THC from Hemp-Fed Dairy Cows Transfers to Milk but Clears After Two Weeks
When dairy cows ate spent hemp biomass, THC transferred to milk at levels exceeding safe human intake thresholds, but became undetectable after 12 days of hemp withdrawal.
Quick Facts
What This Study Found
Less than 1% of cannabinoids from spent hemp biomass transferred to cow milk, but THC levels in milk still exceeded the acute reference dose of 1 ug/kg body weight for human consumers. THC accumulated heavily in adipose tissue and remained detectable there 30 days after withdrawal. CBD and CBDA were detectable in plasma 90 days after hemp withdrawal (post-calving). Milk THC became undetectable after 12 days of hemp withdrawal.
Key Numbers
Less than 1% cannabinoid transfer to milk. THC in milk exceeded acute reference dose of 1 ug/kg BW during feeding. THC undetectable in milk after 12 days withdrawal. THC detectable in adipose tissue 30 days after withdrawal. CBD/CBDA detectable in plasma 90 days after withdrawal.
How They Did This
Dairy cows fed spent hemp biomass (cannabinoid extraction byproduct). Cannabinoids measured in milk, blood, and tissues using UHPLC-MS/MS at multiple timepoints during feeding and after withdrawal.
Why This Research Matters
Spent hemp biomass has excellent nutritional value as livestock feed but is banned in most countries due to THC concerns. This study quantifies the actual risk and identifies a practical withdrawal period that eliminates consumer exposure.
The Bigger Picture
The data suggests a path to safe use of hemp byproducts in dairy farming: a two-week withdrawal period before milking eliminates THC risk to consumers. This could unlock a significant feed resource currently going to waste.
What This Study Doesn't Tell Us
Small number of animals typical for dairy feeding studies. THC accumulation in adipose tissue raises questions about meat safety. 90-day CBD persistence in plasma is unexplained. Specific SHB composition may vary between sources.
Questions This Raises
- ?Is a 30-day withdrawal sufficient for meat safety given adipose THC accumulation?
- ?Why do CBD and CBDA persist in plasma for 90 days after hemp withdrawal?
Trust & Context
- Key Stat:
- THC became undetectable in milk after 12 days of hemp withdrawal from cow diets
- Evidence Grade:
- Well-designed feeding study with precise analytical methods, but small sample size typical of dairy research.
- Study Age:
- 2025 publication.
- Original Title:
- Cannabinoid Distribution and Clearance in Feeding Spent Hemp Biomass to Dairy Cows and the Potential Exposure to Δ9-THC by Consuming Milk.
- Published In:
- Journal of agricultural and food chemistry, 73(22), 13934-13948 (2025)
- Authors:
- Irawan, Agung, Nosal, Daniel G, Muchiri, Ruth N, van Breemen, Richard B, Ates, Serkan, Cruickshank, Jenifer, Ranches, Juliana, Estill, Charles T, Thibodeau, Alyssa, Bionaz, Massimo
- Database ID:
- RTHC-06715
Evidence Hierarchy
Read More on RethinkTHC
- CBD-oil-quality-guide
- anxiety-medication-after-quitting-weed
- cannabis-chemotherapy-nausea
- cannabis-chronic-pain-research
- cannabis-epilepsy-CBD-Epidiolex
- cbd-anxiety-research-evidence
- cbd-for-weed-withdrawal
- cbd-vs-thc-difference
- medical-benefits-of-cannabis
- quitting-weed-before-surgery
- quitting-weed-medication-interactions
- quitting-weed-pregnancy
- quitting-weed-pregnant
- seniors-older-adults-cannabis-risks-medications
- weed-breastfeeding-THC-breast-milk
Cite This Study
https://rethinkthc.com/research/RTHC-06715APA
Irawan, Agung; Nosal, Daniel G; Muchiri, Ruth N; van Breemen, Richard B; Ates, Serkan; Cruickshank, Jenifer; Ranches, Juliana; Estill, Charles T; Thibodeau, Alyssa; Bionaz, Massimo. (2025). Cannabinoid Distribution and Clearance in Feeding Spent Hemp Biomass to Dairy Cows and the Potential Exposure to Δ9-THC by Consuming Milk.. Journal of agricultural and food chemistry, 73(22), 13934-13948. https://doi.org/10.1021/acs.jafc.5c02827
MLA
Irawan, Agung, et al. "Cannabinoid Distribution and Clearance in Feeding Spent Hemp Biomass to Dairy Cows and the Potential Exposure to Δ9-THC by Consuming Milk.." Journal of agricultural and food chemistry, 2025. https://doi.org/10.1021/acs.jafc.5c02827
RethinkTHC
RethinkTHC Research Database. "Cannabinoid Distribution and Clearance in Feeding Spent Hemp..." RTHC-06715. Retrieved from https://rethinkthc.com/research/irawan-2025-cannabinoid-distribution-and-clearance
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.