Provision of straw by a foraging tower – effect on tail biting in weaners and fattening pigs

Straw is one of the most effective routing materials to reduce tail biting in pigs. A so called foraging-tower (FT) enables to provide only small quantities of straw compatible with liquid manure systems. The focus was on the effect of providing straw by FT for the prevention of tail biting in tail docked pigs.

The study was conducted from June 2013 to August 2014 in a conventional farrow to finish herd in Germany, which was affected by tail biting in fattening pigs for several years. Four consecutive batches of 160 pigs each were followed up from weaning to slaughter. The piglets were vaccinated against PCV2 and Mycoplasma hyopneumoniae (MH). At weaning the pigs were randomly selected for the treatment (TG) or control (CG) group. During the rearing period the pigs were housed in the same unit (8 pens/20 pigs per pen) and later in one unit of the fattening barn (16 pens/10 pigs per pen). The pens for TG were equipped with a FT permanently providing an adjusted amount of short-chopped straw. In the pens for the CG an equally sized dummy without straw was installed. Once a week the tail of each pig was scored using the parameters “tail damage” and “blood freshness”. The ammonia content in the air was measured at different locations in the unit and the air temperature was recorded permanently. At the beginning and at the end of the fattening period blood samples were taken from 22 randomly selected pigs and tested by PCR for PRRSV and PCV2 as well as by ELISA for antibodies against PRRSV, SIV and MH. The feed and straw consumption as well as the weight gain of the pigs per pen were recorded.

Tail biting was observed in two pens of the CG (14 pigs) and one pen of the TG (4 pigs) of the second batch during the fattening period. The outbreak was probably caused by a sudden increase of temperature (difference of 11.2°C within one day) and ammonia (30-40ppm) due to a failure of the ventilation system. Across all batches up to 8% of the pigs in each group showed bite marks, but this did not result in tail biting. Serology and PCR reveal infections with SIV and MH in all batches and a circulation of PRRSV (NA-vaccine strain) and PCV2 in two batches each. The average daily straw consumption was 3.7g/pig during the rearing period and 31.9 g/pig during the fattening period. Comparing the daily weight gain and the feed consumption of the TG and CG no considerable differences were detected.

Due to the low prevalence of tail biting in all batches the effect of the FT tower could not conclusively be evaluated. The operation of the FT with an adjusted supply of straw did not affect the weight gain and feed consumption.

Disclosure of Interest: None Declared.