title: Provision of straw by a foraging tower -effect on tail biting in weaners and fattening pigs.
abstract: BACKGROUND
  Straw is one of the most effective rooting materials to reduce tail biting in pigs. A so-called foraging-tower (FT) provides only small quantities of straw compatible with liquid manure systems. The focus of the present study was on the effect of providing straw by FT in order to prevent tail biting in tail docked pigs. Four consecutive batches of 160 pigs, randomly divided into a straw (SG) and a control group (CG) were followed up from weaning to slaughter.
  
  
  RESULTS
  Tail wounds (Score ≥ 2) were detected in 104 out of 12,032 single observations (SG n = 48; CGn= 56) in 9 pens (SGn= 4/32; CGn= 5/32) mainly focused on the fattening period of batch 2 due to a failure in the ventilation system. No significant differences concerning the distribution of Score ≥ 2 in pens of the SG and CG could be identified. Bite marks (Score 1) were documented in 395 observations at animal level (SGn= 197, CGn= 198) in all batches. In the nursery period, the air velocity significantly increased the chance that at least one pig per pen and week showed a tail lesion score ≥1 (p= 0.024). In the fattening period ammonia concentration was positively associated with tail lesions (p= 0.007). The investigation of blood samples revealed infections withMycoplasma hyopneumoniaein all batches and a circulation of Porcine Reproductive and Respiratory Syndrome Virus (NA-vaccine strain) and Porcine Circovirus Type 2 in two batches each. The average daily straw consumption was 3.5 g/pig (standard deviation (SD) = 1.1) during the rearing period and 31.9 g/pig (SD = 7.7) during the fattening period.
  
  
  CONCLUSIONS
  Due to the low prevalence of tail biting in all batches the effect of the FT tower could not be evaluated conclusively. The operation of the FT with an average daily straw consumption of 3.5 g/pig (SD = 1.1) during the rearing period and 31.9 g/pig (SD = 7.7) during the fattening period did not affect the weight gain. Exploratory behaviour seems to cause bite marks (score 1), which do not necessarily result in tail biting. The main outbreak of tail biting was probably triggered by a failure of the ventilation system, which resulted in a number of climatic and air quality changes including higher ammonia concentrations and sudden temperature changes.
authors.affiliation: University of Veterinary Medicine Hannover, Field Station for Epidemiology, Büscheler Str. 9, D-49456 Bakum, Germany.
authors.forename: Carolin
authors.identifier: 0000-0001-5721-4323
authors.initials: C
authors.lastname: Holling
authors.affiliation: University of Veterinary Medicine Hannover, Field Station for Epidemiology, Büscheler Str. 9, D-49456 Bakum, Germany.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Grosse Beilage
authors.affiliation: Veterinary Public Health Institute, Vetsuisse Faculty, Schwarzenburgstrasse 155, CH-3097 Liebefeld, BE Switzerland.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Vidondo
authors.affiliation: Veterinary Public Health Institute, Vetsuisse Faculty, Schwarzenburgstrasse 155, CH-3097 Liebefeld, BE Switzerland.
authors.forename: Christina
authors.initials: C
authors.lastname: Nathues
keywords: Ammonia; Environmental enrichment; Exploratory behaviour; Welfare