|LITTLEJOHN, BRITTNI - Texas A&M University|
|PRICE, DEBBI - Texas A&M University|
|BANTA, JASON - Texas A&M University|
|LEWIS, ANDREW - Texas A&M University|
|NEUENDORFF, DON - Texas A&M University|
|Carroll, Jeffery - Jeff Carroll|
|VANN, RHONDA - Mississippi State University|
|WELSH, THOMAS JR. - Texas A&M University|
Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/3/2015
Publication Date: 4/11/2016
Citation: Littlejohn, B.P., Price, D.M., Banta, J.P., Lewis, A.W., Neuendorff, D.A., Carroll, J.A., Vann, R.C., Welsh, T.H. 2016. Prenatal Transportation Stress Alters Temperament and Serum Cortisol Concentrations in Suckling Brahman Calves. Journal of Animal Science. 94(2):602-609.
Interpretive Summary: Elevated maternal cortisol may alter the fetal environment, thereby altering fetal development. Fetal programming is defined as the fetal response to a specific insult during a critical period that alters the trajectory of development. Alterations in the fetal environment program the fetal hypothalamic-pituitary-adrenal axis to prepare the neonate to survive in a stressful postnatal environment. Such programming may include mechanisms that lead to alterations in the temperament of an animal. Therefore, a collaborative study was conducted with scientists from Texas A&M University, Mississippi State University, and the USDA-ARS Livestock Issues Research Unit to determine if exposing gestating calves to a prenatal transporation event would affect the postnatal temperament and adrenocortical function of Brahman calves. To test this hypotheses, an experiment was conducted that evaluated the effects of a repeated transportation event during five time periods of gestation. Specifically, ninety-six pregnant Brahman cows were assigned to either a transportation group or control group. The transported cows were transported for two hours at 60, 80, 100, 120, and 140 ± 5 days of gestation. The control cows were maintained in the same manner as stressed cows with the exception of being transported. Results from this study indicated that prenatally stressed calves were more stress responsive relative to control calves due to their altered temperament and adrenocortical function. Increased temperament exhibited by prenatally stressed calves may prepare them to survive and thrive in a stressful postnatal environment. Because one’s health begins in utero, this model can provide insight into the genetic and/or epigenetic effects of prenatal stress on postnatal health and performance of animals and humans. This information will be of specific interest to both beef cattle and dairy cattle producers, and veterinarians working with these producers.
Technical Abstract: This experiment examined the relationship between prenatal stress and subsequent calf temperament through weaning. The prenatal stressor utilized was repeated transportation of pregnant Brahman cows for 2 hours at 60, 80, 100, 120, and 140 days of gestation. Prenatally stressed calves (n = 41) were compared to controls (n = 44, dams did not undergo transportation during pregnancy) from 2 weeks of age until weaning (average age at weaning =174.8 +/- 1.3 days). Temperament was defined by pen score (PS; 1 = calm and 5= excitable), exit velocity (EV; meters/second), and temperament score [TS= (PS + EV)/2] and was recorded for each calf on days -168, -140, -112, -84, -56, -28, and 0 relative to weaning (day 0 = weaning). Cortisol concentrations were determined in serum samples obtained on days -168, -140, -28, and 0 relative to weaning. Birth weight and weaning weight were not different between treatment groups (P > 0.1). Pen score was greater (P = 0.03) in prenatally stressed calves (2.84 +/- 0.21) relative to controls (2.31 +/- 0.21). Exit velocity was greater (P < 0.01) in prenatally stressed calves (2.1 +/- 0.14 meters/second) than in controls (1.61 +/- 0.14 meters/second). Exit velocity was affected by a treatment by calf sex interaction (P = 0.04) and was greater in prenatally stressed females. Exit velocity was also affected by day (P < 0.0001). Temperament score was greater (P = 0.01) in prenatally stressed calves (2.45 +/- 0.16) than in controls (1.95 +/- 0.16). Temperament score was also affected by day (P < 0.01). Basal cortisol concentrations were greater (P = 0.04) in prenatally stressed calves (15.87 +/- 1.04 ng/mL) than in controls (13.42 +/- 1.03 ng/mL). Basal cortisol concentrations were greater (P < 0.01) in females (16.61 +/- 1.06 ng/mL) than in males (12.68 +/- 1.02 ng/mL). Cortisol concentrations were positively correlated (P < 0.01) with PS (r = 0.55; P < 0.01), EV (r = 0.4; P < 0.01) and TS (r = 0.55; P < 0.01). Overall, suckling Brahman calves that were prenatally stressed were more temperamental and had greater circulating serum concentrations of cortisol than control calves.