The Variation and Inheritance of Milk Characters

Ellinger, Tage U. H.

doi:10.1073/pnas.9.4.111

Cited by 8 publications

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“…There has been very little analysis of the actual number of weeks a cow gives milk, in terms of curve constants. Ellinger (5) finds no relation of either the maximum daily yield (comparable to our a constant) or persistency to length of lactation, while in this study there seems to be a tendency for the persistency factor to decrease with length of record and for the a to increase.…”

Section: The Relation Of the Constants Of The Individual Time-change contrasting

confidence: 65%

“…In this connection it may be said that there is no evidence of decreased variability in 8-months 5 total yield for the groups of cows having eight lactations, the figures being, respectively 1250-2, 1178-0, and 1263-7 for six, seven, and eight lactations. Whatever selection was taking place in this herd for the time these records cover, does not seem to be based on the continued breeding of fixed individuals.…”

Section: Study Of the Results Inmentioning

confidence: 92%

“…That is, more persistent milkers gave more milk. Ellinger (5) in the same year found no relation between maintenance ability and length of lactation. This indirectly measures the relation with total yield since the latter must depend in no small measure on length of lactation.…”

Section: The Relation Of the Constants Of The Individual Time-change mentioning

confidence: 85%

“…In some later work with Brown Swiss cattle, Gaines and Brock (10) get a persistency value of 97 per cent. Ellinger (5) finds Red Danish cattle to be more persistent than Jerseys. He uses a different technique, not a curve-fitting method, so that the results cannot be compared arithmetically.…”

Section: Discussion and Analysismentioning

confidence: 99%

“…This method has the merit that each lactation may be described by a single mathematical expression which will be high if the yield is maintained near the maximum yield and low if the yield drops off rapidly. Ellinger (5) uses the ratio between gross production in the second and in the first 10-week sections of the lactation period. McCandlish(i9) in 1924 expressed each month as a percentage of the first.…”

Section: Historical Backgroundmentioning

confidence: 99%

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An analysis of the time change in milk production in individual lactations

Gooch¹

1935

J. Agric. Sci.

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IT is well known to dairymen that the amount of milk that a cow gives during an individual lactation is not uniform, month by month, but changes in a rather characteristic way. Moreover, the course of milk production varies from one lactation to another of a single cow and also differs from cow to cow. In her succeeding lactations, a cow tends to have a higher total milk production (20,31). This relation has been studied in considerable detail by many authors, but some of the consequences of the change of milk production with time during a single lactation are not so well known. A cow's milk yield usually starts vigorously and gradually diminishes as the lactation is prolonged. It is the purpose of this paper to study this time change during a single lactation in some detail. The data are quite comprehensive and furnish information on several points which are of considerable biological interest.First, the form of these time changes of milk production during an individual lactation is studied. This trend may be adequately described solely in terms of the initial yield and the rate of decline. The mathematical constants representing these two factors for each lactation are then studied in relation to certain general and biological conditions.The calendar year and the month in which a lactation began are the general environmental facts which are studied in respect to the constants of the individual time-change curves.Of the many biological problems connected with milk production, this paper is concerned with the relation of the constants of these timechange curves to the length of time the cow was pregnant during a given lactation; the age of the cow at the beginning of the lactation; the length 1 Paper No. 198 from the

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Section: The Relation Of the Constants Of The Individual Time-change contrasting

confidence: 65%

Section: Study Of the Results Inmentioning

confidence: 92%

Section: The Relation Of the Constants Of The Individual Time-change mentioning

confidence: 85%

Section: Discussion and Analysismentioning

confidence: 99%

Section: Historical Backgroundmentioning

confidence: 99%

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