Efeito da idade sobre a fertilidade de éguas inseminadas com sêmen diluído, resfriado a 14ºC e transportado

Para estudar o efeito da idade sobre características ovulatórias e de fertilidade, 147 ciclos estrais de 99 éguas foram agrupados em classes por idade (1 - 3-6 anos; 2 - 7-10 anos; 3 - 11-14 anos; e 4 - 15-19 anos), de acordo com o ano do nascimento. As éguas foram inseminadas com sêmen diluído, resfriado e transportado de apenas um garanhão, três vezes por semana (segundas, quartas e sextas-feiras).O controle folicular, por meio da palpação retal, e a rufiação foram realizados diariamente, durante todo o período experimental. Utilizou-se, para o transporte, o sêmen diluído no diluidor de leite desnatado-glicose no conteiner Celle modificado, sendo a dose inseminante de 400 x 10(6) espermatozóides móveis, no momento da diluição final, pré-resfriamento. O tempo médio da coleta do sêmen à inseminação artificial foi de 3,5 horas e a temperatura final do sêmen, no momento da inseminação, de 14ºC. Não houve influência da idade sobre a velocidade de crescimento folicular e o tamanho do folículo ovulatório. A fertilidade decaiu após os 15 anos de idade, traduzida pela diminuição da taxa de concepção/ciclo e eficiência de prenhez, entretanto, não foram observadas características indicativas de senescência até os 19 anos de idade.

Efeito do número de inseminações artificiais sobre a fertilidade de éguas inseminadas com sêmen diluído, resfriado a 14ºC e transportado

Estudou-se o efeito do número de inseminações sobre a fertilidade de éguas inseminadas, três vezes/semana (segundas, quartas e sextas-feiras), com sêmen diluído, resfriado e transportado, de apenas um garanhão. As éguas foram inseminadas a partir da detecção, pela palpação retal, de um folículo de 3,0 a 3,5 cm de diâmetro, em um dos ovários, até a ovulação. Utilizaram-se para o transporte o sêmen diluído no diluidor leite desnatado-glicose e o conteiner Celle modificado, sendo a dose inseminante de 400 x 10(6) espermatozóides móveis, no momento da diluição final, pré-resfriamento. de acordo com o número de inseminações artificiais (IA) utilizadas/ciclo, os resultados de 148 ciclos, de 100 éguas, foram agrupados em: 1 IA, 2IA, 3 IA e 4 ou mais IA. A eficiência de prenhez foi de 4,29; 5,04; 5,67; e 3,43, para 1, 2, 3 e 4 ou mais IA, respectivamente. As características foliculares diferiram em relação à freqüência de inseminações com os maiores valores observados no grupo de éguas inseminadas quatro ou mais vezes. Concluiu-se que menor velocidade de crescimento folicular e maior diâmetro do folículo ovulatório estiveram associados a maior número de inseminações artificiais/ciclo. Na presença de uma concentração espermática adequada, o número de inseminações/ciclo não exerceu influência sobre a fertilidade.

Fertilidade do sêmen eqüino diluído, resfriado e transportado

Objetivou-se neste experimento estudar o efeito do transporte de sêmen equino, entre haras, sobre a fertilidade de éguas inseminadas. Setenta e seis fêmeas da raça Mangalarga Marchador foram distribuídas, ao acaso, com número desigual de repetições, para se estudarem os efeitos do sêmen in natura, transportado ou não, e do sêmen diluído, resfriado e transportado, sobre a fertilidade de éguas e diferentes características reprodutivas. O sêmen foi diluído no diluidor lactose-gema de ovo sem glicerina. As fêmeas foram inseminadas, em dias alternados, com sêmen de apenas um garanhão, com volumes/dose inseminante variáveis dependendo do número de fêmeas a serem inseminadas por dia com determinado ejaculado. Utilizou-se para o transporte do sêmen um contêiner especialmente projetado para este fim (MSP-1). As taxas de concepção ao primeiro ciclo e totais, a eficiência de prenhez, o número de ciclos/égua, ciclos/égua gestante, ciclo/prenhez e prenhez/ciclo, o número de IA/égua, o número de IA/égua gestante e o número de IA/égua vazia não foram influenciados pelos tratamentos. O diluidor de lactose gema, modificado pela retirada do glicerol de sua formulação, constitui uma opção para a diluição do sêmen a ser resfriado e transportado. O suceso do transporte do sêmen, diluído e resfriado, a pequenas distâncias, por período de tempo curto, depende mais de um bom diluídor que de um sofisticado contêiner de transporte.

