Abstract :
The litter used in the deep litter of uninsulated buildings in beef production is expensive. Different litter materials and their mixes have different characteristics. It was determined that the optimum mix of straw, peat and wood chips would reduce litter consumption and still meet the animalsʹ requirements for a thermal environment in a bench-scale study simulating the deep litter in a partially littered pen. However, this appeared to be impossible. The size of the test vessels was 60 cm by 60 cm. There were five different combinations of litter mix of straw, peat and wood chips involved in the trials. The simulation was based on the assumption that the space allowance per suckler cow in the pen was 3·5 m2on deep litter and 4·0 m2on the dung alley and manure (27·5 kg day-1) was deposited evenly in the pen. The temperatures at three heights were measured and the highest and the average temperatures as well as the temperature profiles of the deep litter were determined. Changes in the nutrient, carbon, moisture contents, losses and mass were measured. The difference in physical structure between the five litter mixes tested did not cause any difference in the composting processes of the mixes. The difference in the chemical composition of the mixes did, however, cause a difference. The deep litter consisting of mixes with a high proportion of straw reached a high composting temperature because the straw contained more organic carbon than did the other components. The input of organic carbon into deep litter should be at least 800 g m-2day which is about 8·8-10·2 kg of litter per day and per suckler cow in an optimized partially littered pen. Hence, rather than reducing the litter consumption of deep litter, it should be increased.
