Electrocardiographic Aspects of Singleton Pregnancy and Neonatal Period in American Miniature Horse Breed

Background: During pregnancy, cardiovascular adaptations occur in order to meet maternal demands and adequate support for fetal development, but they are still unclear in the equine species, especially in the American Miniature horse breed. The main hemodynamic changes that occur during pregnancy are increased heart rate, cardiac output, and blood volume. It is necessary to use the reference values for the miniature breeds, in addition to the age range and reproductive condition, so the objective of this study was to evaluate the effect of pregnancy on electrocardiographic (ECG) parameters in mares and also of age in newborns foals of American Miniature horse breed. Materials, Methods & Results: Ten American Miniature Horse mares, between 7 and 19 years old (12.14 ± 4.05 years), 116.85 ± 24.09 kg of body weight were used in the experiment. All these mares were pluriparous, with 5.9 ± 3.5 of births, minimum of 2, and maximum of 12 foaling times. They were maintained in common social group in an indoor house stable with straw bed, with access to an outdoor paddock for several h per day. Twice a day they were fed with hay. Mineral supplements and water were available ad libitum. The ECG were obtained in 10 pregnant mares and in 10 neonates. All females were examined at a representative time of each trimester of pregnancy, at 30, 210, 300 days before and 21 days after delivery. Neonates were examined on different times: first 24 h after delivery, weekly on the 7th, 14th, 21st, 28th and 35th days of age. The ECG parameters considered were the heart rate and rhythm, duration and intervals (P, PR, QRS, QT, T) and amplitude (P, R, S, T) of ECG waves. The mean of pregnancy duration was 319.4 ± 4.97 days. Heart Rate (HR) varied between 51 to 59 bpm during pregnancy and 56 bpm on the 21st day after delivery. Comparing the clinical parameters of pregnant mares, non-pregnant mares and foal a difference was found for HR, Respiration Rate (RR) and Temperature (P = 0.001). All ECG parameters of pregnant, non-pregnant and foal mares showed a significant difference (P = 0.0001), except for the amplitude of the P1, P2 and R waves, which was similar for the 3 groups. The mean values of HR and amplitude of the positive T wave were higher in foals when compared to pregnant and non-pregnant mares, which in turn did not differ from each other. The mean duration of the P wave, PR segment, QRS complex, QT segment and T wave were the same among mares and greater than in foals. Comparing pregnant and non-pregnant mares, there was a difference in only 3 parameters: duration of the QTc segment, amplitude of the S wave and negative T wave. The non-pregnant mares had a longer duration of the QTc segment and a greater amplitude of the negative T wave, while the foals had a greater amplitude of the S wave.Discussion: Although this study did not measure HR at delivery time, it is worth to consider the action of the parasympathetic autonomic nervous system close to delivery, which reduces the HR of mares. This is because at delivery, sympathetic-adrenal activation should be avoided since the increase in sympathetic tone can cause uterine atony via B2 receptors. For this reason, it has been shown that, during physiological birth, horses are under parasympathetic control, and stress response mechanisms are not activated. It was conclude that the morphometry of the waves, intervals and ECG complexes, during the evolution of the reproductive state, the electrocardiographic aspects were generally associated with heart rate (PR and QT intervals). As for neonates, there was a discrepancy among the most of ECG parameters when compared to the adult female, regardless of reproductive status, clarifying the importance of ECG patterns not only for the breed, but also for the age group

Susceptibilidade in vitro a antimicrobianos da Mannheimia haemolytica e da Pasteurella multocida isoladas de ovinos sadios e com doenças respiratórias

Pasteurella multocida e Mannheimia haemolytica (P. haemolytica) estão associadas a enfermidades no sistema respiratório de ovinos. Com o objetivo de avaliar a susceptibilidade in vitro destes microrganismos frente aos antimicrobianos, foram colhidas amostras de nasofaringe (n=180) e orofaringe (n=82) de ovinos com e sem enfermidade respiratória. Dentre os antimicrobianos testados, a sensibilidade foi maior para enrofloxacina (100%) e florfenicol (100%), considerando-se ambas as espécies bacterianas. Observou-se resistência de M. haemolytica e P. multocida à tetraciclina (15,64% e 17,65%, respectivamente) e penicilina (1.82% e 4.2%, respectivamente).Pasteurella multocida and Mannheimia haemolytica (P. haemolytica) are associated with ovine respiratory diseases. With the purpose of observe the susceptibility in vitro of these organisms against antimicrobials, were collected samples of nasopharingeal (n=180) and oropharingeal (n=82) from ovines healthy and with respiratory disease. Among the antimicrobials tested, the sensibility was greater for enrofloxacin (100%) and florfenicol (100%), for both bacteria. The greater resistance indices for M. haemolytica and P. multocida were observed with tetracyclin (15.64% and 17.65% respectively) and penicillin (1.82% and 4.2%)

