Predicting 305-Day Yields from Short-Time Records

Cannon, C.Y.; Frye, J. B.; Sims, J.A.

doi:10.3168/jds.s0022-0302(42)95365-7

Cited by 17 publications

(3 citation statements)

References 2 publications

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“…Fat yields varied 4.0 and 6.0 O/o for the same comparisons. CANNON (14) found that a one-day test taken during the fifth month had a high correlation with the lactation yield based on monthly testing. MCKELLIP and SEATH (39) found little difference in accuracy when comparing the centering date and calendar month method.…”

Section: The Accuracy Of Different Sampling Methodsmentioning

confidence: 99%

The Precision of Some Sampling Methods of Estimating the Milk, Butterf at, Solids Not Fat, and Crude Protein Yield of Dairy Cows

Groenewold¹

1960

Zeitschrift für Tierzüchtung und Züchtungsbiologie

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Section: The Accuracy Of Different Sampling Methodsmentioning

confidence: 99%

The Precision of Some Sampling Methods of Estimating the Milk, Butterf at, Solids Not Fat, and Crude Protein Yield of Dairy Cows

Groenewold¹

1960

Zeitschrift für Tierzüchtung und Züchtungsbiologie

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“…The reasons that are cited most frequently for extending incomplete or in-progress records are 1) reduction of bias from differential culling and 2) earlier identification of high producing cows for planned matings. Reports on extension f~ctors ~nd their application in dairy sire evaluation are in (3,9,11,16 reaffirmed the appropriateness of extending incomplete records. Dommerholt (5) compared lactation curves and milk yields between incomplete and complete records of heifers and concluded that incomplete records can be used for estimating breeding values of sires by extrapolating such records.…”

Section: Introductionmentioning

confidence: 96%

Extension Factors for Trimester Yields of Milk and Fat

Agyemang¹,

Clapp²,

Vleck³

1985

Journal of Dairy Science

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Evidence of problems with sire proofs of extended incomplete records suggests the desirability of another method of evaluating dairy bulls for milk that minimizes the need for extending records by instead considering yields of three parts of a lactation (days 1 to 90, 91 to 180, and 181 to 270) as distinct and separate traits. Records of less than 90 days (or 180 or 270 days) require extension to 90-day (or 180-or 270-day) equivalents. Last sample day production of 17,826, 15,282, and 12,115 firstlactation records of Holstein cows was used to calculate extension factors to predict remaining yields to days 90, 180, and 270 for months of freshening and days in milk. Cumulative remaining yield was computed as the product of days remaining to day 90, 180, or 270, yield on last sample day, and the appropriate extension factor. There were no differences in factors due to age, but factors were different for months of freshening and number of days in milk.

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“…Many workers (1,2,4,5,12,13,14) have developed factors for extending records in progress to complete 305-day lactation yield. From these reports extension factors can aid more rapid evaluation of sires and identification of the best dams for breeding to top artificial insemination (AI) sires in planned matings.…”

Section: Introductionmentioning

confidence: 99%

Extending Lactation Records in Progress to 305-Day Equivalent

Keown¹,

Vleck²

1973

Journal of Dairy Science

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The data consisted of 204,558 complete Holstein lactations in 2,100 herds compiled by the New York Dairy Records Processing Laboratory from 1959 to 1969 All lactation records had to have a 9th or 10th test day to be complete. The generalized least squares analysis used a model including mean, herd-year, and season-age-stage as fixed effects. The error term included random effects of con, and residual variation. Means for specified stages of lactation for milk and fat were estimated for lactations 1, 2, 3, and 4 or greater which were grouped by age of freshening, two age groups for the first three lactations and cne for fourth and later lactations.Extension factors differed from current United States Department of Agriculture factors. The new factors emphasize the need to consider lactation nmnber, season, and age at freshening in extending lactation records in progress. Extension factors differ for each lactation, especially between the first two and later lactations. To consider season of freshening is important for early stages of lactation. Age is important for factors for e~lv stages of lactation but less so as leng~ of lactation increases. Differences due to age also become less important as lactation number increases. Factors for third and later lactations are only slightly affected by age of cow.

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Predicting 305-Day Yields from Short-Time Records

Cited by 17 publications

References 2 publications

The Precision of Some Sampling Methods of Estimating the Milk, Butterf at, Solids Not Fat, and Crude Protein Yield of Dairy Cows

The Precision of Some Sampling Methods of Estimating the Milk, Butterf at, Solids Not Fat, and Crude Protein Yield of Dairy Cows

Extension Factors for Trimester Yields of Milk and Fat

Extending Lactation Records in Progress to 305-Day Equivalent

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