Influence of Pre- and Postpartum Supplementation of Fibrolytic Enzymes and Yeast Culture, or Both, on Performance and Metabolic Status of Dairy Cows

Effects of Addition of Exogenous Fibrolytic Enzymes on Digestibility and Milk and Meat Production – A Systematic Review

Exogenous fibrolytic enzymes (EFE) added to the ruminant diet can increase fiber digestibility and production efficiency. A systematic review was conducted to understand the interactions between EFE and diet on digestibility and animal performance. The database included variables from 384 experiments with EFE and 264 controls from 85 papers published since 2000 (classification criteria: 1) type of study (in vitro, in situ, in vivo), 2) type of ruminants (sheep, buffaloes, goats, beef and dairy cattle), 3) primary EFE activity (cellulases (Cel) or xylanases (Xyl)), 4) forage proportion (FP), 5) type of plant (TP: legumes or grasses), 6) number of ingredients in diets, and 7) application time (AT)). In over 52.85% of cases, EFE improved the degradability of dry matter (DMD), neutral and acid detergent fiber (NDFD and ADFD), in vitro gas production (GP), volatile fatty acids (VFA), the acetate: propionate ratio (A:P ratio), protein and fat milk, milk yield and average daily gain (ADG) (by 7.78–21.85%). Cel improved organic matter degradability (OMD), GP, VFA, milk yield, and milk protein and fat content. EFE in FP≥40% diets enhanced the ADG, and in grassbased diets increased the dry matter intake (DMI). The AT of EFE affected the DMD, NDFD, and ADFD. Significant correlations were found between the improvements of NDFD or ADFD with DMD (r>0.59), milk yield (r=0.64), and ADG (r=0.59). In conclusion, many factors interact with EFE supplementation effects, but EFE consistently enhanced the DMD, NDFD, and ADFD of ruminant diets, which are related to improvements in productive performance.

Improved dairy production through enzyme supplementation

The rumen ecosystem has the ability to transform low grade nutrients to high quality products owing to the numerous micro-flora colonies it harbours which produce different types of degrading enzymes. It has been assumed that normal rumen flora is able to digest only a small portion of the cellulosic biomass enteric rumen. This provides numerous opportunities for improving digestion via enhancing digestibility through degradation pathways in rumen. The modern animal nutrition science has utilized this knowledge to commercially harness enzymes for improving nutrient availability for production enhancement. Broadly categorized as fibrolytic, proteolytic and amylolytic, these enzymes act synergistically with the naturally available enzymes in rumen. Enzyme supplementations improve the digestibility of fibre and increase nutrient absorption and energy availability for production activities across physiological status of the animal. This review summaries response of large lactating ruminants to the external enzyme (in vivo) supplementation in terms of actual milk production, milk composition, body weights, dry matter intake and digestibility of nutrients, as well as to assess the economic benefit in terms of additional expenses incurred and benefit derived with increase in milk production.