Short-term Heart Rate Variability Analysis in Healthy Dogs of Different Ages

Background: The modulation of heart rate by autonomic nervous system may be evaluated by the heart rate variability (HRV), which illustrates the fluctuations between RR intervals. To evaluate this analysis, the intervals between 2 QRS complexes are measured. In general, high HRV values are expected in healthy individuals; otherwise, low values are indicative of organism dysfunction. Studies conducted in healthy humans show that HRV suffers reduction with ageing and that there is autonomic immaturity in neonates. The aim of this study was to describe the characteristic pattern of cardiac autonomic behavior in healthy dogs in different age groups through short-term HRV analysis.Materials, Methods & Results: A total of 87 healthy dogs were studied. HRV was analyzed in time and frequency domain, using Holter and heart rate monitor. It was observed that puppies (below one year old) presented a lower parasympathetic predominance and, consequently, lower HRV values on time domain (SDNN, PNN50% e RMSSD) compared to the other 2 groups and on frequency domain (LF, HF and LF/HF) compared to the adult animals group (between 1 and 7-year-old), which presented higher HRV values when compared to the other groups. Elderly dogs (over 8-year-old) exhibited a natural tendency to decrease cardiac parasympathetic HRV indexes.Discussion: The use of the HRV method as a prognostic index and as an arrhythmogenic marker for various canine heart diseases presents interesting perspectives. However, before it may be employed for these purposes, a better understanding should be established regarding the physiological behavior of autonomic cardiac modulation in different age groups to serve as a basis for future analyses. This study observed that puppies presented higher values for HR and, therefore, shorter RR intervals than the other groups (adult and elderly dogs), what was observed on Holter and heart rate monitor methods (HRM). There were significant differences between puppies and the other 2 groups (adults and elderly) for all time-domain variables using both methods (Holter and HRM methods). SDNN was significantly lower in puppies compared to adults and elderly dogs. In addition, both RMSSD and PNN50%, which were more reliable over shorter periods of time, also presented means and medians that were significantly lower in puppies. Regarding frequency-domain HRV parameters observed on Holter method, these indexes were decreased on the elderly group compared to adult dogs, which is a possible effect of aging. Also, puppies revealed lower frequency-domain HRV parameters on both methods when compared to adult dogs. The influence of age on HRV is possibly related to the stage of development of an individual, starting at conception up to the maturity in relation to the mechanisms that cause variations in HR. There are studies in humans that suggest a gradual increase in parasympathetic activity during childhood, followed by a steady decrease as aging occur. The present study observed the same pattern in dogs. The balance between sympathetic and parasympathetic systems is influenced by age in dogs, which alters HRV values in the short-term. The HRV method´s analysis is relatively simple and non-invasive for assessing cardiac autonomic function; also, it is widely used in human medicine as a risk measure for sudden cardiac death. The 24-hour HRV analysis is highly challenging, as it is time-consuming, expensive, delays diagnosis, and has a large number of artifacts; in this way, standards for its short-term analysis were developed. Keywords: cardiology, autonomic nervous system, heart rate monitor, Holter

ACURÁCIA DOS MÉTODOS OSCILOMÉTRICO (PETMAP®) E DOPPLER PARA AFERIÇÃO INDIRETA DA PRESSÃO ARTERIAL EM CORDEIROS

A fisiologia neonatal possui peculiaridades inerentes à faixa etária. O objetivo do estudo foi monitorar a pressão arterial sistêmica de cordeiros durante o período neonatal. Foram usados 20 cordeiros da raça Ile de France, a partir do nascimento e aos sete, 14, 21, 28 e 35 dias de vida. Os parâmetros analisados foram: frequência cardíaca (FC), pressão arterial sistólica (PAS), diastólica (PAD) e média (PAM) pelo método oscilométrico petMAP®, e PAS com Doppler. Também foi realizada a pressão invasiva para validar os métodos indiretos obtendo a média de 101,52 ± 12,04 mmHg. As médias utilizando o petMAP® foram: FC (156,38 ± 37,46 bpm); PAD (63,80 ± 11,14 mmHg); PAM   (81,58 ± 11,83 mmHg); PAS (112,48 ±15,68 mmHg) e PAS (90,27 ± 12,11 mmHg) com Doppler. Houve diferença significativa na FC e pressão arterial entre os momentos analisados. Os métodos indiretos diferiram entre si em 12,30 mmHg (superestimação de 11%). Comparando com a invasiva, os dois métodos superestimaram os valores da PAS em 4% e 16%, respectivamente, para Doppler e petMAP®. Os resultados mostraram que o método Doppler estabeleceu boa relação com a invasiva, sendo útil para aferição da PAS. O método oscilométrico necessita de maiores estudos para sua utilização em pequenos ruminantes. Palavras-chave: Doppler; oscilométrico; ovinos; período neonatal; pressão arterial sistêmica

