Pharmacokinetics of Cannabidiol in Calves
Cannabidiol’s (CBD) studies have increased over the years due to its analgesic, anti-inflammatory, antioxidant, anxiolytic, anticonvulsant and cytotoxic effects on cancer cells. There are studies in both humans and animals and it is already widely used in humans and dogs. However, there is very little information about its effect on livestock.
For the first time, a recent study evaluated the pharmacokinetics of CBD in calves after a single oral intake that guaranteed a dose of 5mg/kg of CBD.
Considering the multiple studies on this drug, CBD seems to have very good therapeutic effects without associated side effects. In studies performed with dogs, it was concluded that oral administration results in greater bioavailability of the compound compared to transdermal administration. CBD has also been shown to increase comfort and activity level in dogs with osteoarthritis. In horses, CBD has shown positive effects in reducing chronic pain and anxiety.
In livestock species, there is a previous study that evaluated the pharmacokinetics of Cannabidiolic Acid (CBDA), a precursor component of CBD, in which it was concluded that the mean half-life would be 14.1h, which is much higher than the values reported for CBD in dogs. In the present study, Meyer et al reported a half-life of 23h (higher than that of CBDA). This data supports the hypothesis that cannabinoids persist longer in cows than in dogs. In this study, the animals were young and the absorption of drugs should still happen in a similar way to a monogastric. However, it is necessary to assess how these pharmacokinetics results will vary in adult ruminants with all four functional stomachs.
As this study was designed from other veterinary studies carried out in dogs, it will be necessary in future studies to evaluate plasma levels more extensively so the clearance of CBD from the plasma can be determined and the withdrawal period defined in livestock species for consumption.
This study also warns of variations in the amount of CBD available in oil. Quantities vary between products from different companies so it is important to establish protocols for the preparation of these products. The composition of these products is also highly dependent on the stability of the product. Other studies have reported that these products lose 15-20% of the cannabinoids in the first 14 days of storage at 4°C in darkness but then remain stable for up to 1 year. Exposure to oxygen is also a factor that accelerates the degradation of the quantity of cannabinoids present in these oils.
These variations should be considered when performing these studies as results may vary due to this.
In conclusion, this is an important and pioneering study on this subject. But, more studies are needed to be able to evaluate the effectiveness of CBD as a therapeutic agent in livestock species with potential to be used for pain control, appetite stimulation and inflammatory modulation.
Meyer, K, Hayman, K, Baumgartner, J, Gorden, PJ, Plasma Pharmacokinetics of Cannabidiol Following Oral Administration of Cannabidiol Oil to Dairy Calves, 2022, Frontiers in Veterinary Science, Vol.9 – https://doi.org/10.3389/fvets.2022.789495
