The nutritive value of separated milk for pigs. I. A comparison of two diets containing separated milk with a standard all-meal diet

Abstract

One hundred and forty-four Large White weaner pigs were used in each of two experiments to investigate the nutritive value of liquid separated milk. Two experimental diets, one based on separated milk and barley meal, the other on separated milk, soya bean meal and barley meal were compared with control meals of the type used in the Pig Industry Development Authority's progeny testing stations. The amounts of milk in the experimental diets were adjusted so that the lysine concentrations in the dietary dry matter were similar to those of the control meals. All diets were given according to a restricted scale relating daily dry matter allowance to live weight, to a scale relating digestible energy allowance to live weight and to ‘appetite’. In the first experiment, pigs were slaughtered at 200 lb live weight, in the second at 260 lb live weight. Pigs given the separated milk and barley meal diet performed similarly to those given the control meals; those given the separated milk, soya bean meal and barley meal diet had better feed conversion efficiencies than control pigs, particularly over the range 200 to 260 lb live weight. Pigs given diets containing milk had higher killing-out percentages and shorter carcasses than those given the control meals. Diet had no statistically significant effect on the percentages of fat and lean in the sides. The effects of plane of nutrition were demonstrated by the faster rate of gain and poorer carcass quality of pigs fed to ‘appetite’. It was concluded that the nutritive value of separated milk is explained by its high energy and lysine content. There was no evidence of any unknown beneficial factor in it.