ABSTRACT
Hypothermia is one factor associated with mortality in newborn ruminants due to the drastic temperature change upon exposure to the extrauterine environment in the first hours after birth. Ruminants are precocial whose mechanisms for generating heat or preventing heat loss involve genetic characteristics, the degree of neurodevelopment at birth and environmental aspects. These elements combine to form a more efficient mechanism than those found in altricial species. Although the degree of neurodevelopment is an important advantage for these species, their greater mobility helps them to search for the udder and consume colostrum after birth. However, anatomical differences such as the distribution of adipose tissue or the presence of type II muscle fibers could lead to the understanding that these species use their energy resources more efficiently for heat production. The introduction of unconventional ruminant species, such as the water buffalo, has led to rethinking other characteristics like the skin thickness or the coat type that could intervene in the thermoregulation capacity of the newborn. Implementing tools to analyze species-specific characteristics that help prevent a critical decline in temperature is deemed a fundamental strategy for avoiding the adverse effects of a compromised thermoregulatory function. Although thermography is a non-invasive method to assess superficial temperature in several non-human animal species, in newborn ruminants there is limited information about its application, making it necessary to discuss the usefulness of this tool. This review aims to analyze the effects of hypothermia in newborn ruminants, their thermoregulation mechanisms that compensate for this condition, and the application of infrared thermography (IRT) to identify cases with hypothermia.
ABSTRACT
RESUMEN Objetivo. Determinar la presencia de anticuerpos anti-Mycobacterium avium subsp. paratuberculosis (MAP) en venados de cola blanca (Odocoileus virginianus) y venados de páramo (Mazama rufína), capturados en las regiones de la Orinoquía y el Caribe en Colombia. Materiales y métodos. Un total de 44 muestras de suero sanguíneo de venados de las especies M. rufína y O. virginianus fueron colectadas en condiciones de campo entre 2014 y 2016. Se utilizó un kit comercial de ELISA para la detección de anticuerpos anti-MAP. Un animal se consideró positivo a ELISA cuando la relación muestra-positivo (S/P%) fue > 0.4, según lo recomendado por el fabricante. Resultados. El 50% (22/44) de los animales muestreados resultaron positivos, lo que corresponde a 10 hembras y 12 machos. Un 81.8% (18/22) y un 77.3% (17/22) de estos animales seropositivos fueron capturados en la región de la Orinoquía y fueron reportados como adultos, respectivamente. Conclusiones. No se sabe cómo o cuándo se introdujo MAP en la población de ciervos colombianos en las regiones de estudio. La hipótesis más plausible para explicar la presencia de anticuerpos anti-MAP en estas poblaciones silvestres es la transmisión por contacto con el ganado bovino infectado, ya que en ambas regiones estas especies comparten pasturas. Este es el primer estudio en explorar la infección por MAP en animales silvestres en Colombia. Estos hallazgos respaldan la necesidad de realizar más estudios utilizando técnicas de diagnóstico directo, y aproximaciones investigativas que permitan la definición de vínculos en la dinámica de la infección entre mamíferos silvestres y domésticos en Colombia.
ABSTRACT Objective. To determine the presence of anti-Mycobacterium avium subsp. paratuberculosis (MAP) antibodies in white-tailed deer (Odocoileus virginianus) and red brocket deer (Mazama rufína), captured in the Orinoquía and Caribbean regions in Colombia. Materials and methods. A total of 44 blood serum samples from deer of species M. rufina and O. virginianus were collected under field conditions between 2014 and 2016. An ELISA commercial kit was used to detect anti-MAP antibodies. An animal was considered ELISA-positive at a sample-to-positive ratio (S/P%) of > 0.4, as recommended by the manufacturer. Results. The 50% (22/44) of the animals were positive, corresponding to 10 females and 12 males. An 81.8% (18/22) and 77.3% (17/22) of these seropositive animals were captured in the Orinoquía region and were reported as adults, respectively. Conclusions. It is not known how or when MAP was introduced in the Colombian deer population in the study regions. The most plausible hypothesis to explain the presence of antibodies against MAP in these wild populations is transmission by contact with infected bovine cattle since, in both regions, these species share pastures. This is the first study to explore MAP infection in wild animals in Colombia. These findings support the need for further studies using different direct diagnostic techniques and research approaches that allow the definition of links in the infection dynamics between wild and domestic mammals in Colombia.