ABSTRACT


Ernesto Jahn B.1, Germán Klee G.2, José Bustamante M.3e Ignacio Ruiz N.4
 
Two experiments were conducted to determine the effects of liveweight gains duringthe dry period on the performance of dairy cows during the following lactation.SeYenty three European holstein cows were fed, during the dry period, roughagesand industrial by-products. While in lactation good quality pastures were fed.
Three rates of liveweight gain during the dry period were studied: 1. Weight gain(0.7-1.0 Kg/cow/day). 2. Maintenance and 3. Weight loss (-0.8 Kg/cow/day).The cows that lost weight during the dry period produced less milk (P < 0.05)than the group gaining weight. Days open were higher (P < 0.05) for the maintenanceand weight loss groups when compared to the group that gained weight during the dry period. Number of services for conception increased as the nutritionallevel during the dry period decreased. When lowered milk production and increaseddays open are considered, the group gaining weight produced 402 and 708 Kgmore milk than the maintenance and weight loss group, respectively. The weightgain group consumed approximately 300 Kg more feed that contained around 10%crude protein and 20% fibre.
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1Ing. Agr., Ph. D., Subestación Experimental Humán, Instituto de Investigaciones Agropecuarias (INIA) Casilla 767, Los Angeles, Chile. Actualmente en animal Science Research, Merck Sharp & Dohme Rahway, New Jersey, 07065, USA.
2Ing. Agr., Subestción Experimental Humán, INIA.
3Med. Vet., Servicio Agrícola y Ganadero (SAG), Los Angeles, Chile.
4Ing. Agr., Ph. D., Estación Experimental Quilamapu, INIA, Casilla 426, Chillán, Chile.