The increasing litter sizes of modern pig breeds have led to a significant number of piglets that are 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 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 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 were measured. At 24 h, piglets weighing <900 g at birth and the median piglet in birth order were 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 and 12 h (P < 0.001) and between 12 and 24 h (P < 0.05), and higher birth weight, crown rump length, body mass index, and ponderal index (P < 0.001), and a tendency toward 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, compared with 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.

The fetal and early postnatal environment can have a long-term influence on offspring growth. Using a pig model, we investigated the effects of maternal body condition (thin or fat) and maternal gestation feeding level (restricted, control or high) on maternal stress, milk composition, litter size, piglet birth weight and pre-weaning growth. A total of sixty-eight thin (backfat depth about 8 mm) and seventy-two fat (backfat depth about 12 mm) gilts were selected at about 22 weeks. This backfat difference was then accentuated nutritionally up to service at about 32 weeks. During gestation, individual gilts from within each group were randomly allocated to a gestation diet at the following feed allowances: 1·8 kg/d (restricted); 2·5 kg/d (control) and 3·5 kg/d (high) until day 90 of gestation. During gestation restricted gilts had higher levels of cortisol than high and control fed animals. Piglets born to fat gilts had higher average daily gain during the lactation period and higher weaning weights at day 28 than piglets born to thin gilts. Gilts on a high feed level had heavier piglets than those provided with restricted and control allocations. Fat gilts had less saturated fat in their milk at day 21 of lactation and higher unsaturated fat levels. No differences were found in the n-6:n-3 PUFA ratio in the milk between thin and fat gilts. In conclusion, maternal body condition influenced the daily weight gain of offspring up to weaning (day 28) and milk fat composition. Furthermore, maternal feed level during gestation alters maternal cortisol levels and milk fat composition.

No abstract

. 2015. Colostrum production in sows fed different sources of fiber and fat during late gestation. Can. J. Anim. Sci. 95: 211Á223. The objective was to study yield and composition of colostrum and transient milk from 36 second-parity sows fed a standard lactation diet (CON) low in fiber or one of two high-fiber diets based on sugar beet pulp (SBP) or alfalfa meal (ALF), combined with one of three fat sources, palm fatty acid distillate (PFAD), soybean oil (SOYO) or trioctanoate (C8TG) from day 105 of gestation onward. Sows were milked at 0, 12, 24 and 36 h relative to onset of parturition. Jugular vein blood was collected on day 112 of gestation. Plasma acetate content was affected by dietary fiber and fat treatment (PB0.05), indicating altered intermediary metabolism. Colostrum yield, predicted from piglet birth weight, suckling duration and weight gain, was unaffected by dietary treatments (P 0.10). Colostral (24 h) and transient milk dry matter contents were greater in SOYO compared with PFAD and C8TG sows (P B0.05). Colostrum (12 and 24 h) and transient milk lactose contents were greatest in CON-fed sows compared with sows fed ALF or SBP diets (PB0.05). In conclusion, nutrition in late gestation affected the intermediary metabolism and colostrum composition, but did not affect colostrum yield of sows.