SUSTAINABILITY FEED & ADDITIVE MAGAZINE September 2024 83 content as a percentage of DM – which were promptly noticed upon harvest with the NIR. This coincided with a dry season in 2022, which negatively impacted the ME content of grass silage, while the NDF level was higher as compared to 2021. EXTRACTING MORE ENERGY A crude fermentation extract from Trichoderma reesei (VistaPre-T, AB Vista) can be used in total mixed rations to get more energy from forage by forming pits and roughening the fibre surface, hence speeding up the microbial attachment and colonisation, assuring reduced lag time, and greater fibre digestion. A study demonstrated an increase in NDF and acid detergent fibre (ADF) digestibility in an in vitro rumen fermentation model. This was associated with a faster attachment and colonisation of fibre-degrading microbes in the rumen, then resulting in a greater utilisation of both the hemicellulose and cellulose. METHODS TO EVALUATE RATION QUALITY Fecal starch analysis is a method used to evaluate total tract starch digestibility (TTSD). When fecal starch content is lower than 3%, the value is associated with good TTSD. Portable NIR can now be used to measure the fecal starch content in fresh feces, on farms. This enables a quick evaluation of the quality of the ration, and formulation adjustment. Beyond starch, fecal NDF level can be used to evaluate the efficiency of energy utilisation. As an example, fresh fecal samples were collected in eight groups of cows from four different dairy farms in the UK. The NIR predictions indicated an optimal fecal starch level below 3% in all groups of cows, whereas fecal NDF levels were high relative to dietary NDF. After VistaPre-T application, the NIR predictions indicated an 8% average reduction in fecal NDF, which demonstrated the efficiency of VistaPre-T in increasing fibre utilisation. ME normal distribution - all data 2021 ME (MJ/kg DM) Ingot Stat Data: Jun - Oct 21; 1st cut grass silage N=744 Density of probability 0.5 0.4 0.3 0.2 0.1 0 2022 6.00 8.00 10.00 12.00 14.00 16.00 NDF (% DM) NDF normal distribution - all data N= 1541 2021 2022 Density of probability 20.0 30.0 40.0 50.0 60.0 70.0 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Figure 1. Metabolizable Energy content as a percentage of dry matter, comparison between 2021 and 2022 Figure 2. Neutral Detergent Fibre content as a percentage of dry matter, comparison between 2021 and 2022
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