RESUMO
Electronic identification of animals has become increasingly important worldwide to improve and ensure traceability. In warm and hot climates, such as Brazil, boluses can have advantages over ear tags as the internal devices reduce the risks of ear tag losses, tissue damage, and lesions on the ear. Electronic boluses, however, are often perceived as having negative characteristics, including reported difficulties of administration in small ruminants. This paper describes the factors associated with bolus design that affect the swallowing of a bolus in sheep. Other factors that might influence bolus swallowing time have also been considered. In addition, the effect of bolus design on its performance was evaluated. A total of 56 Suffolk ewes were used to assess the ease of administration and retention of 3 types of electronic ruminal boluses (mini, 11.5 × 58.0 mm and 21.7 g; small, 14.8 × 48.5 mm and 29.5 g; standard, 19.3 × 69.8 mm and 74.4 g) during a whole productive year, including pregnancy and lamb suckling. Ewe age (5.6 ± 2.3 yr) and weight (85.07 ± 8.2 kg BW) were recorded, as well as time for bolus swallowing. The deglutition of the bolus and any resulting blockages in the esophagus were monitored by visual observations. Retention and readability of the boluses were regularly monitored for d 1, wk 1, mo 1, and every mo until 1 yr. Time for bolus swallowing differed substantially with bolus type and was greater (P < 0.05) for the standard bolus (32.8 ± 6.9 s) when compared to small and mini boluses, which did not differ (8.5 ± 2.0 vs. 9.2 ± 2.7 s; P > 0.05). The bolus o.d. and length were positively correlated with swallowing time (P < 0.01). The ewe weight was negatively correlated with swallowing time (P < 0.05). At 6 mo all electronic boluses showed 100% retention rate, and at 12 mo, bolus retention was 100%, 94.5%, and 100% for mini, small, and standard boluses, respectively (P > 0.05). At 12 mo, all boluses showed 100% readability, except for small boluses, which had a readability of 94.5%. In conclusion, bolus design affected swallowing time and bolus readability. A reduction in boluses length and o.d. needs to be carried out to provide ease of administration and for boluses to be used as an effective means of electronic identification. Therefore, this study shows that adequately designed boluses are safe and suitable for identifying adult sheep and can therefore be used in hot climates.
Assuntos
Sistemas de Identificação Animal/instrumentação , Sistemas de Identificação Animal/métodos , Rúmen , Sistemas de Identificação Animal/normas , Animais , Peso Corporal , Brasil , Deglutição/fisiologia , Eletrônica/instrumentação , Desenho de Equipamento , Feminino , Ovinos , Carneiro Doméstico , Fatores de TempoRESUMO
La utilización de animales de laboratorio para la investigación biomédica ha tenido un crecimiento importante en nuestro país en los últimos años. La clase de estos animales influyen directamente en la calidad de los trabajos científicos realizados con ellos. El presente trabajo tiene por objeto exponer un panorama general de lo que es el animal de laboratorio. Se analizan las razones de tipo científico, ético-legales y laborales que obligan a que la calidad de estos animales sea apropiada. Se describen las características microbiológicas de los animales convencionales y aquellos clasificados como libres de patógenos específicos. Además, se describen las características físicas que debe terner el albergue para animales de laboratorio. Se concluye que el animal de laboratorio es un modelo biológico de gran valor para la investigación, por lo que su producción y cuidado deben responder a estrictas normas de calidad que aseguren que su uso sea científica y éticamente aceptable