Today on the blog, we are sharing a study by our colleagues: Dr. Lee Johnston from the College of Food, Agricultural, and Natural resources Sciences (CFANS) and Sara Schieck from the swine extension team, regarding floor space allowance and its impact on growth on finishing pigs.
The full article is available online in open access on the Journal of Animal Science website.
Most floor space allowance studies were conducted 20 years ago when pigs were sent to market when they reached 113kg (around 248 lb) whereas pigs are currently sent at 128kg (281 lb). Therefore, guidelines need to be updated.
Experiment 1: Pigs from 27 to 138 kg (59 to 304 lb) were housed providing either 0.71, 0.80, 0.89, 0.98, or 1.07 m2/pig of floor space (respectively 7.64, 8.61, 9.58, 10.55, 11.52 square ft/pig). Growth rate, cortisol concentration and lesion scores were measured for each pig.
Experiment 2: Pigs around 130 kg (286 lb) were housed providing either 0.71, 0.80, 0.89, 0.98, or 1.07 m2/pig of floor space (respectively 7.64, 8.61, 9.58, 10.55, 11.52 square ft/pig).
Initial body weight of pigs was not different across floor space allowances; however, increasing floor space allowance increased final body weight (linear, P = 0.04) and tended to increase ADG (linear, P = 0.06) and ADFI (linear, P = 0.06). Gain efficiency was not influenced by increasing floor space allowance. There were no differences in initial salivary cortisol concentrations across floor space treatments. Similarly, there were no differences in salivary cortisol among floor space allowances 2 and 1 wk before the final weight, when pigs should have experienced the greatest differences in crowding among treatments.
Based on the growth performance and pig welfare data collected in Exp. 1, a clearly optimal floor space recommendation is not apparent. The equation from previously published studies estimates that 138-kg pigs require 0.91 m2 of floor space; therefore, the present study provided 2 treatments below and 2 treatments above the predicted requirement. Our data are clear that pigs in the present study did not respond to floor space allowances greater than the predicted need of 0.91 m2 with improved growth performance or welfare.
In Exp. 2, the floor space needs of heavy market pigs could be studied isolated from the diluting effects of the early growth period that were present in Exp. 1. Results of Exp. 2 indicate that 0.98 m2/pig optimized growth performance of pigs between the weights of 133 and 148 kg.
Pigs marketed at 138 kg BW optimize growth performance when provided 0.89 to 0.98 m2 of floor space per pig. However, the negative effects of low space allocations were mostly observed in heavy pigs. Therefore, the use of a pig removal strategy near the end of the finishing period may be an effective strategy to diminish the negative effects of crowding when pigs are near market weight.