AIM OF THE STUDY In the neonatal adaptation to the extra-uterine life, thyroid hormones play an important role in the process of growth, energy metabolism and thermogenesis. Thyroid hormones profiles were described in newborn calves from different breeds (1), while the influence of gender, birth weight and type of delivery is still unclear. The aim of the study was to compare T3 and T4 plasma concentrations in Holstein-Friesian newborn calves born by vaginal delivery and Belgian Blue born by caesarean section. MATERIALS AND METHODS The study was conducted on 12 Holstein-Friesian calves born by vaginal delivery (VD) and on 12 Belgian Blue calves born by caesarean section (CS). Calves gender, body weight and viability were recorded immediately after birth. Blood samples were collected from jugular vein at 10 and 20 minutes (m), at 6 and 24 hours (h) and at 7 and 14 days (d) of age and plasma stored for T3 and T4 analysis by RIA. The ANCOVA for repeated measures test was used to assess the effect of gender and birth weight on T3 and T4 plasma levels profiles within each group. One-way ANOVA was used to evaluate possible differences in T3 and T4 levels between the two groups in each sampling time (p<0.05). RESULTS All newborn calves were mature and viable. Mean body weight was 34±4.2 Kg for VD (5 females and 7 males) and 53±7.7 Kg for CS group, respectively (5 females and 7 males). Means ± SD of T3 and T4 plasma concentrations in the two groups of calves are reported in table 1. CONCLUSIONS In both groups the T3 and T4 profiles showed an increasing trend from birth to 6 hours of age, followed by a decrease to 14 days of age, as previously reported (1). According to statistic results, T3 and T4 plasma levels were not affected by gender and by birth weight. Statistics evidenced higher T3 and T4 concentrations in the CS calves early after birth, possibly due to the faster process of birth that may result in an immature T4 deiodination system in Blue Belgian calves. Higher plasma levels of both hormones were also detected in the CS calves at 7 and 14 days of age; differences in nutrition or in body weight gain could be responsible for these differences. Unfortunately the association between different type of delivery and different breed within each group does not allow to clarify the real effect of these variables on T3 and T4 plasma levels in newborn calves. REFERENCES 1) Davicco et al, 1982 Reprod Nutr Dev 22, 355-362
Plasma T3 and T4 concentrations in newborn calves: influence of type of delivery and breed.
PERIC, TANJA;
2013
Abstract
AIM OF THE STUDY In the neonatal adaptation to the extra-uterine life, thyroid hormones play an important role in the process of growth, energy metabolism and thermogenesis. Thyroid hormones profiles were described in newborn calves from different breeds (1), while the influence of gender, birth weight and type of delivery is still unclear. The aim of the study was to compare T3 and T4 plasma concentrations in Holstein-Friesian newborn calves born by vaginal delivery and Belgian Blue born by caesarean section. MATERIALS AND METHODS The study was conducted on 12 Holstein-Friesian calves born by vaginal delivery (VD) and on 12 Belgian Blue calves born by caesarean section (CS). Calves gender, body weight and viability were recorded immediately after birth. Blood samples were collected from jugular vein at 10 and 20 minutes (m), at 6 and 24 hours (h) and at 7 and 14 days (d) of age and plasma stored for T3 and T4 analysis by RIA. The ANCOVA for repeated measures test was used to assess the effect of gender and birth weight on T3 and T4 plasma levels profiles within each group. One-way ANOVA was used to evaluate possible differences in T3 and T4 levels between the two groups in each sampling time (p<0.05). RESULTS All newborn calves were mature and viable. Mean body weight was 34±4.2 Kg for VD (5 females and 7 males) and 53±7.7 Kg for CS group, respectively (5 females and 7 males). Means ± SD of T3 and T4 plasma concentrations in the two groups of calves are reported in table 1. CONCLUSIONS In both groups the T3 and T4 profiles showed an increasing trend from birth to 6 hours of age, followed by a decrease to 14 days of age, as previously reported (1). According to statistic results, T3 and T4 plasma levels were not affected by gender and by birth weight. Statistics evidenced higher T3 and T4 concentrations in the CS calves early after birth, possibly due to the faster process of birth that may result in an immature T4 deiodination system in Blue Belgian calves. Higher plasma levels of both hormones were also detected in the CS calves at 7 and 14 days of age; differences in nutrition or in body weight gain could be responsible for these differences. Unfortunately the association between different type of delivery and different breed within each group does not allow to clarify the real effect of these variables on T3 and T4 plasma levels in newborn calves. REFERENCES 1) Davicco et al, 1982 Reprod Nutr Dev 22, 355-362I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
