Genetic selection over the last few decades has resulted in pigs with better feed conversion and leaner carcasses, but it has also led to pigs with a decreased ingestion capacity. This means that appetite has become a challenge to overcome, above all in certain phases of the productive cycle, such as the growth-finishing phase. Voluntary feed intake in pigs is influenced by several factors including environmental conditions (e.g. thermal and social conditions), animal status (e.g., age and physiological status), and feed and feeding conditions (e.g. bulkiness of the feed and feed form).Age.
Nursery pigs take longer than older pigs to eat a set amount – about 10% slower. Feed type. Pellets are eaten faster than meal Hard/brittle pellets and the opposite, dusty feed of any sort, are eaten at least 33% slower and sometimes not at all. Fats unless carefully chosen and kept from going stale/rancid can improve appetite when fresh, but very much the opposite when not.
Taste and smell. For example, pigs are good at detecting mycotoxin presence and rancid fat and will ‘mess-about’ with suspect feed. Some drugs are unpalatable. Ventilation. A low level of ventilation leads to an accumulation of toxic gasses (CO2, SH4, CH4 o NH3) and dust, reducing feed intake. On the other hand, high ventilation levels increase consumption in thermal stress conditions. Wet/partly fermented feed will be eaten, when fresh, very much quicker than ad-lib or limit-fed pellets.
CWF adherents have to be careful that less dominant pigs get their share, which has stimulated such users to explore special formulae for ad-lib wet feeding. Troughs: number and lineal spacing. As the number of troughs increases, so does the feed intake of pigs that are housed in large groups.
Therefore, the reduction of lineal trough space per pig diminishes consumption, though there is no noted interaction between the trough space and the size of the group. Gender of females present a better level of consumption than the males, although these males consume 13% less than castrated males when they are fed ad limitum. This situation, the heavier they are, causes decreased conversion.