Invited review: Influence of climatic conditions on the development, performance, and health of calves

Abstract

The objective of this review is to provide the reader with an overview of thermoregulatory mechanisms and the influence of climatic conditions in different housing systems on the development, performance, and health of calves. Thermic stress is observed in association with extreme temperatures and large temperature variations, but other variables such as relative humidity and wind speed can also contribute to thermic stress. Thermoregulation in calves is similar to that in adult cattle, but especially dystocial calves are more prone to heat loss. Heat or cold stress results in direct economic losses because of increased calf mortality and morbidity, as well as indirect costs caused by reduced weight gain, performance, and long-term survival. The climatic conditions in a variety of housing systems, associated health problems, and strategies to mitigate thermic stress are discussed in this review. The goal of housing is to alleviate the effect of climate on calves and provide a microclimate. Adequate ventilation with fresh air is essential to reduce respiratory disease. Common practices such as raising calves in individual outdoor enclosures have been challenged lately. Recent research seeks to evaluate the suitability of group housing under practical, economic, and animal welfare considerations. Limited results for reducing thermic stress can be achieved by simple measures such as shades or shelter, but additional heat or cold stress relieving strategies can be required depending on the housing system.

Heat Stress Impacts Immune Status in Cows Across the Life Cycle

“…Indeed, Zhai et al (78) found that heat stress increased autophagy in the rumen, duodenum, and kidney of bull calves at 35 days of age, suggesting that nutrient uptake capacity may be altered. Yet, temperature thresholds might vary depending on size, breed, nutrition, behavior, bedding, precipitation and humidity levels, among others [reviewed by (79)]. For instance, calves exposed to increasing temperature for 7 h, did not show signs of heat stress until temperatures approached 32 • C with 60% relative humidity (80).…”

“…A survey conducted in the western and eastern regions of the US summarized 11 housing types for preweaned calves (87). Among the dairy operations surveyed, 37.9% used individual outside hutches and 31.8% adopted individual inside hutch/pen (87), whereas in Canada 88% of calves are housed in hutches (79). The construction materials of outside hutches influence the heat load carried by calves and that potentially affects their growth and health.…”

Mechanisms of protein balance in skeletal muscle

“…These data highlight how adaptive responses to protein nutrition can cross generations in their influence. In addition to nutrition, climate conditions are a major influence on the development, performance and health of livestock [119] yet much remains unknown regarding the regulation of protein balance under these conditions. In an age of increased environmental pressures, these factors are important to consider in the search for novel therapeutic and prophylactic strategies to optimize if not maximize muscle growth and meat production.…”

Severidad y Duración del Estrés Calórico en Terneras y Vaquillas de las Principales Localidades de Lechería Intensiva del Departamento de Lima, Perú

“…Con esta base, StPierre et al (2003) propusieron nuevos índi-ces para estimar el estrés calórico; entre ellos, la duración del estrés calórico y la severidad del estrés calorico que puede medirse con el ITH sobrecarga. El primero es el tiempo que el ITH excede el ITH umbral, y el segundo es el integral de la curva senoidal de ITH sobre el ITH umbral, el cual representa el calor acumulado por encima del umbral durante las 24 ; sin embargo, la severidad y la duración del estrés calórico en las terneras y las vaquillas lecheras no han sido medidas. El departamento de Lima posee importantes localidades de producción lechera (INEI, 2012) y sus características climatológicas de Lima hacen posible la hipó-tesis de que el estrés calórico no solo afecte a los animales en producción, sino que también esté presente en las terneras y las vaquillas.…”