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.