Analysis of the Relationship Between Fatness of Late Pregnant and Lactating Sows and Selected Lipid Parameters of Blood, Colostrum and Milk

This study determined the relationships between backfat thickness in sows on day 104 (±2) of pregnancy, changes in fatness between high pregnancy and lactation (day 21), the body weight of late pregnant sows, the level of selected lipid parameters in blood serum, and basic components and fatty acid profile of colostrum and milk. Backfat measurements were taken using an ultrasound device at the P1, P2, P3 and P4 sites and loin eye height was measured at the P4M site. In late pregnant sows, fatness measured at P1, P2, P3 and P4 and the mean of measurements taken at P2 and P4 were correlated with HDL (+0.491^**, +0.537^**, +0.439^*, +0.483^** and 0.529^**, respectively). Measurements taken at P4 and the mean of P2 and P4 were correlated with cholesterol (CHOL, +0.367^* and +0.372^*, respectively). Correlations were also found between the level of fatness of pregnant sows (P2, P3, P4, (P2 + P4)/2) and the level of HDL at the end of lactation (+0.534^**, +0.440^*, +0.412^* and +0.487^**, respectively). The body weight of late pregnant sows was significantly correlated with the energy and fat levels in colostrum (-0.467^** and -0.429^*, respectively). In addition, it was correlated with the proportion of fatty acids in the profile (C18:2 +0.417^*, C18:3 +0.493^*). Correlations were observed between P1 backfat thickness and the proportion of colostrum fatty acids (C18:1 +0.483^*, CLA +0.475^*), and between P2 backfat thickness and the C20:4 content of milk (-0.421^*). A relationship between backfat thickness measured at farrowing and the levels of selected fatty acids in colostrum was found for P2 and C18:3 (+0.471^*), P3 and C18:0 (-0.608^**), C18:2 (+0.463^*) and C18:3 (+0.517^*), and P4M and C16:1 (-0.513^*). The greater the difference in P1 backfat thickness between late pregnancy and weaning, the higher the content of fat (+0.549**), energy (+0.510^*), C18:0 (+0.493^*) and CLA (+0.488^*), and the lower the content of C14:0 (-0.512^*) and C16:0 (-0.457^*) in milk. The strong correlations of fatness in late pregnant sows and of changes in fatness during late pregnancy and weaning with some blood, colostrum and milk parameters suggest that sows should be evaluated for fatness during their productive life.