Straw or hay as environmental improvement and its effect on behaviour and production traits of fattening pigs

Abstract. Fattening pigs are commonly kept in intensive housing systems with slatted floor which represent a very barren environment, causing poor animal welfare. To improve such conditions a small amount of straw or hay (100 g per animal per day laid daily in a rack) was used in our study as an environmental enrichment (EE). Two replications, each including 96 fattening pigs of both sexes (3 pens of 16 females and 3 pens of 16 male castrates) from 60 kg to slaughter at average 96 kg live weight, were used to test the effect of EE and sex on behaviour, growth rate, and carcass composition. EE significantly increased the proportion of total activity during the illumination period (between 6 a. m. and 2 p. m.) on account of increased occupation with substrate (P<0.01). EE also significantly reduced time spent biting pen bars and frequency of aggressive encounters (P<0.01). The EE increased total activity in female animals during the observation period, but not in male castrates. None of the EE significantly influenced pigs‘ growth rate and lean meat percentage; however females in enriched environment grew slower and had greater lean meat percentage than the castrated males. Provision of a small amount of straw or hay to pigs in intensive housing systems can enrich barren environment in inexpensive and efficient way. Therefore such enrichment can be widely used also in large commercial pig production systems.