1 kenaf was planted April 23,1998, on 13.5 acres for
rotational grazing in 4 paddocks. Grazing of kenaf began on June
24, 1998 when it reached an approximate height of 40 inches.
Grazing of mixed perennial pasture (bahiagrass and bermudagrass)
began on May 15, 1998 when grass height reached 4". Both
types of pasture were fertilized in April at a rate of 68-60-60
lb/ac of N-P-K, respectively, and again in June with 68-0-0 lb/ac.
Kenaf was grazed at a variable stocking rate. Initial stocking
rate was 1240 lb live weight per acre, with a stock density of
4961 lb/A in the first paddock. Midway through the first rotation
(3rd and 4th paddocks, 19 days from the beginning) stocking rate
was increased to 1900 lb/A (stock density of 7599 lb/ac or 43
animals per paddock) and remained through the first half (1st
and 2nd paddocks of the second rotation. On July 29 (35 days
from the beginning) stocking rate was reduced to 1294 lb/A (5177
lb/ac stock density with 17 head). Stocking rate was reduced
again on 8/12 to 905 lb/A (18 head)and again on 8/24 to 529 lb/A
(10 head of tester animals weighing 714 lb/head). Grazing continued
with these animals until they were taken off pasture on 11/24/98.
Put and Take animals were weighed on and off the paddocks and
were used in the calculations for ADG, Animal Grazing Days and
gains per acre for kenaf. Applications We are inexperienced with grazing kenaf but it has shown potential as a forage. Using the knowledge that we have obtained from this experiment to build on we can devise more efficient grazing protocols. The advantage of kenaf is that we were able to get quality grazing until the end of November. This translates into less supplementation with hay and grain after grazing. This is a great economic advantage for raising animals such as replacement heifers that are kept and not sold after grazing. This may be an economical way to maintain brood cows.  Figure 1. Kenaf and perennial pasture with and without supplement, McNeill, MS, 1998. |