Evaluación de los niveles de cortisol, glucosa y constantes fisiológicas luego de la aplicación de un protocolo convencional y alternativo de superovulación en bovinos

Abstract

The neuroendocrine response of the donor was determined by reducing the number of applications of follicle-stimulating hormone (FSH) as a superovulation factor. 8 crossbred Holstein cows were randomly distributed in two treatments (T): T1 (n=4) received a dose of 200 mg of FSH via epidural (EP) on day 4 of the superovulation protocol (SOV), in T2: 300 mg of FSH were administered divided into 8 decreasing doses intramuscularly (IM), on days 4; 5; 6 and 7 of the protocol in the morning and afternoon. The cortisol concentration was determined at 0; 2; 4; 6.24; 26; 28; 30; 48; 50; 52; 64; 72; 74; 76 and 78 hours of day 4. Heart rate (HR), respiratory rate (RR) and glucose levels were evaluated on day 4 at 05:45; 06:05; 08:00; 10:00 a.m.; 12:00; 5:45 p.m. and 6:05 p.m. Cortisol at 0h was similar in both T: T1 (10.9 ± 0.24 μg/dL) and T2 (10.8 ± 0.33 μg/dL) and reached its highest level at 4h in T1 (15.8 ± 1.39 μg/dL) and at T2 (16.4 ± 0.28 μg/dL) with no difference between T (P>0.05). In the following evaluations, cortisol decreased to basal levels in the two T. HR at 05:45h showed similar values in T1 (65.3 ± 1.65 pul/min) and in T2 (66.3 ± 1.43 in /min); however, at 06:05 HR increased in T1 (74.3 ± 1.54 pul/min) and in T2 (84.2 ± 1.73 pul/min) and decreased from 08:00. The same behavior was observed with RF and glucose. It is concluded that taking the donor to the support sleeve to administer FSH is a stressful factor that increases HR, RF, cortisol and glucose, factors that influence the percentage of ovulations in the two T.