Fechas de parto, condiciones meteorológicas y eficiencia reproductiva en vacas de cría

Livestock breeding in our country is one of the main areas within the agricultural activity, and this activity plays a very important role in the country's economy. This activity is mostly carried out in the open air in natural fields, generally of lower productivity. This is why we must take all the necessary precautions to mitigate the adverse effects of the environment in order to achieve a more efficient and productive livestock farming. Observing the increase of temperatures and solar radiation in certain seasons of the year, we sought to study the effect of the ITH on the reproductive performance of the breeding herd. This work was carried out at the Mario A. Cassinoni Experimental Station in the department of Paysandú, National Route No. 3, Km 363. The trial was conducted with approximately 150 Hereford cows and heifers from the breeding herd of the EEMAC. Taking data on calving date, calf birth weight and gestation diagnosis at the next calving, as well as a series of data on climatic factors such as temperature, relative humidity, wind speed, solar radiation and rainfall provided by the plant production department of the Experimental Station, in order to calculate the ITH and ITHajus. This information was analyzed to calculate if there was a correlation between climatic conditions and birth weight or reproductive efficiency at the next service. Although correlation was found between ITH and calf birth weight, the fit of the curve to the data was low. Taking this into account, measures should be taken to mitigate the effects of heat stress on the animals, without neglecting the rest of the environmental factors, since some of them affect the performance of the herd to a greater extent. It would be of great importance to continue investigating the effects of ITH on the productive and reproductive results of the herd in order to have more information about the moments in which heat stress conditions occur and how this affects the animals.