LAUSR

Determining total heat production (THP) in individual sows and litters can be difficult and often requires the use of multiple animals to generate data on a per room basis. These systems may be costly to construct precluding their use by many researchers. The study objective was to develop a low cost indirect calorimetry system to determine THP in individual lactating sows and litters. Six indirect calorimeters were constructed to house 1 sow and litter in a crate throughout farrowing and a 21-d lactation period. Chamber accuracies for O2 and CO2 were evaluated by ethanol combustion. One-week pre-farrowing, 6 pregnant multiparous sows (parity 2.9 ± 0.9; 218.3 ± 38.6 kg BW) were housed individually in each farrowing crate and maintained in thermoneutral conditions (20.9 ± 2.6°C and 43.7 ± 18.6% relative humidity) throughout lactation. On lactation d 4, 8, 14, and 18, indirect calorimetry was performed on all sows and their litters, as well as 2 piglets from a sentinel litter to determine THP. Sentinel piglet data were used to estimate THP for the sows independent of the litter. Sow + litter THP (kcal/h) increased (P = 0.01; 16.6%) on d 8 compared to d 4 and was greater (27.3%) on d 14 and d 18 compared to d 4 and d 8. Sow THP was greater (P = 0.01) on d 8 (401.19 ± 17.15 kcal/h) and d 14 (430.79 ± 12.42 kcal/h) compared to d 4 (346.16 ± 16.62 kcal/h), and was greater on d 14 compared to d 8 and on d 18 (386.16 ± 20.02 kcal/h) compared to d 14. In summary, this cost-effective system can allow researchers to accurately evaluate THP in individual lactating sows and their litters