CLINICAL BIOCHEMICAL DETERMINATIONS IN THE MANGALARGA-PAULISTA HORSE - REFERENCE VALUES

Biochemical values are widely related with environmental agents, sex and age, and are used in disease diagnosis. Numerous reports have been published on the biochemical parameters of different breeds of horses. However, there is a paucity of information concerning Cu-Zn superoxide dismutase (SOD), ceruloplasmin, copper and zinc determinations in the serum. Blood samples from a total of 60 horses of the Mangalarga-Paulista breed, representing three age groups (0 to 4 months old, 6 to 18 months old and adult) were examined. Male horses have a higher mean value of SOD, ceruloplasmin and copper than do females. No significant sex-related difference was observed in serum zinc content of weaned and adult horses. SOD activity was significantly higher in adult animals. Since SOD has a protective effect against superoxide free radical toxicity and possesses anti-inflammatory activity, it is reasonable to assume that the increased activity of this enzyme may be due to an adaptation mechanism which protects the adult animal against oxygen toxicity

Aspectos clínicos, laboratoriais, necroscópicos e métodos diagnósticos da toxemia da gestação em pequenos ruminantes

Toxemia of pregnancy (TP) occurs in the last 6 weeks before birth in sheep fetus gestating a large or multiple lambs. The disease is associated with low concentrations of plasma glucose and markedly increased plasma concentrations of ketone bodies. Toxemia of pregnancy is characterized by clinical signs such as depression of consciousness, neuromuscular disorders, posture and muscle tone, balance, gait and primitive movements (mime chewing, grinding of teeth). The diagnosis of pulmonary tuberculosis in small ruminants is based on clinical and laboratory findings, as well as historical and history. The treatment is controversial, the CS / induction of labor in the initial therapy and glucose precursors. Prevention is based primarily on maintaining adequate nutritional management for each category of animal ownership and is very important because it is a disease of high lethality.A toxemia da prenhez (TP) ocorre nas últimas 6 semanas antes do parto em ovelhas gestando um feto grande ou múltiplos cordeiros. A doença é associada a baixas concentrações plasmática de glicose e notadamente um aumento das concentrações plasmáticas de corpos cetônicos. A toxemia da prenhez caracteriza-se por sinais clínicos como a depressão da consciência, distúrbios neuromusculares, de postura e de tônus muscular, desequilíbrio, andar cambaleante e por movimentos primitivos (mímica da mastigação, ranger dos dentes). O diagnóstico da TP em pequenos ruminantes é baseado nos achados clínicos e laboratoriais, além do histórico e anamnese. O tratamento é controverso, a cesárea/indução do parto na fase inicial e a terapia com precursores de glicose. A prevenção é baseada principalmente na manutenção do manejo nutricional adequado para cada categoria animal da propriedade e é muito importante por se tratar de uma enfermidade de alta letalidade

Escore de Apgar: história e importância na medicina veterinária

The Apgar score is widely used in hospitals around the world as the best method for clinical evaluation of the newborn immediately after delivery. In veterinary medicine studies have been developed to provide effective aid in the identification of risk newborns. The score is used to identify high-risk neonates requiring medical attention, especially in the first minutes of life, promoting a faster and more efficient response.O escore de Apgar é utilizado amplamente nas maternidades de todo o mundo como o melhor método para avaliação clínica do neonato no momento imediato após o parto. Na medicina veterinária, estudos vêm sendo realizados e adaptações ao método original são desenvolvidas para um auxílio eficaz na identificação dos neonatos de risco. A pontuação serve para identificar neonatos de alto risco que necessitem de atenção médica, principalmente nos primeiros minutos de vida, possibilitando, assim, uma intervenção mais rápida e eficiente

Association between handling stress in the corral and rabies antibody titers in selenium-supplemented cattle

This study determined the correlation between serum cortisol levels and rabies antibody titers in cattle primo-vaccinated against rabies and supplemented with dietary selenium (Se). Sixty Nelore male calves (10 to 12 months old) received daily and individual dietary supplementation with 0, 3.6, 5.4 and 6.4 mg Se (groups Gc, G(3.6), G(5.4) and G(6.4), respectively). The animals were vaccinated against rabies (day 0) and subjected to handling stress in the corral for 120 days. Blood sampling procedures were performed on days 0, 15, 30, 60, 90 and 120. Cortisol levels increased until day 90, but had dropped significantly by day 120 (P < 0.01). Rabies antibody titers on days 30 and 90 were similar among Se-supplemented groups; in the control group, rabies antibodies decreased significantly from day 30 to 60, and 90 to 120. Serum cortisol levels and antibody titers were not correlated in most of the groups or blood sampling days. A positive correlation among these variables was found only in G(6.4) on days 60 (R = 0.513; P = 0.05) and 120 (R = 0.644; P = 0.009). In conclusion, repeated handling in the corral stresses cattle, but without compromising rabies humoral immune response