quantitative study of the blood vessels of the pig's skin and the influence of environmental temperature

The vascular supply to the skin of pigs was studied in animals perfused with the dye, monastral fast blue. The arrangement of the blood vessels in control animals was in three plexuses, similar to that in other mammals but with the middle plexus poorly developed. A litter of pigs was divided into two groups at the age of 12 days and one group was raised in a warm room and the other in a cold room. The pigs were killed at age three months when the warm room was 35°C and the cold room 5°C. A quantitative evaluation of the blood supply to the skin of the experimental animals revealed that the pigs from the warm room had more blood vessels in the skin than those raised in the cold; the difference was statistically significant (P < 0.01). In the case of pigs from a second litter reared at 35°C and 20°C, no significant difference in the number of blood vessels was detected.