Height relative to body weight in nursery pigs

Among the physical dimensions of the pig body, the height has received limited scientific focus. During transport, however, where multideck trucks and trailers typically are used, detailed knowledge about the height of pigs is relevant. The body weight of pigs is often known, whereas height is more difficult to quantify as part of the pre-transport management of the pigs. Nursery pigs are one category of European pig production often subjected to long distance transport for further fattening some weeks after weaning. The present study aimed to determine the height of pigs from 5 to 40 kg of body weight, as well as the relation between height and body weight. The height and weight were measured for 1,614 randomly selected pigs (castrates and females) from 10 Danish pig herds balanced between the two large breeding systems, DanBred (DB) and Danish Genetics (DG). From 9 herds, data from 1,435 pigs with 2.8 to 40.6 kg body weight were used for establishing prediction equations, while pigs from the tenth herd were set aside for validation. The study considered using 1) polynomial regressions of various order; 2) power functions; or 3) nonlinear growth curve models. Overall, the third-order polynomial with sex-specific intercept and the power function with sex-specific log-intercept were optimal for prediction. Nevertheless, for feasibility and due to only marginal sex differences, we suggest using common intercepts for prediction of height from weight. Taken together, the results of the present study present data for pig height in the interval from 5 to 40 kg body weight. Further, we suggest that a third-order polynomial or a power function can be used for pigs from at least the genetic systems DB and DG, if the pig height is to be predicted based on body weight.