Cannabinoid production for medicinal purposes has renewed interest in utilizing byproducts of industrial hemp (IH) as a feed source for livestock. However, the presence of bioactive residues in animal tissues may pose a risk to consumers. The purpose of this study was to characterize the plasma pharmacokinetics (PK) of cannabinoids and their metabolites in cattle after a single oral exposure to IH. Eight castrated male Holstein calves received a single oral dose of 35 g of IH to achieve a target dose of 5.4 mg/kg cannabidiolic acid (CBDA). Blood samples were collected for 96 h after dosing. Plasma cannabinoid concentrations were profiled using liquid chromatography coupled with mass-spectroscopy (UPLC) and PK parameters were calculated using noncompartmental methods. The cannabinoids CBDA, tetrahydrocannabinolic acid-A (THCA-A), cannabidivarinic acid (CBDVA), and cannabichromenic acid (CBCA) were detected in all cattle after IH dosing. The geometric mean maximum concentration of CBDA of 72.7 ng/mL was observed at 14 h after administration. The geometric mean half-life of CBDA was 14.1 h. No changes in serum biochemistry analysis were observed following IH dosing compared to baseline values. These results show acidic cannabinoids, especially CBDA, are readily absorbed from the rumen and available for distribution throughout the body.

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Industrial hemp (IH) is defined as Cannabis sativa containing < 0.3% delta-9 tetrahydrocannabinol (THC) and was legalized in the 2018 Farm Bill. The impact of cannabinoids in IH fed to livestock, especially after repeat exposure, has not been thoroughly investigated. Sixteen male castrated Holstein cattle weighting (± SD) 447 ± 68 kg were enrolled onto the study. Cattle were allocated into two treatment groups either receiving IH (HEMP, n = 8) or a control (CNTL, n = 8). Cattle in the HEMP group were fed 25 g IH mixed in 200 g of grain once a day for 14 days to target a daily dose of 5.5 mg/kg of cannabidiolic acid (CBDA). Behavior was continuously monitored with accelerometers and blood samples were collected at predetermined time points for plasma cannabinoid, serum cortisol, serum haptoglobin, liver enzymes, serum amyloid A, and prostaglandin E2 concentrations. The HEMP group spent a mean 14.1 h/d (95% CI 13.6–14.6 h/d) lying compared to the 13.4 h/d (95% CI 12.9–13.8 h/d) for the CNTL cattle (P = 0.03). Cortisol concentrations in the HEMP group were lower than the CNTL group (P = 0.001). Cattle in the HEMP group demonstrated an 8.8% reduction in prostaglandin E2 concentrations from baseline compared to a 10.2% increase from baseline observed in the CNTL group. No differences for haptoglobin or serum amyloid A were observed. These results suggest that feeding IH with a high CBDA content for 14 days increases lying behavior and decreases biomarkers of stress and inflammation in cattle.

The objective of this study was to assess the effects of captive bolt length and breed type on post-stun leg activity in cattle. A total of 2850 Holstein (HOL) and non-Holstein British/Continental bred (NHOL) steers and heifers were observed post-stunning at a large commercial slaughter facility. A pneumatically powered penetrating captive bolt stunner was used with three different bolt lengths: CON, 15.24 cm; MED, 16.51 cm; and LON, 17.78 cm. Hind limb kicking, forelimb activity, take away belt stops, carcass swing and number of knife sticks during exsanguination were recorded for each animal from video recording. Hind limb and forelimb kicks observed ranged from 0 to 25 and 0 to 8, respectively. Analysis of post-stun hind limb and forelimb activity indicated that increasing pneumatically powered penetrating captive bolt length does not decrease post-stun leg activity. There was a higher percentage of cattle experiencing take away belt stops and carcass swing in HOL as compared with NHOL.

The amount of scientific data evaluating sheep pain responses after analgesia treatment is limited. The aims of this study were to compare the efficacy of flunixin meglumine (FLU) and meloxicam (MEL) at relieving post-surgical pain in sheep and to evaluate the utility of the Sheep Grimace Scale (SGS). Thirty ewes were assigned to one of three treatment groups: oral MEL or intravenous FLU to manage pain associated with a laparotomy procedure, or a non-surgical control (CON) group. Behavior and physiologic outcome measures were collected pre-procedure and up to 48 h post-procedure. There were no significant differences in behavior, gait, degree of inflammation or pain around the surgical site when MEL and FLU sheep were compared, suggesting that both drugs provided similar levels of analgesia. Significant differences in behavior, gait, abdominal inflammation and pain were found when surgical sheep were compared to non-surgical controls. More work is needed to characterize the amount of pain relief provided by MEL and FLU. The SGS had moderate reliability between scorers; however, the results were inconsistent with the other study outcome measures. The SGS may have some utility as a pain assessment tool but should be used in conjunction with other pain measures.