Efeitos da rufiação e da manipulação do sistema genital sobre a fertilidade de éguas inseminadas

Estudaram-se os efeitos da rufiação e da manipulação do sistema genital (estocadas) sobre a fertilidade de éguas inseminadas com sêmen fresco (exp. 1) e resfriado/transportado a 14ºC/3,6 horas (exp. 2). No experimento 1 utilizaram-se 42 ciclos de 29 éguas, e no experimento 2, 148 ciclos de 100 éguas, distribuídos aleatoriamente em quatro grupos experimentais definidos por um esquema fatorial 2 x 2, com número desigual de repetições, de acordo com o tipo de rufiação utilizado (éguas rufiadas e não rufiadas) e o tipo de manipulação do sistema genital da fêmea no momento da inseminação (estocadas e não estocadas). Em ambos os experimentos não se observou efeito da estimulação sexual da égua sobre a fertilidade. No experimento 2 não se observou efeito da estimulação sexual sobre a dinâmica de crescimento folicular e ovulação.

Development and characterization of an equine behaviour chamber and the effects of amitraz and detomidine on spontaneous locomotor activity

This report describes the development of a behaviour chamber and the validation of the chamber to measure locomotor activity of a horse, Locomotor activity was detected by four Mini-beam sensors and recorded on a data logger every 5 min for 22 h. Horses were more active during daytime than in the evening, which was at least partially related to human activity in their surroundings. To validate the ability of the chambers to detect changes in activity, fentanyl citrate and xylazine HCl, agents well-characterized as a stimulant and a depressant, respectively, were administered to five horses. Fentanyl citrate (0.016 mg/kg) significantly increased locomotor activity which persisted for 30 min, Xylazine HCl (1 mg/kg) significantly reduced locomotor activity for 90 min. Amitraz produced a dose-dependent decrease in locomotor activity, lasting 75 min for the 0.05 mg/kg dose, 120 min for the 0.10 mg/kg dose, and 180 min for the 0.15 mg/kg dose, In a separate experiment, yohimbine administration immediately reversed the sedative effect of amitraz, This suggests there is a similarity in the mode of action of amitraz, xylazine and detomidine, as yohimbine acts primarily by blocking central alpha 2-adrenoceptors that are stimulated by agents like xylazine, There was also a significant decrease in locomotor activity following injection of detomidine (0.02, 0.04 and 0.08 mg/kg) for 1.5, 3.5 and 5.0 h, respectively, the locomotor chamber is a useful, sensitive and highly reproducible tool for measuring spontaneous locomotor activity in the horse, which allows investigators to determine an agent's average time of onset, duration and intensity of effect on movement.

Intra-articular pressure profiles of the cadaveric equine fetlock joint in motion

The study of the influence of motion and initial intra-articular pressure (IAP) on intra-articular pressure profiles in equine cadaver metatarsophalangeal (MTP) joints was undertaken as a prelude to in vivo studies, Eleven equine cadaver MTP joints were submitted to 2 motion frequencies of 5 and 10 cycles/min of flexion and extension, simulating the condition of lower and higher (double) rates of passive motion. These frequencies were applied and pressure profiles generated with initial normal intra-articular pressure (-5 mmHg) and subsequently 30 mmHg intra-articular pressure obtained by injection of previously harvested synovial fluid.The 4 trials performed were 1) normal IAP; 5 cyles/min; 2) normal IAP; 10 cycles/min; 3) IAP at 30 mmHg; 5 cycles/min and 4) IAP at 30 mmHg; 10 cycles/min. The range of joint motion applied (mean +/- s.e.) was 67.6 +/- 1.61 degrees with an excursion from 12.2 +/- 1.2 degrees in extension to 56.2 +/- 2.6 degrees in flexion, Mean pressure recorded in mmHg for the first and last min of each trial, respectively, were 1) -5.7 +/- 0.9 and -6.3 +/- 1.1; 2) -5.3 +/- 1.1 and -6.2 +/- 1.1; 3) 58.8 +/- 8.0 and 42.3 +/- 7.2; 4) 56.6 +/- 3.7 and 40.3 +/- 4.6. Statistical analyses showed a trend for difference between the values for the first and last minute in trial 3 (0.05>P<0.1) with P = 0.1 and significant difference (P = 0.02) between the mean IAP of the first and last min in trial 4. The loss of intra-articular pressure associated with time and motion was 10.5, 16.9, 28.1 and 28.9% for trials 1-4, respectively. As initial intraarticular pressure and motion increased, the percent loss of intra-articular pressure increased.The angle of lowest pressure was 12.2 +/- 1.2 (mean +/- s.e.) in extension in trials 1 and 2, In trials 3 and 4, the lowest pressures were obtained in flexion with the joints at 18.5 +/- 2.0 degrees (mean +/- s.e.). This demonstrated that the joint angle of least pressure changed as the initial intra-articular pressure changed and there would not be a single angle of least pressure for a given joint.The volume of synovial fluid recovered from the MTP joints in trial 3 compared to 4 (trials in which fluid was injected to attain IAP of 30 mmHg) was not significantly different, supporting a soft tissue compliance change as a cause for the significant loss of intra-articular pressure during the 15 min of trial 4.The pressure profiles generated correlate well with in vivo values and demonstrated consistent pressure profiles. Our conclusions are summarised as follows:1. Clinically normal equine MTP joints which were frozen and then later thawed were found to have mostly negative baseline intra-articular pressures, as would be expected in living subjects,2. Alternate pressure profiles of the dorsal and plantar pouch at baseline intra-articular pressure document the presence of pressure forces that would support 'back and forth' fluid movement between joint compartments. This should result in movement of joint fluid during motion, assisting in lubrication and nutrition of articular cartilage,3. If joint pressure was initially greater than normal (30 mmHg), as occurs in diseased equine MTP joints, joint motion further increased joint capsule relaxation (compliance) and, therefore, reduced intra-articular pressure.4. Peak intra-articular pressures reached extremely high values (often >100 mmHg) in flexion when initial pressure was 30 mmHg. Joint effusion pressures recorded for clinical MCP joints are frequently 30 mmHg. These IAP values are expected to produce intermittent synovial ischaemia in clinical cases during joint flexion.5, Additional in vivo studies are necessary to confirm our conclusions from this study and to identify the contributions of fluid absorption and the presence of ischaemia in a vascularised joint.

