Researchers at Ohio State University found that dietary changes can boost the amount of milk cows produce during the lactation period. Changing elements in the diet to improve herd feed efficiency from 1.3 kg milk/kg dry matter to 1.5, lowers the amount of dry matter cows need to consume to produce a certain amount of milk. From an income perspective, this can result in a significant increase in income over feed cost.
Global Programme Manager Ruminants
Selko Feed Additives
The decisions dairy farmers make to support their herds’ performance also have a big influence on the economics and environmental footprint of their farm. Improving feed efficiency is a proven strategy for increasing milk yield, improving income, and reducing the environmental footprint of dairy farming.
Simply defined, efficiency means producing more without increasing inputs. Recently, the dairy sector has turned its attention toward improving feed efficiency. Given that the cost of feed is the largest contributor to production costs, improving the digestibility of dietary fibre is a key opportunity to drive better feed efficiency.
Research conducted by Trouw Nutrition and leading agricultural universities show the benefits of dietary strategies to improve fibre digestibility in dairy cows. Below are excerpts of a conversation* with Jac Bergman, Global Programme Manager Ruminants at Selko Feed Additives that addresses how improving fibre digestibility can unlock keys to improved efficiency, economics, and environmental sustainability.
What does feed efficiency mean in terms of dairy farming and how is this metric calculated?
Viewed through the lens of dairy farming, feed efficiency can be defined as the amount of fat corrected milk yielded per unit of dry matter consumed. In the U.S. dairy cow efficiency is most often calculated by dividing the kg of Energy Corrected Milk (ECM) by the kg of Dry Matter Intake (DMI). This method of calculating feed efficiency can be adapted to fat and/or energy with various baselines. In the U.S., 3.5% is typically the fat corrected milk measure, whereas in most European nations the standard is 4%.
Other ways for defining feed efficiency, include the kg of milk solids per kg of dry matter consumed, kg of milk per hectare (for cows in pasture environments), kg of nitrogen per kg of nitrogen consumed and kg of milk solids per unit of carbon dioxide output or greenhouse gas generated.
Of course, herds are comprised of individual cows and when calculating feed efficiency for a dairy herd, there can be different efficiency values for cows of different ages or in different lactation stages, so these herd characteristics should be considered.
How much can dietary changes improve feed efficiency?
Researchers at Ohio State University found dietary changes can boost the amount of milk cows produce during the lactation period. Changing elements in the diet to improve herd feed efficiency from 1.3 kg milk/kg dry matter to 1.5, lowers the amount of dry matter cows need to consume to produce a certain amount of milk. From an income perspective, this can result in a significant increase in income over feed cost. As the feed efficiency of lactating cows can vary from <1.3 to >2.0, both income over feed costs and the environmental footprint can vary widely between dairy farms.
What are some factors influencing dairy cows’ feed efficiency?
A long list of factors can influence efficiency, but the four main ones are: ingredient digestibility which relates to feed quality, a cow’s days in milk as herds can become less efficient during the second half of lactation, somatic cell count because poor udder health can reduce milk yields and, rumen acidosis which affects digestion and impedes feed passage.
Among these factors, ingredient digestibility stands out as an opportunity to influence rumen performance and subsequently economics and environmental stewardship. Even the best breeding and management practices will not deliver the benefits if a cow’s rumen function is not operating at an optimal level. Here is where dietary tweaking can help.
How can dietary tweaks support feed efficiency?
More digestible feeds release more energy and protein to the animal which supports better feed efficiency. Improved understanding of the role that dietary, metabolizable protein plays for lactating dairy cows has established a relationship between protein in the diet and milk yield. When considering protein in the diet certain protein elements are especially valuable for supporting ruminal microbes.
Ammonia, amino acids, and peptides (short chains of amino acid) are important. Sources of these acids include rumen degraded microbial protein, rumen undegraded protein and rumen protected amino acids – a more expensive option. While several amino acids are considered essential, they are not provided at required levels within most feed ingredients. Typically, a feed ingredient will have some, but not all of the amino acids. Rumen-protected amino acids are costly but potential benefits can include an increase in milk protein levels, an increase in overall milk yield during lactation and higher milk fat levels.
Milk urea nitrogen is a measure of the cow’s ability to capture nitrogen originating from ongoing microbial protein synthesis in the rumen. The process measures the amount of ammonia processed by the liver, that becomes trapped in the milk. If levels are too high, the result can be reduced nitrogen efficiency and both fertility and rumen function may start to decline.
Trace minerals provide an interesting option for supporting feed digestibility. Careful attention to the trace minerals included in a cow’s diet can have a big impact on rumen function and thus the digestibility of the dairy cow’s diet.
How does trace mineral management support rumen performance in dairy cows?
Trace minerals are an essential part of ruminant rations. As the basal diet does not supply these essential nutrients at adequate levels, they must be supplemented. But not all trace minerals sources are the same and the source of trace mineral has been shown to play a big role in how much of the mineral is available for use by the animal.
