Cow Heat In Cow

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Introduction: The continent of Africa is considered as tropic and is subject to elevated temperatures. As the increase in the surrounding temperatures, dairy cattle increase the process of sweating and panting in order to lower down the temperature of their body. This is so because, the other ways of realesing temperature in to the surrounding environment become less efficient because of the elevated temperatures in the surroundings. And the period is heat is prolonged. And if humidity is high too, it causes hurdle in the process of sweating and thus heat from the body does not dissipate.Temperature of the rectum and temperature-humidity index increases thus results in decrease intake of dry matter eventually milk yield decreases. Previous…show more content…
The effects of hot, humid conditions are thought to be mediated through an effect on cow body temperature. Therefore the environmental factors external to the cow would contribute to stress. Berman et al. (1985) suggested that the upper limit of ambient temperatures at which Holstein cattle may maintain a stable body temperature is 25 to 26°C, and that above 25°C practices should be instituted to minimize the rise in body temperature. However, in the Southeast one of the major challenges is the combined effects of high relative humidity with high ambient tem-perature. At a temperature of 29°C and 40% relative humidity the milk yield of Holstein, Jersey and Brown Swiss cows was 97, 93, and 98% of normal, but when relative humidity was increased to 90% yields were 69, 75, and 83% of normal (Bianca, 1965).heat stress) while the displacement of the cow from the cow’s resting state would be the response to the external stress, or heat strain. The processes of conduction, convection and radiation are all dependent on a thermal gradient, thus as air temperature rises above a critical point the thermal gradient is reduced and heat dissipation is less effective. Evaporative cooling is an effective means of cooling cattle but is compromised by high relative humidity which impedes evaporation, making it difficult to cool…show more content…
Indices with larger weights on humidity seem to be more suitable for humid climates. On the other hand, in climates where humidity does not reach levels that could compromise evaporative cooling,indices with the most emphasis on ambient temperatureare preferable. Atemperature-humidity index (THI) is a single value representing the combined effects of air temperature and humidity associated with the level of thermal stress. This index has been developed as a weather safety index to monitor and reduce heat-stress-related losses. Different animal species and humans have different sensitivities to ambient temperature and the amount of moisture in the air. However, from June to August, THI climbs from 76 to 81. In these months, even with use of evaporative cooling, THI5 cannot drop below 7 (Figure 6). This may explain the sharp decline of milk production from June to August. Milk production begins to recover from heat stress in October when THI5 is <72. Distance between herd and weather station, km 32 9

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