ANIMALS AND MINERALS

Hawera Star, Volume LI, 3 January 1931, Page 13

ANIMALS AND MINERALS

IMPORTANCE) OF LIME.

Dr, On*, of the Itowett Institute, rays: “It is easy to calculate from ■ the known composition of the carcase 1 of animals, or of products such as milk, and eggs, the amounts of each of the ‘ different minerals which must be all-, sorbed from the intestine and retained ! in the body for the building up of the ‘ bones and other tissues in growth, or. used for the elaboration of products | such as milk or eggs. For example,. calcium (calculated as lime, CaOl is [ present in the bodies of store cattle i to the extent of about 2 per cent., and! of growing pigs to the exent of about j l per cent. Therefore, young cattle i putting on 21‘b per day live weight,, woulld need to absorb and retain rather' more than I oz per day, and- pigs put-! ting on the same weight, about loz. f Every gallon of milk contains about, -4 <>■/... hence a cow giving 4 gallons of, milk a day would lose each day about loz. in the milk.

! “Only part of what is contained in the food is absorbed from the intestine and even what is absorbed is not all available for formation of new tissue or for milk, because there is a continuous loss in the excretions. Hence the food must contain more than i.s required to be retained in the body or secreted in the milk or eggs. “Of the minerals und'er discussion, the one most difficult of absorption ■ i calcium. The proportion absorbed from the intestine may vary from practically nothing to over 70 per cent., according to the nature of the ration. A young sucking animal can absorb and retain over 70 per cent, of the calcium in its mother’s milk. On the other hand, on a badly balanced ration poor in calcium, and in the factors which facilitate its assimilation, the amount absorbed may be practically nil. One of the most import- 1 ant factors in the assimilation of lime is vitamin J>, which is abundantly present in milk, green food and codtliver oil. and which is believed to be formed in the body itself under the in- j flrence of ultra-violet rays, which are' present in direct sunshine. The amount' of calcium required in the ration i.s | thus less when the ration contains j foodstuffs rich in vitamin D than when it consists of cereals and commercial, '•-nroducts. which are relatively poor in this vitamin. It is also less in the I [case of animals kept in the open than! in animals kept continually indoors. ' “Estimates have been made by vari- ' ous authorities of the amounts of lime and phosphorous required by animals. Thus one writer has estimated that a calf should receive 2-3 oz. of calcium j (as CaO) and 1 oz of phosphorus ( P 205) per day, and another writer I estimated that a- four-monthis-old pig l .should receive from I-3oz to loz of each of these per day. The requirements of dairy (tows have been estimated at from two to four times the amount of calcium in the milk se-' creted.

“In estimating the requirements of animals for the practical purpose of balancing up the ration by supplying whatever is deficient, the best and safest method is to take a* the .standard the milk of the species, or for cattle the composition of good pasture. Wo know that for young animals, so far as the minerals required in largest amount are concerned, milk contains these in the right proportins, and we at.so know that good pasture is an ideal food for milk cows, and, therefore, presumably well balanced in all its constituents.”