Sulphate trace minerals have been used as a source of trace mineral supplementation in ruminant rations for the past 75 years. They are also commonly used in footbaths because they readily release trace metal ions known to be antimicrobial. While this mode of action is good in footbaths where free metal ions can detach and attack hoof related infections, such properties are highly undesirable in the rumen. Inside the rumen, sulphate salts are highly soluble upon contact with moisture, followed by their release of high concentrations of free metal ions that can now attack rumen, fiber digesting bacteria.
Additionally, as trace minerals break down following contact with moisture, they can interact with other essential ingredients and additives in the feed, potentially reducing the value of costly feed ingredients.
What can farmers do to protect their herds and their business from the challenges posed by sulphates?
Choosing a trace mineral source that is not soluble is a good first step in preventing the harm posed by sulphate minerals. Hydroxy forms of trace minerals are largely insoluble at a pH of 4 or higher. As the rumen pH of dairy cattle is typically in the range of 6 to 6.5, hydroxy trace minerals are essentially insoluble (inert) within the rumen. In the abomasum, where the pH is usually below 3, IntelliBond crystals dissociate layer by layer, resulting in a gradual and sustained release of trace metal ions in the cow’s duodenum. This strategic release supports the higher bioavailability of hydroxy trace minerals by the animal to support performance.
Can the choice of trace mineral support other desirable activity in the rumen?
As rumen fermentation improves, the production of volatile fatty acids which serve as an important source of energy increase. A trial including two group of animals compared animals fed sulphate trace minerals to a group receiving IntelliBond. Feeding IntelliBond resulted in an increase of volatile fatty acid production in the rumen of 11%, resulting in an increase in propionate production of 15% compared to animals receiving the control diet.
Another trial conducted at Cornell University in New York State found that cows fed hydroxy trace minerals had increased milk production in early lactation compared to cows fed sulphate trace minerals. And from an efficiency perspective, cows fed hydroxy trace minerals reached peak production sooner and produced 3.5 liters more milk at the peak of lactation. The dynamics of lactation persistency in dairy cows indicate that 1 kg of extra milk at peak lactation is equal to 200 kg of extra milk per lactation. Other studies conducted with IntelliBond have shown a significant increase in fat corrected milk.
Beyond improving efficiency and the environment, how can strategies to support fiber digestibility support producers’ economics?
Feed efficiency is a key driver of dairy farm profitability. By tweaking the diet to improve fibre digestibility – like replacing sulphate trace minerals with hydroxy trace minerals – cows can produce more milk from the same amount of feed. Depending on the milk price, the incremental cost to supplement a cow with IntelliBond throughout her entire production cycle can be earned back within 3 to 4 weeks, resulting in a strong return on investment and a significant improvement of income over feeding costs on the dairy farm.
References available upon request
How can hydroxy trace minerals improve fibre digestibility?
Microflora in the rumen play an essential role in digesting dietary fibre. However, the soluble nature of sulphate minerals can allow oxidative salts to dissociate and reduce microflora’s ability to digest fibre. Multiple peer-reviewed studies have shown that completely replacing sulphate trace minerals with IntelliBond hydroxy trace minerals resulted in a significant improvement of fibre digestibility. A meta-analysis of 14 studies carried out with IntelliBond hydroxy trace minerals showed an average improvement of NDF digestibility of 1.7%. Prior University research conducted with dairy cows has shown that each one-point difference in NDF digestibility can represent an extra .25 to .3 kg of daily Energy Corrected milk production.
In general, how do you place a value on a high efficiency cow?
Research from cows tracked at five commercial farms provides some good data to support both the economics and environmental benefits of efficiency. Cows were grouped in quadrants and researchers examined the performance of the top performing 25% and least efficient 25%. The highly efficient cows generated about 49% more profit depending on input costs and milk price. Cows in the least efficient group tended to eat more dry matter and concentrate compared to their highly efficient counterparts – yet they produced abut 10 kg less milk per day.
And from an environmental perspective, cows with high feed efficiency have been found to generate less methane and produce less manure compared to less efficient cows. The FAO reports that livestock production is responsible for 14.5% of all global greenhouse emissions, of which the dairy sector accounts for about 2.2% of greenhouse gas emissions. Thus, improving dairy cows’ productivity can support efforts to reduce methane release.
*This conversation is based on a webinar broadcasted in collaboration with Dr. Mike Hutjens from the University of Illinois.
About Jac Bergman, DVM
Graduated from the Veterinary Faculty in Utrecht, the Netherlands in 1990. Worked for 4 years in private practice and the Ambulatory clinic of the Utrecht Veterinary Faculty. Joined Intervet Animal Health in 1994 and worked there for 20 years in various roles. Currently working with Trouw Nutrition as Programme Manager Ruminant Feed Additives.
