Rumen Is The Core Of Feed Efficiency
The rumen is actually the cornerstone of feed efficiency: it is the main first organ of the bovine digestive tract.What can I do to further optimize it?
Feed efficiency can be defined as the ratio between performance and feed consumption. In dairy farming, performance can be expressed by energy-corrected milk (ECM), which takes into account milk production but also considers protein and fat content. Feed consumption is usually expressed in kilograms of dry matter intake (DMI). Feed intake is continuously measured in beef cattle, poultry or pig production to control economic performance.
Feed efficiency is very low
Although it has a large impact on the income of farmers, the feed efficiency of farmers or dairy products is very low. Some studies have measured feed efficiency in dairy herds and have demonstrated important changes: 1.1 to 1.9 kg ECM / kg DM. In terms of revenue, this difference represents $5.00/bovine/day (from Cabrera, 2009), assuming a milk price of $0.26/kg and a diet cost of $0.22/kg DM). Feed efficiency monitoring is becoming increasingly important to ensure agricultural income. In fact, milk prices in different markets are still volatile and tend to decline, while global raw material prices are rising.
What can explain the change in feed efficiency?
Important changes in feed efficiency can be measured in animals and many possible causes have been identified. This includes milk days, weight changes, activities, etc. However, the main factors are related to the feed itself: feed ingredients, raw material digestibility - especially feed - and distribution, palatability or rumen pass rate.
Historically, the protein level of dairy farmers has exceeded the requirements of cattle, especially to offset the natural use of protein by dairy cows. Photo: Jan Willem Schouten
The rumen is actually the cornerstone of feed efficiency: it is the main first organ of the bovine digestive tract. This large vault has an extensive microbial community that is responsible for the digestion of nutrients and distribution to host organs and tissues. The rumen associated with the mesh is indeed a very effective fermenter that breaks down dietary ingredients: starch, cellulose, protein, and a lesser degree of fat. In several processes occurring in the rumen, rumen function is expected to have two main outcomes:
1. Volatile fatty acids (VFA)
2. Metabolisable Protein (MP).
From a rumen perspective, increasing feed efficiency means the maximum availability of these two nutrients in the gut.
Historically, the protein level of dairy farmers has exceeded the requirements of cattle, especially to offset the natural use of protein by dairy cows. In fact, studies have shown that less than 30% protein intake can usually be recovered in the form of milk protein. Nutritionists can also recommend this approach to provide adequate supply of essential amino acids for intestinal absorption. However, rumen capture and protein degradation, as well as changes in microbial synthesis, can randomly alter the amount and distribution of MP supplied to the gut, which is not easily controlled under agricultural conditions.
Up to 80% of ruminant energy supplies come from VFA. Rumen fermentation mainly produces acetic acid, butyric acid, lactic acid and propionic acid. After years of research, the level and proportion of each VFA for optimal rumen efficiency was determined and constituted a nutritional standard. Due to the high concentration of concentrates in modern dairy farming, rumen function is disrupted, which may result in an imbalance in VFA ratio. An increase in concentrate intake has been shown to increase the production of acetic acid and lactic acid and lower the rumen pH. In the short term, this strategy can actually lead to more VFA production through the important and rapid starch degradation of the concentrate. However, the gradual decline in rumen pH leads to non-ideal conditions for the development of cellulolytic bacteria. This results in a decrease in fiber digestibility, which in turn leads to an increased diet of ruminants.
Protein and energy efficiency are important and relevant. In fact, microbial synthesis of proteins is energy-dependent, and recent studies have shown that "synchronizing" the time of energy supply with protein degradation maximizes protein synthesis and minimizes nitrogen waste to ammonia.
Which strategy can improve feed efficiency?
Starting from the basic principles, feed should be selected based on its digestibility and nutrient bioavailability. These parameters can be monitored using the following metrics:
· Total Digestible Nutrients (% of Dry Matter)
· Digestible Energy (Mcal/kg),
· Protein Digestion rate (%/h) or
· Metabolizable Protein (g/day).
Then, as mentioned earlier, the ration should take into account the synchronization and balance of rumen protein and carbohydrate digestion.
Since the past few decades, there has been a profession in the market that offers solutions to increase the supply of enteral bypass nutrients. They include protein sources (formaldehyde, heat, reducing sugars, etc.) and single amino acids that are treated in different ways to prevent rumen degradation of fat or ethylcellulose encapsulation. Although these solutions have shown consistent results for feed efficiency, they only provide a limited amount or type of nutrients to the animal's gut.
Then, another added method is to use plant genetics. This new perspective is more comprehensive because plant genetics is added to the overall diet and can affect proteins and energy from all the different feed ingredients (feed, grain, diet, etc.). There are many types of plant biology, and some of the most effective feed efficiencies are:
• Tannin: a complex polyphenolic compound of plants. Their type and concentration may vary greatly depending on the extraction. Their properties specifically allow for binding to proteins, but the amount and quality of the extract is very important to ensure adequate binding in the rumen and release in the gut.
• Essential oils: secondary metabolites and volatile constituents. There are a variety of families with different ways of acting. In the literature, these compounds show antimicrobial activity and can affect the metabolism of rumen microbes and rumen proteins and energy.
• Spices such as paprika extract. They have demonstrated that cows can be increased in different trials and are associated with an increase in the natural buffer secreted by saliva, which has a positive effect on rumen pH.
Tested in the Holstein herd
One of the products, Valopro, was recently tested differently in field trials in Ontario, Canada. After 1 month of control before the experiment, 70 Holstein cows were supplemented with 20 g/day of product within 4 months. Milk production increased from 29 to 32.2 L/N/day, protein content increased from 3.15 to 3.27%, and fat content decreased from 4.31 to 4.05% (mainly due to dilution). During the trial, protein, energy and feed efficiency increased from 16%, 15% and 15%, respectively (Figure 1). In the context of the trial, farmers' income increased by $58.3 per day due to increased milk production and lower feed costs.
Monitoring feed efficiency has significant economic advantages. It allows farmers to regularly adjust the nutrition of the herd in order to maximize milk production income. The use of single or mixed plant biology can be part of a global approach to improving feed efficiency. This product can be implemented in two different ways: top feeding or diet optimization to improve performance or reduce feed feed costs without degrading animal performance. Due to optimization, it is very interesting to reduce the cost of food, especially in the case of low milk prices and high raw material costs.