Endocrinology of pregnancy and parturition in bitches

Os mecanismos relacionados ao controle endócrino do período gestacional e parto em cadelas ainda não estão totalmente elucidados. Desta maneira, a presente compilação de trabalhos científicos referentes aos principais eventos durante a gestação e o parto em cadelas tem por escopo a atualização sobre a endocrinologia em tais eventos fisiológicos e a divulgação sumariada dos conhecimentos gerados a partir das pesquisas científicas na área. É de conhecimento comum que a síntese e a secreção da progesterona, originária principalmente do corpo lúteo, são de extrema importância para manutenção e conseqüente progresso da gestação. Ainda, os níveis plasmáticos desse hormônio podem ser utilizados como método para predizer o momento do parto na espécie canina. Adicionalmente, a relaxina é detectada somente em cadelas gestantes, portanto sua detecção pode ser considerada um método de diagnóstico de gestação. Durante a segunda fase da gestação, observa-se liberação pulsátil de prolactina, simultaneamente ao aumento dos níveis de estrógeno. Entretanto, a influência do estrógeno no mecanismo de secreção de prolactina ainda é incerta. Por outro lado, ao final da gestação, evidencia-se queda dos níveis de progesterona e aumento dos níveis séricos de estrógeno, decorrente principalmente da ação do cortisol fetal. Tais eventos, associados à liberação de PGF2α pelo útero, culminam com o início do parto. O aumento das contrações uterinas e a expulsão fetal ocorrem principalmente pela ação da ocitocina. Entretanto, a ação desse hormônio não requer necessariamente o aumento das concentrações plasmáticas, sugerindo haver uma ação autócrina ou parácrina da ocitocina em cadelas. Embora os estudos relacionados à endocrinologia da gestação e do parto em cadelas tenham elucidado diversas interações e padrões hormonais, tais processos ainda não estão totalmente descritos, uma vez que as cadelas apresentam particularidades reprodutivas que as diferem das demais espécies. Neste particular sentido, futuras pesquisas devem ser conduzidas para contribuir com o conhecimento técnico-científico nesta espécie.The mechanisms related to the endocrine control of pregnancy and parturition in bitches are still unknown. Thus, this compilation of scientific articles referred to canine pregnancy and parturition aims to update on the endocrinology of the main physiological events and to disclose in a summarized manner the knowledge generated from scientific research. It is known that the synthesis and secretion of progesterone mainly originated from the corpus luteum are of utmost importance for pregnancy maintenance. In addition, plasma levels of this hormone can be employed as a method to predict the onset of parturition in bitches. Moreover, relaxine is present only in pregnant bitches; therefore its serum determination can be considered as pregnancy diagnostic method. During midgestation, it is observed a pulsatile release of prolactin simultaneously to increased levels of estrogen. However, the influence of estrogen on the mechanism of prolactin secretion remains unknown. On the other hand, decreased levels of progesterone and increased concentrations of estrogen are observed at the end of pregnancy, as a consequence of enhanced fetal cortisol synthesis. These events in association to the release of uterine PGF2α trigger the onset of labor. The increase in uterine contractions and fetal expulsion occur mainly as an oxytocin influence. However, the action of this hormone does not necessarily require the increase in plasma concentrations, suggesting an autocrine or paracrine mechanism of action in bitches. Although studies related to canine endocrinology of pregnancy and parturition have clarified several hormonal interactions and patterns, these mechanism are not fully described, as the bitches have reproductive characteristics that differ from other species. Additional research should be undertaken in order to improve technical and scientific knowledge in this species

Canine neonatal clinical evaluation through Apgar score and body temperature under distinct whelping condition

