The voluntary intake of the lactating dairy cow and its relation to digestion

J.B. Hutton, J.W. Hughes, R.P. Newth and K. Watanabe

Ruakura Agricultural Research Centre, Hamilton

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Proceedings of the New Zealand Society of Animal Production. 1964, 24: 29-42

Differences in voluntary intake, milk production and in the apparent digestibility of energy consumed by fistulated and non-listulated twin cattle were examined using cows fed exclusively on fresh pasture herbage over a full lactational period. Both intakes and productions of the fistulated cattle were consistently lower than those of their non-fistulated twins.

For the former, estimates were obtained of the quantities of ingesta present in the reticulo-rumen, and the rate of flow of fluid through the reticula-omasal orifice was also determined. These were related to dry matter intake and to the apparent digestibility of the herbage energy consumed.

Highly significant regressions of D.M. intake on the amount of D.M. present in the reticula-rumen and on total fill were obtained. Application of these relations to the prediction of gut fill in non-fistulated cattle is discussed.

The possibility that voluntary intake in the lactating grazing cow might be limited by the physical capacity of the reticula-rumen was also examined, but no evidence to support this was obtained.

Keywords: NZSAPAB;

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