The increasing litter sizes of modern pig breeds have led to a significant number of piglets that are being born undersized (‘small’ piglets) and some have been exposed to different degrees of intrauterine growth restriction (IUGR). The aim of this study was to investigate the physiology and capability to ingest colostrum of these small piglets suffering from various degrees of IUGR, to see if their IUGR score could be a useful tool for easy identification of piglets in need of an intervention in the colostrum period.
Piglets were classified at birth based on head morphology. Piglets were classified either “normal”, “mildly IUGR” (m-IUGR) or “severe IUGR” (s-IUGR) based on the head morphology. Blood samples were collected at birth and at 24 h, and colostrum intake during two 12-h periods and blood metabolites at 0 and 24 h measured. At 24 h, piglets weighing less than 900 g and the median piglet in the birth order was sacrificed, and organ weights and hepatic glycogen were measured.
Overall there was an influence of the piglets classification on most characteristics with normal piglets having a greater colostrum intake between 0 - 12 h (P < 0.001) and between 12 - 24 h (P < 0.05), and higher birth weight, crown rump length, body mass index, ponderal index (P < 0.001) and a tendency towards a higher vitality score (P < 0.069) than s-IUGR piglets. There was a time×IUGR interaction, with plasma glucose levels being lowered (P < 0.001) and lactate levels elevated (P < 0.001) in s-IUGR piglets at 24 h compared with normal and m-IUGR piglets. Some differences were found in electrolytes; sodium plasma concentrations were greatest for normal piglets (P < 0.05) and highest at 0 h (P < 0.05). At 24 h of age, s-IUGR piglets had a higher heart (P < 0.001) and brain percentage (P < 0.001) and a lower liver percentage (P < 0.001) relative to body weight than normal piglets. In addition, s-IUGR piglets had less hepatic glycogen than m-IUGR piglets and normal piglets.
The present study showed that the physiology of piglets in the colostrum period was affected by IUGR status at birth, and their intermediary metabolism was altered due to different colostrum intakes. Furthermore, it was demonstrated that the head shape of newborn piglets is a good selection criteria for identifying piglets that need oral supplementation during the neonatal stage.
Intrauterine growth restricted piglets defined by their head shape ingest insufficient amounts of colostrum. C. Amdi, U. Krogh, C. Flummer, N. Oksbjerg, C. F. Hansen, and P.K. Theil. J ANIM SCI jas.2013-6824; published ahead of print October 1, 2013, doi:10.2527/jas.2013-6824