Influência de ondas de calor sobre estimativa de consumo de ração e desempenho reprodutivo de matrizes suínas

Abstract

Firstly, the objective to determine the relationship between the occurrence of heat waves and the prediction of voluntary feed intake of sows in the Triângulo Mineiro / Alto Paranaíba mesoregion, Minas Gerais, Brazil. The Temperature and Humidity Index (THI) were calculate from to determine the occurrence of heat waves from 2008 to 2017 in Araxá, Frutal, Ituiutaba, Patos de Minas, Patrocínio, Uberaba and Uberlândia. The estimate of voluntary food intake with and without the occurrence of heat waves, and the economic prediction of revenue based on food intake were calculated. The sows raised in Ituiutaba and Frutal had the lowest consumption estimate during the actual occurrence of heat waves, with 3.969 kg and 4.648 kg / day, respectively. Heat stress represented a reduction in revenue of R $ 74.60 per litter. The predominance of heat waves reduces the voluntary feed intake of sows. In the second study, the objective was to identify the occurrence of heat waves and to verify their effect on the reproductive performance of commercial farm sows in a tropical environment. The THI was calculate from to determine the periods of heat waves from 2013 to 2019. In this period reproductive data from a commercial farm equipped with fans and misting were made available with information from 51,578 inseminations. The effect of heat waves on the number of pregnancies, farrowing and abortions and the influence of the birth order on the reproductive performance were evaluated. May, June, July and August were the months with the lowest average number of days with heat waves. The total of 2,156 days evaluated, there were 1,163 days of heat waves. The number of pregnant sows that gave birth and aborted did not differ between the control (without heat waves) and hot (with heat waves) groups. Swine breeders reared in a tropical environment showed a higher number of piglets born alive and litter weight was registered in sows from second to fifth order of birth in relation to nulliparous, primiparous and sows with 6 or more births, with results similar to those in temperate regions. The lowest number of live births, litter and piglet weight and the highest number of stillbirths, dead at birth, mummified was observed in matrices with 6 or more births. The occurrence of heat waves during insemination period of sows reared on a commercial farm with fans and misting does not influence the number of pregnancies and abortions in the tropics.