Determination of the milk yield of sows and correction for loss of weight due to metabolic processes of piglets during suckling

SUMMARYIn determining the milk yield of the sow by weighing the litter before and after suckling, loss of weight due to metabolic processes must be considered.An experiment is described to investigate the loss of weight of piglets caused by metabolic processes between two consecutive weighings, and to investigate the relationship between this loss on the one hand and the body weight and the age of the piglets on the other. Weight changes of 15 litters of average 9·8 piglets were studied during 66 weighing periods of 16 minutes, by putting the pigs in a cage, fixed on a differential balance. Each weighing period consisted of 8 periods of 2 minutes, so that in all, loss of weight was studied during 528 2-minute periods.</jats:p

The quantitative effects of feed restriction in fattening pigs on weight gain, efficiency of feed utilisation and backfat thickness

From the published data summarised in Table 1, it was calculated that, at an average degree of feed restriction of 15·8 %, daily weight gain decreased by 12·50% (or 0·78% for each 1% restriction), feed conversion efficiency improved by 3·96% (or 0·31% for each 1% restriction) and backfat thickness diminished by 7·63% (or 0·53% for each 1% restriction).Equations were calculated to show the degree to which daily weight gain, feed conversion efficiency and backfat thickness change with increasing feed restriction (Figures 1, 2 and 3).As the degree of feed restriction increases, the decrease in daily weight gain becomes relatively greater and the decrease in backfat thickness relatively smaller. Efficiency of feed utilisation, however, improves at first, but eventually decreases as restriction becomes more severe.It is thought that the equations found can be used, within certain limits, to calculate the average effects of feed restriction for different breeds of pigs, which when fed ad libitum consume 2·7 kg. meal ration (of normal composition) per day and have a growth rate of about 750 g. daily from 30 to 90 kg., and backfat thickness of about 37 mm. when kept under average environmental conditions.</jats:p

ÉTUDE COMPARATIVE DE FARINE ET DE GRANULÉS CONCERNANT LA CONSOMMATION, LE GAIN DE POIDS ET L'EFFICACITÉ ALIMENTAIRE CHEZ DES PORCELETS SOUS LA MÈRE

International audienc

ÉTUDE COMPARATIVE DE FARINE ET DE GRANULÉS CONCERNANT LA CONSOMMATION, LE GAIN DE POIDS ET L'EFFICACITÉ ALIMENTAIRE CHEZ DES PORCELETS SOUS LA MÈRE (1)

International audienc