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Oxytocin and the stress response in beef cattle: Opportunities and Limitations

Wagner, Brooklyn K.
http://rave.ohiolink.edu/etdc/view?acc_num=osu1555325284731452

Abstract Details

2019, Doctor of Philosophy, Ohio State University, Animal Sciences.
Changes in the physiological, psychological, and behavioral manifestations of stress have been observed in association with increases in circulating oxytocin. Providing oxytocin intra-nasally has been shown to attenuate stressor-induced hypothalamo-pituitary-adrenal (HPA) axis activation in humans and non-human primates, however anxiolytic effects may be context and species specific. The first study, presented in Chapter Two, aimed to investigate the effect of intra-nasal oxytocin supplementation on stressor-induced activation of the HPA axis in beef cattle. I hypothesized that oxytocin would attenuate activation of the HPA axis, ultimately decreasing plasma cortisol and adrenocorticotropic hormone concentrations. This study demonstrated that oxytocin treatment did not affect measured indicators of the HPA axis activation and confirmed that restraint and isolation stress increases cortisol in Bos taurus heifers compared with heifers subjected only to isolation. In addition, an endogenous release of oxytocin was detected in response to restraint stress. The extreme nature of restraint and isolation stress may have overshadowed any effect of intra-nasal oxytocin. The second study, presented in Chapter Three, aimed to investigate the effect of intra-nasal oxytocin on cattle subjected to a more intermediate stressor – transportation. I hypothesized that Bos indicus cattle treated intra-nasally with oxytocin would have a less extreme increases in cortisol concentrations and changes in immune parameters when subjected to handling and 6 h road transportation compared with cattle treated intra-nasally with saline. This study confirmed that short-duration road transportation induces signs of an acute inflammatory response, however no effect on the HPA axis was detected. In addition, intra-nasally administered oxytocin altered leukogram numbers such that specific leukocytes returned to baseline more quickly in calves given oxytocin. The low dose and mild nature of the stressor may explain lack of substantial effects HPA axis activation. The third study, presented in Chapter Four, aimed to evaluate the pharmacokinetics of three different doses of oxytocin administered intra-nasally. Using a continuous sampling timeline was crucial in assessing an accurate dose-response curve for intra-nasal oxytocin. Results from this study coincide with previous studies investigating different intra-nasal doses in that pharmacokinetic parameters remained the same across doses. An intermediate half-life of oxytocin was established for oxytocin administered intra-nasally in Bos taurus steers. Furthermore, this study added to the limited existing knowledge regarding appropriate doses and sampling timelines necessary to obtain meaningful results in studies utilizing intra-nasal oxytocin. The final study, presented in Chapter Five, aimed to investigate oxytocin and cortisol in lactating and non-lactating cows. Previous authors have reported greater oxytocin concentrations paired with attenuated increases in cortisol concentrations in lactating sheep; non-lactating sheep were shown to have greater cortisol concentrations in response to restraint stress. I hypothesized that intra-nasally administered oxytocin would attenuate activation of the HPA axis in non-lactating beef cattle comparable to attenuation observed in lactating cows. Results indicated that lactating and non-lactating cows had similar plasma concentrations of oxytocin. However, an attenuated increase in cortisol concentration was observed in lactating cows compared with non-lactating cows. Hormones other than oxytocin, such as prolactin, may be involved in facilitating the stress hypo-responsive state observed in lactating mammals. Overall, the present work does not support intra-nasal oxytocin as an attenuator of the HPA axis in beef cattle subjected to restraint and isolation or transportation stress. The rapid disappearance of oxytocin from plasma following intra-nasal administration, confirmed by experiments presented in Chapters Four and Five, indicates that any action of oxytocin is most likely not at the adrenal level; however, more investigations would be needed to confirm this notion.
Anthony Parker (Advisor)
Francis Fluharty (Committee Member)
Sheila Jacobi (Committee Member)
Kathryn Proudfoot (Committee Member)
Alejandro Relling (Committee Member)
155 p.
Agriculture; Animal Sciences
Oxytocin; intra-nasal; intranasal; stress response; HPA axis; anxiolytic; cattle

Recommended Citations

Citations

  • Wagner, B. K. (2019). Oxytocin and the stress response in beef cattle: Opportunities and Limitations [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1555325284731452

    APA Style (7th edition)

  • Wagner, Brooklyn. Oxytocin and the stress response in beef cattle: Opportunities and Limitations. 2019. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1555325284731452.

    MLA Style (8th edition)

  • Wagner, Brooklyn. "Oxytocin and the stress response in beef cattle: Opportunities and Limitations." Doctoral dissertation, Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1555325284731452

    Chicago Manual of Style (17th edition)

osu1555325284731452
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