SPECIAL STORY FEED & ADDITIVE MAGAZINE November 2023 67 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. PRE-DIGESTION OF FIBRE WITH VISTAPRE-T TO RELEASE MORE ENERGY A crude fermentation extract from Trichoderma reesei (VistaPre-T) 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 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 utilization of both the hemicellulose and cellulose. FECAL NDF AND STARCH TO EVALUATE CARBOHYDRATE UTILISATION 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 farm. This enables a quick evaluation of the quality of the ration, and eventually adjust formulation. Beyond starch, fecal NDF level can be used to evaluate the efficiency of energy utilization. As an example, fresh fecal samples were collected in 8 groups of cows from 4 different dairy farms in the UK. The NIR predictions indicated an optimal fecal starch levels below 3% in all the 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. TWO FORMULATION STRATEGIES TO INCREASE THROUGHPUT AND LOWER CARBON FOOTPRINT WITH VISTAPRE-T VistaPre-T can be formulated into the total ration to save cost. In dairy diets, VistaPre-T can generate approximately 10 MJ of additional energy (coming from 0.8 MJ energy uplift per kg of forage DM, given a cow consumes 12.5kg of forage DM per day on average). This extra energy iu equivalent to 300g of protected fat per cow/day. A study was performed involving 147 Holstein-Friesian dairy cows in the UK. After assigning the energy uplift value to VistaPre-T, the least-cost reformulation allowed to reduce the ground maize, molasses and protected fat usage, while adding more grass silage. In addition to a 9% increase in milk yield with no effect on milk composition, VistaPre-T resulted in a 15% reduction in the carbon footprint of fat and protein corrected milk. Figure 1. Metabolizable Energy (ME) content as a percentage of dry matter, comparison between 2021 and 2022 Figure 2. Neutral Detergent Fibre (NDF) content as a percentage of dry matter, comparison between 2021 and 2022
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