Composição corporal e exigências nutricionais de bezerros holandeses do nascimento aos 100 dias de idade / Body composition and nutritional requirements of Holstein calves from birth to 100 days of age

AUTOR(ES)

Cesar Conte Guimarães Filho

DATA DE PUBLICAÇÃO

2008

RESUMO

Body composition and net requirements for energy, protein, calcium, phosphorus, magnesium, sodium and potassium were estimated by using 20 Holstein calves, non-castrated, with average initial body weight of 37.5 kg. The animals were distributed in randomized blocks, with 16 animals subjected to treatment that consisted of two ages of weaning, with the same consumption of milk (300 liters) and two ages for the supply of hay, using the following treatments: Treatment 1 – weaning at 65 days of age with constant supply of 5 liters of milk from 6 to 65 days, plus hay after 20 days of life, Treatment 2 - weaning at 95 days with supply of 4.5 liters of milk from 6 to 35 days, 3.5 liters of milk from 36 to 65 days and 2.0 liters of milk from 66 to 95 days, plus hay after 20 days of life; Treatment 3 - weaning at 65 days with constant supply of 5 liters of milk from 6 to 65 days, plus hay after 65 days of life, and Treatment 4 - weaning at 95 days with supply of 4.5 liters of milk from 6 to 35 days, 3.5 liters of milk from 36 to 65 days and 2.0 liters of milk from 66 to 95 days, plus hay after 65 days of life. When completing 6 and 100 days of age, references and treatments calves, respectively, were slaughtered and all parts of the body of each calf was weighed, sampled, dried, pre-degreased, and the amount of total nitrogen, ether extract and macrominerals determined. The body energy was determined multiplying the levels of protein and fat to their energy content (5.6405 and 9.3929) and adding them. The body content of protein, fat, energy, calcium, phosphorus, magnesium, sodium and potassium were determined with regression equations of the logarithm of the content of each constituint, as a function of the logarithm of empty body weight (EBW). The derived equations of prediction of the constituents represented the net requirements of protein, energy and macromineral for gain of 1 kg of EBW. Regression equations were adjusted for the logarithm of the content of each constituent in the body, as a function of the logarithm of empty body weight (EBW) of the animals. There were increases in the quantities of fat, protein, energy, phosphorus, magnesium and potassium and decreases in the amounts of calcium and sodium, as the body weight of animals increased. The net requirements of protein and energy for gain of 1 kg of EBW for a calf of 100 kg body weight was 165.34 g and 1.76 Mcal, respectively. For macrominerals the requirements were 14.17 g for Ca, 13.55 g for P, 0.34 g for Mg, 1.54 g for Na and 2.10 g for K.

ASSUNTO(S)

holstein calves nutritional requirements exigências nutricionais nutricao e alimentacao animal body composition composição corporal bezerros holandeses

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