Effect of Exogenous Fibrolytic Enzyme Application on Productive Response of Dairy Cows at Different Lactation Stages

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.

Effect of exogenous fibrolytic enzymes in total mixed ration on milk yield, composition, feed efficiency in Holstein Friesian crossbred cows

An experiment was conducted to evaluate the effect of exogenous fibrolytic enzymes (EFE; 800 IU/g endo 1,4- β glucanase, 700 IU/g 1 (3),4-β glucanase and 2700 IU/g endo 1,4-β xylanase) @ 240 mg/kg total mixed ration (TMR) feeding on milk and components yield as well as feed utilization efficiency in Holstein Friesian [HF] crossbred cows. Twenty early lactating HF crossbred cows having uniform 4% fat corrected milk (FCM) yield and body weight were used to access the effect on nutrients intake, milk yield, milk composition, feed conversion efficiency and cost of feeding. The crossbred cows fed EFE supplemented TMR produced more milk, 4% FCM and milk fat. The supplementation of EFE resulted in higher milk solid not fat (SNF), protein and lactose as well as higher milk fat and total solids (TS). The consumption of nutrients/kg 4% FCM were less in EFE group cow, whereas only numerical improvement in nutrients intake/kg milk was noticed. The gross protein and energy efficiencies were significantly improved on EFE supplementation. The return over feed cost was 15.87% higher for cows fed EFE supplemented TMR compared to control TMR. In conclusion, feeding of EFE produced significantly higher 4% FCM and milk fat with improved feed conversion efficiency and better economic returns in HF crossbred cows.

Effects of Saccharomyces cerevisiae-based direct-fed microbial and exogenous enzyme products on enteric methane emission and productivity in lactating dairy cows

The objective of this experiment was to investigate the effects of a Saccharomyces cerevisiae-based direct-fed microbial product (SDM) and an exogenous enzyme product (ENZ) on enteric methane emission, milk yield and composition, total-tract digestibility of nutrients, ruminal fermentation, and nitrogen excretion and secretion in lactating dairy cows. Eighteen Holstein cows were used in a 3 × 3 Latin square design experiment with three 28-d periods. Treatments were (1) control (no additive), (2) 28 g of SDM/d per cow, or (3) 10 g of ENZ/d per cow. Treatments were top-dressed at the time of feeding. The basal diet consisted of (dry matter basis) 60% forage and 40% concentrates and contained 16.5% crude protein and 32.0% neutral detergent fiber. Treatments had no effect on enteric methane production, yield (methane per kg of dry matter intake, DMI), or intensity (methane per kg of energy-corrected milk yield). Carbon dioxide production was similar among treatments. Compared with control, SDM increased milk yield by 2 kg/d without affecting DMI or feed efficiency. Supplementation of the diet with ENZ did not affect DMI, milk yield, or feed efficiency. Concentrations and yields of milk fat, true protein, and lactose, and energy-corrected milk yield were not different among treatments. Neither SDM nor ENZ had an effect on total-tract digestibility of nutrients or nitrogen excretion and secretion. Concentration of total volatile fatty acids (VFA) in ruminal fluid was increased by both SDM and ENZ, and rumen pH was decreased by SDM compared with the control. At levels similar to the control DMI, the increased concentration of VFA in ruminal fluid of cows receiving SDM suggests an increased postruminal supply of energy and may partly explain the increased milk yield with that treatment. However, it is important to note that milk composition and energy-corrected milk yield were not affected by treatment.