Concentração de lactato sérico em ovelhas e cordeiros mestiços (1/2 Suffolk) nascidos em eutocia

Influence of prenatal corticosteroid therapy on neonatal vitality and utility as a labor-inducing agent in Santa Inês ewes

Since the 1970s, maternal corticosteroid therapy has been used successfully to induce labor. This allows for better monitoring of parturients and provision of first aid to neonates, improving neonatal viability, as this treatment induces maturation in a variety of fetal tissues, thereby reducing morbidity and mortality. Although the effects of corticosteroids are well known, few studies have investigated the influence of this therapy in Santa Inês sheep. This study aimed to evaluate the efficacy of dexamethasone at two doses (8 and 16 mg) to induce lambing in Santa Inês ewes at 145 days of gestation and assess its effects on neonatal vitality. For this study, 58 ewes raised in an extensive system were investigated. Pregnancy was confirmed after artificial insemination at a set time or after controlled mounting. Ewes were separated into three groups: an untreated control group (G1: 0 mg) and groups treated with two doses of dexamethasone (G2: 8 mg and G3: 16 mg). In total, 79 lambs were born. Their vitality was assessed based on their Apgar score, weight, temperature, and postnatal behavior. SAS v9.1.3 (SAS Institute, Cary, NC) was used to analyze data, considering a 5% significance level for all analyses. The births in the induced groups occurred 48.4 ± 22.1 h after induction, while the ewes that underwent non-induced labor gave birth 131.96 ± 41.9 h after placebo application (p < 0.05), confirming the efficacy of dexamethasone to induce and synchronize labor. The induced and non-induced neonates had similar Apgar scores, temperatures, weights, and postnatal behavioral parameters (p > 0.05). This study showed that inducing labor in Santa Inês ewes at 145 days of gestation with a full (16 mg) or half dose (8 mg) of dexamethasone is an effective technique and does not compromise neonate vitality.

Comparison of electrolyte and acid-base balances of Dorper breed ewes between single and twin pregnancies

ABSTRACT: During pregnancy there are modifications in the metabolic profile of sheep that may predispose to the occurrence of metabolic disorders, of which pregnancy toxaemia (PT) is highlighted. Blood gas analysis is detects changes in acid-base and electrolyte balance effectively. The objectives of this study were to study the acid-base and electrolyte balance of sheep during gestation and in the immediate peripartum (up to 48 hours postpartum), comparing single gestation with twins. Sixty healthy sheep of Dorper breed, two to five years old were raised in a semi-intensive system and were divided in two experimental groups: Group 1: 30 ewes, with ultrasonographic diagnosis of single fetus gestation; Group 2: 30 ewes, with ultrasonographic diagnosis of twin pregnancy. The experimental moments were defined as: MI-immediately after artificial insemination (control); MG30 - 30 days of gestation; MG90 - 90 days of gestation; MG120 - 120 days of gestation; MG130 - 130 days of gestation; MG140 - 140 days of gestation; MP - lambing; MPP1 - 24h postpartum; MPP2 - 48h postpartum. At all times 1mL of blood was collected per jugular vein puncture for blood gas evaluation in a portable equipament (I-Stat®). The pH, carbon dioxide pressure (PCO2), bicarbonate (HCO3-), base excess (BE), sodium (Na+), potassium (K+), chloride (Cl-), ionized calcium (Ca+2), lactate, anion gap (AG) were mensured and strong ion difference (SID) were calculed. This work showed that there were changes in acid-base and electrolyte balance in pregnant ewes, due to the decrease in BE, HCO3-, TCO2 and increase of lactate and AG during gestation, but the pH remained normal and did not present any difference among moments in both groups. Comparing the groups, single-gestation ewes presented higher alkaline expenditure at delivery than twin-gestation, evidenced by lower levels of BE and HCO3-. Lower Na+ levels were observed in prepartum; drop in K+ values with advancing gestation; hyperchloremia and hypocalcemia during gestation according to the reference standards for species; decreased iCa+2 levels in the final third of gestation in both groups. It was concluded that the ewes of this study were healthy until the last moment analyzed (48h postpartum), although have shown greater consumption of the alkaline reserve in the peripartum, being more explicit in the single gestation animals. In addition, this situation can be physiological and result in increased energy demand during gestation, more exacerbated by peripartum.

Assessment of serum lactate levels, blood glucose values and blood gas values in sheep, newborn lambs and placenta

ABSTRACT: Newborn animals, in the fetal-to-neonatal transition, usually face several challenges in their first 24 hours, including issues with acid-base balance, glycemic levels and oxygenation. Difficulties to overcome such issues have caused several deaths among newborns. Therefore, studies have been carried out in order to evaluate them. The main purpose of this study is to evaluate the correlation between the serum lactate level in the mother, in the placenta and in the newborn. Moreover, the study measured the lactate level, blood glucose level and blood gas level in the first 24 hours. Tests were carried out right after birth, and at 4, 8, 12 and 24 hours after. Lactate levels were quite similar to the placental levels (p=0.991) which, in turn, were significantly different from the mother’s (p=0.011). Results showed that, shortly after birth, the production of lactate in the placenta is part of the issue. Along the first 24 hours, the study observed a reduction of the levels of lactate in newborns; the levels were closer to the normal index levels for the species. Regarding the blood gas test results, we observed mild metabolic acidosis at birth; acid-base balance was completely stable at the end of the period.