Agression, vocalization and underweight in piglets born from gilts with lameness

Problems in the locomotor system are common in pregnant gilts and its occurrence can cause pain and stress which compromise their welfare. Lameness is a multifactorial condition, caused by nutritional factors, floor abrasiveness, social instability, among other factors. Glucocorticoids secreted in pregnant gilts under stressful conditions, can cross the placental barrier, affecting brain structures that modulate affective states and social behaviour of the offspring. Gait scores of 22 pregnant, group-housed gilts were assessed six times with intervals of two weeks between evaluations. Scores from 0 to 5 were assigned to each gilt according to a previously validated scoring system. A score of 0 represented gilts without lameness and a score of 5 represented gilts with the highest lameness score. At 107 days of pregnancy gilts were transferred to individual farrowing pens. Lame gilts were treated according to a standard protocol (Flunixin Meglumine for 4 days and antibiotic). At 28 days of age, piglets were weaned, weighed and distributed in four uniform body size groups. Lesions resulting from fights were counted in each group on days 28, 29 and 30. Two days afer weaning, vocalization and activity levels were evaluated in each group using an open field and novel object tests. For the statistical analysis, piglets were grouped according to the degree of lameness of their mother. Group A corresponded to piglets (P) of mothers (G) with lameness 0 and 1 (n=8G; n=58P), group B to piglets of mothers with lameness 2 and 3 (n=9G; n=60P) and group C to piglets of mothers with lameness 4 and 5 (n=5G; n=38P). Data analysis was performed depending on the normality of the variables through ANOVA or Kruskal-Wallis tests at a significance level of 5%. Pairwise comparisons were performed using Tukey and Kramer (Nemenyi) test with Tukey-Dist approximation for independent samples. All analyzes were performed in the programming language R. Group A piglets had fewer lesions at days 28 (P<0.05) and 29 (P<0.05) than group B piglets. Although the litter size was not signifcantly different between groups (P=0.223), group B piglets were the heaviest (P<0.05) and group C piglets were the lightest (P<0.05). Additionally, group A piglets vocalized more than group B piglets (P<0.05) when they were subjected to the novel object test. We conclude that lameness in pregnant gilts have negative effects on the offspring, affecting weight gain, increasing aggressiveness and altering vocalization.