ABSTRACT
A feeding program for high producing Holstein dairy cows and its economical evaluation

Carlos Pedraza G.1 , Claudia Wernli K.1 y Alfonso Chacón S.1
 

An intensive milk production programme was studied, at La Platina Exp. Sta. (INIA, Santiago, Chile), during three years, and was compared with a programme with lower yielding cows and less use of concentrates. Twenty five cows, with two or more calvings and with the highest yields in the previous lactations within the dairy herd, were selected and received 2 kg concentrate/cow/day during two weeks priof to parturition. After calving, the animals were tested during 60 days, fed 500 /0 of the diet's dry matter as concentrate and 50% as forage: lucerne soiling (during spring-summer-autumn) or a mixture,of corn silage and lucerne hay (60: 40, during winter). Cows that accumulated 1,500 It during the first 60 days were selected; then two groups were fed according to yield (< 22 and > 22 It/day), receiving 4 and 8 kg of concentrate/day plus forage ad libitum, and milk productions were adjusted according to the Wood's curve (y = anb e-en). Milk yields increased significantly (P < 0.05), from the first to the third season (6,188a, 6,240ab, and 6,630b It, for a 300 days lactation); peack productions, at days 55, 53 and 42, were 26.9, 26.6, and 27.5 It/day; monthly declination rates were 6.60, 5.81 and 5.33%; and concentrate intake (kg/liter of milk produced) were 0.318, 0.315 and 0.297, for the three years, respectively. The economical study indicated that the intensive system during the third season (SAP3) was the most profitable, presenting a marginal rate of return of 61,2%, value that is in the limit to recommend its adoption, considering the risks in its implementation.

Keywords:
1 Estación Experimental La Platina (INIA), Casilla 439, Correo 3, Santiago, Chile.