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ABSTRACTS
The amount of ration, the protein content and its quality must all be considered, there-
fore, by the dairymen.
Fats, carbohydrates and minerals.—The dairy cow cannot produce milk to the extent
of her inherent capacity unless her ration is completely balanced with at least 4 per cent
mineral content. The fat content of the milk is influenced very little by the fat content
of the feed, but the total production is influenced as such. Carbohydrates (starches,
sugar and cellulose) furnish heat and energy and are converted into body and milk fat.
A cow ' out of condition' frequently is suffering from mineral deficiency. She
will die quicker without minerals than any other food material. Iodine deficiency
causes enlarged thyroid. Sodium and chlorine are most commonly added as ordinary
salt. Calcium and phosphorous are added next often; these minerals make up 90 per
cent of body ash and give the skeleton its strength. Calcium is contained in limestone,
bone meal, oyster shell; phosphorous in bone meal ; roughages supply both. Legumes
are rich in calcium. Rarer minerals are supplied in ordinary feeds.
Vitamins.—Dairy calves are not usually deficient in vitamins, although mature
animals are frequently border line cases. Calves and cows convert carotene into vitamin
A in the liver. Deficiency of this vitamin in the diet of pregnant cows may lead to
premature expulsion of the foetus. Carotene is found in green feeds. Guernsey milk
contains more carotene than Holstein since the conversion of carotene to vitamin A is
much less in the Guernsey cow. Vitamin D helps in bone calcification ; rickets denote
a deficiency of this vitamin. Vitamin D comes from the sun's rays, or from forage
cured in the sun. Most animals get sufficient from these sources. Definite deficiency of
vitamin E may cause sterility. This vitamin is found in the germs of seeds, green
grass etc. in limited quantities.
The cow synthesizes sufficient vitamin C for her
own needs. Vitamin B is usually supplied in adequate amounts in ordinary feeding.
Feeding young animals and dry cows.—Colostrum supplies most of the vitamin
requirements of the newly born calf; it also contains anti-bodies essential to the health
of the calf. Good rations or feed of good quality, in adequate quantities, insures healthy
and well developed young stock ; the first two years of life are very important. Un-
restricted bone and muscle growth, adequate nutrients during pregnancy and a reserve
at parturition are essential for the growing heifer as well as the dry cow.
Feeding for production.—Too little attention is given to the feeding of the milking
cow. The animal must be properly prepared for calving and a full lactation, for the
extra demands in the first weeks of the lactation and for economical production. There
is a definite relationship between the value of the feed and of the milk ; the feeding must
give and maintain the largest spread between the cost of the feed and the returns for the
animal's milk. Increase the ration by half a pound daily until the production ceases to
respond.
The dairyman today is faced with two facts ; (1) milk must be produced economically
and (2) since milk is used largely as a human food the cows should be fed in a manner
that the greatest nutritive content in the milk is realised. [J. N. W.]
Relation between conformation and anatomy of cows of unknown producing
ability. W. W. SWETT and R. R GRAVES (1939). Jour. Agric. Res. 58 (3); 199-
235.
I N connexion with the studies of the interrelationships of conformation, anatomy and
producing ability in dairy cows, which were begun a few years ago, the authors
made this study of the correlations between external dimensions and internal anatomy
on a number of animals sent to Swift and Co., Chicago, for slaughter. No production
records were available on the animals.
Approximately 24 hours after the animals were last fed, 17 body measurements were
taken; they were usually weighed six hours after the last feeding and were slaughtered
24 hours later. All ante mortem data except live weight were taken by one person to
assure as much uniformity as possible.
Thirty-one post-mortem items were recorded together with several internal measure-
ments of the thoracic cavity. Complete data on 250 and partial data on 350 cows were
obtained. A little difficulty was encountered in preparing some of the organs. Since
the omasum was ordinarily ' hashed' with its contents for tankage, 50 were hashed,
recovered and weighed. Their average weight was added to that of the other three
stomachs to give the weight of all.