Dairy cows have an important role in providing food security for humankind by converting human-inedible food, such as forage and byproducts, to human-edible, high-quality protein, micronutrients and essential fatty acids. However, the importance of dairy cattle to human life is being challenged because of concerns that cattle may have a negative impact on the environment and climate change.
Dairy cattle’s unique digestive system allows them to eat foods humans can’t, but during the digestive process they produce methane, which is a greenhouse gas. Dairy cattle also have a poor efficiency of converting feed protein into milk protein, with higher levels of protein and nitrogen excreted in the manure than other livestock species. Some of the excreted nitrogen in the manure is converted to the greenhouse gas nitrous oxide.
The dairy industry has experienced continuous change from the development of new technologies, new understanding of the cow’s biology that can be used to improve her efficiency and new management practices. From these advancements, the knowledge gained was primarily directed internally, leading to improved dairy farm profitability through improved nutrition and farm management practices. However, new external forces are developing and are expected to become a reality that will change the landscape of the dairy industry. These external forces are coming in an effort to decrease the impact that the dairy industry has on the environment. This includes decreasing methane emissions and reducing nitrogen excretion to make the dairy industry more greenhouse-gas friendly. It is possible that we will see dairy farms directly influenced by government subsidies, tax credits and regulations.
Dairy farms may also be able to sell carbon credits to other companies wanting to show an improved environmental footprint of their business. Milk processing companies may want to add labels to their product packaging and use marketing material showing that their milk products were produced with greenhouse-gas friendly methods, thereby requiring dairy farms to change their farming practices. The goal is for dairy farms to get to balanced carbon creation and utilization with the term “net zero” soon to become a common term in our vocabulary.
Through controlled research and on-farm trials, our company has developed a holistic approach implementing precision formulation and specific management recommendations. Our company provides a ration-balancing platform that optimizes the balance of nutrient supply with the nutrient needs of the high-performance cow. The precision of this ration modelling maximizes dairy farm profitability and reduces the environmental impact by 1) optimizing conversion of feed ingredients to produce fat and protein yield, 2) balancing all sources of energy ingredients used, 3) feeding a proven phytogenic blend and 4) selecting the best protein and amino acid sources in the diet to meet the rumen protein needs and metabolic amino acid demands, which decreases methane emissions, nitrogen excretion and nitrous oxide output.
Nutrition strategies that improve the conversion efficiency of feed to milk have been shown to decrease methane production. As demonstrated in Figure 1, by improving milk efficiency (energy-corrected milk/dry matter intake, or ECM/DMI) from 1.4 to 1.6, lactating dairy cow methane emissions can be reduced by 15%. Formulating rations that support a dairy cow’s ability to reach her full genetic potential will decrease methane production per gallon of milk produced. Specifically, supplying without overfeeding the nutrients needed by the high-performing cow, she becomes more efficient, resulting in less production of methane and excretion of nitrogen. Our model also considers current ingredient prices, which have risen dramatically over the last year, and the rates and digestibility of each ingredient. Utilizing extensive nutrient testing, our company evaluates the availability and utilization of each ingredient, enabling us to define the optimal cost ration to reach maximal production of milk volume and component yield with the lowest emission of greenhouse gases.
Ingredient selection and the amount of each ingredient included in dairy cattle rations affect the production of enteric methane and nitrogen excreted. For energy ingredients such as carbohydrates and fat sources, selecting the sources and amounts used directly affect the methane that comes from the animal and manure. Through laboratory analyses and precise ration modelling, the rates and digestibility of each source is considered for sugar, starch, soluble fiber, neutral digestible fiber (NDF) and fatty acids. Each are evaluated to find the best blend of ingredients that optimize rumen efficiency, metabolic energy availability and lowest methane production.
