Grazing Pressures and Animal Performance from Pearl Millet1

In the Gulf Costal Plain adapted summer annual forages such as pearl millet [Pennisetum typhoides(Burm.) Stapf and C. E. Hubb] are generally higher in energy content than perennial grasses and are capable of producing higher rates of gain. However, practically no data are available which define animal performance at different levels of forage utilization. The lack of definitive data on which to base a grazing program with pearl millet prompted this study which determined liveweight gains of weanling cattle grazing ]pearl millet and evaluated the relationships between gain, forage yield, forage quality, grazing pressure, and profitability. A hybrid pearl millet ‘Millex 23’ was seeded at the rate of 15 kg/ha on Thenas (Fluvaquentic Eutrochrept; coarse, loamy, mixed, thermic) soil and fertilized with 112 kg/ha each of N, P2O5, and K2O in each of 2 years. Weanling crossbred beef calves were used as tester animals and grazed at stocking rates ranging from 3.73 to 11.35 animals/ha. Liveweight average daily gains (ADG) from 0.27 to 1.01 kg were shown to be a non‐linear function of forage availability and a positive linear function of percent in vitro dry matter disappearance (IVDMD) available forage. Percent IVDMD of available forage varied from 36.29 to 63.57% and was inversely related to length of trial. Neutral detergent fiber values for available forage were negatively correlated with ADG (r= −0.84). Maximum profitability, expressed as return per ha, was found at intermediate grazing pressure and was dependent upon the magnitude of positive or negative margin between the time of purchase and the time of selling. Maximum profit occurred at greater grazing pressures as the positive margin between selling and purchase price increased. The most important factor affecting the profitability of grazing pearl millet was the differential between buying and selling price of the cattle. Aside from this factor, which the farmer seldom controls, grazing pressure is the most important determinant of profit. It was concluded that the greatest profit or least loss occurs at medium grazing pressures which, in this study, was approximately 2 kg of available forage per kg of animal liveweight.