Herbage allowance, pasture quality and milkfat production as affected by stocking rate and conservation policy

N.A. Thomson, J.F. Lagan, D.A. McCallum

Taranaki Agricultural Research Station, Ministry of Agriculture and Fisheries, Normanby

Proceedings of the New Zealand Society of Animal Production. 1984, 44: 67-70

Both stocking rate and time of conservation had a significant (P<0.05) effect on milkfat yield/cow which resulted in large differences between treatments in terms of milkfat production/ha. At the low stocking rate, milkfat production/ha was 645 and 619 kg, and at the high stocking rate 642 and 705 kg for the respective early and late conservation treatments.

These differences in animal performance are attributed to differences in pasture allowance in early lactation and to the proportion of dead matter in the pasture over summer and autumn. The proportion of stem in pasture had little direct effect on dairy production but over time it may have contributed to the pool of dead matter causing lower milkfat yields in summer and autumn.

The adoption of a high stocking rate and late conservation policy maintained adequate pasture allowance (33 to 35 kg DM/cow/d) in early lactation and a sufficiently intensive grazing pressure in October and November to prepare pastures of low dead and high green content over summer and autumn.

Keywords: NZSAPAB; Dairy; milkfat production; time of conservation; stocking rate; pasture allowance