K . Maijala Livestock Production Science 65 2000 1 –18
13
development in many experiments. Ca intake has or uncultivated pasture or as conserved products,
also decreased development of breast cancer. beet tops, marrow kale, straws, residues from shift-
ing of grains, brewery residues and from the sugar industry. Cattle can utilize even non-protein-nitro-
6. Lactose intolerance and milk allergy gen. Digestibility of organic material decreases only
by 0.74 per 1 increase in fibre content, while the Some concerns about the involvement of milk in
corresponding figures for horse, pig and hen are some health disturbances have been voiced Gurr,
1.25, 1.55 and 1.96. In digesting fibre-free feed cattle 1999. One of these is lactose intolerance, caused by
show no advantage, but at 30 fibre content of feed incomplete secretion of lactase enzyme. This is
cattle and sheep are clearly superior to the other common in countries in which historically milk has
species. In many countries the ability of cattle to not been part of the daily diet. In countries with
harvest its feed directly from the place of growth traditional use of milk lactose intolerance is more
without human labour and from areas where no rare, for example in the Nordic countries in the range
cultivation is possible is important. There are about 5–17 Vesa, 1997. The intolerance is often incom-
twice as many permanent grasslands and pastures plete: a lactose intolerant person can take 5–10 g of
than cultivated areas or tree plantations in the world. lactose daily without problems. Soured milk is less
Forest areas, of which a part is used for grazing, problematic than fresh milk. Marteau et al. 1999
comprise almost three times the cultivated area. In concluded from the available literature that ingestion
northern latitudes the relative competing-ability of of milk products with lactose in doses of normal to
grass crops is better than of grain crops, since fairly high consumption 200–500 ml at a time
grasses can better utilize the spring moisture and leads to mainly non-disturbing gastrointestinal symp-
long summer days and do not suffer from the autumn toms in lactose maldigestors.
rains. The further north one goes the more important Another disturbance is ‘milk allergy’, occuring in
grassland farming becomes. 1–3 of children under three years of age. However,
10–50 of infants allergic to cow’s milk proteins 7.2. Animals don’t always compete with human for
may also develop signs of allergy to soya. Milk food
proteins are usually blamed, because they are the first ‘foreign’ proteins to be encountered by most
Because of the natural ‘bioreactor’ of its rumen infants Gurr, 1999.
cattle do not necessarily compete with man for food. Gurr considers that the general validity of many
However, because of the fixed costs, like mainte- contentions on milk can be effectively countered on
nance feed and buildings, man has attempted to scientific grounds, although it is clear that some
increase the yield and growth rate of cattle above the individuals may have specific intolerance to milk
levels which can be achieved with plain roughages. constituents.
So, food useable for humans is used also for cattle production as a ‘catalyzer’, especially in industrial
countries. This type of food contributes increasingly
7. Some biological and general aspects deserve to the total feed energy of a cow as production
