Feed preference, nutrient digestibility and colon volatile fatty acid production in growing South African Windsnyer-type indigenous pigs and Large White×Landrace crosses fed diets containing ensiled maize cobs

•Digestibility, preference and colon volatile fatty acid production of ensiled maize cob diets were tested in two breeds.•Diets containing ensiled maize cobs had preference and digestibility of nutrients values comparable to control.•The SAWIP had higher preference for diets containing maize cobs than the LW×LR.•The SAWIP had greater digestibility coefficients of nutrients than the LW×LR in the high fibre diets.

A study was carried out to evaluate feed preference, nutrient digestibility and colon fermentation in growing South African Windsnyer-type Indigenous pigs (SAWIP) and Large White×Landrace crosses (LW×LR) fed diets containing ensiled maize cobs. Three treatments; CON (control diet without maize cobs), LMC (low maize cob level diet) and HMC (high maize cob level diet) were evaluated. Preference was assessed in 64 LW×LR (45±6.7 kg) and 30 SAWIP (21±3.6 kg) by offering the pigs choices between a common reference diet and a test diet. Apparent total tract digestibility (ATTD) and colon fermentation were determined using 15 LW×LR and 15 SAWIP pigs weighing 70±6.9 kg and 49±8.1 kg, respectively. There were breed by diet interactions (P<0.05) in period 1 (P1; days 0–3) for preference of diets but none in period 2 (P2; days 3–6). The SAWIP’s preference for the CON was greater than for the HMC diet (P<0.05). The two breeds’ preferences for the LMC and HMC diets were lower (P<0.05) than the 50% preference index in P1. The ATTD coefficients of crude protein (CP), acid detergent fibre (ADF), hemicellulose (Hemi) and amylase determined neutral detergent fibre (αNDF) in the HMC were greater (P<0.05) than in the CON. The SAWIP had greater (P<0.05) NDF digestibility coefficients than the LW×LR. There were breed×diet interactions (P<0.05) for proportions of isobutyric acid (IBA) and butyric acid (BA), IBA concentration and acetic to butyric acid (AA:BA) and BA:IBA ratios. The LW×LR had greater concentrations of total volatile fatty acids (VFA) (P<0.05) than the SAWIP. The results provide a basis to promote ensiling as a way to improve utilisation of maize cobs. The influence of breed of pig needs to be considered when formulating diets containing fibrous ingredients.