Influence of climatic conditions on tympanic temperature and milk production in grazing cows

Abstract

Vasconcelos et al 2020). Animal's body temperature is traditionally estimated through rectal and vaginal measurements; however, alternative methods like tympanic temperatures (TT) also constitute a reliable measure since some studies reported no statistical difference with rectal temperatures (Sellier et al 2014;Shu et al 2021) and high correlation with vaginal temperature (r = 0.77; Bergen and Kennedy, 2000). The differences associated with the anatomical sampling point and its response time were also validated in other studies (Scharf et al 2011;Sellier et al 2014;Godyń et al 2019). TT is an attractive alternative measure Abstract The present study aimed to analyze large volumes of tympanic temperature (TT) data to identify its use as a physiological indicator of climatic conditions and its relationship with milk production in grazing cows under tropical lowland conditions. Three dairy farms and 21 multiparous early lactation cows were included in the study. Seven animals were equipped with tympanic temperature wireless sensors within each farm, and permanent information was collected hourly for 22 days on average. Ambient temperature (AT), relative humidity (RH), wind speed (WS), precipitation (PP), and THI information were obtained from meteorological stations located close to each farm. Statistical analyses included Spearman correlations and random coefficient regression models (P < 0.05). TT presented moderate and significant correlations with AT (0.35 to 0.49), SR (0.25 to 0.32), THI (0.35 to 0.49), and RH (-0.35 to -0.49). Climatic variables like AT, PP, SR, and WS were the most contributing factors to TT prediction (R 2 =0.42 to 0.86). Grazing dairy cows in tropical scenarios accumulate heat during the day and dissipate it at nighttime, although higher producing animals deal with more problems to reach thermal homeostasis. Correlations between TT and daily milk production varied according to animal yield; however, higher TT values were related to the most productive cows. The effect of TT on milk production prediction was not conclusive among farms, possibly by animal management or others characteristics of the systems. TT determination through remote sensors allows a reliable diagnosis of the physiological temperature response to climatic conditions.

Environmental Factors That Affect the Sanitary and Nutritional Variability of Raw Milk in Dual Purpose Livestock Systems of Colombian Orinoquia

“…Similarly, it has been observed that in Holstein cows exposed to stressful temperature and humidity indices > 78 (equivalent to an average of 33.8 °C and 36% of maximum ambient temperature and minimum relative humidity, respectively), milk components such as fat, protein, lactose, TS, and SNF were significantly reduced [ 31 ]. In lowland tropical conditions, it has been shown that climatic variables such as mean temperature and solar radiation increased the tympanic temperature of tropical dairy cows, reducing their performance with values above 38.9 °C [ 32 ].…”

Efecto del clima sobre la respuesta térmica en vacas de diferentes grupos raciales en trópico bajo

“…De acuerdo, a la ubicación de cada uno de los sistemas ganaderos se le asignó la estación meteorológica más cercana. La distancia entre las estaciones y los sistemas estudiados fue: Sistema uno (6.2 km), Sistema dos (5.4 km), Sistema tres (5.6 km) y Sistema cuatro (6.5 km) (24). Las variables analizadas fueron temperatura ambiental (°C), radiación solar (cal/cm 2 ), humedad relativa (%), velocidad del viento (m/s) y precipitación (mm).…”