Effects of feeding sheep rations containing hemp stubble on nutrient digestibility, rumen parameters and animal performance

Gaye Krebs, Daniel De Rosa, Dana White, Bronwyn Blake, Kenneth Dods, Christopher May, Zi Tai, Edward Clayton, Emma Lynch

Research output: Other contribution to conferenceAbstract


The residue (stubble) following the harvest of a hemp crop for seed could be a useful feed for sheep (and cattle); however, the feeding value of this residue is unknown. The stem contains only trace amounts of tetrahydrocannabinol (THC), and it is generally believed in the wider hemp community, that grazing animals will not accumulate enough THC in their meat to be harmful to humans. However, this has not been previously investigated. Fifteen Merino wethers were maintained in individual pens and fed one of three pelletised experimental inclusion diets, as a 0% (Control), 28% (Hemp 1), and 56% (Hemp 2) pellet that delivered a diet meeting the nutrient requirements of the animals. Over the 42-day feeding period (following 14 days adaptation period), inclusion of hemp stubble had no adverse effects on either intake or live weight gain of the sheep. Including the hemp stubble in the diets resulted in improved nutrient digestibility as well as changed the profile of volatile fatty acids in the rumen, increasing the molar proportions of iso-butyric, iso-valeric, hexanoic and heptanoic acids. Volatile fatty acids are the key source of energy to sheep and cattle. Tetrahydrocannabinolic acid (THCA) was the only cannabinoid found in the plasma of the sheep fed the hemp-containing diets, and this was found at very low concentrations (< 16 g/L). THCA was also detected in the liver of two sheep fed the Hemp 1 pellets (208 and 381 g/kg DM) and two sheep fed the Hemp 2 pellets (163 and 201 g/kg DM). Cannabidiol (CBD) was detected in the liver of one sheep fed the Hemp 2 pellets (188 g/kg DM), but no liver THCA was detected in this sheep. Delta-9-tetrahydrocannabinol (Δ9-THC) was detected in the kidney fat and subcutaneous fat of all sheep fed hemp stubble while THCA was also detected in the subcutaneous fat of one of the sheep fed the Hemp 1 pellets. Four of the five sheep fed the Hemp 1 pellet and one of the five sheep fed Hemp 2 pellet had very low levels (52-72 g/kg DM) of Δ9-THC in the meat (loin). No other cannabinoids were detected in the meat. Current food standards regulations in Australia prohibit presence of any cannabinoid residues in commercial meat products; thus, either review of these food standards or determination of a withholding period is required to enable the safe feeding of hemp-stubble to sheep.
Original languageEnglish
Number of pages2
Publication statusPublished - 2022
Event3rd Australian Industrial Hemp Conference - Country Club Tasmania, Prospect Vale, Australia
Duration: 22 Mar 202225 Mar 2022
https://researchoutput.csu.edu.au/admin/files/269243811/Proceedings_of_the_3rd_Australian_Industrial_Hemp_Conference.pdf (Proceedings)
https://australianindustrialhempconference.com/event-information/submissions/ (Call for papers)


Seminar3rd Australian Industrial Hemp Conference
Abbreviated titleExceeding the vision
CityProspect Vale
OtherThe objective of the biennial Australian Industrial Hemp Conference is to serve as a national platform for growers, researchers, processors and end-market buyers. Industry participants attend our conference to present and discuss concepts, key issues, hot topics and the latest findings in growing, producing, and the marketing of all types of industrial hemp products.

The AIHC was conceived and designed by its founder Robert Bell to both add value and to assist in the future expansion of the industrial hemp industry and its community. From its inception, the AIHC has been supported and sponsored by the conferences’ key partners, the Australian Industrial Hemp Alliance, AgriFutures and Midlands Seed. This year, the newly formed national Australian Hemp Council is also involved in the event.
Internet address

Grant Number

  • PRJ-013007


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