Short communication: salivary cortisol concentrations and lying behavior of ewes in response to semi-laparoscopic and laparoscopic embryo transfer

TL;DR

This study found that embryo transfer procedures in sheep did not cause significant stress, as measured by cortisol levels and lying behavior.

Contribution

The study compares stress responses in ewes undergoing two embryo transfer methods and finds no significant differences in stress levels.

Findings

Salivary cortisol concentrations increased temporarily but returned to baseline within 24 hours.

Lying behavior patterns changed post-surgery but were not significantly different between groups.

Both embryo transfer methods caused similar stress responses compared to handling alone.

Abstract

This study compared the short-term effects of the laparoscopic and semi-laparoscopic embryo transfer (ET) procedures on salivary cortisol concentrations and the lying behavior of ewes. In total, 40 ewes were synchronized for ET and placed randomly into individual pens 2 d before the operations. On the day of the operations, laparoscopic (L, n = 15) and semi-laparoscopic (SL, n = 10) ET were performed. At the same time, control animals (Control, n = 15) were placed into the laparoscopic cradle for 6 min without an ET procedure. Monitoring of standing and lying behaviors started 24 h before the surgery and lasted until 24 h after the procedures were completed. Saliva samples were taken 4 times during the experiment and assayed for cortisol concentrations. Saliva cortisol concentrations were elevated in all groups 1 (Control: 4.8 ± 0.5 ng/mL; L: 5.1 ± 0.5 ng/mL; SL: 4.2 ± 0.7 ng/mL) and 2 (Control: 5.5 ± 0.5 ng/mL; L: 5.9 ± 0.5 ng/mL; SL: 4.8 ± 0.7 mg/mL) hours after the procedures compared to the initial concentration (Control: 3.8 ± 0.5 ng/mL; L: 3.7 ± 0.5 ng/mL; SL: 3.1 ± 0.7 ng/mL), and returned to the basal levels for the end of the 24-h post-surgery period (Control: 3.4 ± 0.5 ng/mL; L: 4.1 ± 0.5 ng/mL; SL: 3.5 ± 0.7 ng/mL). There were no significant differences in the cortisol levels among the groups. There was no difference in the total lying time between the groups 24 h before or after the surgery. The average length of lying bouts calculated for the 24-h post-surgery period increased in all groups from the 24-h pre-surgery period, with a parallel decrement in the number of lying bouts (P < 0.05). Our results suggest that the laparoscopic and semi-laparoscopic ET did not cause more stress in the ewes than the handling procedures related to surgery and preparation.

The laparoscopic and semi-laparoscopic embryo transfer procedures did not cause considerable stress to the ewes.