ABSTRACT


Melvin G. Greeley1 y Juan José Romero T.2
 
Two experiments were conducted simultaneously (June to October 1963) in order to explore the posibilities of formulating concentrates for lactating cows with by-products of national industries (wheat bran and middlings, dry beet pulp) and to determine the minimun required protein contents for such type of concentrates. An incomplete latin square design was used, with groups of 3 cows each and 35 days periods with 21 pre-experimental and 14 days of observations. The basal ration in both cases consisted of corn silage fed ad libitum and alfalfa hay in proportion to 1,5% body weight. In Trial Nº 1, concentrates composed of wheat bran and 2nd class wheat flour, as exclusive energetic components, were compared with one formulated with corn, as a control. A protein supplement was added to all three concentrates in sufficient quantity as to yield 14% Crude Protein; resulting T. D. N. content was 66,7, 81,9 and 79%, respectively (all figures estimated by Tables of "Feeds and Feeding", F. B. Morrison) (7). Concentrates were fed according to daily individual productions in a ratio of 1 Kg. for every 4,5 Kg. F. C. M. produced. In Trial Nº 2, local by-products (beet pulp and wheat bran) were combined with a protein supplement so as, maintaining constant a 70% T. D. N., levels of 14 and 18% Crude Protein were reached in 2 different concentrates, wich were compared with a commercial concentrate of 20% C. P. that acted as a control. In this case, concentrates were fed at a rate of 2 Kg. per every 4 to 4,5 Kg. F. C. M. produced.
Keywords:
1 Ph. D., Coordinador de Producción Animal de la Oficina de Estudios Especiales, 1962-1964.
2 Ingeniero Agrónomo M. S. Proyecto Producción Animal, Estación Experimental La Platina. Instituto de Investigaciones Agropecuarias. Profesor Auxiliar Cátedra Producción Lechera, Facultad de Agronomia, Universidad Católica de Chile.