Another component of our holistic approach is feeding products comprised of specially selected phytogenics, which are standardized and protected in a microencapsulated matrix. This provides a natural solution of proven technologies to alter rumen fermentation for favorable production responses. Data from 17 lactating cow trials have shown a 2.6% improvement in milk production and decrease in milk urea nitrogen (MUN) by cows fed a proprietary phytogenic formulation. These targeted phytogenics impact the rumen volatile fatty acid (VFA) profile by lowering acetate production and increasing propionate and butyrate production (Table 1). This results in more available energy, which can be used for production, with less methane released. Additionally, as shown in the trial reported in Table 1, this formulation decreases ammonia production in the rumen and increases amino acid flows from the rumen. The net result is an increase in metabolizable protein for milk protein synthesis and a reduction in nitrogen excretion.
Protein nutrition and optimization is complex in dairy cattle because of the need to provide nutrients for both ruminal microbes and the metabolic needs of the cow or growing heifer. For the rumen, consideration needs to be given for the amount of rumen degradable protein, peptides and soluble protein to meet the requirements of the diverse microbial species breaking down carbohydrate to VFAs and making amino acid-rich microbial protein. The microbial protein produced in the rumen only supplies around 60% of the protein required by the high-producing cow. To allow her to reach her genetic potential, the remaining 40% of the protein is supplied with rumen bypass protein.
The intestinal digestibility and amino acid profile of the bypass protein has a large impact on milk yield and fat and protein percentages of the milk. Most nutritionists use plant protein sources that have been heat treated, or animal proteins such as blood meal, along with rumen-protected sources of lysine and methionine to supply the needed bypass amino acids. Animal protein sources are high in lysine, which is one of the amino acids in short supply in most rations. With the value of milkfat and protein on dairy farmers’ milk checks nearing an all-time high, the benefit to supplying the optimal supply of bypass amino acids has never been more critical to farm profitability. Additionally, the cost of all bypass protein sources have increased, but rumen-protected amino acid sources haven’t, which makes it more profitable to feed rumen-protected amino acids. With precise protein modelling, the diet is balanced with the most digestible sources of bypass protein and with the optimal ratio of amino acids, which allows for a lower-protein diet. This approach results in decreased methane emissions, nitrogen excretion and nitrous oxide emissions.
The digestibility of animal protein sources – such as blood meal, meat and bone meal, and feather meal – are known to be more variable and lower than plant sources, yet they are widely utilized in lactating cow diets. Our company conducted a trial with control cows receiving 0.5 pound of blood meal and the treatment cows receiving 0.4 pound of a bypass protein blend and 0.1 pound of ADM’s rumen-protected lysine. The plant protein blend and rumen-protected lysine diet was lower in total protein and bypass protein; however, our model predicted a similar level of performance because of the higher digestible sources of protein and better supply of metabolizable lysine. By replacing the blood meal with more digestible sources of bypass amino acids, the cows produced similar levels of fat and protein with a higher conversion of feed to fat and protein yield and a substantially higher income over feed cost (IOFC) (Table 2).
Additionally, the conversion of consumed protein to milk protein was dramatically improved as protein efficiency was improved from 25.6% to 33% for cows receiving the bypass protein blend and rumen-protected lysine diet. Researchers use MUN as proxy for the amount of protein that is lost and nitrogen that is excreted. In this test, MUN was dropped from 14 to 11.7 milligrams per deciliter when fed the bypass protein blend and rumen-protected lysine ration. By optimizing the bypass amino acid supply and digestibility, the total level of protein fed can be reduced along with achieving increased metabolic efficiency, resulting in a reduction of methane emission and nitrogen excretion.
Improved dairy cow efficiency, health and profitability, while decreasing methane emission and nitrogen excretion, can be achieved with a more precise ration-formulation approach. Often, dairy producers use milk production per cow as their criterion for success but overlook that an improvement in feed efficiency has a three-fold higher relationship to profitability. Utilizing a targeted approach focused on balancing carbohydrates being fed, feeding highly digestible protein sources balanced on amino acids and feeding specially selected phytogenics, strategically improves conversion of feed to milkfat and protein while reducing the production of volatile compounds that contribute to greenhouse gas production and climate change.
References omitted but are available upon request. Click here to email an editor.
