Response of vital functions, Apgar and cortisol in the prognosis of vigor against neonatal factors of lambs

Abstract

The management of lambs during the neonatal period has been studied in several researches due to the vital and hormonal organic adaptations undergone by the calf after birth. However, gender, number of pups and type of delivery play an important role in understanding neonatal vigor. The study of these groups with the monitoring of clinical evolution and cortisol metabolism becomes an indispensable subsidy for a better understanding of this neonatal phase, aiming to minimize the losses generated. The objective of this study was to evaluate the influence of gender, number of pups and type of delivery in the prognosis of neonatal vigor of lambs through clinical and cortisol diagnosis. Thirty crossbred Santa Inês lambs with Dorper in the neonatal phase were divided into three groups: male and female, number of pups (single and twin) and type of delivery (eutocic and dystocic). In each group, clinical evaluation of heart and respiratory rate, rectal temperature, Apgar score and weight were performed; and with the exception of cortisol, all evaluations were performed at fifteen and sixty minutes, as well as at twelve and twenty-four hours. In addition, blood samples were collected for cortisol dosage obtained in two moments at fifteen and sixty minutes using the radioimmunoassay technique. Among the three experimental groups related to lamb vigor, the heart rate was the only one that showed lower mean values (P0.05) at twenty-four hours in the male group 90.00±20.20bpm, twins 96.44±20.02bpm and eutocic 93.25±18.11bpm. Differences in respiratory rate values were observed in the eutocic group (64.00±14.75mpm) at twenty-four hours. In the group of males there was a significant reduction in body temperature during the evaluation moments (P0.05). Lambs from the group of twins showed lower body weight during the evaluations. At both times the analysis of serum cortisol was less than at sixty minutes. It was concluded that soon after the birth there were marked changes in the physiological parameters and weight of Santa Inês lambs, but were not enough to cause negative effects on the vigor of the neonates, indicating the occurrence of effective neonatal adaptation capacity in this species.