Energia digestible y metabolizante de las pajas de leguminosas para los óvidos

Abstract

lt has been determined the digestible and metabolizable energy content of the folowing legume staws, usualy employed as feed for the sheep in our Country: lentil straw (Lens esculenta. Moench), one-flowered tare straw ( Vicia monanthos, L), chickling vetch straw (Lathyrus sativus, L), lentil vetch straw (Ervillia sativa), vetch straw (Vicia sativa, L), field pea straw (Pisum sativum, L), chick pea straw (Cicer arietinum, L), bean straw (Phaseolus vulgaris , L), and horsebean straw (Vicia faba, L), var minor).

The trials were carried out with six «Churra» breed weathers, using metabolic cages which alowed a perfect control of the feed ingested and a cuantitative collection of feces and urine. The trials lasting for about one month, included the preliminary period: the collection period and a rest period of 10 days lengh each one. The feed level was about 500 gs. dry matter daily for each animal.

To know the gross energy an adiabatic bomb calorimeter was employed. The urine samples were freeze-dry and the feces oven-dried at 60°C.

lt was carried out an analysis of the correlations existing among the various types of energy, the different nutrients and the membrane substances (cellulose, lignin and pentosans) for each legume straw.

The legume straw have a gross energy content of 4.200 Kcal / Kg. dry matter. lt was not found any correlation between the gross energy content and the chemical composition of the straws.

The digestible energy content of the straw was of 2.300 Kcal/ Kg. dry matter, varing from 2.662 ± 20 Kcal/Kg. dry matter to 2.042 = 27 Kcal/Kg. The digestibility of the gross energy being 56 %, with a maximus of 62,6 % and a minimun of 51,9 %.

lt was confirmed the high correlation between the digestible energy content and the digestibility of the organic rnatter (0,924). It is pointed out the higt negative correlation (-0,790) between the lignin content and the digestible energy.

The metabolizable energy content was 1.970 Kcal / Kg. dry matter, as a mean for the straws studied, varyng from 2.239 ± 27 to 1.710 ± 32 Kcal/Kg. The metabolizability of the digestible energy being 84,7 %, and 47 % for the gross energy. The energy excreted in the urine was of 160 Kcal/Kg. dry matter ingested, whilst the energy losses of methane, were 193 Kcal/Kg. dry matter. It is verified the high correlation between the digestibility of the organic matter and the metabolizable energy content (0,972).

The correlation between lignin content and metabolizable energy was negative (---0,840).

It is showed the great concordance of the urine energy, both calculated ausing the ecuation proposed by BLAXTER, in which the heat of combustion of the urine is related to the crude protein content of the diset, and the values experimentally obteined. lt was found a high correlation between the nitrogen content of the dietrand the urine energy (0.867).

It is pointed out that for the legume straws studied the metabolizable energy content may be predicted with the use of the ecuation proposed by NEHRING.