Detection and differentiation of Leptospira spp. serovars in bovine semen by polymerase chain reaction and restriction fragment length polymorphism

In view of the importance of venereal transmission of bovine leptospirosis, the objective of the present study was to apply the polymerase chain reaction (PCR) to 26 serovars of Leptospira interrogans, L. borgpetersenii, L. santarosai, L. noguchii and L. biflexa, to determine the detection threshold in semen samples and to evaluate the possibility of differentiation among serovars using 19 restriction endonucleases. The results showed that all serovars were amplified and the detection threshold in semen samples of a bull was 100 bacteria/ml. Using endonucleases we could classify the 26 serovars into eight groups. The present results show that PCR is a method of great potential for the detection of Leptospira spp, at bovine artificial insemination centers. (C) 2000 Elsevier B.V. B.V. All rights reserved.

Effect of intraluminal distention on microvascular perfusion in the equine small colon

Objective-To determine the effect of experimental intraluminal distention on microvascular perfusion of the small colon in horses.Animals-6 mixed-breed healthy horses (mean age [+/- SD], 9.1 +/- 2 years).Procedure-Under general anesthesia, the small colon was exposed by celiotomy and 3 segments were demarcated. In 1 of these segments, intraluminal obstruction was created by placement of a latex balloon inflated to a pressure of 40 mm Hg (obstructed segment). The other segments were the sham-operated segment and the control segment. Microvascular perfusion was evaluated in the mucosal, submucosal, muscular, and serosal layers by injection of 15-mum-diameter colored microspheres into branches of the caudal mesenteric artery. Recovery of microspheres was performed by tissue digestion, washing, and centrifugation. Distribution of microspheres in the intestinal layers was evaluated by direct observation of stained frozen sections by light microscopy.Results-A significant reduction was observed in total microvascular perfusion of obstructed segments, which was 26.4% of that of control segments. This reduction was not evident in the mucosal layer.Conclusions and Clinical Relevance-Intraluminal distention of the equine small colon wall can promote ischemia by a reduction in microvascular perfusion in the intestinal wall. Intestinal layers do not seem to be affected to the same extent, because the absolute value for mucosal perfusion did not decrease in the obstructed segment.

Thermography and ultrasonography in back pain diagnosis of equine athletes

The object of the current study was to evaluate the efficacy of thermography and ultrasonography in the diagnosis of thoracolumbar lesions in Quarter Horse athletes and associate the different types of lesions found with the athletic modality practiced. Twenty-four horses were admitted to the Surgery Service for Large Animals of the Veterinary and Animal Science Faculty, UNESP, Botucatu, Brazil, with complaints of back problems. All the horses were submitted for physical examinations to confirm the existence of thoracolumbar alterations and then for thermography and ultrasonography Thermography was used to map the lesioned areas of this region and ultrasonography for lesion characterization. The lesions found were supraspinous desmitis, interspinous desmitis, dorsal intervertebral osteoarthritis, and impingement of the spinous processes or kissing spines. The existence of a relation between the type of event practiced by the horse and the type of lesion found was determined. In horses that competed in the barrel race, a predominance of lesions in the thoracic caudal, thoracolumbar, and cranial lumbar regions occurred, with intervertebral osteoarthritis and interspinous desmitis being the most common. In cutting horses, most of the lesions were observed in the caudal lumbar region, whereas horses competing in reining showed a preferential location for lesions in the middle lumbar, with a predominance of supraspinous desmitis and myositis. Thermography associated with ultrasonography was shown to be efficient in the diagnosis of the thoracolumbar lesions of these horses.