The energy requirements of Holstein-Friesian heifers during rearing and pregnancy under the tropical conditions of Cuba. 1. Determination of dry matter and energy assimilation and of the live weight development and energy expenditure |
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| Authors: | L Zarragoitia M Gabel S Poppe |
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| Institution: | Instituto de Ciencia Animal, La Habana, Cuba. |
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| Abstract: | In an individual feeding experiment with 48 Holstein-Friesian heifers divided into 3 groups, the effect of various energy levels on live weight development and energy expenditure in the age bracket of 97 days (78 kg live weight) to conception (350 kg LW) and from conception to calving (500 kg LW) was investigated. Rations with differing concentrate--roughage ratios were used. The differentiation of energy intake per day between groups 1 and 2 and group 3 amounted to 7.5% in the 1st development period and to 20% between group 1 and groups 2 and 3 in the 2nd development period. There were significant differences in the live weight gain of 95 g/animal and day in the first development period (up to conception) and of 81 g/animal and day in the second period of development (from conception to calving). Under the tropical climatic conditions the energy expenditure in these studies was approximately 10% under the energy expenditure recommended by the NRC (1978). While there was a clear reciprocal relation between energy expenditure and live weight gain in the first period of development, this relation was less distinct in the second period of development. |
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