The effect of oat hulls, added to the basal ration for pregnant sows, on reproductive performance, apparent digestibility, rate of passage and plasma parameters

Abstract

Thirty‐five Large White x Landrace sows were housed in individual stalls during gestation and were fed a standard diet (DE, 13.2 MJ kg⁻¹) supplemented with oat hulls (OH), such that the ratios of basal diet to OH were 1:0, 9:1, 7:3 or 1:1. Digestibility and balance measurements were made during 7‐day periods beginning on days 45 and 90 of gestation. During a 3‐week lactation all sows were fed a standard diet (calculated DE, 12.5 MJ kg⁻¹, CP, 152 g kg⁻¹). Increasing OH intake increased mean net maternal weight gains and P2 fat depths during pregnancy and tended to increase total litter weight at birth. Sow‐milk solids content and litter weight gain during the 3‐week suckling period also tended to increase (nonsignificant), following increasing OH supplementation during gestation. Increasing OH intake tended to increase VFA and reduce cholesterol concentration in blood plasma at 56 days of gestation. The time taken to consume the once‐daily feed allowance increased and gastrointestinal transit time decreased as OH intake increased. The apparent digestibilities of the major nutrients were significantly depressed with increasing levels of OH in the diet but the total amounts of nutrients absorbed increased. The following values were calculated for OH by the difference method: apparent digestibility of DM, 0.31; apparent digestibility of ADF, 0.17; DE, 6.25 MJ kg⁻¹; ME 6.01 MJ kg⁻¹.