The New Zealand climate is generally favourable for grassland farming. Stock are not housed in winter, and their feed requirements are normally provided by pasture and other farm-grown feeds. Very little reliance is placed on purchased feeding stuffs. Over the country as a whole, however, important variations in climate affect the suitability of land for different systems of livestock farming.
Feed requirements of a herd of dairy cows over a year are more demanding and less flexible than is the case with a flock of ewes producing fat lambs. While in milk, a cow needs more feed than when she is dry, and with seasonal dairying the herd is milked for about 10 months and dry for two. Those engaged in dairying in districts tending to suffer from shortages of pasture growth due to dry summers or prolonged winters face difficulties in organising farm-feeding programmes. Shortages of feed are overcome by growing special fodder crops, conserving surplus grass as hay and silage, buying feed, and so on. As all such steps involve work and cost money, dry summers and long winters are matters of concern to dairy farmers. Turning now to the sheep situation, the time interval with heaviest feed demands is much less than is the case with dairying. Lambs may be sold fat when four months old, and in districts with dry summers it is possible to have a proportion of them off the property before feed shortages develop. Where long winters are experienced, mating can be arranged so as to have the lambs arriving on the scene when spring feed is also on its way. Fat-lamb production thus fits quite well into conditions where dairying output can only be sustained by high added feeding costs.