The effect of a lactic acid bacterial inoculant on maize silage

Abstract

Maize silage is an important forage in South Africa and it is often made without the use of any additives. Very little information on the fermentation dynamics of maize silage under local conditions is presently available. The aim of this study was to determine if the adding of a lactic acid bacterial inoculant to maize at ensiling will improve the fermentation dynamics of maize silage and to determine the effect of the inoculant on the intake and growth of lambs. Maize was harvested at the hard dough stage with a Feraboli 930 silage chopper and ensiled with or without the addition of a lactic acid bacterial inoculant in 18 laboratory silos for each treatment. Silos were 1.5 l glass jars, equipped with a special lid with springs which enables gas release only. The fermentation dynamics during ensiling was determined by opening three silos on day 1, 2, 4, 10 and 95 of ensiling. The adding of the inoculant to maize at ensiling did not result in a more rapid drop in pH and higher levels of lactic acid. For the intake and growth study maize was ensiled in thirty 210 l drums lined with a plastic bags for each treatment. The material was compacted, the bags were closed and a concrete paving stone (20 kg) was placed on top of the bag. The intake and growth of South African Mutton Merino lambs fed inoculated and untreated maize silage was determined. 2 groups of 14 lambs weighing 26.4±1.9 and 26.4±1.6 kg were randomly allocated to the control and the inoculant treatment, respectively. The average daily gain of lambs fed a diet consisting of either 60% control or inoculated maize silage over a growth period of 60 days was 239±26 and 255±44 g day −1, respectively. The feed conversion efficiencies were 4.94 and 4.93 kg DM feed kg −1 live weight gain for lambs fed the control and inoculated silage diets, respectively. Although the laboratory study showed very little effect of adding a lactic acid bacterial inoculant to maize at ensiling, lambs tended to consume more of the inoculated silage.