Essential Oils, Enzyme Mixtures Provide Ionophore Substitutes For Dairy Cows
The researchers said that supplementing feed with essential oils, the enzyme mixture supports rumen fatty acid and milk production efficiency and may provide an alternative to the use of antibiotics in dairy cow diets.
In a series of joint experiments, an international research team from Brazil and the United States studied essential oil mixtures and enzyme amylases as an alternative to ionophore use in dairy diets. The team is studying the effects of bovine digestion, rumen fermentation and milk production.
"The hypothesis of this study is that EO [essential oils] and EOA [essential oils and amylases] can replace MON [monensin] in dairy diets without reducing animal performance," the researchers said. “In addition, we expect dietary supplementation of EO and amylase to produce a synergistic effect on rumen fermentation, nutrient digestibility and milk production in dairy cows.”
Researchers say adding essential oil blends and amylase to dairy cow diets can increase the rumen concentration of butyrate, branched-chain fatty acids and acetate, and reduce NH3-N levels. “The milk production efficiency is improved by feed additives, and the second experiment proves that there is no difference in milk production efficiency,” they added.
"Either EO or EOA can replace MON without reducing animal performance," they said. "There is no evidence that EO and amylase have a positive synergistic effect on milk production, but EOA may increase milk protein content and yield. ."
Research team members published their findings in the Journal of Dairy Science.
Why use essential oils and enzymes?
Researchers say that as emerging economies increase their wealth, people are more interested in the supply of meat and milk. This demand is expected to double by 2050. Despite increased demand, farmers face challenges including lowering greenhouse gas production pressures, competition with human feed ingredients, and restrictions on the use of antibiotics and growth promoters, they said.
Previous studies have been conducted to explore the use of feed enzymes and plant extracts to increase nutrient use in ruminants rather than using ionophore antibiotics.
Researchers say ionophores and antibiotics have been used to reduce the risk of acidosis and ketosis and improve feed efficiency. However, alternatives have also been studied, including essential oils (EO) and enzyme products.
“Essential oils are aromatic compounds extracted from plants by fermentation or distillation, are antibacterial, promote propionic acid production in in vitro studies, and improve milk and FCM production in dairy cows,” they said. Similarly, enzymes have been explored for use in ruminant diets.
They say that in recent years, due to rising feed costs, the price of enzymes has fallen, and people have reconsidered the use of additive enzymes. They added: "The addition of enzyme products with amylase activity to dairy diets increases the digestibility of the diet and the milk production of the cows."
They said that previous studies also reported that the addition of EO and amylase (EOA) diet improved cows' FCM production compared to cows fed monensin.
Although some evidence suggests that EOA supplements may promote milk production in dairy cows, little is known about the use of feed additives in rumen fermentation, cow performance and digestion.
"The purpose of this study was to evaluate the effects of feed additives (MON, EO and EOA) on nutrient intake and total apparent digestibility, rumen fermentation, microbial protein synthesis, serum glucose and urea concentrations, milk production and composition, and N. Utilization in cows."
In the first feeding study, the researchers said that eight intubated cows had a 4-day diet for 21 days - 7 days of sample collection and 14 days of domestication. Rotate the cow to another test diet at the end of each period.
The diet included a control without a feed additive (CON), a diet containing monensin (MON), a dry matter of 13 mg / kg, and an essential oil of 44 mg / kg dry matter (EO) in the diet, or they said that essential oil supplements Diet with alpha-amylase 330 kg novo units / kg of dietary dry matter (EOA). Enzymes and essential oil mixtures are commercially available, and the mixtures include thymol, eugenol, vanillin and limonene.
They said that the total apparent digestibility of nutrients, rumen fermentation, nitrogen (N) use, blood glucose and urea concentrations, microbial protein synthesis, and milk production and composition were evaluated for dairy feed additives. Samples of feed and additives were collected for analysis with milk, rumen digest, urine and feces.
The researchers said that in the second feeding experiment, 30 cows received three diets - the MON, EO and EOA diets used in the early trials - for 9 weeks.
Overall, the researchers said that the results of the two studies were similar to several factors in supplementing diet cows.
“Therefore, EO or EOA can replace MON in dairy cow diets while maintaining performance,” they said.
The researchers said that in the initial feeding study, the nutritional intake and digestibility of the cows in all groups remained unchanged. However, the use of feed additives tends to improve the digestion of dry matter and crude protein as well as lower concentrations of rumen NH3-N.
They said supplemented feed also increased the concentration of acetate, branched-chain fatty acids and butyrate in the rumen. Cows in diets with EO and EOA showed lower pH, more NH3-N and tended to have more total volatile fatty acids than cows that received the MON diet.
The researchers said that no time-interaction treatment was found for rumen fermentation measurements.
They said that cows in the supplement diet showed an increase in the efficiency of N transfer to milk, and cows on the EOA diet performed better than the EO diet. The use of supplements did not change milk yield or composition, but did increase milk production.
In the second trial, they said, cows showed similar nutrient intake and digestibility, although those in the EOA diet often consumed more dry matter than the EO diet. Milk production in the diet is similar to blood metabolites.
They say cows that receive MON or EOA in their feed contain more milk protein than cows in the EO diet. “Feed additives increase the concentration of acetate, butyrate and branched-chain fatty acids in the rumen fluid, while treatments with EO contain higher concentrations of ruminal butyrate and NH3-N,” they added.