The efficiency of utilization of forage oats in relation to the quantity initially available

Abstract

Two experiments on the efficiency of utilization of oats by Merino sheep are reported. In the first experiment eight plots with a range from 2730 to 4850 kg dry matter per ha were stocked at c. one sheep per 40 kg of forage. In the second, five plots with approximately equal quantities of forage oats were stocked at c. one sheep per 18, 29, 38, 44, and 50 kg of forage. The data were analysed by regression, ordination, and canonical analysis. Over the range of availabilities examined in experiment I there was no indication that increased dry matter availability reduced the efficiency of utilization. In experiment II, however, increased grazing pressure was associated with an increase in the total liveweight gain and metabolizable energy harvested from a constant quantity of forage; this implied lower efficiency at the lower stocking pressures. The higher digestibility of the forage on some plots in the first experiment was associated with an increased rate of dry matter intake and a reduction in wastage; this effect appeared to be independent of the original planned comparison. It was concluded that within the range of availability studied, forage digestibility and stocking pressure were probably more important determinants of the efficiency of utilization of oats than was the quantity of forage available.

The influence of sward characteristics on the herbage intake of grazing calves

“…Although the influence of the digestibility of the diet was dominant, variations in the weight and green/dead ratio of the herbage and in sward structure also had significant effects on herbage intake in Expt 2 (equations 3-5). Similar sets of variables have been shown to influence the herbage intake of grazing sheep (Arnold & Dudzinski, 1967 o, 6;Allden & Whittaker, 1970;Hedges, Wheeler & Williams, 1973). Arnold & Dudzinski (1967a, 6) found that the influence of variations in the weight and height of the sward on intake was considerably greater than in Expts 1 and 2, probably because in their experiments the range of values for each variable was lower.…”