The gaseous exchange between an organism and the environment is measured by respirometry or indirect calorimetry. Once the oxygen consumption (O2) and the production of carbon dioxide (CO2) and methane (CH4) are known, the energy losses by gas and heat can be calculated. Energy metabolism and methane production have been studied in the Calorimetry and Metabolism Laboratory of the Federal University of Minas Gerais, located in Belo Horizonte, Minas Gerais, Brazil. Animals used are mainly Zebu cattle and their crossbreeds that represent most beef and dairy cattle breed grazed on tropical pastures. System calibration and routine work are addressed in this text. The results obtained on respirometric chambers are expressed in net energy (NE), which can be net energy for maintenance (NEm), lactation (NEL), weight gain (NEg), and pregnancy (NEp). NE is, in fact, what is used by the animal for maintenance and each productive function. The values of k (conversion efficiency of ME into NE) for maintenance (km), milk (kL), weight gain or growth (kg), and pregnancy (kp) are determined. Thanks to the peculiarity of the respirometric technique, the same animal can be evaluated several times, in different physiological states and planes of nutrition.
Part of the book: Animal Husbandry and Nutrition
Animal behavior is a function of species biology, interaction with the environment and experience previously acquired. Natural taming is a set of techniques used to tame the animals without stress and with patience and respect. They are conditioned to follow man’s commands in a quiet way, resulting in more reliable and productive animals. Cattle learning process has enabled the development of management techniques, such as the interactions between them and humans. These techniques aim to use the cattle natural behavior during the management operations, allowing gathering and moving the animals to other areas of the pasture, corrals or even outside the farm. These techniques are mainly important when cattle are raised on pasture, with less contact with people, resulting in less herd control and greater reactivity of animals to management. Many repetitive exercises are used, conditioning the animal in a gentle and progressive manner, without the use of force and pain, to obtain the desired commands. It is an activity that requires patience, bringing good results, better than those achieved through traditional taming, which can cause many traumas.
Part of the book: Animal Welfare