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Studies in Milk Records: The Influence of Foetal Growth on Yield

Published online by Cambridge University Press:  27 March 2009

William Gavin
Affiliation:
Lord Rayleigh's Dairy Farms, Terling, Essex.

Extract

In a previous paper on the “Interpretation of Milk Records” the following points were dealt with:

I. Selection of a figure definitive of a cow's milking capability.

II. The influences affecting such a figure.

(a) The usual methods of describing a cow by her total yield per calendar year, per lactation, or per average week are inconvenient both for practical breeding on a large scale and for definite enquiry on the inheritance of milk yield or its possible correlation with other characters. The figures are inconvenient because a variety of circumstances which affect them must be stated for every individual case before such figures can be reliable. Chief of these circumstances are age of cow, length of lactation, number of weeks dry before calving, interval between calving and subsequent service, and time of year of calving.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1913

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References

page 309 note 1 Journal Royal Agricultural Society, 1912, p. 153.

page 309 note 2 I.e. the highest figure common to three entries in record book, whether yields are recorded daily or weekly. What is aimed at is really the correct maximum day-yield: the stipulation that it should have appeared three times is merely to avoid the errors associated with a single sampling.

page 317 note 1 v. Marshall, Physiology of Reproduction, 1910, p. 583.

page 317 note 2 In other cases the ovarian influence is established, as in the growth of the mammary glands at puberty in woman, which does not take place if the ovaries have been previously removed. It must be admitted that from this and other observations their influence certainly appears to be anabolic, and so in a contrary direction to milk-flow.

page 317 note 3 Knot, “Abnormal Lactation,” American Medicine, vol. II. 1907. Cases given of virgin girls who were nurses secreting copious supplies of milk as a consequence of allowing infants to apply this excitation. Also cases in which suckling occurred in a bull, a male goat, a wether, and in men. Quoted from Marshall (loc. cit.).

page 318 note 1 Marshall (loc. cit.) gives a case where secretion was induced by repeated attempts at milking. A mare which had never had a foal could be made to yield milk by this means at any time for years.

page 318 note 2 Mackenzie, Quart. Journ. Exper. Physiology, IV. 4, 1911. Schäfer, Proc. Royal Society, B. LXXXIV. 1911.Google Scholar

page 318 note 3 Gavin, Quart. Journ. Exper. Physiology, VI. 1, 1913.Google Scholar

page 318 note 4 Hammond, Quart. Journ. Exper. Physiology. In course of publication.