Full text in pdf format

 

Various persistency measures and relationships with total, partial and peak milk yields*

 

 

N. GenglerI,II; J.F. KeownI; L.D. Van VleckI

IAgricultural Research Division, University of Nebraska, Lincoln 68583-0908, NE, USA. Send correspondence to J.F.K.
IIPresent Address: Aspirant FNRS, UER de Zootechnie, Faculté des Sciences Agronomiques de Gembloux, B-5030 Gembloux, Belgium

 

 

ABSTRACT

Seven persistency measures and their relationships with total, partial and peak yields were studied. Heritabilities, genetic and phenotypic correlations were estimated using mixed model equations with multiple trait restricted maximum likelihood (REML). Data were from 31,482 first lactation Belgian Holstein-Friesian cows. Differences in direction and size of the correlations between measures of persistency and total yield were found. Two types of measures were used. Persistency measures based on ratio showed positive correlations to total yield. Measures based on standard deviations of test clays or partial yields were correlated negatively with total yield. Correlations with partial yields also showed a similar pattern. Genetic correlations between ratio methods and peak yield were positive. Ratio methods not only describe persistency, but are highly influenced by total yield. Methods using standard deviations of test day yields showed a similar problem, but the influence of the level of total production was negative. Heritabilities of several persistency measures were above 0.10. After considering these results, a newly defined method, based on the standard deviation of partial yields, emerged as the best choice to describe persistency and for use in genetic evaluation of persistency.

Keywords: milk yields.

 

 

REFERENCES

Congleton Jr., W.R. and Everett, R.W. (1980). Error and bias in using the incomplete gamma function to describe lactation curves. J. Dairy Sci. 63: 101-108.

Danell, B. (1982). Studies on the lactation yield and the individual test day yields of Swedish dairy cows. III. Persistency of milk yield and its correlation with lactation yield. Acta Agric. Scand. 32: 93-101.

Ericson, K., Danell, B. and Rendel, J. (1988). Crossbreeding effects between two Swedish dairy breeds for production traits. Livest. Prod. Sci. 20: 175-192.

Ferris, T.A., Mao, I.L. and Anderson, C.R. (1985). Selecting for lactation curve and milk yield in dairy cattle. J. Dairy Sc. 68: 1438-1448.

Gaines, W.L. (1927). Persistency of lactation in dairy cows. Univ. Illinois Agric. Exp. Stn. Bull. 288: 355-427.

Gengler, N. (1990). Etude de la persistance des productions laitières pendant la lactation chez la vache pie-noire. Travail de find d'études. Faculté des Sciences Agronomiques de Gembloux, pp. 1-96.

Grossman, M., Kuck, A.L. and Norton, H.W. (1986). Lactation curves of purebred and crossbred cattle. J. Dairy Sci. 69: 195-203.

Johansson, I. and Hansson, A. (1940). Causes of variation in milk and butterfat yield in dairy cows. Kungl. Landtbr. Akad. Tidskr. 79: 1-127.

Keown, J.F., Everett, R.W., Empet, N.B. and Wadell, L.H. (1986). Lactation curves. J. Dairy Sci. 69: 769-781.

Madsen, 0. (1975). A comparison of some suggested measures of persistency of milk yield in dairy cows. Anim. Prod. 20: 191-197.

Mahadevan, P. (1951). The effect of the environment and heredity on lactation. II. Persistency of lactation. J. Agric. Sci. 41: 89-93.

Sanders, H.G. (1930). The analysis of the lactation curve into maximum yield and persistency. J. Agric. Sci. 20: 145-185.

SAS Institute Inc. SAS/STAT® (1989). User's Gudide, Version 6, Fourth Edition, Volume 2, Cary, NC:SAS Institute Inc.

Schneeberger, M. (1978). Der Verlauf der Laktationskurve and die Schätzung der Milchleistung beim schweizerischem Braunvieh. Diss. no. 6168. Swiss Fed. Inst. Technol.; Zürich, Switzerland, pp. 1-136.

Shanks, R.D., Berger, P.J., Freeman, A.E. and Dickinson, F.N. (1981). Genetic aspects of lactation curves. J. Dairy Sci. 64:

Sölkner, J. and Fuchs, W. (1987). A comparison of different measures of persistency with special respect to variation of test-day milk yields. Livest. Prod. Sci. 16: 305-319.

Wood, P.D.P. (1969). Factors affecting the shape of the lactation curve in cattle. Anim. Prod. 11: 307-316.

 

 

* Published as Paper Number 10933, Journal Series, Nebraska.