Benefits of feeding rumen protected lysine during transition period.


The transition period for dairy cows, or periparturient period, is generally considered to span the time-frame 3-weeks prior to 3-weeks post parturition.  During each of these 3-week periods, cows are challenged with negative energy and protein balance due to higher requirements of either 1) prepartum conceptus growth and mammary gland development or 2) postpartum milk production.  The negative protein and energy balance are worsened by a natural drop in prepartum DMI and a slow rise in postpartum DMI.  In addition, these cows typically experience immune deficiency during the transition period.  Neutrophils and lymphocytes content of the blood may be depressed as much as 25-40%, lessening the cow’s ability to ward off infections.  A compromised immune system predisposes a cow to mastitis, metritis and retained placenta.

While both protein and energy are important, there is evidence that supplying adequate protein during transition period is more impactful on milk production compared with energy (Larson 2014). The metabolizable protein (MP) requirement for a typical Holstein close-up cow is estimated to be 1,125 g/d (Cornell Net Carbohydrate and Protein System version 6.5.5).  To account for herd variability, a practical target for MP was suggested to be 1300g/d by Van Saun and Sniffen (2014).  However, cows require amino acids and not simply crude protein, therefore the supply of indispensable amino acids is paramount.  Methionine and lysine are the first two limiting amino acids in typical dairy diets (NRC 2001).

Supplemental rumen-protected methionine (RP-Met) has been extensively researched and shown to be beneficial when fed prepartum as well as during lactation.  Feeding  RP-Lys prepartum is also becoming a common and reliable practice resulting in increased DMI and milk production (Socha et al. 2005, Elsaadawy et al. 2022).

A recent multi-faceted study conducted by the University of Illinois evaluated the effects of feeding RP-Lys (AjiPro®-L, Ajinomoto Health & Nutrition North America, Inc.) to cows during the transition period on nutritional status, milk production, immune function, reproduction and calf performance.  Eighty-nine multiparous cows (parity: 3.3 ±1.1) were assigned to either a RP-Lys supplemented group or Control prepartum.  After calving, each group was divided into either a RP-Lys supplemented group or Control in a 2X2 factorial design.  Cows fed RP-Lys consumed 98 and 160 g/day of metabolizable lysine (m-Lys) pretpartum and postpartum, respectively (roughly 70g of AjiPro®-L).  Control cows consumed 80 and 143 g/d of m-Lys prepartum and postpartum, respectively.  The researchers found that cows fed RP-Lys prepartum consumed1.3kg more feed dry matter during the first 4 weeks after calving compared with Control cows (18.1  vs 16.8 kg/d, P=0.08) (Fehlberg et al. 2020).  This higher energy intake supported a significant increased production of energy corrected milk (48.8 vs. 44.2 kg/d, P=0.02), fat (1.9 vs. 1.7 kg/d, P=0.04) and protein (1.4 vs. 1.3 kg/d, P=0.04).  In addition, supplementing cows with RP-Lys either pre or postpartum, reduced plasma BHBA concentrations.  Immune function of cows consuming RP-Lys prepartum was improved as evidenced by a lower concentration of haptoglobin during the first 2 weeks after calving and higher oxidative burst of monocytes at day 7 after calving (Fehlberg et al. 2020 ADSA abstract).  In addition, cows consuming RP-Lys pre and postpartum had less uterine inflammation at 18 and 25 days after calving compared with Control cows (Guadagnin et al. 2020). Calves from cows fed RP-Lys prepartum had similar birth weights but consumed 2.5% more milk replacer dry matter in their first 6 weeks and had fewer number of medicated events (Thomas et al. 2022).


Providing adequate amounts indispensable amino acids, especially lysine and methionine, to cows during the transition period can prime them for a successful lactation by increasing dry matter intake, improving energy and protein balance, improving immune response and reducing uterine inflammation.  In addition, calves from cows fed supplemental RP-Lys prepartum were more vigorous.


  • Supplement RP-Lys to prepartum cows to equal a total of at least 90-95g of m-Lys per head per day. This includes dietary and microbial m-Lys.
  • Be aware that lower dry matter intake as calving approaches will also increase the need for supplemental RP-Lys to maintain 90g/d intake of m-Lys.
  • For best results, continue feeding RP-Lys to cows after calving and during lactation to meet their lysine needs.
  • Choose a RP-Lys product that has third party research that verifies it is stable in the TMR and is efficacious to deliver metabolizable lysine to the cow.
  • AjiPro®-L is the most reliable RP-Lys product in the dairy market.

Elsaasawy, S. A., Z. Wu, H. Wang, M. D. Hanigan and D. Bu. 2022. Supplementing ruminally protected lysine, methionine, or a combination improved milk production in transition cows.  Frontiers Vet. Sci. 9: 780637

Fehlberg, L. K., A. R. Guadagnin, B. L. Thomas, U. Sugimoto, I. Shinzato, and F. C. Cardoso. 2020. Feeding rumen-protected lysine prepartum increases energy-corrected milk and milk component yields on Holstein cows during early lactation. J. Dariy Sci. 103:11386-11400.

Fehlberg, L. K., A. R. Guadagnin, B. L. Thomas, U. Sugimoto, I. Shinzato, and F. C. Cardoso. 2020. Feeding rumen-protected lysine prepartum enhanced plasma indicators of liver function and increased oxidative burst capacity postpartum in Holstein cows.  ADSA abstract #w53, J. Dairy Sci. 103(Suppl. 1), 281-282.

Guadagnin, A., L. Fehlber, B. Thomas, Y. Sugimoto, I. Shinzato, and F. Cardoso. 2020. Effects of feeding rumen-protected lysine during the transition period on postpartum uterine health and follicular dynamics of Holstein cows.  ADSA abstract #272, J. Dairy Sci. 103(Suppl. 1), 106.

Larson, M., H. Lapierre and N.B. Kristensen.  2014. Abomasal protein infusion in the postpartum transition dairy cows: Effect on performance and mammary metabolism.  J. Dairy Sci. 97:5608-5622.

National Research Council. 2001. Nutrient Requirements of Dairy Cattle. 7th rev. ed. Natl. Aca. Sci., Washington. DC.

Socha, M. T., D. E. Putnam, B. D. Garthwaite, N. L. Whitehouse, N. A. Kierstead, C. G. Schwab, G. A. Ducharme, and J. C. Robert.  2005. Improving intestinal amino acid supply of pre- and postpartum dairy cows with rumen-protected methionine and lysine.  J. Dairy Sci. 88:1113-1126.

Thomas B. L., A. R. Guadagnin, L. K. Fehlberg, Y. Sugimoto, I. Shinzato, J. K. Drackley, and F. C. Cardoso.  2022. Feeding rumen-protected lysine to dairy cows prepartum improves performance and health of their calves.  J. Dairy Sci. 105:2256-2274.

Van Saun, R. J. and C. J. Sniffen. 2014. Transition cow nutrition and feeding management for disease prevention. Vet. Clin. Food Anim. 30:689-719.

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