Em medicina veterinária, a mortalidade neonatal nas primeiras semanas de vida alcança percentuais próximos a 30%. A inabilidade em proceder a correta análise clínica e o déficit no conhecimento técnico-científico são os principais responsáveis pelos elevados índices reportados. Neste trabalho, objetivou-se padronizar a avaliação clínica neonatal por meio do escore Apgar e temperatura corpórea em neonatos caninos nascidos sob diferentes condições obstétricas. Foram estudados 48 neonatos caninos, alocados em três grupos: grupo A \2013 eutocia; grupo B \2013 distocia materna; grupo C \2013 cesariana. Aos 0, 5 e 60 minutos do nascimento foram avaliados: temperatura retal, freqüências cardíaca (FC) e respiratória (FR), coloração de mucosas, tônus muscular e irritabilidade reflexa. Às cinco últimas análises foram atribuídas notas (0-2), conferindo aos neonatos o escore Apgar (0-10). Os dados foram analisados utilizando-se ANOVA e Newman-Keuls (p'< OU ='0,05). Houve queda significativa datemperatura retal e hipotermia ao longo dos 60 minutos para todos os grupos. Aos 0 e 5 minutos, a temperatura corporal do grupo C foi inferior aos demais. Neonatos nascidos por cesariana apresentaram menor vitalidade aos 0 e 5 minutos pós-natal, como conseqüência dos agentes anestésicos. A FC, tônus muscular e irritabilidade reflexa foram superiores no grupo B imediatamente ao nascimento, em função da maior liberação de corticóides por estresse fetal. A avaliação isolada da FR não foi precisa para identificar possíveis alterações respiratórias, sendo recomendado associá-la a outros métodos semiológicos e exames complementares. A inspeção de mucosas demonstrou ser uma variável pouco fidedigna para predizer neonatos com graus leves de alterações cardiorrespiratórias. Em contraste aos demais filhotes, os nascidos de cesariana apresentaram cianose imediatamente ao nascimentoIt is known that canine mortality rate is up to 30% in the first weeks of life. Technical and scientific deficit related to veterinary neonatology is conspicuous. The aim of this study was to standardize neonatal clinical evolution through the Apgar score and body temperature under distinct obstetric condition. Forty-eight canine neonates were allocated into 3 groups according to whelping condition: group A \2013 eutocia; group B \2013 maternal dystocia; group C \2013 cesarean section. Immediately after birth, 5 and 60 minutes later, the following assessments were performed: Apgar score (0-10; heart beat, respiratory effort, muscle tone, reflex irritability and mucous color) and rectal temperature. Data were analyzed using ANOVA and Newman-Keuls at p'< OU ='0.05. There was a significant reduction in rectal temperature and hypothermia for all groups along the 60 minutes of birth. Group C neonates presented lower body temperature at birth and 5 minutes later. Cesarean section newbornsshowed lower vitality, as a consequence of fetal cardiorespiratory and nervous depression caused by anesthetic agents. Muscle tone, heart rate and reflex irritability were higher in group B immediately at birth because of an increased corticosteroids release due to the fetal stress. Respiratory rate was not accurate to predict respiratory distress; hence detailed pulmonary auscultation should be performed. Mucous membrane color assessment was not reliable for the diagnosis of superficial to mild cardio-respiratory alterations. Cesarean section newborns presented cyanosis immediately after birth, however all evolve satisfactorily at 5 minutes of lif

A clinical and hemogasometric survey of neonatal lambs

In order to provide adequate medical assistance to neonates, the extent of vitality impairment has to be investigated through complementary exams, as well as clinical assessment. This investigation aimed to identify the physiological changes that occur during neonatal adaptation and to develop a clinical approach that can be performed during the first hour of life in neonatal lambs born through vaginal eutocic labor. The neonatal vitality of 14 Santa Ines lambs was verified using the Apgar system and rectal temperature at birth and after 5 and 60 min after birth. From the total number of neonates, 7 lambs were randomly selected for blood gas analysis and glucose immediately at birth and 1 h after birth. The lambs had hypoglycemia immediately after birth, as well as acidosis due to metabolic and respiratory causes. Given their hypoxemia at birth, lambs immediately exhibit tachycardia and tachypnea. However, neonatal lambs reached Apgar score superior than 7 after 5 min of birth. Ovine neonates are relatively mature at birth, with adequate thermoregulation and active mechanisms to compensate for physiological acid-base imbalances. In conclusion, a systematic clinical examination of newborn sheep should include the implementation of the Apgar score coupled with the confirmation of any acid-base imbalances. Further research should evaluate neonatal adaptation to this critical period over a longer period of time. (C) 2012 Elsevier B.V. All rights reserved.FAPESP [2006/50485-7

Peripartum clinical and hemodynamic evaluation of Holstein cows under distinct obstetric conditions

