Effect of feeding a gestation diet to sows for 5 days post-farrowing and feeding a liquid mixture of milk replacer and starter diet to suckling piglets on growth, selected health parameters and faecal microbiota of suckling pigs on two research farms

This study involved 50 sows and was a 2 × 2 factorial arrangement with factors being sow feeding [lactation diet throughout lactation (CON) or gestation diet for the first 5 days of lactation, followed by lactation diet (GEST5)] and creep feeding from day (d) 5 after birth [dry pelleted starter diet (DPS) or liquid mixture of milk replacer and starter diet (LMR+S)]. The study was conducted on two research farms, one in Ireland (IE) and the other in Switzerland (CH). All sows were limit-fed the gestation diet until farrowing. During lactation, both sow treatments followed the same feeding curve with daily digestible energy allocation increasing from 58.1 to 135 MJ between d1 and 28. Sow feed intake, weight and backfat depth and piglet weight and total dry matter disappearance (TDMD) of creep feed during lactation were recorded. On d5 after birth, milk was collected from sows on both farms and sow faeces was collected at CH for short chain fatty acid (SCFA) analysis. Following weaning at d29 ± 0.2 in IE and d25.5 ± 1.3 in CH, pigs were followed until d43 post-weaning (pw) in IE (<i>n</i> = 7 pens/treatment) and d14 pw in CH (<i>n</i> = 11 pens/treatment). In IE, faecal samples were collected from sows before farrowing and on d5, 12 and 26 after birth and from piglets on d2, 5, 12 and 26 after birth and on d7 and d41 pw for microbiota analysis. Feeding GEST5 did not affect overall sow feed intake, backfat depth or weight loss during lactation on both farms (<i>P </i>> 0.05) but reduced the solids, fat and SCFA content of milk and increased faecal SCFA in CH (<i>P </i>< 0.05). In CH, LMR+S-fed pigs had higher TDMD than those fed DPS, while in IE, DPS had higher TDMD than LMR+S (<i>P </i>< 0.05). However, neither GEST5 nor LMR+S influenced pre- or pw pig growth or diarrhoea prevalence on either farm (<i>P </i>> 0.05). In IE, on d5 post-farrowing, GEST5 sows had a higher relative abundance of <i>Prevotella</i> and <i>Succinivibrio</i> in their faeces compared to CON (<i>P </i>< 0.05) and both GEST5 and LMR+S increased bacterial alpha diversity in piglet faeces on d7 pw (<i>P </i>< 0.05). In conclusion, while providing a gestation diet during the first 5 days of lactation increased physical feed intake then, it did not increase overall lactation feed intake in sows. Additionally, creep feeding a liquid mixture of milk replacer and starter diet to suckling piglets did not improve pre- or pw pig growth.