Feed & Additive Magazine Issue 2 March 2021

ARTICLE 70 FEED & ADDITIVE MAGAZINE March 2021 supplies as predictors of milk production and milk protein yield. The results showed that Met and Lys supplies are better predictors of both milk produc- tion and milk protein yield than the supply of MP. This is because when one of the AA is limiting, this effectively causes an oversupply of all other AA’s to the cow. When the missing block (the limiting AA) is provided, a new molecule of milk protein can be synthesised. Therefore, the surplus of other amino acids will decrease, and the utilisation efficiency of MP will be improved. When dairy nutritionists rely only on the amount of MP available with no consid- eration for limiting AA’s the actual milk yield will - in almost all cases - be lower than expectation. This clearly indicates that although the supply of total MP might be adequate, the balance of the available AA’s can be incorrect, which limits milk production. It is widely accepted that by formulating with individual AA’s, the improvement in MP utilisation efficiency will provide the dairy nutritionist with an opportu- nity to formulate diets with lower CP content with- out compromising milk yield and milk components. However, it is important to accurately predict the exact amount of metabolisable Met or Lys which can be used by the individual cow to reach this level of precision in our diets. Accurate and precise measure- ment techniques are imperative for obtaining reli- able experimental results on N and AA utilisation. Knowing the rumen protection rate and intestinal availability of the RP-AA supplement, gives us the primary AA availability to the host animal (Hristov et al., 2019). Kemin’s experience indicates that when AA nutrition is implemented, applying the latest available nutritional knowledge and with the right rumen protected AA supplements (both methionine and lysine), improved animal performance with im- proved nitrogen efficiency (Table 1) is observed. In conclusion, cutting-edge ruminant nutritionists are already balancing their diets for AA’s rather than crude protein. Adopting the concept of balancing for individual AA’s can bring endless opportunities for maximising dairy herd profitability. With con- tinuously increasing protein feed prices and milk production costs, dietary reformulation using a lower crude protein content whilst balancing for AA’s, us- ing rumen protected Met and Lys, can maximise MP utilisation, as well as dairy cow production, health, and fertility. Additionally, balancing for the first two limiting AA’s will decrease the overall N excretion to the environment, improving N and feed efficiency. Table 1. Milk components and productivity expressed as percentage of increase after amino acid implementation related to non-amino acid use. TPAS-19-1075. (*) Return on investment. Kemin Amino Acid Program Milk Production +7.5 % Milk Fat +8.6 % ROI (*) 4.9 Milk Protein +5.6 % Milk Casein +5.2 % Plasma Urea -26.7 % N efficiency +5.8 % With continuously increasing protein feed prices and milk production costs, dietary reformulation using a lower crude protein content whilst balancing for AA’s, using rumen protected Met and Lys, can maximise MP utilisation, as well as dairy cow production, health, and fertility.