Haemodynamic differences between pancuronium and vecuronium in an experimental pig model.

OBJECTIVE: To compare baseline cardiovascular function in anesthetised pigs using either pancuronium or vecuronium as a neuromuscular blocker. STUDY DESIGN: Retrospective, non-randomized comparison. ANIMALS: Norwegian Land Race pigs (Sus scrofa domesticus) weighing mean 42 ± SD 3 kg. METHODS: One hundred and sixteen animals from four different research protocols premedicated with identical doses of ketamine, diazepam, atropine and isoflurane, and anaesthetised with pentobarbital, fentanyl, midazolam and N(2)O were arranged into three uniform groups with respect to neuromuscular blocking agent: pancuronium bolus of 0.063 mg kg(-1) followed by 0.14 mg kg(-1) hour(-1) (n = 54), low-dose vecuronium 0.4 mg kg(-1) /0.2 mg kg(-1) hour(-1) (n = 29) and high-dose vecuronium 0.6 mg kg(-1) /0.3 mg kg(-1) hour(-1) (n = 33). RESULTS: The majority of cardiovascular parameters demonstrated no significant differences between groups. For heart rate, there was an overall group difference, p = 0.036. Dromotropy was low in the pancuronium group, with an increased normalised PR-interval compared to the high-dose vecuronium group, median 0.200 interquartile range (0.190, 0.215) versus 0.182 (0.166, 0.199), p < 0.05. Left ventricular compliance was increased in pancuronium-treated animals, demonstrated as a reduction in the nonlinear end-diastolic pressure volume relationship ß compared to both vecuronium groups, 0.021 (0.016, 0.025) versus 0.031 (0.025, 0.046) and 0.031 (0.022, 0.048), p < 0.05. The linear end-diastolic pressure volume relationship EDPVR(lin) was reduced as well in the pancuronium group, compared to the low-dose vecuronium group, 0.131 (0.116, 0.169) versus 0.181 (0.148, 0.247), p < 0.05. CONCLUSIONS: There are only minor haemodynamic differences when using pancuronium compared to vecuronium in the fentanyl-pentobarbital-midazolam-N(2)O anesthetised domestic pigs. Furthermore, increasing doses of vecuronium have minimal haemodynamic effects. CLINICAL RELEVANCE: Experimental studies in pigs using either pancuronium or vecuronium as a neuromuscular blocking agent are comparable with regard to cardiac and haemodynamic performance.

Effect of a homeopathic complex on reproductive performance in a commercial pig farm.

BACKGROUND AND AIM: Alternative therapies based on homeopathy can be effective in improving reproductive performance in intensive pig breeding. In this study, the effect of a homeopathic complex on reproductive performance of sows under intensive farming has been investigated. MATERIAL AND METHODS: Over period of three years, 186 sows were recruited from a farm where a large proportion of animals were suffering from prolonged weaning-to-oestrus intervals (WEI) and weaning-to-service intervals (WSI). Sows were allocated to two groups; once per month, one group was given a homeopathic complex (Borax 10 mK plus Lycopodium 10 mK), while the other group was given a hydro-alcoholic solution (placebo). The follow-up period started one week before the expected date of oestrus, continued for two pregnancies and ended after the weaning of the second farrowing. To evaluate reproductive performance, during the follow-up we collected data on quantitative parameters such as the average number of stillbirths, newborns, and repeat services per farrowing. Time-related data such as WEI, WSI, length of the two pregnancies and weaning periods were also collected to measure the length of the follow-up of each sow. Differences in quantitative parameters between the two groups were evaluated using parametric and non-parametric statistics. Time-related data were used to plot Kaplan-Meier curves and in Cox regression models to evaluate whether treated sows had a higher probability of experiencing a shorter follow-up in comparison to untreated sows. RESULTS: We did not found significant differences in the number of newborns, while the number of stillbirths was higher in the treatment group, even if the difference was slightly significant (p-value = 0.03). The number of repeat services was lower in the treatment group, and this difference was highly significant (p-value < 0.001). Results from the Cox regression models suggest that the end of the follow-up was reached by sows of the treatment group at about twice the rate of sows of the control group (model 2, Hazard Ratiotreatment = 2.27; 95%CI: 1.56-3.24).

GnRH antagonist inhibition of luteinizing hormone secretion and ovulation in the pig.

