[Sows and piglets--nutritional interactions].

Nutrition energy transfer from sows to piglets is unusually intensive in the suckling period. Due to this transfer, the sows increase their relative standard energy metabolism up to four times, that means to the boundary of the long-term sustainable maximum. They cannot cover these large energy outputs by feed intake, therefore they are catabolizing their own body tissues during suckling and lose about 15% of their live weight. Through milk, which is an energy-rich high-fat diet, up to 1.76 MJ/kg and day of energy (in the first week) are transferred to piglets, and/or up to 2.26 MJ/kg0.75 and day of energy (in the second week), which enables them to double their live weight at birth within the first 7 to 10 days. Milk transfer is of behavioral character in the system dam and litter. In a short time, it assumes a form of cyclic, collective synchronized suckling which is repeated more than twenty times a day and consists of several phases. But the piglets are able to feed not only on genuine milk but also from other sources from the second week of life. Then their weaning begins. They enter from the suckling period to a long, several-week period of weaning, in which some of their functional characteristics are changed fluently, others in a cascade manner. Proper, and to all participants adequate development of this transfer is depending on numerous circumstance which need not always be real. One of the reasons is that birth is such a large load for piglets that they cannot be competitive partners to their less loaded mates in the competition for sources of nutrition. Their participation in the unusually intensive, episodic, delicate transfer of nutrients conditioned by many factors is insufficient, full of failures. Hence they do not sufficiently utilize their growth potential, and do not often survive. Nevertheless, they are so functionally adaptable so that they can live without mothers, in isolation, being able to drink a liquid diet.