As distocias na espécie bovina são normalmente corrigidas por manobras obstétricas, sendo a extração forçada um procedimento obstétrico de risco, podendo causar injúrias tanto maternas quanto fetais. Partos induzidos com administração de ocitocina exógena nas inércias uterinas podem levar ao comprometimento fetal pela hipotensão e bradicardia materna, pois a ocitocina participa de regulações endócrinas e neuroendócrinas de órgãos como o coração e rins. O objetivo deste estudo foi comparar as mensurações de frequência cardíaca (FC), pressão arterial não-invasiva (PA) e eletrocardiograma de fêmeas bovinas da raça Holandesa agrupadas segundo a condição obstétrica: eutocia (G EUT; n = 10); distocia com manobra obstétrica (G DIST; n = 10); inércia uterina com infusão de ocitocina (G OCT; n = 10); nos seguintes momentos: pré-parto, intraparto, pós-parto imediato e uma hora após o parto. Os traçados eletrocardiográficos denotaram ritmo sinusal normal em todos os períodos. Observou-se taquicardia em todos os grupos, sendo que apenas no G OCT a FC pós-parto (111 ± 23 bpm) elevou-se estatisticamente em relação ao pré-parto (94 ± 11 bpm). Houve acréscimo significativo da PA no intraparto do G DIST (PA média = 101 ± 24 mmHg), decorrente de contrações uterinas e abdominais mais intensas. As fêmeas bovinas do Grupo OCT não apresentaram aumento significativo da PA diastólica intraparto em relação ao pré-parto como observado nos G EUT e G DIST. Os resultados apresentados demonstram que a distocia com correção manual eleva a pressão arterial das fêmeas bovinas, enquanto a administração de ocitocina altera momentaneamente as variáveis hemodinâmicas com possível efeito bradicárdico e hipotensor intraparto, impondo adaptação circulatória materna frente às alterações do partoBovine dystocias are commonly assisted through obstetric procedures. However, manual traction delivery can be a dangerous strategy for the treatment of dystocia as it may lead to maternal and fetal injuries. Use of oxytocin for uterine atonia or hypotonia to induce contractions may compromise fetal welfare due to maternal hypotension and bradycardia, because this hormone regulates renal and heart endocrine and neuroendocrine actions. The aims of this study were to compare heart rate (HR) measurement, non-invasive blood pressure (BP) and electrocardiograms records of Holstein cows during the first stage of labour, intrapartum, immediately after calving and one hour later of physiological birth and dystocia. The animals were allocated in: group EUT – eutocia (n = 10); group DYST – dystocia with obstetric assistance (n = 10); group OCT – uterine inertia treated with oxytocin (n = 10). The electrocardiograph tracing showed a normal sinus rhythm during all parturition. Tachycardia was observed in all groups, however, group OCT showed higher heart rate immediately after calving (111 ± 23 bpm) than prepartum evaluation (94 ± 11 bpm). During labor, DYST G presented significantly higher BP (Medium BP = 101 ± 24 mmHg), due to uterine and abdominal strengthened contractions. Group OCT cows didn't show significative elevation on diastolic BP during calving as occurred on EUT and DYST groups. The present results indicate superior blood pressure on manual traction delivery of bovine females, while oxytocin infusion altered transitorily hemodynamic variables with a possible bradicardiac effect and intrapartum hypotension and impose maternal circulatory adaptation during parturitio

NEOTROPICAL ALIEN MAMMALS: a data set of occurrence and abundance of alien mammals in the Neotropics

Biological invasion is one of the main threats to native biodiversity. For a species to become invasive, it must be voluntarily or involuntarily introduced by humans into a nonnative habitat. Mammals were among first taxa to be introduced worldwide for game, meat, and labor, yet the number of species introduced in the Neotropics remains unknown. In this data set, we make available occurrence and abundance data on mammal species that (1) transposed a geographical barrier and (2) were voluntarily or involuntarily introduced by humans into the Neotropics. Our data set is composed of 73,738 historical and current georeferenced records on alien mammal species of which around 96% correspond to occurrence data on 77 species belonging to eight orders and 26 families. Data cover 26 continental countries in the Neotropics, ranging from Mexico and its frontier regions (southern Florida and coastal-central Florida in the southeast United States) to Argentina, Paraguay, Chile, and Uruguay, and the 13 countries of Caribbean islands. Our data set also includes neotropical species (e.g., Callithrix sp., Myocastor coypus, Nasua nasua) considered alien in particular areas of Neotropics. The most numerous species in terms of records are from Bos sp. (n = 37,782), Sus scrofa (n = 6,730), and Canis familiaris (n = 10,084); 17 species were represented by only one record (e.g., Syncerus caffer, Cervus timorensis, Cervus unicolor, Canis latrans). Primates have the highest number of species in the data set (n = 20 species), partly because of uncertainties regarding taxonomic identification of the genera Callithrix, which includes the species Callithrix aurita, Callithrix flaviceps, Callithrix geoffroyi, Callithrix jacchus, Callithrix kuhlii, Callithrix penicillata, and their hybrids. This unique data set will be a valuable source of information on invasion risk assessments, biodiversity redistribution and conservation-related research. There are no copyright restrictions. Please cite this data paper when using the data in publications. We also request that researchers and teachers inform us on how they are using the data