A GnRH antagonist, Ac-D-p-Cl-Phe1,2, D-Trp3, D-Arg6, D-Ala10 GnRHb (Organon), was utilized to determine the effective dosage and duration to inhibit LH secretion in the pig. In a preliminary trial, barrows received either 10, 50, or 250 micrograms/kg BW of the GnRH antagonist. Secretion of LH was inhibited within 30 min for a duration of 12 h with the 100 micrograms/kg dose but persisted for greater than 48 h with the 250 micrograms/kg treatment. A second study determined effectiveness of the antagonist for inhibiting ovulation in cyclic gilts. At first detection of standing estrus, cyclic gilts were treated with either saline (control), 100, or 200 micrograms/kg BW of the GnRH antagonist (GnRH1). A second group of GnRH antagonist gilts received 200 micrograms/kg BW of the GnRH antagonist approximately 8 h prior to standing estrus (GnRH2). The GnRH1-treatment failed to inhibit or delay ovulation. Ovulation was inhibited and estrous cycles lengthened in GnRH2-treated gilts. These preliminary results suggest that ovulation in the gilt can be inhibited if the GnRH antagonist is administered prior to the LH surge.

Differential bronchial and pulmonary vascular responses to vagal stimulation in the pig.

The pulmonary and bronchial vascular responses and changes in bronchial tone upon vagal stimulation (240 impulses at 2 Hz or 10 Hz) were studied in anaesthetized pigs paralyzed with pancuronium. The acetylcholine-evoked vasodilatation in the tracheobronchial circulation had the same magnitude when using pancuronium or succinylcholine as skeletal muscle relaxants. Atropine-sensitive bradycardia, hypotension and bronchoconstriction were observed upon vagal stimulation. A vasoconstrictor response in the pulmonary vascular bed and clear-cut vasodilatation in the bronchial circulation supplied by the bronchial artery also occurred upon vagal stimulation. The vagally-evoked increase in pulmonary vascular resistance was markedly reduced after atropine while the bronchial vasodilatation was unchanged. This suggests that the vagally-induced increase in bronchial blood flow was not secondary to changes in the pulmonary circulation. Furthermore, the pulmonary vasoconstrictor response caused by vagal stimulation under control conditions is probably explained by reflex sympathetic activation due to the fall in systemic blood pressure. These data indicate selective vagal non-cholinergic influence of blood flow in the bronchial vascular bed compared to the pulmonary circulation.

Evaluación de una vacuna experimental contra ojo azul en cerdos mediante las pruebas de inmunogenicidad, inocuidad, potencia y medición de la inmunidad pasiva en lechones / Evaluation of the passive immune response and protection confered by a blue eye inactivated vaccine in pigs

El ojo azul (OA) es una enfermedad de etiología viral que se caracteriza por producir encefalitis en lechones, falla reproductiva y opacidad corneal. Sin embargo, todavía no se cuenta con una vacuna para prevención y control de esta enfermedad. EL objetivo de este estudio fue evaluar la respuesta inmune y la protección conferida por una vacuna inactivada contra OA. Para la prueba de inmunogenicidad e inocuidad se usaron 10 cerdos destetados, fueron vacunados a las 6 y 8 semanas de edad. Se midió la respuesta inmune humoral por la prueba de sueroneutralización (SN) frente a 100 dosis infectantes cultivo celular 50 por ciento (DICC 50 por ciento) por ml del paramyxovirus de ojo azul cepa 1987 (POA-87). Los resultados de la prueba de SN indicaron que la media de anticuerpos fue de 1:32. No se presentaron reacciones locales o generalizadas, ni aumento en la temperatura de los cerdos vacunados y no vacunados en contracto (mezclados). Se midieron los niveles de Acs por SN cada mes y 6 meses después de la primera aplicación de la vacuna. Se realizó una prueba intradérmica (ID) observándose en la zona de inoculación una reacción de hipersensibilidad tipo IV en 3 de los 7 cerdos inoculados con POA-87 purificado. Además fueron vacunadas 6 hembras gestantes a las 4 y 2 semanas preparto, se midió la respuesta inmune humoral en el suero y calostro de las hembras y se determinó el grado de inmunidad pasiva transmitida, midiendo los niveles de Igs en el suero de los lechones a los 4, 28, y 38 días de edad. En este caso, la media de Acs por SN fue mayor a 1:16, con disminución del 85 por ciento a los 28 días y del 100 por ciento a los 38. En la prueba, de potencia se utilizaron 2 cerdas gestantes, una recibió dos aplicaciones de vacuna antes del parto. El desafío de las dos camadas se hizo a los cuatro días posparto; se observó mortalidad del 100 por ciento en los lechones de la hembra no vacunada, y protección del 71.4 por ciento en los lechones de la madre vacunada. La SARH señala como requisito mínimo un 80 por ciento de protección; sin embargo, de acuerdo con los resultados y análisis comparativos realizados se concluye que la vacuna inactivada contra el paramixovirus del ojo azul (POA) en cerdos, objeto de esta investigación, deberá ser sometida a un estudio con un mayor número de animales para comprobar que este biológico puede alcanzar una protección mayor al 80 por ciento y que es apta para el control de la enfermedad del Ojo Azul