The effect of lactation of intake in the dairy cow

J.B. Hutton

Ruakura Animal Research Station, Hamilton

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Proceedings of the New Zealand Society of Animal Production. 1963, 23: 39-52

A comparative study has been made of the voluntary intakes and productions of lactating and non- lactating identical twin cattle stall fed exclusively on fresh pasture herbage. Data were obtained for 36 weeks, commencing at calving, in both the 1960-61 and 1961-62 dairying seasons.

Both level and pattern of intake differed markedly within sets. Intake differences averaging approximately 50% were obtained in favour of the lactating twins.

A mean difference of 0.7 units was recorded in the apparent digestibility of the energy consumed, higher values being recorded by the non-lactating group in all but four weeks.

In neither group was a useful relation obtained between the apparent digestibility of the energy consumed and voluntary intake.

Results between and within both groups of cows emphasized the importance of differences in the physiology of the animal in determining level of intake under ad lib. feeding. Within-set differences in voluntary intake determined at the same time on identical pasture herbages averaged 131 kcal digestible energy per unit metabolic size during one of three 12week sub-periods. This was equivalent to a difference of 1.65 lb D.M. per 1OOlb liveweight. These results have been discussed in relation to the requirements of feeding trials in which a measure of appetite is required. The inadequacy of currently available data on this subject is stressed.

Keywords: NZSAPAB;

Last Updated 24-08-2000