August 26, 2025

Histidine: a limiting amino acid for dairy cows, with Dr. Alexander Hristov, Penn State University; Matt Budine, Progressive Dairy Solutions

58 minutes

Dr. Hristov gave a webinar titled “Histidine: a limiting amino acid for dairy cows” on March 4, 2025, and joins the podcast in this episode for a deeper dive into the topic.

Panelists introduce themselves and give some background on their interest in histidine (00:52)

Dr. Hristov gives an overview of his webinar presentation, touching on some of the first research projects that showed lower protein diets resulted in no change in plasma methionine, but a decrease in plasma histidine. When dietary protein decreases, the cow relies more on microbial protein to meet her needs. Histidine content is about 20% less than methionine content in microbial protein. He also notes there are some short-term reserves of histidine in the body, so short-term studies may not show a histidine deficiency when indeed there is one. (7:08)

Matt gives some perspective as a consulting nutritionist about the importance of histidine in diet formulation for his clientele. He agrees with Dr. Hristov about the higher requirement for histidine compared to methionine, and he generally formulates diets with 1.1 times more histidine than methionine. (12:38)

The panelists share their experiences with the responses observed from providing additional histidine to lactating cows, including milk and component yields and changes in dry matter intake and body condition. They also talk about how muscle loss can mask a histidine deficiency in the short term. (15:43)

The panelists discuss the challenges in determining histidine requirements and finding reliable sources of highly bioavailable histidine. (24:04)

Why is rumen-protected histidine not commercially available? Clay explains it is due to the high cost of histidine. There are no feed-grade sources, and using human-grade sources is cost-prohibitive. Dr. Hristov notes swine nutritionists are starting to pay more attention to histidine, which might bring the cost down if demand increases. Matt notes aquaculture is also interested in histidine. (33:58)

Matt comments that increasing fat content can be problematic for cheese plants. He sees increasing milk protein yield may be the next frontier of dairy nutrition and histidine might play an important role. The panel discusses the role milk pricing has played in the increased fat content. (37:32)

The panel discusses what other amino acids might be important in dairy nutrition as research continues. They also touch on methane mitigation and reducing methane intensity per unit of milk. (43:45)

Panelists share their take-home thoughts. (54:31)

View Dr. Hristov’s webinar on this subject by visiting https://balchem.com/anh/podcasts-webinars/histidine-a-limiting-amino-acid-for-dairy-cows-2/

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By Balchem Animal Nutrition & Health

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