Morphometry of newborn piglets and its relevance at weaning: new approach.

Context. The strategic management of pigs raised in an intensive system has been conducted, in general, according to the average weight of piglets after weaning. Different models using morphometric parameters to predict the probability of any of the three weight classes (light, medium, and heavy) occurring post-weaning present themselves as an alternative to help the producer conduct these strategic managements. Aims. This study aimed to evaluate the development of suckling piglets by using morphometric parameters. Methods. A thousand simple samples were extracted at random from 268 piglets for the training data, which represent 70% of the original data set (384 piglets). The remaining 116 piglets (test data) were excluded from the analysis so as to verify the performance of the prediction (probability of each weight class to occur). Afterwards, the results were compared with the real weight class of the piglet at weaning. The variables in this research were birth weight (PWB), lactation length (Lac), and morphometric parameters of body length (BL), heart girth (HG), body mass index (BMI), ponderal index (PI), surface:mass ratio (SM), and parity order (PO). Different models were developed to predict the probability of any of the three weight classes (light, <3.967 kg; medium, 3.967-5.095 kg; and heavy, >5.095 kg) occurring at piglet weaning on the basis of their parameters 1 day postpartum. An adjustment of the ordinal regression was proposed to predict the weight classifications. Key results. The model with a significant effect of the Lac variables was selected. Conclusions and implications. One day after birth, light-weight and heavy-weight piglets, regardless of their morphometry, have a high likelihood of remaining in the same weight class at weaning. However, this does not apply to medium-sized piglets with diverse morphometry. [ABSTRACT FROM AUTHOR]