Resumo

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.(AU)

Resumo

A criopreservação de sêmen é uma importante estratégia para o armazenamento de material genético de reprodutores ovinos e caprinos, considerados superiores do ponto de vista fenotípico, mas especialmente, pelos seus méritos genéticos. Hoje no Brasil apenas uma central regulamentada pelo MAPA está ema atividade, o que significa que existe pouca dose de sêmen comercial à disposição para programas de melhoramento genético. Programas de banco de sêmen podem ser realizado nas fazendas, entretanto, tem seu uso limitado a propriedade onde está o reprodutor. Neste caso, apesar de maiores limitações de estrutura e equipamentos para a execução do serviço, o domínio das variações da técnica de congelação de sêmen e o cuidado com as questões sanitárias dos reprodutores possibilitará ao Médico-Veterinário a execução do serviço com níveis adequados de segurança e qualidade das doses de sêmen produzidas. O objetivo deste estudo é apresentar e discutir critérios e metodologias para congelação de sêmen de pequenos ruminantes em diferentes condições, fruto de diversas experiências e trabalhos desenvolvidos por nosso grupo e outros, nos últimos vinte anos, e que tem possibilitado resultados satisfatórios.(AU

Sperm cryopreservation is an important strategy for the storage of genetic material from ovine and goat breeders, considered superior from the phenotypic point of view, but especially for their genetic merits. Today in Brazil only one center regulated by the Ministry of Agriculture, Livestock and Supply is in operation, which means that there is little dose of commercial semen available for genetic improvement programs. Semen bank programs can be carried out on farms; however, their use is limited to the property where the breeder is located. In this case, despite greater limitations of structure and equipment for the execution of the service, mastering variations in the semen freezing technique and taking care of the health issues of the breeders will enable the Veterinarian to perform the service with adequate levels of safety and quality of semen doses produced. This study aims to present and discuss criteria and methodologies for freezing semen from small ruminants under different conditions, the result of several experiences and works carried out by our group and others, in the last twenty years, which have enabled satisfactory results.(AU))