Differences in body temperature between black-and-white and red-and-white Holstein cows reared on a hot climate using infrared thermography.

Heat stress is one of the greatest issues of the dairy industry in regions with hot climate. Since coat color appears to be related to heat stress adaptiveness, we compared rectal temperatures and surface temperatures of Red-and-white (RW, n = 14) and Black-and-white (BW, n = 16) Holstein cows using infrared thermography in both cold (July; mean temperature: 15.5 °C) and hot (March; mean temperature: 30.5 °C) seasons in Southern Brazil. Thermographic images were taken from the left side of the animal at a distance of 4 m. The images obtained were then analyzed using the software Testo IRSoft. The variables obtained by thermography of the body surface include the temperature of non-pigmented patches, obtained using the average of five spots on white patches in a rectangle drawn on the body of the cow from the scapula to the ilium of the cow until the middle of the ribs; the temperature of pigmented patches, obtained using an average of 5 pigmented spots on the same rectangle; the temperature at the hottest spot and the temperature at the coldest spot, within the same rectangle. Rectal temperature measures were taken by a mercury thermometer during milkings. In our findings, during the cold season, RW cows had lower temperatures on the surface of pigmented spots (p = 0.01) but did not differ from BW animals when comparing rectal temperatures (p = 0.70). During the hot season, however, RW cows had lower temperatures on white spots (p = 0.049) as well as lower rectal temperatures (p = 0.029). These results suggest that the red coat phenotype presents less absorption of solar radiation, retaining less heat.

Utilização de embalagens tetra pak(r) como isolante térmico no revestimento de escamoteadores para leitões / Using tetra pak(r) packaging as insulation coating piglets' creeps

Foram conduzidos dois experimentos em laboratório e em condições de campo para avaliação da eficiência térmica da embalagem Tetra Pak(r)como isolante térmico em escamoteadores aquecidos. No experimento em laboratório, foi utilizado o delineamento inteiramente ao acaso, adotando-se dois tratamentos (com e sem revestimento de embalagens Tetra Pak(r)) com 15 repetições (dias). O experimento em condições de campo foi conduzido na sala de maternidade de suínos. O delineamento foi inteiramente ao acaso, adotando-se dois tratamentos com 12 repetições. Os tratamentos foram: escamoteadores aquecidos com e sem revestimento interno com embalagem Tetra Pak(r). Foram medidos os dados de temperatura ambiente, umidade relativa do ar, temperatura superficial do piso, temperatura superficial da pele, comportamento e ganho de peso dos leitões lactentes. O uso da embalagem Tetra Pak(r)como isolante térmico no revestimento de escamoteadores manteve a temperatura ambiente confortável (32°C), proporcionando conforto térmico aos leitões lactentes.

Two experiments were conducted in laboratory and field conditions to evaluate the thermal efficiency of the Tetra Pak packaging as insulation in heated creeps. In the laboratory experiment a completely randomized design was used, adopting two treatments (with and without packaging coating with Tetra Pak(r)) with 15 repetitions (days). The experiment under field conditions was conducted in a swine nursery. The design was completely randomized, adopting two treatments with 12 repetitions. The treatments consisted of heated creep with and without Tetra Pak(r) lining. The data measured were ambient temperature, relative humidity, surface temperature of the floor, surface temperature of skin, behavior and weight gain of suckling piglets. The use of Tetra Pak(r) packaging as insulation in creep coating maintained the ambient temperature comfortable (32 °C), providing thermal comfort to suckling piglets.