ABSTRACT The replacement rate of dairy cattle is, on average, 35%, while cattle will leave the herd for reasons other than health events; this rate is not sustainable. Replacement rate can be defined as the percentage of lactating cows that leave the herd and are replaced by new primiparous cows. Societal pressure has led to the implementation of a veterinary feed directive (VFD), established in 2017 to restrict supplementing antibiotics in feed or water to livestock without written consent from a veterinarian. Then in 2023 further legislation was introduced requiring veterinarian consent to administer any prescription drugs. While this had little impact on the dairy industry when first implemented, the aim of the VFD is to lessen the likelihood of further microbial antibiotic resistance in livestock production. To help improve the resilience of cows to pathogens, research has been done to investigate naturally occurring compounds that may help decrease the need for antibiotic use. β-Caryophyllene (BCP) has been demonstrated to possess anti-inflammatory properties. In this experiment, 20 mid or late lactation dairy cows, enrolled using a randomized complete block design, received two lipopolysaccharide (LPS) intramammary challenges 28 days apart and received 1 of 2 treatments for 42 days: 1) CON (basal TMR); 2) BCP, consisting of 5 mg/kg of body weight, as liquid BCP delivered as a top dress treatment and mixed in with the top 20% of the ration. No changes in dry matter intake, body weight, milk yield or components were observed between treatment groups. BCP supplementation resulted in a lower haptoglobin concentration during the first LPS challenge and a lower somatic cell count (SCC) prior to the second LPS challenge. Plasma haptoglobin concentrations were lower in the second LPS challenge and a higher peak in SCC was observed in BCP cows. I conclude that supplementation of BCP during a LPS intramammary challenge lessens the systemic inflammatory response experienced by late lactation dairy cows.
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