Digestibility and effect of copra cake on rate of gain, feed efficiency and protein retention of fattening pigs.

Sixteen barrows and 16 gilts of average liveweight 40 kg were fed on diets containing 0, 10, 20 or 30% copra cake. The copra cake replaced an equal weight of soyabean-maize meal in the diet. The rates of gain were 705, 719, 543 and 438 g/day and the ratios of feed per unit of gain were 3.21, 3.11, 3.83 and 4.91 for 0, 10, 20 and 30% copra cake diets respectively. Feed intake was reduced when 20 and 30% levels of copra cake were included in the diet. Reduced consumption, digestibility and possibly poor lysine availability and protein digestibility of copra cake are advanced as the main contributing factors for decreased rate and efficiency of gain when copra cake was incorporated beyond 10%. In a second experiment 18 female pigs weighing between 40 and 60 kg were put into metabolism cages and fed diets containing five to 30% copra cake. The copra cake replaced an equal weight of wheat bran. Faeces and urine were collected and analysed. The digestibility of copra cake was found to be low especially for protein (56.3% for true protein) Protein retention was reduced by high levels of copra cake inclusion. It is concluded that high levels of copra cake reduce performance of fattening pigs due to reduced feed intake and poor protein digestibility. Ten % seems to be the optimum level of inclusion.