Objective—To determine effects of parturition on glucocorticoid
receptor (GR) expression in neutrophils,
serum cortisol concentration, and total blood leukocyte
and neutrophil counts in periparturient dairy cows.
Animals—23 Holstein cows.
Procedure—Blood samples were collected from 8
multiparous and 5 primiparous periparturient cows at
various times from 28 days before parturition until 14
days after parturition. Glucocorticoid receptor expression
in neutrophils, serum cortisol concentration, and
total blood leukocyte and neutrophil counts were
determined. Results were compared with results
from control samples obtained from 5 multiparous
and 5 primiparous Holstein cows in midpregnancy.
Results—Neutrophils from periparturient cows had
49% reduction in GR expression at calving, compared
with GR expression 2 to 4 weeks before calving, and
39% reduction, compared with neutrophils from cows
in midpregnancy. Reduction in neutrophil GR expression
began 1 week before calving and was most severe
at calving and 24 hours after calving; a significant difference
in GR expression was detected between primiparous
and multiparous cows. Serum cortisol concentrations
and total leukocyte and neutrophil counts were
significantly increased at calving and returned to baseline
values by 24 hours after calving. Significant negative
correlations were detected between neutrophil GR
expression and serum cortisol concentration, total
leukocyte count, and neutrophil count.
Conclusions and Clinical Relevance—Reduced GR
expression in blood neutrophils of periparturient dairy
cows was associated with increased serum cortisol
concentrations, leukocytosis, and neutrophilia. Thus,
GR down-regulation in neutrophils may be involved in
periparturient neutrophil dysregulation and may cause
increased susceptibility to mastitis. (Am J Vet Res
OBJECTIVE To investigate risk factors for the development of pasture- and endocrinopathy-associated laminitis (PEAL) in horses and ponies in North America.
DESIGN Case-control study.
ANIMALS 199 horses with incident cases of PEAL and 351 horses from 2 control populations (healthy horses [n = 198] and horses with lameness not caused by laminitis ) that were evaluated in North America between January 2012 and December 2015 by veterinarian members of the American Association of Equine Practitioners.
PROCEDURES North American members of the American Association of Equine Practitioners were contacted to participate in the study, and participating veterinarians provided historical data on incident cases of PEAL, each matched with a healthy control and a lameness control. Conditional logistic regression analysis was used to compare data on PEAL-affected horses with data on horses from each set of controls.
RESULTS Horses with an obese body condition (ie, body condition score ≥ 7), generalized or regional adiposity (alone or in combination), preexisting endocrinopathy, or recent (within 30 days) glucocorticoid administration had increased odds of developing PEAL, compared with horses that did not have these findings.
CONCLUSIONS AND CLINICAL RELEVANCE The present study identified several risk factors for PEAL that may assist not only in managing and preventing this form of laminitis, but also in guiding future research into its pathogenesis.