Effect of Pelleting on Energy Intake of Sheep from Forages Cut at Three Stages of Maturity

Abstract

Pelleting decreased energy digestibility of energy intake (Kcal./WKg.0.75) by wether lambs for all forages at all stages of maturity, with the effects of pelleting becoming more marked with successive growth stages. Percent increases for pelleted early, medium and late cuts were: orchardgrass: 21, 48, 64; timothy: 24, 32, 94; alfalfa: 9, 36, 114. With pelleted forages, the decreases in digestible energy intake associated with advancing maturity were due chiefly to decreases in energy digestibility because stage of maturity had little or no effect on gross energy intakes. Conversely, both energy digestibility and intake affected the decrease in digestible energy intake as maturity advanced with the chopped forages. Pelleting decreased energy digestibility of early, medium and late cuts by 9, 7, and 11% for orchardgrass; 9, 11 and 8% for timothy; and 0, 9 and — 1% for alfalfa. Pelleting had a variable effect on fiber digestibility of the alfalfa but consistently depressed fiber digestibility for the grasses at all stages of maturity by an average of 16.3%. Stage of maturity had no consistent effect on the changes in digestibility due to pelleting. All forage cuts were hammermilled through a ⅛ in. screen. Nevertheless, mechanical analysis with U. S. Standard sieves showed hammermill screen size was not a reliable description of particle size distribution. With advancing maturity, particle size of the ground orchardgrass and timothy tended to increase.