Dairy Cow Feed
Balancing Amino Acids in Dairy Cow Feed
Amino Acid Profile of Protein Sources
Bacteria in the rumen play a significant role in supplying necessary energy and nutrients to cows. Still, some necessary nutrients come from the portion of feed ingredients that escapes degradation in the rumen.
Metabolizable protein (MP) is the protein available to cows for maintenance, growth, pregnancy and milk production. Usually 50-70 percent of MP is derived from microbial, or rumen bacterial, protein. This rumen bacterial protein utilizes rumen degradable protein and non-protein nitrogen, and has an amino acid profile that resembles that of a cow’s muscle and milk protein.
The rest of a cow’s MP must be supplied from rumen undegradable protein (RUP). The amino acid profile for RUP is mainly dependent on the feed ingredients in a cow’s diet.
As shown in table below, most feed ingredients that are typically used in a cow’s diet are very low in lysine and methionine in terms of percent of crude protein (CP). This is one of the main reasons that lysine and methionine tend to be deficient for protein synthesis in cows.
Total Mixed Rations
Total mixed rations (TMR) is a common method used to optimize dry matter in a feed and thus increase nutrient availability for herds. TMR contains the right balance of nutrients a dairy cow needs in each mouthful. This balance of nutrients results in a more stable environment for the microbes that live in the rumen, which enable the cow to properly digest food. As a method, TMR helps dairy farmers and nutritionists improve feeding efficiency, and it helps dairy cows achieve optimal milk production.
Using TMR requires farmers to mix additives and supplements such as rumen-protected products in the dairy cow’s feed prior to feeding it to the cows. The additive may need to remain in the TMR up to 24 hours before the dairy cows consume it. TMR can have a moisture proportion of around 40-50 percent, and this high-moisture environment may render the rumen-protected product vulnerable. This is why it’s important to ensure the stability of a rumen-protected supplement before using it in TMR.
See the TMR Stability Test here.
Dairy Feed Options
While all cattle use energy and nutrients from feed for normal bodily function and growth, dairy cows have different needs at different stages of production. Pregnant and lactating cows, for instance, expend much of the energy from feed for pregnancy and lactation, respectively, so they require a dairy cow feed with higher energy content.
What are the ingredients in dairy feed?
Today, an average dairy cow produces 6-8 gallons of milk daily.2 In order to maintain that level of production, a dairy cow needs close to 100 pounds of feed, including 50 pounds of dry matter, each day. When lactating, a dairy cow cannot consume enough forage to reach her nutritional needs, so a feed that is balanced with grains, supplements and minerals is especially important.
During a dairy cow’s time of peak production, she may require anywhere from 3 to 10 times as much protein and energy as she needed in late gestation.3
The feed for a lactating cow in peak production should contain:
- Higher energy content.
- More nutrients.
- Added fat.
- Added crude protein.2
Additionally, lactating cows require different nutrition at different stages of lactation related to how much milk they produce. The table below describes these different nutritional needs.
Table: Milk Yield and Nutrient Guidelines for Lactating Dairy Cows2,4.
Supplementing the lactating cow’s diet
AjiPro®-L offers dairy nutritionists flexibility in feed formulation, allowing them to raise the proportion of lysine in total metabolizable protein (Lys/MP ratio) without negatively affecting rumen fermentation. Farmers and nutritionists can use AjiPro®-L combined with a rumen protected methionine source to maximize nutrition.
Below are the recommended amounts of MP, MP-Lys, and MP-Met to feed cows in order to maximize microbial protein.
We also recommend the amount of AjiPro®-L to use. Keep in mind that the amount of AjiPro®-L you will use depends on the size of your herd and goals for feeding:
- Knapp, J. and St.Pierre, N. (2011) Blood meal variability affects dairy performance. Feedstuffs Vol. 83, No. 10.
- Macdonald Campus of McGill University, Faculty of Agricultural and Environmental Sciences. Feeding the Dairy Cow During Lactation. [Handbook].
- Chiba, L. I. (2014). Animal Nutrition Handbook 3rd.
- Kavanaugh, S. (n.d.) Feeding the Dairy Cow.