The effect of nesting material on the nest-building and maternal behavior of domestic sows and piglet production.

Nest building is an important part of maternal behavior in domestic pigs. The aim of the study was to assess the effect of nesting material sawdust vs. straw on sow behavior 24 h before and after birth of the first piglet (BFP) and piglet production. Sows, housed in farrowing crates, were randomly divided into 2 treatments: sawdust (n = 12) and straw (n = 13). Sawdust and straw were provided during the pre- and parturient period; after parturition, straw was given to both experimental groups. The prepartum nesting period (the time interval between the first and last nest-building records, including all other activity and resting before BFP), the nesting records (number of nesting records), nesting duration (duration of all nesting records), the start and termination of nesting, and the frequency of prepartum postural changes were collected 24 h before BFP. After BFP, number of nesting records and time to first sucking of the litter were collected. Frequency of postural changes and duration of udder access were collected 24 h after BFP during 3 time periods (during parturition, from the end of parturition to 12 h after BFP, and 12 to 24 h after BFP) and the frequency of nursing during 2 time periods (from the end of parturition to 12 h after BFP, and 12 to 24 h after BFP). Piglet BW gain and mortality were estimated 24 h after BFP. Data were analyzed using PROC MIXED and the probability of the piglet mortality using PROC GENMOD in SAS. Nesting material did not affect (P > 0.10) most of sow prepartum nesting behavior and had no effect (P > 0.10) on the prepartum frequency of postural changes. Sows from the sawdust treatment had a longer nesting period (P < 0.05), and nest building tended to start sooner (P < 0.10) than in the straw treatment. Nesting material had only a small effect on later maternal behavior. Sows from the straw treatment tended to have more nesting records after BFP (P < 0.10). The frequency of postural changes was affected by the interaction (P < 0.01) between treatments and time period: sow from the straw treatment had more postural changes during parturition compared with other time periods and sawdust treatment. No effect (P > 0.10) of the nesting material on piglet BW gain and mortality was found. The results suggest that sawdust compared with straw as nesting material provided to sows before and through parturition does not negatively affect maternal behavior during the 24 h before and after parturition or piglet production. Therefore, sawdust can be recommended as a suitable nesting material for farrowing sows when straw is not available.

Preweaning housing effects on behavior and physiological measures in pigs during the suckling and fattening periods.

The effect of the preweaning housing system on the stress response of pigs before weaning and during fattening was studied in 33 litters of domestic pigs. Three preweaning housing systems were compared: barren crate (standard farrowing crate without straw), enriched crate (20% larger crate, with straw), and as a control, a farrowing pen (pen, 60% larger than the barren crate, with straw). At 25 d of age, pigs were tested with an isolation test and 1 d later with a human approach test (HumanT). Pigs were weaned at 28 d of age. At 3 and 6 mo of age, pigs were tested with an isolation-human approach test. The latency and frequency of squeal calls and locomotor activity were analyzed for all 3 tests, whereas physical contact with the human was also analyzed for the HumanT and isolation-human approach test. At 6 mo of age, the pigs were transported to a slaughterhouse. One day before transport, immediately after transport, and 1 h after transport, saliva samples were taken for cortisol analysis. The pH of the LM was also measured 45 min after slaughter. Preweaning housing system affected (P < 0.05) the probability of squeal vocalizations, the latency of locomotion, and the duration of locomotion during the HumanT. Pigs from the enriched pens vocalized less, had a longer latency to move, and performed less overall locomotion than pigs from the barren crates. Preweaning housing system did not affect behavior of fattening pigs. Cortisol concentrations before and after transport were not affected by preweaning housing system. An interaction of cortisol concentrations and housing systems was observed between the control sample and the sample taken immediately after transport in pigs from the barren crates (P < 0.05) compared with pigs from the enriched housing systems. Meat from pigs reared in the barren crate tended to have lower pH (P < 0.10) and that of pigs reared in enriched crates had lower pH (P < 0.05) than meat of pigs reared in enriched pens. No differences were observed between pigs from barren or enriched crates. Our results suggest that enrichment of the preweaning environment through enlarged space, provision of straw, and free movement for the sow had a positive effect on the coping behavior of pigs before weaning and prevented an increase in salivary cortisol concentration immediately after transport and a decrease in meat pH 45 min postmortem at the age of 6 mo. Minimal enrichment of the commercial farrowing crate did not affect behavior and physiological measures in pigs before and after weaning.